I fear that I may have created a problem for myself 🙂


I'm building a speaker using a BMS 12S305 (12", linear Xmax 11mm).
Using the formulas used by some manufacturers the calculated Xmax is around 14mm.
The design critieria, that has resulted in this choice is a compact, luggable cabinet and a decent output down to 40Hz (decent as in 110++ dB)



Given my need for transporting the speaker around I really need to have some kind of grille in front of the speaker to protect against physical damage.
Usually I use the standard round grilles that fits just over the speaker, but on examination it looks as if the membrane will hit the grille when pushing the speaker near its maximum extension.


I am not fan of the speaker wide nets (they seem to flimpsy to provide any real protection).


So: are there other options for protecting the membrane from physical harm or does anyone know of a method to provide more space between the membrane and the grille?


Regards
Martin



PS: This may not be the correct forum, but I guess it is here most experience with high Xmax-speakers is found

I want to introduce a new product I have been working on for the past years.
It's now available for pre-ordering, which will be shipped in the end of februari, in order of payment.

ZOUDIO AIO4CH: 4-channel amplifier with DSP and Bluetooth



Features:
-4x45W class D amplifier (can also be configured as 2.1 or 2.0)
-Bluetooth V4.2 APT-X with True Wireless Stereo
-Configurable DSP
-Easy to use Windows configuration tool
-Small format with high efficiency

Screenshot configuration tool:


As can be seen, a lot of the settings can easily be changed, such as:
-Start and maximum volume
-Battery protection voltages
-Input (left/right/mono) and output (4.0/2.1/2.0) configuration
-13 general filters (equalizers) en 5 filters per channel (crossovers)
-2 equalizers which can be enabled with a button (e.g. indoor/outdoor, bass-boost)
-Volume dependant (dynamic) equalizer
-Delay per channel

This thread can be used for questions about specifications and how to use the products. Remarks and suggestions for improvement are also welcome for this and future products.

Productpage (datasheet, configuration tool download, ordering): click here

What would be a good sounding low Rp triode for a line stage? Requirements - Rp under 2K and low gain, like under mu=10.

Possibilities include:
7233 - 230 ohms
A2293 - 380 ohms
6S19 - 420 ohms
12B4 - 1K
6CK4 - 1.2K
6AH4 - 1.8K

6BX7 - 1.3K (double triode)

4P1L - 1.5K (in triode) DHT (needs 25mA or more)
71A - 1.7K DHT (getting rarer and more expensive)

There are also all the 6AS7/6080 type tubes and bigger DHTs like 2a3/6B4G/6C4C but that would be overkill.

Long time builder, inexperienced designer. Attempting to make a simple low noise mic pre, with a high impedance input suited for dynamics & ribbons. Came across this circuit by Bob Cordell, dual jfet LSK489 with presumably an impedance in the many many mega-ohms. Anyone built one of these or something similar?



https://www.cordellaudio.com/JFETs/LSK489appnote.pdf page 11/12


I’m mainly trying to figure out the line driver, be nice to use both halves of the 4562 or I could just whack a THAT1606 on the end. Or use a 1646 instead of the 4562 entirely but it might be too hungry coming straight off the transistors without an opamp buffer? Or of course simply do an impedance matched driver after the existing buffer like so



The other thing is this pre apparently provides 60dB, it’d be nice to bring that up to 70. I’m not sure if that’s better squeezed out of the transistors at the front end or done at the end with an opamp?

Any thoughts? Thanks in advance

Hi all,
I'm looking at using the transport from my CDB630 and rebuilding/modifying to improve performance. Seems to the the floppy clamp/holder could be improved along with other mods to reduce vibration. Read someplace about a magnetic clamp or some other design? Maybe move it into a better chassis (thick aluminum w/vibration damping)? I added damping to the top cover, 1lb brass weight on top and sorbo iso-feet under chassis, which all made an improvement. I still like the DAC (crown S2) out to a tube stage, but might want to try a different DAC just to compare?
Or maybe someone has a Cambridge, Sony, Teac, etc transport for sale?

Hey guys,

has nobody some experience with the device mentioned above? It comes in two versions.

I am starting a new project. I am updating the satellite speakers of my system.

Last year I completed an active 3-way system with SB 12” woofer, SB 6” ceramic mid driver, and SB 1” ceramic dome tweeter. The Hypex amps located in the satellite stand, providing 250 W for the woofer, 250 W for the mid, and 100 W for the tweeter. The bass driver is mounted in its own cabinet, located a few feet behind the satellite. Crossovers are 200 Hz and 2 kHz. I have been astonished at how excellent the SB ceramic drivers have been. https://www.diyaudio.com/forums/multi-way/352767-active-3-hypex-sb.html

I always intended this system to be a learning experience, and I had always planned to build a more refined system later using better drivers. Originally, I was leaning toward ScanSpeak revelators or illuminators. I plan to keep the woofer boxes, and with the modular design with the amps in the stands and separate woofer boxes I can painlessly update the satellite speakers.

In October I purchased a pair of Satori textreme tweeters and a pair of Satori textreme 6” mid drivers. I made a set of measurements using a 24” x 24” test baffle, and later a prototype box. I posted the results here Link. https://www.diyaudio.com/forums/multi-way/343831-sb-acoustics-textreme-61.html post 608

I have begun construction of the new satellite speakers. The new cabinets will be similar, but not quite identical to the old ones. Like the SB ceramic boxes, I do plan to build a double thick front baffle, 1.5 inch thick. The sides will be profiled with a 1.5 inch radius round-over bit, exactly like the SB ceramic boxes. This new build will use a 2 layer plywood baffle instead of a composite solid wood / plywood baffle. Before I did not have enough experience with veneer to confidently apply it over a curve, so I used solid wood. Now I know I can do it with veneer. The top edge will be chamfered at 45 degrees to a depth of 1.5 inch.

The SB ceramic box is 13" H x 10" W x 9" D. The new box will be 13.5" H x 10" W x 9.75" D. So slightly taller, slightly deeper. The arrangement of the internal braces will be different. I learned a lot while making the first cabinets ("learning" is code word for screw-ups). I attached my simulation of the baffle diffraction effect on the tweeter response.

I do not have any digital representations of the cabinet design (CAD or Sketchup). I did that kind of thing for 30 years and it feels too much like work... I like pencil and paper.

I value everyones input. As I optimize the filters, I will share my measurements, subjective opinions, and my thought process...

Hello,

I've been involved with music for decades, actively in the past, but since I realized my talent didn't match my expectations , I prefer listening music. I enjoy my classical record collection and have switched to tube devices with full-range speakers in recent years. I hope my hearing lasts for a long time.

Best regards from Austria

Franz

It does not have the "Philips" logo on it, is this real?

Please help

$180 shipped in USA.

When I opened the package it FELT like the cardboard had never been opened before and the cardboard looks new.
As if the cardboard had never been bent past a certain point.
On both sides of the box the cardboard felt like it was never opened before. Do you know what I mean?
BUT THIS DOES NOT MEAN THEY ARE NEW.
I have no way of testing them.
If you want to test them I am in Nashua, NH, USA.

(3) NOS RCA 12BH7 12BH7A BLACK PLATE D Getter VACUUM TUBES 58455 -- NH USA --

Even if its from an alternative reality, just lets have dreams

No HiFi here! Just Audio.

I bought 4 mini PC; all of them have the audio jack missing the connection to the mass when off. So if your speakers remain on, you hear an annoying hum.
When you turn on the PC, everything is fine, no more hum, if you check with an Ohm meter, the mass is now connected.

I solved this issue by connecting the audio mass to the mass of the mainboard with a short bridge. Very simple to do, but you must be very careful.

The operation doesn't need any explanation, just look at the pictures.

BTW, you better replace the SSD pad with one 1mm or 1.5mm thick, the stock one doesn't touch the bottom panel, so it is useless. I also removed the SSD label. The right pad stays with the bottom panel, not with the SSD, when you open the PC.

Cheers!

Here is a visual log of how I built my PassDIY (Designed by Wayne Colburn) Pearl 2 phono amp.

I happened into a pair of boards when I was at Burning Amp this year, and as I just finished building a Pearl 1, I was extremely interested in hearing how the new version was going to sound! I love phono preamps for some reason, and I am always interested in a good circuit.

Being at Burning Amp also gave me a chance to sit with the esteemed Mr. Colburn and pick his brain for a bit to see if I could glean any hints as how to build it successfully. In my opinion I was extremely successful. The circuit is fantastic!! Here is how I built mine ---





Thank you planet10 for redrawing the PSU schematic! 😀

I had a very nice Plitron 30v+30v 50VA transformer that I wanted to use for this project. Yes, it's a bit more voltage than required, but it's not too far off, and it's fairly easy to "throw away" a few volts when you have excess current to play with. So after posting a few question to people I came up with this plan for the unregulated powersupply.

The component choices were made as follows; MUR860 diodes because I had them, but actually because they are close to the ideal diode for a low-noise supply. They are very fast recovery and also soft recovery. Wayne did say that those attributes are quite important for a line-level (and more so for phono) PSU. They also fit the PSU PCB that I am using. If I didn't have anything on hand and need to order some diodes, I would get MUR820's --- they have more than adequate voltage ratings but are even faster!

Anyway, the 50v 6800uf caps were chosen because they were at a 'sweet spot' on size vs. cost. You could use bigger or smaller if you like, but I would have at least 10,000uf (total) per rail.

10ohm 3W dropping resistors because I had some as well, and I needed to start somewhere.

The .22uf snubber cap was a suggestion from Wayne, he did a bunch of testing and found that value to give the most benefit in a single cap. 2.2k 3W was chosen as a bleeder because (yep, you guessed it…) I had them on hand - that value is used as a bleeder in Pass power amps.


Now after all that, I must digress at this point and say that all this is necessary because I'm using the transformer with the excess voltage. If you didn't have anything in your box and needed to order a new transformer, something like this would be appropriate -- Antek - AS-0522

Also, you actually are able to mount big 'snap-in' style caps (10mm lead spacing) to the Peter Daniel board - like so;


These are 10,000uf 50v caps, BTW.


Cool! And it also could be mounted in a much smaller case if that is your style.

For reference, here is the schematic of the original schematic posted in the project.




Anyway, back to our regularly scheduled program.

I ordered a pair of Par-metal chassis for this build, model 20-12083B website here - Par-Metal (12"x8"x3")







The PSU going together -







The rectifier board is from Peter Daniel (Audiosector.com) and was actually from a gainclone board. It's compact and very well designed. A LED will be added to it later.

