EDITOR'S NOTE:
This thread has been split from the thread Burning Amp BA-3
http://www.diyaudio.com/forums/pass-labs/195303-burning-amp-ba-3-a.html


For those who were not at BAF 2011, here are the bits of my talk on the
balanced version of the BA-3.

Here is the schematic. Note that the two input Source load resistors have
been combined instead of going to ground.

😎

Hello everyone ! 😀

I was wasting my time on Google, and came accros this :





Spherical Speaker Enclosure (Ported) - Dayton PS95-8 by B_Rich - Thingiverse

I'm a newbie, so i have NO idea what i'm looking at.
But i like the way it looks !

What are your thoughts on it ?

I'm about to start the build of a set of 0.4x karlsonator, but those "drops" stoke my curiosity 🙄

Thanks !

Laurent 😉

I'm trying to locate triode curves for a vintage B424 triode tube. All I found were curves with the grid voltage versus anode current. I would rather like to have a set of grid curves with anode current versus anode voltage. As this is more easy to work with for me. So I decided to give ChatGPT a try. After some initial discussions with ChatGPT on how to get the curves printed, ChatGPT suggest to download and install GNUPlot. This can be downloaded for free from https://sourceforge.net/projects/gnuplot/files/gnuplot/

In order to get accurate triode curves it turned out that it is most helpful to give ChatGPT a list with triode data points derived from the odd graph on the old tube data sheet.

First you have to tell ChatGPT that you need it to produce the code for GNUPlot. Then you tell it to use the emperial triode model formula.
Next you need to supply all the available data of the tube. My data for the B424 looked as follows:

The triode properties are S=3.0 mA/V mu=24 Ri=8kOhm for the curves max anode voltage 250V, max anode current 10 ma and negtive grid voltage between 0 and -8 V in steps of -0.5V. The measurements are as follows at grid voltage 0 volt at anode voltage 50V 0.8 mA - 100V 3.2 mA - 150V -8.3 ma. At grid voltage -2V at anode voltage 50V 0.1ma - 100V 0.9 mA and 150 V 3.5 mA. At grid voltage -4 V and anode voltage 100V 0.1 mA - 150V - 1.0 ma. At gid voltage -6 V and anode voltage of 150 V 0.1mA anode current. Can you calculate a similar triode curve model for me ?

ChatGPT summarised the data as follows and then started calculating the optimal parameters for the best fitting curves:

Got it! Let's proceed by analyzing the new tube's data and refining the triode curve model for it.

Step 1: Data Summary​

Tube parameters:​

• S=3.0 mA/VS = 3.0 \, \text{mA/V}
• μ=24
• Ri=8 kΩ= 8 \, \text{k}\Omega
• Max voltage: 250V
• Max Current: 10mA
• Grid voltage range: 0V to −8V-8V

Step 2: Refining the Model​

We’ll use the same empirical formula:​

Ia=Is(Vb+μVgVp)αI_a = I_s \left( \frac{V_b + \mu V_g}{V_p} \right)^{\alpha}
Where:

• Is is the scaling factor.
• α controls the curve shape.
• Vp is set at 100V.

Step 3: Calculating Parameters​

We’ll need to fit the observed data to this model to find the optimal values of IsI_sIs and α\alphaα for the new tube.
Let’s compute these values next!
The optimized parameters for the new tube are:

• Is≈3.37 mAI_s \approx 3.37 \, \text{mA}Is≈3.37mA (scaling factor)
• α≈2.21\alpha \approx 2.21α≈2.21 (exponent controlling curve shape)

Step 4: Updated GNUplot Script​

Now, let's update the triode current equation in the GNUplot script for this new tube:



This file was cut and pasted into Microsoft Notebook and saved as b424.plt in the documents folder.
You then open GNUplot and type at the command prompt load 'b424.plt' and press enter.
A window with the plotted curves will open.
You then check if the data points you took fit the curves.
The fit was pretty accurate.



If GNUplot does not deliver the required output then feed the error code, or remarks on what happens (or not happens) to ChatGPT and it will gennerate a new code for GNUplot to try again.

Love to hear your experiences on this subject.