Now I got a pair of empty boards, without the matched jets like you get when you buy from PassDIY. So I needed to match the Jfets for Idss. Here is a good reference article - Transistor matching

It's simple - a 9v battery, DMM set to MA, a couple of clip leads and the Jfets.







Here is the assembly of the PSU enclosure --



And this photo shows the wiring around the power entry module and the ground breaker-



The connections from chassis to earth to ground are exactly is drawn in the schematic.


As I'm looking through my photos, I realize that I have no photos of the board being stuffed. (Then again, stuffing a board isn't all that exciting…) But I did need to take a photo to show where you place DMM leads to test the rail voltage.



One thing this photo does show is that although I have all the resistors installed, I don't have a jumper in the R15 spot. So, just in case you didn't see it in the article, (and I most certainly didn't see it either…) you need to put a jumper in R15.

So by this point I'm getting down to final assembly, the boards are mounted, the RCA's and other connections are in the chassis and it all need to be wired together.

One problem, the unregulated DC from the CRCRC filter is +/- 47v. That's too much to put into the regulators.


The original 10ohm resistors in the CRCRC filter were obviously not enough resistance to reduce the voltage, so I reached into my somewhat meager supply of high-wattage resistors and kludged up this -


Now the eagle-eyed of you will notice that they are not symmetrical... and that is because the (+) rail draws more current than the (-) And all I was trying to do was get the voltage at the input of the regulators somewhere between 40 and 29. Fewer than 40v as that is the maximum the 7*24 regulators can have on the input, and at least 29 because the regulators need at least 5v more than the output in order to regulate properly. They are now about 31v.



Here is the entire power supply, the power entry module has a switch and fuse, you can see the 35amp bridge isolating the PSU ground from the safety earth, the toroid, rectifier board with snubber and LED, then the CRCRC filter.
The output from the PSU, positive, negative and ground are isolated from the chassis. The umbilical is just a 3-conductor cable.

Just for reference, here is a photo of the backs of the enclosures -


The guy that I had do some machining for me screwed up the RIAA enclosure and did it upside-down. 😱 In the grand scheme of things this is not a big deal, but it did mess up my wiring, specifically where the power cable got routed. The original plan was for it to be on the other side, and the power cable about 1/2 the length that it wound up being.



Now this rat's nest is not the final wiring, but it is quiet. Very quiet. I will get around to a nicer looking routing in the near future.

Here is a quick overview of how it's grounded;

Safety Earth - only connected to the primary side of the PSU and PSU chassis.

V+, V-, Vgnd floating in both chassis.
Input and output RCA jacks floating.
Ground lug connect to chassis.
PCB starground, (a lonely, unlabeled hole under C4 and above C12) connect to ground lug.




And then the lug is connected to the chassis, I just used a longer screw in the pem nut, a tab and a metal nut to insure good conductivity.



So by this point all I needed to do was clean up the wiring.


Wiring after the clean-up. It looks better and is quieter. Awesome!! The trick is to get everything routed as close to the chassis as possible.


The stealth blue power indicator. 😀 😀 😀 On top is the umbilical.
There is a place for an LED and dropping resistor on the PSU board, and the 'light' is nothing more than an extremely small hole (>1mm) drilled in the faceplate and the LED pointing towards it. You need to look for the hole when it's off. 🙂 In the future I will probably have some CNC engraving done on the faceplates. But I do like the unassuming look of all black...

The umbilical is a 3-conductor wire from the surplus store, sheathed in techflex and terminated with '4-pin microphone connectors' from RadioShack


The completed Pearl 2. Shown with Turntable for scale.

This build is complete, it sounds fantastic and is astoundingly quiet. This is the first project I have done in a long time that was quiet (specifically PSU hum and radiant hum) from the very beginning I'm very happy with the results.

Now I need to sell off some of my random excess gear and buy a Shelter 501 cartridge... 🙂 🙂 🙂

A very special thanks to Wayne making this project available to the DIY community, and also to my buddy in California who sent me a few important parts to get this project completed. (You know who you are.) 🙂



Mouser cart for the Pearl 2 PCBs - Thank you avdesignguru!

Note: BOM does not include C7, any R20 input loading resistors or any additional input loading capacitors.

Power supply is a separate BOM that would be based on builder's preferred design.

Mouser Electronics

A pair (2 pcs) of Faital Pro HF10AK compression drivers for sale, including a matching pair (2 pcs) of Faital Pro STH100 horns, all are brand new in factory boxes. Drivers are 8 ohm version.

These need no introduction and are usually sold for alot more. I paid almost double my selling price. My loss is your gain and I want these to go to a good home.

Price is $390 shipped to the lower 48 US states.

Hi all,

I was wondering if there is an old thread to point me to about how to customise the Onken / Fonken / etc. cabinets for different drivers, or if not, if somebody familiar with these can run me through the tuning process in general terms to make sure I'm not missing any considerations. I've read through and searched within a few Onken-related threads but not found anything comprehensive, but that doesn't mean it isn't out there. I've also definitely seen a few threads asking for advice about specific drivers lead to comments about appropriate box sizing but suggest that tuning will need to be done for them but can't find anywhere saying what this would entail.

Additionally, I've seen other threads saying that some designs for these behave like traditional ported enclosures and others function like aperiodic ones, and I'm not sure which the spreadsheet is for (presumably not aperiodic) nor if the design considerations are different for the other type.

I've been looking at the 2011 thread by Togril on creating an Onken for the Tang Band W5-1611SA, who seemed pretty happy with how their build went. I have the SAF model of the same driver sitting unused at the moment, so I thought I'd see if I came to the same sort of parameters before I start building anything (and I've got some fairly hard space constraints where I'll be putting these speakers that would mean that if I can find a way to design it to be marginally shallower that would help too).

I'm aware that there is a spreadsheet by one of the gurus of these speakers out there - the one by Cyr-Marc Debien from 2000 - and have been playing around with it. As far as I can see, the goal is to figure out an enclosure of about the right volume that is a sensible shape (with the usual considerations around ratios of length/width/height as for any other box) for the driver parameters whilst keeping enough box depth to allow for the required vent length that the calculator spits out. Some drivers will basically be unsuitable, and others can easily be fit into these constraints.

Where I'm getting confused is around decisions to do with vent dimensions - obviously making these wider or longer or changing the total number of them will dramatically change the required vent length, but I'm assuming they also impact sound in other ways so have no idea what I should be picking here as a starting point or what changes are generally likely to be 'safe' vs causing other issues.

Assuming this spreadsheet is a good way for me to design a box, I was also hoping to clarify some parameters / outputs in the spreadsheet itself that have me confused:

Firstly, why there are separate fields for "effective vent length" and "corrected effective vent length" and what is being corrected for? I'm assuming the corrected one is what I should be aiming to use in the final design, but wanted to make sure I'm using the right one, as in the tests I've done it is usually 10-20% different to the 'effective' one.

Secondly, what is the impact of changes to the "n=" / "Onken alignment" parameter on the final result? I'm assuming the 6.34 was what the original bass cabinets 60+ years ago (presumably designed by trial and error) ended up having once more modern simulation/calculation methods were applied to the old designs, and the 5.7 is a better compromise that has since been identified mathematically, but I'm not sure what it is compromising on or what changes up or down from this 'ideal' value are likely to do.

Finally, what influences the tuning frequency for the box/vents that this spits out, aside from driver parameters? Fb is one of the calculated values and can't be set by the user. With other vented enclosure calculators (or at least subwoofer ones) this is something that I believe the designer usually decides on along with box size, target Q etc, and these then are used along with the (fixed) driver parameters to determine the vent parameters, both area and length. Here it seems we are coming at this from the other side - based on a given vent area and driver parameters, a fixed 'optimal' volume, Fb, and Q are set, and the required vent length to achieve this is output. Is this understanding correct?

Hopefully someone can set me straight or otherwise point me towards resources that will help me figure this out on my own!

in putting together the ingredients to have a good crossover/speaker measurement and design station, some doubts are emerging about the various connections between the sound card and the speakers.
and if instead of using active speakers (which I do not own) but which I see most people using, I exit the computer with the USB sound card (new), go to an amplifier and then to the passive speakers? (just completed)
could this be a valid path?

I have for sale, brand new in original factory boxes, never used, mounted whatsoever. They're NOT B-stock or gray market. Purchased locally brand new from factory authorized dealers.

DBX Driverack Venu 360 loudspeaker processor (96k sample rate, with AES/spdif inputs), brand new in original box with manual, sells regularly online for about $1000. Asking $600

QSC GX7 2 ch professional power amplifier, 800W/ch @ 8 ohm, 1200/ch @ 4 ohm. Very clean sounding, reliable, light weight. Brand new, sealed in factory box. Sells regularly online for about $900. Asking $500

Both units priced for quick sale at almost half of the regular selling price. Also advertised locally for sale in my area.

Shipping only to lower 48 states - pls ask me for a quote.

Send me a PM for more info if you're interested.

Hi,

I'm a high-end audio enthusiast, interested by modding, tweaking, and restoring things. I love vintage speakers and amplifiers, have a tiny collection of cool old gears (cabasse sampan 311, celestion ditton 33, jmlab 913, luxman amps, Sansui amps) and some modern stuff (hypex, topping dac, adam audio active speakers).

I've done some mic tweaking too, DIY builds. I'm a musician and a videographer, so I use a lot of my builds for work.

I'm based in the south west of france, near Pau, and i'm a long-time reader of diyAudio forum.

Hi all, I own a DAC North Star Supremo. I was struggling to get an ASIO driver for Windows 10. Lucky me got support though the provider is not in business anymore so I found here a thread on it and I will share the driver for anyone who is interested

I have an old Sound Concepts Image Restoration Control IR2100 that I bought in the early 1980s, and it's gotten unlistenably noisy. Is there anywhere I can get it overhauled with new caps, etc.? How much would it cost?

I am in the need of 20 pieces to restore my vintage gear. Also would need 0.047 uF/600V. Maybe you have that many in your drawer or just few to let them sold. Thanks.

Here is my latest project, a linear tonearm. I thought I'd take a step away from the amplifier arena and give it a go, this is 1.5 weeks of work from start to finish and the sound
Is fabulous. Being mechanical without servo, carriage weight is of utmost importance!.


Colin

Hello,
I have a question about the Sabourin Speaker from Troy Crowe.
The horn consists of 3 stages. The 1st has an 15,5° angel and 47,2° on the sides.
Can anyone please explain why that is 47,2° and not 45°?
Fr.gr.
Olco

Hello everyone, I just finished a new NAP 250 clone.

I had already made two other versions of the NAP 250, but as a hobbyist, I made mistakes and learned along the way how to correct them and tune this amplifier, thanks in part to other members of the diyAudio community.
My previous clone can be seen here:


So, I'll present my new version here. I can provide my files for those who wish to build one and/or conduct further tests and delve deeper into the design of a NAP250 clone.

This time, it's not a truly original clone; the objectives were as follows:

- Find other transistor references that could be used for the NAP
that were both of better quality to improve audio quality and more robust.

- Switch to plastic transistors for simpler and less expensive construction.

- Make the amplifier more stable and able to handle low loads (1 ohm for a musical signal).

- Integrate the NAP and NAPS on the same PCB, with full alignment of the power transistors and drivers to place them on the same heatsink.

-Place the VBE on the heatsink for better control of the output stage bias.

-Improve the ground plane, which was done with the help of jpk73.

-Make an effort to minimize the design and reduce the final cost.

-Add a regulator for the amplifier's input stages, which was done thanks to the work of jpk73. I used his schematic. The goal was to improve sound quality.

-Add speaker protection, which was made possible thanks to Bigun's TGM10 design. This protection was modified by jpk73 based on suggestions from various forum members; mine is based on jpk73's schematic.


-After simulating in Ltspice, I slightly modified some values to achieve a slight improvement in the phase and gain margin while maintaining the same THD. These are the values Naim has used on some NAP140s.

Once finished, I encountered a NAPS stability issue with the modifications I had made. I was able to resolve this issue with the help of as_audio:


I added a Hypex module that does softstart/standby mode and thermal protection.

the main PCB with NAP/NAPS :


the front regulator base on LM317/337 :


The HP protection PCB TGM 10 :




square wave signal 100 mv 10 Khz in on a capacitive load of 1uF with 6,8 ohms with a NAPS rail (up trace is the output signal, down trace is the NAPS rail)



square wave signal 100 mv 10 Khz in on a capacitive load of 1uF with 6,8 ohms with a front regulator rail



square wave signal 1 Volt 10 Khz in on a load of 6,8 ohms with a NAPS rail



Sinusoidale wave 2,6 volts 1 kHz load 6,8 ohms with a NAPS rail :

I have spent 2 days searching the web for USB-DSD USB drivers for my new to me North Star Incanto DAC. Their website is gone and wayback machine only has one ZIP file which doesn't install drivers on windows (at least on my computers, fails every time)

Does anyone out there have the driver package for North Star or whatever I might need to get USB working on this DAC?

Look forward to any help.

Thanks!

PS Using Foobar-2000 as a player in WIN 7 if that makes any difference

Hi all,

Just a quick review of the ADMARK AD42 amplifier, which can be found from Alibaba



I am always skeptical of amps from Alibaba, you really dont know what you get. But honestly, this one surprised me a decent amount.

My test setup consists of 4x 8 ohm 1000w, wired 2 in series and 2 paralelle to maintain 8 ohm.

Measured voltage: 146 v on volt meter
Measured Vrms: 155 v on oscilloscope

Converted wattage: 3000-3200w 8 ohm
I was unable to test bridge mode.

There is a 10ms peak or so, that goes above this, but I wasn't able to capture it. Its so quick it will likely not be audible before falling to rms voltage above.

Notes: This is with the peak light off, it quickly falls apart at above this voltage. The peaking is not very pretty and will destroy your speakers instantly, do not overload this amplifier.





Official specs

Per a theory written in 1960 by Benjamin Bauer, a 2-channel stereo system is flawed by a compromise as each ear hears both speakers (crosstalk). I have been intrigued by this for over 40 years since purchasing the Sound Concepts IR2100 in 1982 (which I still have). This thread will concentrate on older analog solutions such as the Hughes AK-100, SRS PRO 220, Behringer EX-1, and others. Although an electronic solution is not without its own issues, using a stereo imaging processor can bring some enjoyment to music. At this retirement stage of my life, I prefer things to be simple and comfortable. I find having an external processor to be preferable to the acoustic solution of having to have a mattress or a 4x8 sheet of plywood attached to my nose and cones or baffles on my ears. Please feel free to jump in with your thoughts, comments, likes, and questions.

A great little amplifier from @tombo56 and details here - https://www.diyaudio.com/community/...te-low-power-class-a-amplifier-my-way.404147/ sounds excellent with high sensitivity speakers like my Klipsch Forte. I was using with a 12vac transformer paired with Prasi LT4230 regulator based CRC psu. Some pics of my build are also documented in the same thread.

Expecting $175 including CONUS shipping. Few pics of as-is unit for reference. High quality parts from Mouser/Digikey the laterals from Profusion PLC.

Best offer.
Please post in thread in possible.
Some dimensions are in the pics, in mm.
I can post more pics later.

Amplifier/transistor HEATSINKS -- TRIAD TRANSFORMER TY-84 TY-81 TY-69S TY-101 -- NH USA -- amp

I have developed a new 5.25in 2 way bookshelf speaker to go with the Vera-Link TWS Bluetooth amp. It’s a vented 2 way bass reflex design superbly finished in rosewood veneer and equipped with a custom voiced crossover using quality components (film caps and heavy inductors, and premium wire wound resistors). The woofer is a treated paper cone with a large motor and the tweeter is a 25mm soft dome with low distortion and a smooth silky response. The voicing is similar to my other speakers but the crossover is lower at 1500kHz and asymmetric filter slopes with all positive phase for realistic transients. I would say that the speakers have a punchy bass and a delightfully fun and musical sound signature. I have put several of my playlists through them and it all sounds great.

Speaker Dimensions: 17cm W x 24cm D x 30cm H

This was early crossover development with P2P Wago connectors:


I’m going with the all film cap crossover on the right. The one with the bipolar cap on left was just a sample for grins.




Here is the assembled speaker with the Vera-Link amps installed:


Setup in my bedroom (amp on dresser not being used):


The Vanguard Scout is a super sounding and beautiful looking speaker and will be offered at only $299 a pair. But if you buy it with the Vera-Link TWS Bluetooth amps together, the introductory bundle price is only $449.

Summary of Vanguard Scout:

The Vanguard Scout is a compact 2 way bass reflex speaker with a 5.25in treated paper cone woofer and a 25mm silk dome tweeter in superbly crafted rosewood veneer cabinet with a satin finish. What makes the Scout special is the crossover and how it is voiced to provide a smooth presentation with pinpoint imaging and a wide soundstage. The crossover uses high quality custom inductors and film capacitors typically seen on speakers costing 10x the price.

The crossover is a unique asymmetric topology that produces crisp and accurate percussion. The bass extension is deep for its size with a 60Hz -6dB point. The silk dome tweeter provides resolving highs while maintaining a smooth sound that is low in distortion. The treated paper cone woofer has a natural and lively sound with a slightly warm midrange that’s perfect for vocals. The balance and voicing of the Vanguard Scout is optimized for non fatiguing listening pleasure with all genres of music.

This speaker is the perfect introduction into great sound. Paired with the VeraLink TWS Bluetooth amplifier, it provides a complete music system - simply add your smartphone or other streaming decide with Bluetooth connectivity such as an Amazon Dot (Alexa) which enables multi-room playback capability.

SOLD OUT
Have two pairs of AD1862N-J graded chips. Totally new and unused - not even inserted into sockets before.
A pair of the chips + shipping to you registered & trackable = Singapore Dollars 120 (approximately US$92)
Payment by Paypal FF only please. If you are unable to use this mode of payment, I apologise that I have no other ways to accept the funds.
Thanks.

Hi - I want to replace these ageing caps in my tube preamp - not sure of the values - 1 of them says '100M + 100M' and the other 2 say '32M + 32M' - any ideas ???

Not an audio circuit, but given the knowledge base here with large inductors, tubes, and high voltage, I am throwing out an idea for comments.
The attached is a circuit I am thinking about for fast demag of a large inductance. The AC source is continuously variable from 0-100V although it typically will run between 10 and 30. When the system is active, DC current flows through the inductor, and the IGBT must be switched on. When the system shuts off, AC power drops to zero, and the rectifier free wheels the inductance. At that point, polarity across the rectifier switches, and the IGBT must shut off quickly. This applies the nonlinear resistor in series with the inductor. L/R increases, and the magnetic energy is quickly dissipated vs simply allowing it to freewheel through the internal resistance.

The green circuit is not really subject to change. The red is what I am toying around with. I would like to keep things as passive as possible - no DC/DC converters or big charge pumps. A few of my current challenges:

a. At low voltages, I struggle to get the current sources up, as well as the problem of not having sufficient voltage to turn the IGBT on. Fortunately, switching frequency is extremely low, so I am not overly concerned with slow rise times. Fast fall time is a benefit.
b. Trying to keep watt dissipation low - the red circuit will end up being epoxy potted, with maybe one small heatsink sticking out.
c. Voltages can get pretty high (still working out actual maximums), so my transistor choices are limited.
d. Debating if the active Miller clamp is really necessary.

I probably have more thoughts as this develops, but wanted some extra eyes to put a sanity check on this.

안녕하세요 여러분.
모두 잘 지내고 계시길 바랍니다.
저는 4방향 패시브 크로스오버 네트워크를 설계했으며, 제 디자인에 대한 전문가의 피드백과 제안을 부탁드리고 싶습니다.

다음은 시스템에 대한 간략한 개요입니다:

드라이버 유닛

• 트위터: Accuton C25-6-158
• 중간 범위: Accuton C90-6-079
• 미드우퍼: Accuton C173-6-191E
• 우퍼: Accuton C173-6-191E (second unit)

목표 교차점

• 우퍼: 370Hz 이하
• 미드우퍼: 390Hz ~ 707Hz
• 중간 범위: 681Hz ~ 2.8kHz (매끄러운 핸드오프)
• 트위터: 2.8kHz 이상의 자연스러운 확장

디자인 접근 방식

• 크로스오버 포인트는 고전적인 LC 필터 이론을 기반으로 계산되었습니다.
• 기울기, 임피던스 보정(조벨 네트워크) 및 구성 요소 값의 미세 조정은 AI(ChatGPT) 상담을 통해 지원되었습니다.
• 부드러운 주파수 응답, 위상 일관성, 왜곡 최소화 및 고급 성능 특성을 달성하는 데 중점을 두었습니다.

추가 참고 사항

• 증폭기의 임피던스 평탄화와 더 나은 부하 동작을 보장하기 위해 필요한 경우 Zobel 네트워크를 적용했습니다.
• 목표는 정밀도, 자연스러운 음색, 그리고 오디오 애호가 수준의 해상도를 결합한 시스템을 만드는 것입니다.