Amongst way too many other projects I have a pair of LX mini's that first I didn't have the room/placement for and then a friend loaned me his 521.4's to use and that de-motivated me from starting the mini's. So loaned the un-assembled mini kit and four Wyred 4 Sound mAmps ( mono amps) to my friends grandson. He's got them done and they don't work with the mAmps -he can feed the miniDSP x-over into a stereo amp he has and each channel sounds great -but no go with the mAmps -muffled distorted sound when he tries to feed them from the mini-DSP crossover. I last used the mAmps four or five years ago to drive my SEAS A26's -they worked fine then . I'm wondering if the miniDSP x-over requires a common ground for amp inputs ?

Whoohoo 😀 :

https://audioxpress.com/news/beyma-launches-near-and-mid-field-high-end-transducer-series
http://www.beyma.com/nmf/

https://www.beyma.com/speakers/Fich...akers-data-sheet-low-mid-frequency-10NMFS.pdf


https://www.beyma.com/speakers/Fichas_Tecnicas/beyma-speakers-data-sheet-low-mid-frequency-8NMFW.pdf


https://www.beyma.com/speakers/Fichas_Tecnicas/beyma-speakers-data-sheet-low-mid-frequency-6NMFW.pdf


They look promising!

I have a Monacor SIA-548ROHS soldering iron with the SIC-520 soldering station and need to know the wiring on the 5 pin connector.

Regards, Gerrit

Hi,
If you come across a power valve with a UX or B5 or B7 base (hollow pins) and they seem to have no emission, resoldering the pins often effects a cure, I'm sure we've all done this. Occasionally though, this doesn't cure the problem.
I recently bought a pair of DA42's listed as untested apart from heaters - one was fine, the other failed to work. Resoldering didn't work either, so I tried a 'trick' that had worked in the past.
Use a piercing saw to cut across the pin, part way through the pin, about 3mm from its end. Then cut a slot from the pin tip to meet the first cut - carefully open out the pin to allow access to the electrode wire, often found unsoldered internally - scrape away the inside surface of the pin and the wire - use flux and resolder making a firm joint - bend the opened pin back to shape and reflow.
With luck you will have a working valve.
The DA42 responded well and is now working fine!
This may seem a little severe but has saved several valves over the years🙂

v1 Documentation

Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.


Update 2021 for Muses v2 ( Muses 72323 )

One Set include:

• programmed Microcontroller
• unsoldered Controller PCB
• 1 or 2 (or more) unsoldered Muses PCB

The price for each v2 PCB is 12€, for the programmed Controller 16€.
Worldwide shipping by registered mail depending on destination.


v2 Documentation
https://1drv.ms/b/c/b432c13e92ba6eca/EcpuupI-wTIggLRNnAAAAAAB1d8cTDwYM8IskRWEmMwKPg

Mouser BOM
Muses Volume

I've played around with building portable battery-powered sound systems over the past 10 years, with my focus being on "Bike Raves" recently which combine free party culture with the freedom of cycling
Before I launch in to the new project, I will provide a bit of background and share what I've built previously...

What is a Bike Rave? A party on wheels is a simple description - Dom Whiting's DnB on a Bike is an example, and there are events like that around the world regularly drawing thousands of participants
Down here in Melbourne, 500 would be a big number... and in Sydney even 100 would be considered a decent turnout

Here are some of my video snippets from 2021 and 2023 Melbourne Bike Raves, and if you search insta etc you'll come across great footage of the bigger events elsewhere

My work has previously been fairly rushed and scrappy but it's become more refined with each version of system I build, and I'm hoping to progress further again
I'm about to embark on an ambitiously scaled project - putting as much sound as I can on a DIY Carla Cargo trailer, and yes I'll have to build the trailer too

So why is this in the Subwoofers forum?
Because my focus right now is on squeezing the most I can out of the 12" Eminence drivers I have on hand:
6x Delta 12 LFA, 2x DeltaLite 2512 and 2x OEM sub drivers that measure T/S close enough to the 12LFAs that they'll fit the same boxes.

The limitations of size, weight and amplification available make for an interesting balance of compromises - leaning towards lightweight and efficient with a lot of output 60hz and up
Sticking with the current drivers (it's not economical to try and sell them to buy new ones) also limits my alignment choices too

Calling the intended cabinets "bass boxes" is a way of dodging the fact they won't have much sub as such 😉

I've almost landed on final design for now, and with the above intro out of the way I will share the build details as it soon progresses...