이 디자인에 대한 피드백, 개선 제안 또는 중요한 인사이트를 주시면 대단히 감사하겠습니다.
시간과 전문 지식을 제공해 주셔서 대단히 감사합니다!

Here is a PDF of of the Pearl 3 from Burning amp 2023 for those of you whom already have circuit boards.





EDIT: Video presentation on Pearl 3 for BAF '23 can be found here - https://burningampfestival.com/videos/


EDIT: Build documentation "Pearl 3 Phono Build Doc-1.0d" is attached below. Version 1.0d is the most current. Download and print.


EDIT: Interview with Wayne about Pearl 3 - #881

EDIT: Modushop/ HiFi200 Chassis set available here - https://www.diyaudio.com/community/threads/pearl-3-burning-amp-2023.404054/post-7538807 https://modushop.biz/site/index.php?route=product/product&product_id=971

EDIT: Online build guide - https://guides.diyaudio.com/Guide/Pearl+3/28

EDIT: SMD soldering tutorial using Pearl 3 - Login to view embedded media

Hi all, I’ve been enjoying my first DIY amp quite a bit, bringing it out for several gigs, tweaking a few things here and there, and seeing a trajectory of steady improvement with the voicing.
However, there is an issue which I don’t know how to address. I’m hearing an extraneous noise accompanying certain notes, it’s a kind of crunchy rumble. Sometimes I think I’m hearing a distorted sub-tone an octave down.
It only happens on certain notes, and they seem to correlate to mechanical resonance which you can hear if you tap on the tubes or the chassis. The same pitches you hear when doing this, can sometimes get excited into a slow feedback type of noise. The same pitches, when you play them on the guitar, get this extra crunchy whoosh-y rumble added. It doesn’t seem to make a difference how I set the volume on my guitar vs on the amp.
These are behaviors I can notice while playing at home. They’re maybe a bit too subtle to be noticed on a gig scenario. I’m playing louder on gigs, but there’s also other musicians playing and it just gets buried. It would doubtless be a better if the amp didn’t do these things.
Attaching the schematic. V1 is a C3G and yes I’ve got it running at really high gain, but again the offending sound doesn’t seem to care how hard I’m driving the input.
V2 is 6SN7 and this one seems to be the most sensitive, microphonically. The resonance seems to be localized there. I’ve tried swapping in different 6SN7’s, they all act the same. Drivers are 6SL7 and outputs are KT66. Generally the amp sounds pretty good, I’m just pleased it works at all, let alone well enough to play out with.
I hope that someone recognizes the behavior which I’ve described as best I can. Thanks for your thoughts.

I'd like to order (2) matched pair of these Tung-Sol KT170 tubes. I have heard that when they first came out, they had some issues and then supposedly fixed whatever it was that was causing problems. I'm not certain of this, just relaying what I read and heard.

My question is does anyone know where I could buy some that would have the latest batches from Tung-Sol? I've also read where they do take a rather long time to settle/burn-in?

Thanks in advanced!

Made me chuckle youtube.com/watch?v=Us6hQLwG1S8&ab_channel=BBCArchive

The classic tower speaker. We all know it. It is burned into our brains. It stands well off the floor. It has impressive looking multiple woofer in a line going up. It impresses friends. It sells loudspeakers. An absolute staple in the hifi world. If you ask the average person on the street to draw you a picture of a hifi speaker I'll bet my speaker collection that they draw sketch out a tower on that piece of paper.

So lets discuss the dark art of multiple woofers. I am going to ask some questions along the way. For this we will focus on the 500hz and down end of the woofers. Just to simplify things a bit

1. Multiple woofers because the sensitivity of woofers is, in general, lower than the mids and the highs.

We have all padded down a tweeter. We have all experienced the loss of sensitivity because of those resistors. Everyone knows that more speakers equals more louder. I hear it is +3db. I have a question though. Lets take 2 woofers. Specifically, lets take two 8 ohm 6.5" woofers. Dayton RS150-8 for example. I probably wouldn't ever use these but its easy for me to sim this.

Lets look at a single woofer and lets say we are only going to use it from nill up to 500 hz.

We have about 89 db sensitivity there. Lowest impedence is 6.0 ohm.

Cool, we have a baseline. Now, lets add a second woofer. We will wire this one in paralell

Alright, now we have jumped up to about 95 db sensitivity. +6db. We are now down to 3 ohm

Let's now wire that woofer in series.

Alright, we are back where we started. 89 db except now we have a 13 ohm lowest impedence. So, what happened to all of sensitivity increase?

It went out with impedence is my guess. Then was ou6r previous +6db gain from the impedence as well? I do not know.
Do we only gain our +6 db when wire in paralell or are we getting +3db from the dual speakers and +3db from the impedence?

Lucky for us, there is a 4 ohm version of this driver. Lets compare a single 4 ohm and series 4 ohm.
91.7 db, 2.8 ohm lowest impedence Same in series, 91.7, 2.8 ohm


Now, we can decipher that adding another woofer in series doesn't make it play louder. However, two woofers with the same impedence as one woofer gives us a +3db sensitivity.
The two in parallel with a combined impedence of 4 ohm is about +3db louder than a single driver with an impedence of 4 ohm.

Is this how this works then?
2. Crossover values diminish with lower woofers

Lets take a look at inductor values
Lets cross at around 250 with an 8 ohm. 3 mh is needed. 43 uf cap. You see we are crossing 90db at 204 hz with these values

Now, same values with a 4 ohm driver. We see we would need higher values of components to cross as low as the 4 ohm driver. We are crossing 90 at around 300 hz now.


So, from this we need higher values with an 8 ohm driver. So what if we use two 8 ohm drivers in paralell.
95 db at 109 hz. Cool, this looks nicer. Look at all that low end gain and we get to use lower values for components

Alright, one more time but in series.
Booooo, well that stinks. Now we end up with a hump where we don't want it and it looks like we have actually lost high end extension
If we do try to use the low end here we would need huge components and we get no gain. Lose lose situation as far as I can tell.


Ok, so with this, I have concluded that there are senstivity benefits, low end extension benefits, and lower value component values if we use multiple woofer but ONLY if we use them in parallel. Am I on the right track here? I am not seeing why anyone would wire them in series other than to save their amplifier because it has an impedence limitation and all they have lying around are lower impedence drivers.

I am seeing how we get more low end extension with two drivers. At least in theory

3. More Cone area = More Bass
Now this I have heard all my life. However, when I start to run this through the ringer of physics, I am not seeing it play it out the way I would expect.

Lets toss a single 10" woofer, a single 12" woofer, and dual 10" woofers into WinISD.
5' box for the single 10, 6' for the single 12, 10' for the dual 10"

We have wayyyyyy more cone area with the dual 10 yet, basically no more bass extension even though we doubled the box size. Not only this but the single 12 still hits harder. I see this across the board with any driver I have ever tried to sim in whatever combination. It doesn't matter. Never does multiple smaller drivers hit as low as a single large cone. Never. I could sim drivers all night long (and I have) and not see this standard change.

So, is WINISD completely off base? I find that hard to believe because I have used it in conjunction with Hornresp and have had it spit out eerily accurate results in the world I reside.

Does more cone area just mean louder? It doesn't mean lower?

4. Floor Bounce and Diffraction

These two, in my mind, are combined. Far as I can tell, the floor and the diffraction are two metrics that combine to give you a low end response. The baffle step takes away, and, if done right, the floor can give back. Or the floor can take away. Or the floor can take away AND give back. Ahhhh, the wizardry begins.

I understand these the least. Or rather, I have done the least testing with these. I fully understand the physics of what is happening.

I am a visual person so lets do some examples. I just learned how to do this so let me know if I am doing this entirely wrong. Which I think I might be.

6" woofer at 20" heigh on a 10" baffle where you'd normally place a single woofer close to mid.
We lose about 6 db off low end to the baffle.

Then we gain some from the floor at 20".

Then we get the summed response and we end up with that stupid dip at 100 hz that I have experienced in a build and very much annoys me. Though we still gain some bass so thats cool.


Lets slap a second woofer on the floor. Right down below. I have seen some speakers designed like this and honestly do not understand how they get away with the phase issue unless they are crossing very low like 120hz or something.

Doesn't matter! We still get a stupid dip at 100 hz.

Questions:
Do I sum two woofers together in this simulator?
How do you avoid the 100 hz dip? Do you need to go up much higher from the floor? WMTMW style?
Is there any way to apply this to a simulated response just for design purposes and factor this in?

Hi,

as I am too late for both parties, I'm looking now for the two PCBs:

• GlassWare Aikido Cathode Follower aka ACF from John Broskie - either "classic" or 12Vac, noval (!) tube buffer
• Tube-I-Zator (or Tubizator) PCB - SRPP I/V for TDA154x

Please, consider that I live in Germany.

I'm not very much interested in a kit, but don't hesitate to write me, even if you'd like to sell an assembled board.

Thank you!

Kia Ora (greetings) from New Zealand.

I enjoy modding and restoring audio gear.
I have b&w cm7 speakers, rotel pre and power amps, and various other gear from manufacturers like Enlightened audio designs, Sansui, Luxman, Assemblage, Denon, Arcam etc.

Hello everyone who looking for Sound!


After years of expirience the output transformers for current and voltage output DACs have been developed. Transformers tested with following DACs: ES90x8S/K2M/PRO/Q2M, AK4x9x, PCM56/58/63, PCM1702/04, AD1862/65, PCM1792, PCM1794A, TDA1541/43, DSC dac and others. Speaking in general, transformers can be suited for any current or voltage DAC both in SE or PP modes.

These transformers are made on high permeable cores, have the low DC resistance at desirable inductive impedance to achieve the best frequency response of the DAC. Transformers provides significant sound quality improvement compared to other output versions. Your music will begin to live a new life, it will sparkle with a naturalness without plastic nervousness 🙂




D60 trafos.
Transformers I/V stage for iancanada DM9038Q2MPi DAC


Transformers I/V (V/I) stage Twisted Pear Audio Buffalo-IIISE PRO DAC




D46 trafos:



The simplest way to connect my transformers to your circuit without soldering directly to pins (sometime DIYers wants to try different types in quick manner for example) is to use receptacles from Mill-Max:

1-st way is using receptacles with the soldered to them wires. PN is ED90595-ND


2-nd way is using through-hole type of receptacles for PCB (PN is ED10169-ND):



Here are some impressions from iancanada IanCanada's Latest RPi GB Goodies Impressions... and your tweaks, mods and hints...