Hello

I am going to make the Stan curtis 60w class a amplifier. I tried this amp many years ago when in my early twenties and the project failed. Now I have more experience I wold like to try again. I have all the parts but need the PCB artwork. I thing the original project was published in ETI winter audio edition in the mod 1980's.
I have just heard this amp made with the original PCBS and I was very impressed with the sound. Does any one out there have the mag for sale or a copy of the pcb artwork so I can get some PCBs made. I would like to keep to the original artwork

regards

Nick

I've always loved tinkering around with all kinds of power amplifiers. The lm1875 is a real steal, offering awesome sound quality and super simple, cheap external components. I totally recommend it as a starter project for any beginner looking to get their hands dirty. Can't wait to learn a lot from diyaudio in the future!"

Hello here
Will anyone please help me with the Box plan for Aplair Pencil 10.3 plan. I have bought an Alpair 10.3 but can't locate the Pencil 10.3 box plan. Thanks

At some point I had promised to introduce my personal equalizer. The internal working title of this fantastic RIAA EQ was: "EXakt Mk2, perhaps the better MF-V(90) LPS clone."
First of all, it's not a clone ...

tbc

HBt.

Has anyone tried LM25122 in dual phase? I tried it but on loads higher than 5amps, only master side takes the load.
Does anyone have any idea?

Hi I could anyone help repairing an old Pioneer FX-K9 component car radio cassette,

The dc-dc converter looks like it's failed, it there to power the display which isn't functioning, completely dead.

voltage readings on the dc-dc converter as follows

Pin no 1 0.040 v dc
no 2 0.359 v dc
no 4 12.76 v dc
no 5 0.040 v dc
no 6 0.040 v dc
no 7 0.040 v dc
no 8 0.001 v dc

the part number is obsolete so I'm looking for a possible substitute, does anyone have any experience or knowledge of working with this or similar dc-dc converters?
any help or suggestions appreciated.

I have a service pdf if required, thanks

Hello everyone,

I purchased the SB Acoustics ARA from madisound about half a year ago and have been wondering if it's possible to upgrade these further without buying new speakers.

https://www.madisoundspeakerstore.c...ra-2-way-speaker-kit-pair-with-cabinets-2694/

Currently they use the MW16P-4 woofers (https://www.madisoundspeakerstore.c...w16p-4-black-egyptian-reed-cone-woofer-4-ohm/) and was wondering if I could possibly swap those with the new MW16TX-4 woofers (https://www.madisoundspeakerstore.c...satori-6-mw16tx-4-textreme-cone-woofer-4-ohm/) without messing with the crossover. I have the BE tweeters so the crossover was designed with a 2300 hz crossover I believe. I'm not too familiar with the crossover so I didn't want to mess with that too much.

I've seen an audio store online sell a configuration with the TX woofers but they also say they changed the crossover without much detail as to what changed.

I'm probably simplifying it too much to hope that I can just swap the woofer but just wanted to get a second opinion.

Appreciate any responses. Thanks!

As I have shared in other posts...Im looking to use this shape as an enclosure and it coincided with a voight pipe


however many peeps intimated under powering using it as a single driver solution so Im running this question here...what are the thoughts about creating an opposed piston manifold and putting in the base of the enclosure with a down firing port? (Just prelim)




If anyone is interested in helping with this project, I would be happy to pay the time with a set of these sent over to you/you pay freight 🙂
Trying to make something special but my skill is in making them...not the intricacies of component choice/config etc...just a thought

Thanks

Hello there!

I've been a passive reader in the forums for a while, and have been anyways interested in building things and diy. I recently wanted to build a Bluetooth speaker system on my own for as cheap as possible, but pretty good quality.

I am totally a beginner in any diy audio systems. I went ahead and imported the Dayton Audio TCP115-4 which was nowhere available in India directly for any reasonable price.

Now note that my whole build process is a trial and error and not really structured in any way. I mostly work on the weekends and whenever i get free time on this.

Now started my search for an amp.

I initially wanted some sort of DSP to process the signal and pass it over to a mono amp. But I couldn't find any good DSP for a reasonable (cheap) price. There was ADAU1401 which I heard about, but need to be imported from China and no seller seem to ship them to India at present.



But then I found Wuzhi Audio ZK502-M for a relatively cheap price. I don't have any DSP control or anything, but it is a 2x50W amp with built in birth, 3.5mm jack and USB. For the time being, it should serve my use.



My plan was to power it from a 3s Lithium ion battery pack, so I had bought 3x18650 cells, BMS and a battery holder (I don't have a spot welder). But it's only now that i noticed, though the amp says it has an input voltage range of 5v-24v, the output power totally depends on how much you feed it. So I needed something close to 20V.

Now with that in mind, my plan was to make a 5s battery pack, but I wanted to be able to charge it with USB C. Sadly, the best I could find was 4s charging board. So ordered 4s charger, extra batteries and 4s bms, plus a DC-DC boost converter (along with some fuse, charge indicator led, switch, etc), and a 4700uF capacitor to the input power of the amp.



Now that i have the electronics sorted out, I tried this setup out in a 10L water can. The sound was good, but a bit muffled. My original plan was to go with no tweeter for the time being and add it later on, but I now understood that won't be a good idea.

So off to buy a good tweeter and building a crossover.



Got myself Dayton Audio ND16FA-4, and couple of components for the passive crossover (will post the xsim simulation and other details in a separate post), and built everything.



The sound felt pretty good



Now came the biggest hurdle: The enclosure. I don't have any wood working tools, so working with MDF or wood would have been tough. I thought of another idea (inspired from the design of other bluetooth speakers). To use a 5 inch pipe, placing the speaker on one end. I couldn't get any 5 inch pipe nearby, so I bought a 6 inch one and a 6 inch to 4 inch reducer. Drilled some mounting holes on it, covered the surface where the tcp115 will meet it with some foam tape and mounted it. But now came the tweeter. Where do i attach it? I didn't want to drill a hole in the pipe.

I didn't have much time at this point, so the tweeter laid outside on the ground for a few days while i was testing it this way. I also found it was difficult to get a grill for the speakers, and a lot of things required really custom stuff.



Now this is not cheap or economical, but I've always wanted a 3d printer. Felt this is the right time, and got myself one.

I printed one custom mount to mount the tweeter just over to the side of the woofer, and the grill.



Wrapped the pipe with some fabric vinyl and now it, lined the sides of the inside of the pipe with some acoustic foam and filled with polyfill. For the crossover, currently I just twisted all the connections and covered each component with foam tape, and then one round of foam over all. Then pushed it inside the pipe. The polyfill just keeps it there in place.



Now what's left for me is to put the batteries, amp and other electronic components inside the enclosure and close up the other side.



Posting some images🙂



Please do share your review/suggestions

It is with much reluctance and sadness that I’m forced to sell my terrific Wolverine EF3-3 power amplifier. Fully operational, in pristine unmarked condition and completely finished in every way, this is a great amplifier! It’s a fantastic sounding amplifier that I thoroughly enjoyed building, and it’s provided me with many hours of audiophile enjoyment.

Unfortunately, in our small UK house I don’t have a specific music listening room, so I’m set up in a spare bedroom - which of course then needs to double up as a bedroom if/when required. Hence, available space for amps, etc. is at an absolute premium and I discovered the Wolverine enclosure (Dissipante 03/400B) was bigger than I’d imagined and was becoming a physical inconvenience!

So, it’s time to let it go and allow someone else to enjoy using this amazing amplifier.

Wolverine Build Guide Forum: htpps://www.diyaudio.com/community/threads/diy-class-a-b-amp-the-wolverine-build-thread.385920/

Built by me using version 4.0 pcb’s, components exactly as per the recommended BOM specification at that time. All components obtained from reputable sources (mostly from Mouser, remainder from Digikey, RS Components, Farnell, etc.). Photos attached and in brief, the specification is:

• 2 x Wolverine v.4.0 & IPS pcb’s, fully populated as per recommended BOM, using:
• Driver transistors: Toshiba 2SC4793 & 2SA1837
• Output transistors: Onsemi NJW0281 & NJW0302
• Pcb heatsinks and some other items from @fireanimal, from DIY Audio Wolverine Build Forum.
• Linear power supply: 35 volt transformer supplying PSU board designed by ‘Circuit Basics’, which provides ~51 volts to amp boards. This equates to approx. 100W per channel output into 8 ohms.
• Soft start module with remote switch on/off and indicator.
• DIY ‘ground lift’ module.
• Speaker protection pcb’s (from DIY Audio Wolverine Build Forum - @Felix design, v.1.0), which provide short circuit, overcurrent, overheating, DC protection and power on delay and immediately switches speakers off to prevent audible pops/noise whilst turning amp on/off. – htpps://www.diyaudio.com/community/threads/diy-class-a-b-amp-the-wolverine-build-thread.385920/post-7772925 and also https://github.com/felix1024/SpeakerProtect
• RCA sockets & speaker posts from HiFi Collective.
• Van Damme, Mogami and silicon internal wiring where appropriate.
• All housed in Modushop Dissipante 03/400B 3U enclosure (440mm x 405mm x 122mm) with 4mm silver front panel and inner baseplate fitted. I’m also including an unused, brand new, (still unwrapped!) 10mm aluminium front panel. I was intending to replace the front panel, but never got around to it!

As far as I recall my total build cost for this was around £1,200. Comments and reviews on the Wolverine Build Forum site suggest that to obtain a commercial amplifier of this sound quality you’d be looking at paying many times that figure. I’m asking £800 or sensible offer. I’m in the UK so, due to the weight, I think shipping overseas might be difficult and costly. I therefore think this would be more suitable for someone also in the UK, who can possibly collect (I’d be happy to drive a reasonable distance to meet half-way or something). Or I’m happy to rig it up for a demonstration if you want to attend to see it working before purchase (I live in Chepstow).

Any questions, send me a PM anytime.

My SAT tonearm's ground wire broke on the inside of the arm pillar and am trying to fix it myself.

I'm attempting to attach the broken end of the wire to the rest of the wire bundle so that I can pull it through the arm pillar from the headshell end. When I pull it far enough through the arm pillar, I should be able gain access to the broken end and resolder the ground wire to the other, broken end.

Unfortunately, I'm having difficulty attaching the broken end to the rest of the wire bundle to allow me to pull it through without it snagging and catching on something. I've tried bundling all the wires together with thread, dental floss, and packing tape but each has failed for a variety of reasons. In each case the wires get hung up somewhere when I try to pull them through.

I'm looking for advice on how I can securely attach the broken wire so that it can be pulled through with the rest of the bundle.

See pictures.

This is my go at an external power supply for the SL-1200.

After a conversation with Wayne Colburn of Pass Labs, learning that he has made a few SP-10 PSU for in-house use, a few things became apparent - Get the bridge diodes out of the TT and just have DC on the umbilical. Use 1N4007 diodes, for whatever reason they sound the best, in this case even better than exotic high-speed diodes. Snub the bridge on the AC side with a .22uF film cap. Use multiple stages of RC filtering.

The biggest improvement is of course, no transformer vibration on the platter, easily done merely by locating the transformer outboard of the TT chassis, and this is what I was originally planning to do - but converting umbilical to DC wasn't much more work.

Does it sound good? Of course! And the best part is that I'm not even done yet, the stock regulator hasn't been replaced... (mainly because I ran out of time...) 🙂 🙂 🙂


The first thing to be done is remove the bridge diode and snubber caps.


These were located in the holes now visible.


An umbilical is added. The white 3rd wire is capped off, but still there if I need it for something in the future. The bare metal wire is the shield drain, to be attached to ground.


Fused IEC plug, switch, microphone connectors used for the umbilical.


All to be placed into this ABS enclosure.


There is no reason not to use the stock transformer, it's the proper voltage, soft-mounted, has a beautiful mu-metal shield, and is free with the purchase of a turntable.


(3) 4700uF 63V volt capacitors, (2) 10ohm 3W resistors, .1uF polypropylene bypass cap, all wired up in a CRCRC filter. Why those values? I had them on hand. If I needed to buy new, I would probably use similar values.


And here it is with the bridge to the side. (The yellow is the transformer secondary.) The eagle-eyed among you will notice the 1K bleeder resistor across the cap bank.


The final configuration of the umbilical attachment to the PCB.


The insides after the modification. I utilized the now unused AC power switch to switch the strobe.


A few zip ties to attach the wire to the studs for strain relief, and of course the obligatory ferrite clamp.