And here is the page from Andrea Ciuffoli: DSC Output transformers test

Dimensions D46 type: OD=46mm, H=24mm
Dimensions D60 type: OD=62mm, H=30mm

Frequency Responce of transformer with ES9038q2m at 1.4VRMS (~8kOhm in secondary loaded on 100pF cable): 20Hz=-0.3dB, 20kHz=-0.2dB (rel.1kHz):


Same, but with 470pF in parallel with secondary:


The possible output level and the LF losses are depends on the output current of the DAC (and I/V resistance).

Here is an example of connection:


Here you can find prices and all the contact info: https://ivxformers.com

Lead time depends on existing orders. Thanks.

The relevant current documentation for my transformers available here: Output transformers for DACs

Ok, been stuffing the boards with parts I have available. If we are looking at the board horizontally on top right IRFP240 it looks as if there is an insertion hole missing for one end of the 470r resistor.

Also, the BOM states that there are 4 sk170 matched, where on the board do they go?

Over the past few months I have been sorting out my measurement techniques using the loopback scheme and have built a REW impedance rig.

Apologies this may be a long post.

Drivers - SB WO24P-4 woofer, Morel EM1308 Dome Mid, Morel ET448 Tweeter.
Box - Approx 40L sealed and medium stuffed with polyester toy stuffing. (re-purposed Akai SW125 box)

I finally got round to making a set of measurement the other day and have tweaked my active crossover to a point where I like the sound and theoretically it models well. The caveat here is that the room I have done the measurements in is not very large and has furniture in so quite a few reflections sothey are not perfect and have been smoothed. Measurement were taken at 1m at tweeter height and around 85dB loudness (roughly calibrated against mobile phone dB meter).

I took measurement from -90 to +90 degs for each of the drivers without moving the mic (note the Tweeter and Mid are both domes and so have protection capacitors, measurements taken with and with out these in place). I took nearfield for the woofer 1cm from the centre dust cap (sealed enclosure) and then impedance of each of the drivers in the box (with and without protection caps just for interest).



The results for the woofer seemed to suggest I am on the right track. The nearfield looks to be close to a Max Flat alignment which is what I was after. The 1m measurement aligns Ok with the manufacturer data and shows the baffle step below around 350hz (360mm wide baffle). Also the Impedance curve matches the Winisd output almost identically (peak : 32ohms at 47hz). So the box look pretty good for the WO24P-4 woofer.



I have been running a Minidsp Nanodigi crossover for a while and have had great fun playing with different slope filters and arrangements and also comparing it to crossover designs in VituixCad that seem to align quite well.

A quick check on the step/impulse response delays between the tweeter and the mid./woofer seem plausible at approx 5mm for tweeter to mid and 75mm for tweeter to woofer. So reference feedback seems to be working and has now embedded the acoustic offset into the phase measurements.

I then loaded up the +cap tweeter/mid and woofer measurements into VituixCad and played around with a few different designs with different slopes for an active crossover, these ranged from BW6 to LR24 in various combinations. The aim was to get a fairly flat on axis frequency response, align phase of each driver as close as I could (min 1 octave either side of the crossover point) and then have an in-room response that tried to follow a slope of 0.9dB/octave (or 6dB form 100hz to 10khz). Note, I did not merge the nearfield so it has room bass reflections under around 300hz.

Without documenting all of the various trials and errors, I settled on the following scheme that seems to meet most of the requirements quite well. To me this sounded the best subjectively, it has a fairly large soundstage with decent separation between the instruments and has a natural and lifelike presentation. I could stand the vocals being a little more forward but this is the only minor criticism. Bass is plentiful in my 10ft x 10ft x 8.5ft [ceiling] room with the speakers pushed a little into the corners.



So, having got a sound I liked I then tried to replicate this with a passive crossover (using the -cap measurements and measured impedances)........and this is what I came up with.

and with mid Inverted

This is basically a simple LR12 electrical topology which ends up being an acoustic LR24 on the woofer/mid crossover and LR12 on the Mid/Tweeter. There is a damping resistor on the mid with a shaping resistor in the low pass parallel leg. There is an L-pad on the tweeter. The resulting impedence curve looks manageable for most modern amps with a low of 3.2ohms at 110hz but is definitely a 4ohm design.

Now the bit where I would like a bit of critique of what I have done to tame the rising frequency response of the tweeter that is seen in many Morel units. I added a small inductor in series to tip over the curve at around 8Khz and then added a notch at around 10khz. This seems to flatten things off nicely but is having and inductor in series in a tweeter circuit a good idea and will it affect the sound negatively?

In general think the p[assive version matches the design aims and the active system fairly well.

Finally, before I splash some cash on crossover components to see if this scheme sounds as good as the active version (would be happy if it did), for the woofer inductor is it Ok to use a 1mm/18awg iron core coil or do I need to go 14awg Air coil and also for the 100uF capacitor is something like a Jantzen eLeCap 5% Electrolytic Bipolar Capacitor Ok to use or again do I need to go for a Jantzen CrossCap? Just trying to keep the cost sensible at the moment until I know it is Ok. The rest of the Caps are affordable using Jantzen Standard and the coils will be 18AWG Air Coils.

Anyway, congratulations for getting to the end, and thanks in advance for any comments left. Everyday is a school day for me!

Hugh has been doodling on LTSpice and he came up with something really extraordinary: a 43% efficient SE Class A amp that can drive 39w into an 8ohm load with the usual Aksa-approved harmonic profile and low phase shift. The amp uses only 6 bog-standard actives and employs the excellent Aksa Lender front end to drive what seems like standard complementary MOSFET output stage using the venerable and easy to find IRFP240 and IRFP9240 outputs. However, it is not a push-pull amp though, but operates in SE Class A with an active CCS controlled by a cleverly wired PNP CCS controller. Please note that this active CCS is no longer based on the Pass Aleph topology but a PNP-controlled P-channel with symmetric sense resistors. The amp should really be called an Aksa Lender Nirvana.

So we have 4x TO-92's, and two TO-247 MOSFETs. Together, with only a +/-27v supply, they combine to make 39w into 8ohms with a predicted 0.019% THD AT 12w, and of course, always dominant H2 and a monotonically decreasing higher order harmonics. Output impedance is predicted to be less than 50mOhm at 12w into 8ohms at 1kHz and DF is 160. Quite a powerful amp given the rather low 27v rails. 27v rails happen to be what you get when you use an SLB PSU with a 22v trafo like an Antek AS-3222. Gain is 28.5dB, and phase shift is only 5.3deg at 20kHz.

Here is the rough schematic from LTSpice:


More detailed analyses and sims to come...

Later to be followed with the usual P2P vero-build, and then hopefully, a real PCB verification build and full measurements.

Enjoy!

A huge thank you to Hugh for continuing to give us these gems!

Edit Sept 21, 2023: Looking for Cliffs Notes on the BOM and some and hints on what parts to use etc by Voiceofposeidon here: https://www.diyaudio.com/community/...8ohm-class-a-amp.344540/page-107#post-6920076

Edit May 25, 2020: detailed O-scope max power clipping tests by AndyR using his 4-ohm variant Alpha Nirvana with +/-21v rails:
Alpha Nirvana 39w 8ohm Class A Amp

Short story - good for 34W into 2.1ohms loads! Not bad for true Class A amp (cannot ever go into Class AB - it simply softly clips when pushed).

Edit Oct 31, 2019: latest version 2 schematic of amp


Predicted FFT with v2 for 2.83Vrms into 8ohm, THD=0.0039%:


And if we increase power to about 12.5w into 8ohm, we still see a nice monotonically decreasing harmonic distortion profile. THD is now about 0.016%:


Edit Nov 27, 2019: Measured max output before clipping is 51.6vpp into 8ohms, or about 41.6w into 8ohms. This is with +/-28.5v rails.









Edit Nov 29, 2019 - Grounding scheme schematic (post 279):


Produces background noise FFT like this:


Some measurements at 3.16vrms into 10ohms with a Cayin N3 DAP as 1kHz osc source, obtained 0.0041% THD and mostly 2nd and 3rd harmonic:


GB thread for this amp here:
Alpha Nirvana 39W SE Class A Amplifier GB

Tips and tools on how to do professional clean looking SMT/SMD soldering:
Alpha Nirvana 39w 8ohm Class A Amp

Edit Dec 14, 2019: BOM in easy to read .XLSX format: https://www.diyaudio.com/forums/att...8ohm-class-amp-alpha-nirvana_bom_001-xlsx-zip
Mouser Shopping Cart for BOM here. Do not modify cart - please save to your own shopping cart as a new project before changing.

Edit Jan. 3, 2020: please note that the Mouser shopping cart above needs to have parts for snubber boards increased by 2x as there are parts for 1 board only. The BOM is for one amp board so needs to be doubled for stereo. Double following: (R1001, R1002, C1002, V1001)

Edit Dec 26, 2019: AndyR did a lot of due dilligence to put together a very nice BOM for both the 8ohm and 4ohm versions of this amp here:
Alpha Nirvana 39w 8ohm Class A Amp
Thank you, AndyR!

Edit Apr 24, 2020 - Dual Monobloc Connection Diagram is using SLB and SFP boards:


As built schematic verified and tested to work:


Edit Apr 19, 2022: beautiful build by Steve (Sledwards12375):


Edit July 12, 2024: @AKSA said in this post that 2.2A quiescent current is needed for 4ohm variant of this amp. So size your trafo accordingly.

I'm always on the lookout for teeny speaker of ridiculous quality and a couple years back I spied these bad boys:


These i believe were called the Maximus 7s. I bought them Dan P. of CSS at a bargain price of $600. They sounded great as is....but I had other plans 😈.

I’ve started building the Ellam FLEX two-way. Thanks for the reassurance that 400V caps can be used in the crossover design. I’ve sourced Mundorf MCAP 400V DC polypropylene caps with the same µF values as shown in the schematic, instead of the much more expensive Superior Z.
Cabinet work is underway — I’ve done everything so far without power tools, except for a basic IKEA cordless drill, and I don’t even have clamps. The crossover is quite big and heavy, so I’ve decided to keep it outside the box. I’ll share photos soon. Looking forward to any tips or feedback from others who’ve built this design!

Hi,

I have a 110V 60Hz Mark Levinson 433 three channel amplifier that I need to convert to 220V 50Hz. I succeeded in obtaining the propper IC chip from Mark Levinson but they don't have the corresponding PCB.