The PSU schematic


This is stage one of my PSU modifications, a different regulator of some sort will be next....
EDIT - and here it is:

After reading this fantastic article - Using 3-pin regulators off-piste: part 1

I have installed the first LM317 based regulator in my SL-1200. There is not a specific schematic in the article, look at the one on page 1 of the 'off-piste' article, and all you do is replace R2 with a Zener reference and make sure you include C2.

I did mine point-to-point and covered up all in heatshrink as I don't want anybody copying me directly, as it's a point-to-point salad of wire and tape. Do as I say, not as I do and all that...

It works wonderfully, sounds great, and took about 15min to install.


Here it is... not particularly exciting.


Lift the motor PCB and remove the old pass transistor and wires. (You could just cut the old wires and splice if you desire)


It mounts in the same position as the old transistor.


Don't forget some kind of insulator under the regulator - the old transistor was a 'full-pack' and did not need an insulator.


The regulator needs to be grounded here, at the turntable center ground.


Schematic

Questions or comments warmly solicited.

Thank you for looking.

Repairing a bryston 3B IV and one channel is distorted and one of the output transistors has an Hfe of 1.5 where as the others is are over 100. It is a BR6522 PNP TO-3 ...no cross, I've read Mj15004 (140v) but all I have is a 2N6584 (80v) the rails are +-65. Should I chance it?

here because i enjoy guitars and want to work on them as well as amplifiers.

Hi!

I am building a prototype of the amp, it will be monoblock, 200W output, 4xGU-50.
I have a dilemma, which side should be the face, with front panel?
Usually monoblocks have short face. But if to make the front panel on the long side it will be 19" rack mountable. Which road should I choose?

The front panel will contain only power switch and volume control. Rear panel will contain power socket, fuse, output binding posts, RCA and XLR sockets, RCA-XLR switch.

Hello,

I am working on an Audison AV5.1K, which came to me missing diodes D11, D12, D15 and D16. Does anyone have a schematic for this amplifier or could you tell me the reference of those diodes? Thank you.

HI folks, i have passive interest in Audio from my childhood. Actually my dad was a lecturer in electronics so saw him building amps n other stuff. Had grew up with these audio equipment around me all the time.

As i grew up i had the itch to build my self. But i dont hav formal academics in electronics , (just basic electronics). Many times i got chickened out in the last minute cos of lack of subject expertise. Now i finally built some courage n want to seek guidance from members here. Look forwards. Cheers!

Chasing an orphan (or a set I suppose) PT-214 or PT-2K 16 ohm horn tweeter to replace a blown one in my CS-A50s.

Thank you

Hello. I am a budding DIY audio enthusiast who focuses on infinite baffles, line arrays, and large PA systems. I am planning a few different speaker and subwoofer builds for 2025 and figured diyAudio would be a great resource to gather and share knowledge.

Hi, all...

I'm getting ready to build my first t-line enclosure (fingers crossed!). I think I'm okay on the calculations and overall design, but I'm not 100% sure where the port "begins" (on the end of the subwoofer). Below is a diagram of the box...

Would you start measuring the port's length at (a), (b), or (c)?

I would love to hear your thoughts. Thanks for the help!

Hey guys ! So I am trying to copy the tone control + loudness circuit from a 1989 Sony amplifier. However I am completely stuck, and everyone else I ask seems to be, at what does that DOT near the potentiometer mean ? 🙂)

So basically that is a stereo pot, it has 6 outputs as expected, two go to signal, two go to ground, and two send the signal forward, in a stereo design. However, it looks like there is a 7th pin that is not connected to anything, and from the pictures I saw on the net ( I don't have access to the amp anymore ) , the pot itself actually does have 7 pins, one larger. What could this be ( mention, it is not a loudness switch, it has a manual loudness switch that does what S304 does in the picture ). Also , the Source Direct switch which the pin serves is a separate button, but to me it seems that the pin is on when source direct is off, so in normal listening mode. Also, the volume does not press or click anywhere , it just turns. Any ideas ? Thanks !

Hi!

I'm looking at the N78 pentode, got some for next to nothing. Interesting tube, but I'm confused at the suggested operation voltages for push-pull in both pentode and triode modes. The values are much higher than the ratings, and this is in a datasheet. Can someone please explain?
Thank you!
Jose

This could be a useful compilation. Especially for me.🙂
Mine is Mark Knopfler's Kill to get Crimson.