The PCB is simply a jumper that I could build easily. Would anyone have the graciousness of helping me with the propper jumper configuration? Or maybe a picture of the jumper PCB for 220V? 🙏🙏🙏😊

Hi,

I have a 110V 60Hz Mark Levinson 433 three channel amplifier that I need to convert to 220V 50Hz. I succeeded in obtaining the propper IC chip from Mark Levinson but they don't have the corresponding PCB.

The PCB is simply a jumper that I could build easily. Would anyone have the graciousness of helping me with the propper jumper configuration? Or maybe a picture of the jumper PCB for 220V? 🙏🙏🙏😊

Hi. Having a (hopefully) small problem with my Quad99 system, so joined to see if anyone has had a similar experience and can help guide me.

Got time on my hands at the moment - feel in the mood to upgrade something ! Limited technical knowledge but her to learn from experts

I have a total of nine PCM63. Please refer to pictures.

Sold separately or as a lot. Open to offers.

Ships from Sweden.

Regards
R

I have a (silent) PC in the living room, which ran numerous virtual machines including a music/media one. However, there were some complications with that idea, so ultimately the whole PC became dedicated just to browsing the internet and streaming/playing music & movies on the TV. Even running the crossovers, DSP & EQ became farmed out to a raspberry Pi in USB 'gadget' mode. The big PC is therefore a bit unnecessarily large and under-utillised for this, so I intend to pass it onto a relative with more needs than myself, and build a more modest little media/HTPC machine for myself.

I know there are lots of tiny fanless machines that would suffice, but I'm reluctant to downgrade 'too' far or lose too much flexibility/connectivity (external ports, RAM and nvme SSDs etc). Partly because I want years of future-proofing and partly because I don't need to achieve the 'absolute' minimum in power or size. It won't be left on 24-7 and something like a 2u rack-mount case would fit quite nicely with my amps. It really just needs to be modest 'enough' to cool passively without fans or tall internal heatsinks (and I don't want the complication of water cooling etc). So, maybe a 'T' flavour of an intel CPU (though they seem less readily available to consumers) or a standard i3 CPU might be the sweet spot. The latter are around 60W TDP but rising to only 90-110W even on turbo. I vaguely recall it is possible to cap the turbo on some higher-end CPUs too, though whether that is wasteful over getting a lower-end one to begin with I don't know.

My thoughts (so far) are for a modest but normal desktop processor in a case with sides (and/or front) that comprise heatsink(s). Such passive HTPC cases are available - at huge price - and suggest that handling a CPU up to ~95W is a reasonable aspiration. But I already have several large Conrad heatsinks, of the type sometimes seen forming the walls of class-A or AB amps. Also, heat-pipes are available for the DIYer, which could be used to thermally bridge the CPU to the case's wall, so I think/hope that a DIY solution may be possible for modest money.

Though I'm probably reinventing the wheel here, so if anyone has been there or got useful suggestions I would of course be interested to hear!
Kev

Gentlemen,

in my workshop I have these active S1A "Professional Studio Monitor"
loudspeakers for repair. The amplifier is defective. Resolved, this is an
ADAM schematic collection now.

A diagram of this module would be useful. It is made by Hypex of the
Netherlands, no designation on it but date 10 Jul 2003. It carries a vast
number of NE5332 ops and two TDA7294 power amps, one LM339 and
one TL074 are also visible. Should be manageable to repair, but all traces
and joints are very small - doesn't help my eyes.

The Adam company which is in Berlin says that they don't have any
documentation and can not repair it. Since many of these were sold
it would be good to have them fixed in the true sense of sustainability.
I suspect that other people have problems with the amps also.

I understand that the head of R&D of Hypex is also around in this forum.
Will he be willing to assist?

Any help is highly appreciated, thanks.

EDIT: Diagram for S1A is in post 10.

Diagram for ADAM P33 (UCD-Version) is in post 152.
Schematic for ADAM P7 is in post 12,
Service manual for ADAM P 11 A UCD see post 154,
same for P11A analog in post 205
P22a manuals are in post 155
S2A ICE schematics in post 218
S2X documents are in post 258
ADAM S2.5A and S3A schematics added in post 89 and 90
Model S1A (and others) transformer mounting precaution in post 19.
Model F7 is in post 149
ADAM S3XH Service Manual is in post 153.
ADAM S3XV Service Manual is in post 170.
ADAM S4XH papers are in post 232.
ARTIST 6 documents in post 208.

I found links to a few magazine articles in German testing the well known classic Fostex enclosures, and usefully also recommended filters to flatten the frequency response. These filters could be of interest as well in other enclosure designs as they work higher up in the frequencies.

This is linked from the site of a German dealer of horn speakers and kits, often using Fostex drivers.

It is interesting to see how the drivers and well known enclosures perform. These were articles from the magazine Hobby-Hifi which I like to buy whenever I am back in Europe.

Hence:

• The elegant small FE103 horn. I was always curious about it. They say, as the measurement shows, that the bass is not impressive when measured properly in free air, but it is a lot more full sounding against a wall (as expected). Also useful is their recommended correction filter on page 4 (effect is shown in the frequency plot), plus an optional impedance correction when used with a tube amp:
  https://eckhorn.com/bk-103.html?file=files/jpx/content/download/bk103.83.pdf
• The BK108 horn for FE108EZ. Correction filter on p9:
  https://eckhorn.com/bk-108.html?file=files/jpx/content/download/TESTBERICHT-BK108.pdf
• The old enclosure for the FE206En. Unfortunately the shop’s filter is not published; however there is an interesting addendum measuring the FE206En in the FE208EZ enclosure. It has better bass in it and thus this enclosure is recommended instead, unless if you have a small room.
  https://eckhorn.com/bk-206.html?file=files/jpx/content/download/bk206.82.pdf
• FE208EZ in its enclosure with T900A super tweeter. The magazine publishes its filter next to the shop’s filter, the response looks better with the magazine’s filter.
  https://eckhorn.com/bk208-mk-ii.html?file=files/jpx/content/download/BK208.pdf
• FE166 horn with the FE168EZ or the rare limited FE163En-S and T90A tweeter. Filter including correction added on p9. Recommended to put this box against a wall.
  https://eckhorn.com/bk166.html?file=files/jpx/content/download/BK166.pdf
• BK83SOL enclosure also tested with FE83En and FF83WK. Correction filter on p10 is said to work well with any of the 3 drivers.
  https://eckhorn.com/bk83sol.html?file=files/jpx/content/download/BK83Sol.pdf
• BK12M with FE126En or now rare FE108-SOL (they really like this last driver). Correction filters on p8 (FE126En) and p9 (FE108-SOL). Best to put against a wall. They also compare with small FE103 horn and BK108 for FE108EZ. FE108SOL is the best sounding according to the magazine, and would be even better in the BK108 enclosure - more bass.
  https://eckhorn.com/bk-12-m.html?file=files/jpx/content/download/BK-12m.pdf

If I would build one of these enclosures I would use 3 terminal plugs so I can connect before and after the correction filter to experiment.

Hello everyone.
I'm looking for a reference schematic to better understand this amplifier.
The problem is that there's no volume control (it's set to high) and it's very noisy.

It would be something like this:

Greetings Friends. I've been fascinated by the 6C33C since I first laid eyes on it, and I've been kicking around an idea for a simple SET amp featuring the triple nipple. Borrowing the driver (and schematics) from the 6336 SET Amp by @Suncalc this amp uses cathode bias and the high voltage swing driver to make ~15 watts of Class A power.



Edcor's CXSE25-600 is a 25-watt OPT with a 600 ohm Primary and 8 ohm Secondary. According to my dummy math, 360v to the OPT will give a Va-k of 250v and a Vk of 88v, with a 400 ohm Kr.
Eliminated the volume control from the input, replaced with a 250k resistor.
Grid Leak Resistor for the output stage changed to 200k. Grid Stopper necessary?
Not sure how to calculate the K bypass cap.



Surprisingly the Hammond 372JX provides all the power needed. The output stage's cathode resistor eats so much b+ that there's no problem getting the 300v for the driver stage.
Enough capacitance for such a large current draw?
Better to take the driver stage power from before or after the 2nd choke?
Thoughts?

thanks for taking a look!

w

I have diy a 2,5 way 9 drivers linesource with pointsourse "function/treat"

And I have now listened to a few different filters for 1-2 months, & have started to minimize the number of components as I felt that neither a notch filter nor even using HP added anything in terms of sound.

Real happy with the sound even if maby some small tweaks is left on the xover, but use 2 different xover today for left and right speaker.
I want to finish them and mount the "finish xover" on a plate inside the speaker, so the speakers is "completely finished" to be connected from my amp.

I have a bad habbit to not finish my diy´s xover, and have loose hanging xover on the floor and parts everywhere.
And sometimes my kids ran into them, so i have to almost "start over"

So this time I WILL "finish them"!

Is any of these 6 parts xover "better" purely technical, phase wise, impedance etc ?
The wiggle at 1300 hz dont exist in my measurements from 2 meters or further away, and i sitt about 3,2-3,5 meters from the speakers.

Today crossed around 3K to the WG tweeter

best regards John

Does anyone have a schematic for the Foster (also called Fostex) LC300 3 way crossover? I have a pair of Goodman's speakers with the Foster crossover. I want to rewire the speaker and don't know which connections go where.
Thank you

Ian

Was donated a pair of these today, Crossover attached
The woofer (2519Aa Japan) looked promising with a low Fs & Qt, parameters:
Fs 20.75; Re 7; Qe .38; Qm 5.53; Qt .35; Vas 142.38; Sd 314; Le .84; eff 87.6
did some sims, Woofer looks good in 60L (Optimus oix is 38L), tuned to 22Hz
all this fun & I haven't listened to them yet....

The Big Q: Do I restore them to original, or 'improve' them to my own taste....???????

Bugger, just realised I left the tweeter switch out of the xover diagram, give me a few minuets....

I'm looking for a small, fanless miniPC to run my JRiver server and Tidal. W10.
I have a small HP laptop and an even smaller AERO FARA but both have a fan that is disturbing at serious listening.
Also would like an USB-C/Thunderbolt connection for the display.
And a bunch of USB ports of course.
Any tips?

Jan

https://de.aliexpress.com/item/1005...MIrJrh_sL7jAMVkJ9oCR1oBBgQEAQYASABEgKwA_D_BwE

As the thread title. Could this be the new kid on the block that is both cheap and good enough (or better) performer? Is this model usable in a poroject and what can we do to solve possible shortcomings or is it OK as it is? Mine is on its way and I am curious. Are you too?