I'd like to try a LPS on this preamp. The preamp has an internal ±15V supply, powered by an external transformer but I don't want AC anywhere near a phono preamp.
I can't find a schematic for this unit. Has nobody put it under the microscope yet?

Need to thin the heard a bit on drivers. But before they head out the door starting to build a library of motor current distortion measurements. First on the chopping blocks is a pair of Dayton PA380-8 15" woofers. They are used but in very good condition (see photos)

I measured the impedance of both drivers, came out to 31.6 and 32Hz (Factory spec is 31.6Hz)
I also measured the motor current distortion of one of the drivers at 2.83V/4V/8V.
They are heavy so will be advertising on FB Marketplace locally, folks in Central Texas/Austin area are the primary target. Willing to ship and pricing accordingly for the diyAudio folks.
$75/Pair + Shipping.
Shipping estimates to Norcal $70, New York State, $60 according to Pirateship.

This seems eerily similar to a fault I had on a previous amp, but somehow different.


This current amp is not producing equal PWM signal to the output stage, bridging pins 1 & 2 of U513 does make close to equal pulses but not quite equal. With pins 1 & 2 open, the voltage seen at the LM319 pin 4 is too high to allow proper oscillation at around 3.3v where I would expect it to be around 2.2 or so (it needs to be right in the middle of the triangle wave seen at pin 5 during idle conditions).

This board version doesn’t seem to have an offset pot it only has a clip pot, so I can’t do some of the testing shown in the attached thread. U503 and U513 are already replaced with no change, the amp showed up with a smoked pair of output filter caps which were also replaced (a pair of .22’s near one of the chokes, can’t see the designator anymore but they go from either output leg to ground). Question is, where is this extra voltage coming from?

Came across this when I went to search John Kreskovsky's web site.

"This website will close Sept 1, 2019"
"Thanks for your support over the years."


Music and Design

Excuse me if this is old news --I've not kept up with things recently.

Peter

For sale 6 month old pair of Purifi 1ET400A modules.
Good working condition.

Free CONUS shipping included.
PayPal F&F preferred, or plus 3%

Thanks

My First Watt M2 clone has been reliable (and great sounding) for two years since I built it. It recently blew a fuse (it looks like on startup). I replaced the fuse and tested with some sacrificial speakers. All was well, and it ran for a couple of weeks before blowing a fuse today. I guess the first question is, is it a bad idea to bump up the fuse values and see what happens? The current fuses are 2 amp 125v. Is that conservative? The next question is why might it blow fuses now when it didn't before? Which leads to the third question, should I start diagnosing instead of putting in higher value fuses?

Good afternoon,

I'm working on this JP 43. Something is causing it to protect, shutting down the drive. Card removed, tested out of circuit, works great. I removed the diode, drive fires up no problem. Outputs, Output drive card and power supply fets are all removed. Input voltage is 12.5v

Problem is, I can't figure out for the life of me where the voltage is coming from. I can't seem to trace that 10v to any source.

Thanks in advance. Pictures coming.

I'm looking for an app that will run frequencies and tell me what's also going on using my ears instead of a microphone, however I'd need to know what frequency is playing and it'd be nice to have allot of frequency sweeps avaiable.
Really, I'm just trying to go down an EQ rabbit hole here and can't quite find a good app to do this on Android. On PC sure but all I really have is a really good DAP so I'd like to just do it on Android.

I have a lovely pair of slippers which I obviously wear around the house. Problem is, whenever I touch my hifi equipment I get a shock.
I know the slippers are the culprit because if I don't wear them.... We'll, no shock.

Floor is vinyl.

How can I modify my slippers?

Hello everyone.
Perhaps a silly question. I am trying to repair a Sony HMK313 three-in-one music center.
It originally came with a ceramic cartridge, but I want to put in a MM magnetic cartridge.
Can I place a magnetic phono preamplifier internally and connect its output to the ceramic phono input of the equipment?.
Would the resulting frequency response be adequate?
Greetings and thanks.

Hello to all!
Not so new, and not so young, I feel miserable when I have to dump electronics. So I never do. A pile of things added on top another, so this is why I have come to the realms of diyAudio. Let my journey begin...