I recently purchased a Marantz PM-66SE KI Signature (the same circuit as the PM-40SE, PM-44SE and PM-66SE, but with a toroidal transformer, a sprinkling of 'boutique' capacitors and a copper-plated chassis.

N.B. The PM-66* variants have an extra transformer winding for the remote control features.

Whilst it appeared to be fully-functional (** I normally listen with the 'Source DIRECT' button engaged **), I was concerned by the amount of heat dissipated by Q801 & Q802.

I resolved to reduce the amount of heat dissipated by these transistors with the minimum amount of circuit modifications and parts.

I noted that R802 had been replaced. I also noted that Q801 was loose! Too much heat in a TO220 package.

Marantz_PM-66SE_KI_1_small.mp4
Marantz_PM-66SE_KI_2.mp4

N.B. I had a Marantz PM-44SE that used to intermittently drop-out the speaker relay, then re-engage a few seconds later. That amplifier 'disappeared' before I could investigate the cause (I now suspect Q801 as aove).

After measuring the voltage drops across R802 (47R / ~5V drop) and R804 (47R / ~3V drop), I determined that the +24V rail was supplying ~100mA (worst case - speaker + source direct relays engaged) and the -18V rails was supplying ~66mA (worst case - ALL LEDs illuminated).

It's not surprising that (according to 'the Internet') R802 is the most common failure with these amplifiers - it's severely underrated. It's a design oversight!.
R804, D804 & D805 also take a beating in the default configuration.

Marantz_PM-66SE_KI_PSU.jpg
Marantz_PM-66SE_KI_Resistor.jpg

** When I disengaged the 'Source Direct' relay, I lost the right channel (intermittently). Re-engaging the 'Source Direct' relay restored the right channel (always).

After replacing ALL the semiconductors and capacitors, the amplifier was completely destroyed. 😱
The above sentence is completely untrue and is precisely what happens when you believe 'misinformation' on the Internet. 🙄

The right channel could be restored (temporarily) by moving the large ribbon cable (WV01), but would disappear minutes/hours later.
After chasing the intermittent problem, I discovered that the (never used) 'Balance' control had been 'whacked' by a previous (l)User.

Resoldering ALL the pins restored normal operation (but for how long?).

Balance_Control_Knob.jpg

PCB's and some full kits "recently" purchased (early Oct 2024) received from JLCPCB as an ode to @Mark Johnson , @lhquam , @tombo56 , & @Zen Mod for all they have given to the community.


UPDATE May 2: (See the table for price/availability. Shipping is about $6 in USA. International shipping tends to be a lot more.)

• IPS Boards for M2x - Milpitas IPS9 available currently (eventually there will be IPS6 and IPS7 kits available and IPS8 Cederburg PCBs). Making kits up takes a lot of effort, so it'll be a few weeks before these are posted.

• Yes It Can Drive An F4 (YICDAF4) full kits available. 15 qty stereo kits available with (or without) tightly matched B546C BJTs. Parts kits without the PCBs are also available if that's all that's needed.

• BJT Simple Matcher Full kits available. (around 10 left)

• AmyAlice Full kits available (still have lots). Really nice 2oz outer copper, 2mm board thickness, and ENIG finish!

• Korg B1 Soft Heat Kits available.

• H9KPXG Full kits available. Made up about 10 kits. (2oz outer copper, purple PCB)

• VRDN Full kits are almost done. Need a couple more weeks to get them completed and figure out cost. (2oz outer copper, blue PCB)

• Cheapomodo R3 Full kits available (18 kits available now).

• R25 PCBs by tombo56 available for those wanting to try out the active rectifier approach to a PSU (Limited quantity on hand). These are the updated version of the R21 boards now as a single PSU package. Really nice 2oz outer copper, 2mm board thickness, and HASL finish!

• Holy Grail PCBs and unmatched FETs (FQA28N15P/ITXQ36P20P) available (matching not necessary according to Lynn). Also have some FQA36P20 if you'd prefer those over the ITXQ36P20 although they seem to be the exact same part overall. Some matched N to N and P to P by Vgs (measured at 50°C, 1A, 24V) are available if needed.

• A few FQA40N25/FQA36P20 are available as well, so that's what you need for XRK and AKSA's Alpha Nirvana 39.

• Some matched by Vgs of IRFP140/9140 parts are available if anyone wants those. They are IR brand and are N channel matched and P channel matched, not N to P though for awareness. Quads and a few octets available as well matched N to N and P to P by Vgs (measured at 50°C, 1A, 24V).

• Replacements for the Toshiba 2SK2013/2SJ313 are FQA3N30/FQP3P20 are also available matched for either NN and PP, or NNPP (matched at 20mA, 40°C, 24V)

• Now that the KSC/2SC3503E & KSA/2SA1381E are near unobtainable, the KEC versions KTC3503-Y and KTA1381-Y are available for super good price. Not matched yet, however, that could likely be done if needed. Need to still figure out how to do this, so it'll be a while to get it all done by Vbe and Hfe.

• A few remaining ACA Mini "Modification" kits suggested by @ClaudeG are available as well. Reference this link.

• HPA-1 boards with the hard to find components are available for a few interested folks. (Includes hard to find Tightly matched FQP MOSFETs, Harris IRF610, & TIP122/127 darlingtons)

• Willing to 3D print items for super low cost (a buck or two). Search "3D" under the "Parts" to see what has already been posted. Some examples are the vertical Antek transformer mount and Zenductor II "chassis" feet. The designs are shared freely if you have access to a 3D printer. We can make up a custom design for your needs as well if that's helpful.

• Lastly, I have a Vinyl cutter if anyone wants custom stickers made up to put on an amp, or preamp. I'm willing to make a small quantity for custom designs (not bulk orders as it's really time consuming to "weed" the vinyl). Send me a PM if that's something I can help with.

Send me a PM and I can provide more details. All this stuff is what I wanted to build and just got in bulk with the hopes of helping others out as well with a "reverse group buy" approach.



Yes It Can Drive An F4 Full Kits - (just PCB's shown of course in picture


Mark Johnson's BJT Simple Matcher


Holy Grail by @lhquam


FETS (Not matched) for Holy Grail (FQA28N15/IXTQ36P15) for Holy Grail


VRDN - Voltage Regulator De-Noiser by @Mark Johnson [2 oz outer copper, HASL]


AC Power Relay Soft Start - H9KPXG by @Mark Johnson [2oz outer copper, ENIG]


Milpitas for M2x Amp by @Mark Johnson


Pearl 3 PSU Board(s) "UDP3" by @Mark Johnson


AmyAlice by @Mark Johnson [2mm thickness, 2oz outer copper, ENIG]



Korg B1 Soft Heat by @Zen Mod



Tombo's R25 PCBs (replacement for R21 boards with PSU) [2mm thickness, 2 oz outer copper, HASL]


Mark Johnson's Cheapomodo Full Kit

hello folks,
here is something i have been working on for some time.
I am willing to offer the pcbs as a group guy.
let me know if there is interest.
I will share a bom to GB subscribers, all mouser based, if GB goes ahead.
regards
Prasi

Edit 1: Group buy closed for THT PCBs, but still open for SMD PCBs. More info in the below link.
Group Buy List
group list qty_new - Google Sheets
Schematic SMD LT4320 rectifier LT4320 based active rectifier
Schematic THT LT4320 rectifier LT4320 based active rectifier
Schematic LT4320 CRC PSU PCB: LT4320 based active rectifier

Edit 2: Revision in prices. (price drop!)
LT4320 based active rectifier

Edit 3: GB closed for SMD PCBs. Only last 10 pairs of THT pcbs remain.

THT BOM BY MERLIN EL MAGOO LT4320 based active rectifier

EDIT 4: New GB for LT4320 based CRC PSU PCB Started..PCB's Produced and being shipped..-Completed and closed...
1. The Design: LT4320 based active rectifier
2. The PCB design: LT4320 based active rectifier
3. Physical PCB's: LT4320 based active rectifier
4. The BoM : LT4320 based active rectifier

EDIT 5: Group buy sign up has begun for modified SMD and THT rectifier boards with ENIG finish and earlier LT4320+CRC PSU PCBs. Please sign up at the below google sheet with your DIYA username and qty required against each pcb type.
LT4320 based active rectifier
Some 3D views of how the actual PCB assembly looks like
SMD: LT4320 based active rectifier
THT: LT4320 based active rectifier
CRC PSU PCB : LT4320 based active rectifier

EDIT 5: HAVE ALOOK AT PAGE 78 AND 79 FOR ALL PCB DESIGN IMAGES, SCHEMATICS AND 3-D MODELS AT ONE PLACE.

Does anyone know a source for Ohm F 4-ohm voice coils (original spec)? All I'm able to find is a replacement 8-ohm version.

Alternatively, any "better" options to consider?

I don't know if this guy's speaker will ever be marketable but he's got a playing prototype, and I've not seen anything like it before.

If I'm understanding the concept correctly; a typical digital audio setup recreates a music signal as a mixture of pure sine waves that mix and interact via the Fourier transform principle, and the mixing occurs within a digital processor, upstream of the power amp(s) and speakers.

In contrast; in this guy's setup the mixing of the component sine waves occurs at the speaker itself. That is; driving each speaker are twenty separate signal processors feeding pure component sine waves into twenty amp channels-- discretely driving twenty drivers in each speaker. As such, the Fourier transform occurs at the speaker itself, as the separate driver outputs blend together in front of the speaker.

That's a lot of digital processors and amp channels so even if this guy succeeds in taming all the gremlins, it's a complicated and expensive setup.

Enjoy!

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This is a built kit from PE. $145 shipped CONUS. It's heavy for its size so shipping will probably not be cheap. If anyone local wants it we can talk a cheaper price

Hi,
Below is a comparison of various motor structures for subwoofers.

JBL's differential drive wins. Its both coils are overhung and yet produces less distortion, please see Figure 8A on page 7 in attached technote. a) Can anyone tell why?
My guess is that since both the coils are wound opposite to each other on the same pole piece its inductance is nullified (maybe very little remains) as compared to other technologies. In a typical subwoofer the inductance is fairly high due to 4 layer windings and it varies as the voice coil moves in and out, when coil is in the inductance is more and when coil is out the inductance is less. This produces audible distortion. Since differential drive has very less inductance it can firstly go higher in frequency and produce less excursion related distortion. b) Am I making the right conclusion?

Also, the whitepaper states symmetrical field geometry, I dont understand how it helps as ultimately both coils are overhung and will have same non linearity of typical overhung designs. c) Can anyone please explain how symmetric field geometry works to reduce distortion?

If b) is true then it means we could just use multiple small subwoofers instead of 1 big one as the inductance of smaller drivers is less, even if it changes with excursion, the resulting distortion will be higher up in frequency than subwoofer use, hence harmless. d) Do you agree? Of course, XMAX of smaller drivers is less than a bigger one, agreed. For this discussion, let us keep it aside.

Please provide your thoughts for a), b),c) and d).

Attached is technical note of differential drive.

Thanks and Regards,
WonderfulAudio

Hi all. I've been bitten by the repair/restore bug. I'm currently waiting for a relay to (hopefully) complete a Sony TA-S9000es repair, and then moving on to a Sony TA-N9000es. Thanks in advance for all of your support.

Other victims:
Sansui 2000
Olson RA-194

a url or a copy of the schematic would be a big help. Thanks.

The ZEN Amplifier concept is simple. But it works great.
Here is such an amplifier but with less current and uses IRF610 as MOSFET.
It makes a simple and sweet headphone amp.

Building shouldn't be difficult.
The heatsinking it takes is not so much.
There is some THD, but it is mainly 2nd harmonic.
So, it would be good listening.

The amp is designed for 32 Ohms headphones.
For other impedances it may need tweaking to make it alright.

Just ordered the PFA10K from ShennDare, a very new design it seems.

REEEEEAAAALLY hoping it's useable, feeling a bit apprehensive.
If all else fails I hope it is possible to delegate it to subs only...

Edit:
Link

Dear all,
My name is Martin and I live in Germany.
For a couple of years now, I've been collecting and trying to repair vintage audio gear (mainly SONY receivers, amps, and turntables from the 70s and 80s), but I still consider myself a beginner.
I hope that one day I can also share my knowledge with the diyAudio community.
Best,
Martin

What is offered:

4x pieces of a speaker protection module as shown in the thread here:
https://www.diyaudio.com/community/...-universal-speaker-protection-circuit.415149/
enough for 2 stereo amplifiers.

Since the MOSFETs used are tricky to solder effectively at home, the boards will be provided with the MOSFETs already soldered. The rest of the parts will need to be supplied by the subscriber. They are easily available and in stock at Mouser, DK etc. The modules use SMD parts with the smallest at 0603, but most are larger than this - I'm only saying this as some people do not like using SMD parts. Full BoM and build/test instructions will be provided on paper as is usual.


Technical details:

The built units can be used for amps with total voltage from 24V to 100V, either single or dual rails. It must be run from the existing amplifier rails and you do not need an additional auxiliary supply. Current draw is less than 15mA per rail. The boards are designed to be mounted on the amplifier heatsink - one TO-126 transistor is configured to be bolted to the heatsink - it will dissipate up to 1W.

If using BoM values the units provide a start up delay to avoid turn-on thumps of about 3s and will trigger after the DC level exceeds the threshold for around 2s. The trigger voltage is around 1.2-2V depending on components used.

Board dimensions are 30x58mm

The boards are designed so that a mirrored pair can be made using the same PCB, making input and output wiring simpler and neater for each channel in a stereo amp.
By design, the protection is latching - i.e. it does not automatically reset for a long period. You will want to figure out why there is DC on the output before resetting the latch! It is also possible to manually reset the latch for testing etc.

Costs:

€60 for a set of 4x boards, with 2x MOSFETs per board pre-soldered. Tracked and insured postage anywhere in the world is €15. The rest of the parts will cost about €30 per stereo pair without any volume discount, depending on where you shop for them.

If you would like to take part, please add your DIYaudio name below here along with the number of sets you would like to sign up for. 1 set = 4 channel protection PCBs (2x stereo amps).

Example:

woodturner-fran - 1 set

The group buy will require a minimum of 20 participants/sets. When the group buy closes, it is expected that ordering and delivery will take about 3 weeks, and once the units are here and verified, I will send invoices to each participant. As usual, no payment until the boards are here and ready to distribute. Previous experience shows it will take an average of 2 weeks to arrive anywhere else in the world.

Thanks for your interest!

Just checking if anyone knows what i can use for a replacement for a TC4427COA that's marked C2 on a Sundown SFB 8000D?

Hello i want to build a diy 15 inch pa top speaker with a horn in a box now idk if the box 15LB100-8W is good for this use I have a specications for speaker but I never design a box now i guess that a I have to get a winisp and put in that spec and box parameters now idk and also i was thinking of using it as a subwoofer for some time iuntil i get other parts is that like going to be a problem?

Recently I got Tektron EL34PSE intergrated amp with 6SN7 as input/driver tube.
My version is older version with 6SN7 connected as two gain stages (picture 1).
New updated version is using 6SN7 in SRPP configuartion (picture 2).
Is there any benefit to convert old version to new one?
Also is there enough gain in 6SN7 in SRPP configuration to drive two EL34 in PSE?

Greetings to all of you.
After lurking in the shadows of the DIY community I decided to get socially involved in my next project, and present you the building process of THE LOUDSPEAKER 1 of Troels Gravesen.

Objectives:
-Taking the time in design. I truly believe in aesthetics. A nice presented dish is part of the meal, so is with speakers... I enjoy the process of trying and finding a pleasing form etc. Would be great if you could help me with this part of the process. I well know that tastes are different thou there is a common silver lining, I would like to find it with your help!
-going full monty in building process, meaning, giving 110% of my abilitys. I am a young carpenter, so I I have the tools. What I luck is experience...
-making this speaker as if I would make it for a costumer (and a wealthy one as well 🙂 thinking dubai luxury is a good guide line.
-sharing ideas and experiences with you guys, gone are the days of working alone in a basement. This part I am specially excited about!

Inspiration

As for now, the living voice vox project is my inspiration. I foresee disagreement on the aesthetic side but one thing is clear, the vox project is the most perfect, implacable wood working I've seen anywhere! That's exactly what I'm on about.


Disclaimer
So, to summarise, I will take the time with this one so please do not expect quick results.... 🙂 let's make it insane.

Could be cool if you could check other works of mine:
Troels Gravesen DIY loudspeakers - YouTube
And
NEXT4 DIY Loudspeaker Project - YouTube

So, looking forward for you insights. I take all comments as long as it's stays constructive and positive 🙂

Update 8.3.2013- you can now skip the page turning and see the video here:
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Hello DiyAudio community,

TL;DR: This is a USB transport for audio output (up to 8ch) and input (2ch for now) and user device control (e.g., DSP management) from PC (MacOS/Linux/Windows) thru I2C/GPIO. Including bootloader for remote firmware update, flexible device configuration, HID interface, multiple audio output options, integration with SigmaStudio (simultanious audio playback and ADAU DSP configuration). Compact module available in USB-C and USB-B versions, isolated or non-isolated.

Latest docs, config tool, link to buy:
http://york.eclipsevl.org/

So, the story started when I needed a USB transport for audio output and another channel for device control, such as for managing DSP.

Last time, I solved this problem using a USB hub and a USB to Serial converter. This way, I assembled the required interface from 4 chips:
https://www.diyaudio.com/community/threads/audio-transport-module-york.406025/
(first post)

I tried to combine everything into one XMOS chip. This was also a working solution, but there was a big problem with the availability of the chips, especially in the desired package.

Thus, developing the transport on the pic32mz seemed the most logical to me. The first prototype module was based on Dortonyan’s project from Vegalab: in terms of circuitry, it almost completely repeated the original project and was designed for two-channel audio output, plus a serial interface. During testing of the firmware based on the original source code, several problems were identified when working in different OSs. The serial port was also not fully implemented.
I posted my version of the firmware with fixes in the original thread and on GitHub: https://github.com/eclipsevl/york_pic32mz_uac2_osfw/

After that, I continued working on the functions I needed. The following features were implemented:

1. Bootloader. Necessary for firmware updates via USB, without a programmer.
2. Flexible device configuration using a PC utility (which is also used for firmware updates).
3. HID interface for transmitting service information and device configuration. Initially, I planned to use the serial port, but HID is much more suitable.
4. Serial interface, which can be optionally enabled.
5. Various additional audio output options: s/pdif, 8-channel TDM, dual i2s (for using some DACs channel-by-channel in mono mode). Recently I also added support for old dacs with clock/data/latch interface. I.e. direct connection to dac ICs such as AD1862/PCM1702 etc is also possible without glue logic.
6. Various clocking options: module oscillators, external clock (slave mode), internal PLL clocking.
7. I2C port and library for integration with SigmaStudio: for simultaneous audio input/output and DSP ADAU programming.
This last feature is currently a unique combination and fits well into DSP projects: https://www.diyaudio.com/community/threads/freedsp-octavia.393804/page-18#post-7625685

The configuration and firmware update utility looks like this:

Device name and PID/VID settings


Audio interface settings:


Input of up to 2 PCM channels, up to 192kHz (384kHz with external clocking at 1024fs)
Output of 2 PCM channels, up to 192kHz
(384kHz with external clocking)
Output of 8 channels in TDM8 mode (up to 96kHz, clocked by PLL)
Output of 8 channels in 2xI2S mode
Output of 2 S/PDIF channels, up to 192kHz clocked by PLL



And of course, in the simplest version, this module can work similarly to any USB interface, in slave or master mode.
DSD has not been tested yet.


Photo of the module, second version.

The additional 4-pin connector can be configured as i2c/uart/gpio, and is also used for forced entry into the bootloader (in case of unsuccessful software update).



Available in two versions: USB-C and USB-B. The transport itself is quite compact: it fits into an area of about 2x2 cm - which is important for integration into other devices.
So I'm working on a smaller PCB with same functionality.

Later I'm going to release a software library to basically enable anyone to create their own app for PC to control custom devices: toggle GPIO of USB module/send I2C transactions.


The module is available with USB-B or USB-C, the price is 49 Euro.
For purchase PM me. Also available on Tindie:
Multichannel USB UAC2+HID+CDC interface York

I'm open for requests for additional features but whether it is going to be added to the firmware depends on hardware limitations and time required to implement it.

Latest version of config tool:
https://york.eclipsevl.org/york_config_tool.zip

P.S. Huge thanks to:
1. Alexey (Dortonyan) for publishing the project. His work laid the foundation, and without it, this project would never happen.
2. Beta testers of the first version: @CyberPit, @Ludilu

UPD Oct 28th 2024:
Documentation draft attached

UPD Feb 17th 2025:
Latest docs, config tool, link to buy:
http://york.eclipsevl.org/