What is CTA-2034?
And how does it differ from the 'normal' SPL curve?

These sell for $1.40 ea now plus shipping so how about If your not old like me these used to be mega highly rated. I absolutely loved em and installed hundreds, this was back in the day when i could here a resister change. (before I read about confirmation bias)

If these are new to you then here are the specs.
Vishay 11DQ10

I am designing a new speaker using the audio horn x shaped horn with a hf1440, a sealed 15” midrange, and a cardioid like woofer playing from around 200hz down, one for each channel.

I am considering a damped u frame, either a single 18” or a slot loaded U frame with 2 12”s.

a damped u frame has a cardioid like response, and I am trying to create a subwoofer that won’t cause the bass to travel excessively through my condo. I could also make an active cardioid sub, a ripole, or many other designs. A regular dipole or h frame would probably be less optimal as the subs would have to be placed within 3 feet or so of a wall.

Anyone have any idea which. Woofer/sub. design would be my best bet for high sound quality, while leaking from my listening space as little as possible and cancelling unwanted bass energy?

Dear Friends
I am having trouble with the amplifier mentioned in the subject, I am unable to find out the cause of the oscillation shown in the video below.
I have replaced most of the electrolytic and film capacitors, including the ceramic capacitors. With the exception of one capacitor, the replaced components have no effect on the oscillation, except for the 10pF ceramic capacitor connected to the collector-base of transistor Q5 / Q10 (MPSA42). Increasing this changes the oscillation frequency and decreases it's amplitude, but even at 100pF the excitation is not eliminated (although the amplitude is an order of magnitude lower).
I have read elsewhere that it is not advisable to increase this capacitance too much, as this will increase the distortion. Also here on the forum I read that the collector-base capacitance (Ccb) of the transistor in the voltage amplifier stage is important, although it is not very high for the MPSA42 (~3 pF). Someone suggested the KSC3503/KSA1381 or the 2SC2682/2SA1142 pair.
Please help me where to look further? Thank you very much!



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Jeff Rowlan Model 5 amp.
Concerning circuit board part number 5010. I need a 14 pin IC extension because one of the pin ends broke off.

Anybody here fans of the big race? The start was noon local time today amidst almost zero wind but they're cruising now...
I'm in awe of yoyng, Ms. Violette Dorange. 23 years old and running headlong into the toughest sail race there is. Fair winds and following sea isn't realistic but the sentiment remains. Go get 'em girl. Amazing bravery and a highly skilled sailor, well beyond what one would expect of one so young...
For the uninitiated, this is a solo, nonstop, unassisted race around the world.

This is brand new, I purchased for a project that is on this site. Overdrive These are 329 Euros atm but out of stock. If you read the thread there are ways to install a defeat toggle for the 6db of boost for anyone who like. DIY. (from memory @wolf_teeth links to another site with more detail)

Im selling everything very cheap to thank DIY audio for all its help over the years.

$100 shipped USA.

I'm working on a guitar effects switcher, where I can add all of my pedals in individual loops and turn on any combination at the press of a button. I was almost done, with a working prototype, when I came across a video about running pedals in parallel with a dry signal which caught my attention.

Having looked across the web for some schematics, I came across this one, which looks simple enough: https://www.runoffgroove.com/splitter-blend.html

Now, before I go off building it, I have to wonder if I actually need the buffering (though the phase switch is definitely something useful in this scenario). The two switcher loops I'd want to be able to run in either series or parallel would be the last ones (for delay and reverb), sitting in the amp's own effects loop and looking the schematic, there's already some buffering there, hence the question: does it really need extra buffering? That would make sense if I was running a totally unbuffered dry signal through it, but here I think I'm just overengineering.

An additional, more theoretical question is: why does the schematic above use such big values in what I see as high pass filters (combinations of 220uF/1M or 10uF/1M). If I got my calculations right a 22nF would suffice for Fc < 20hz

Amp effects loop schematics:

Hi all,

just wanted to report excellent experience so far with aluminium nitride insulators for TO247/TO3P and TO264 sourced from China/AliX.
The are flat, they don't break (at least not when they fall down the bench) and they conduct heat extremely well - my scientific proof:
Compared same thickness pads (0,6mm) made from alumium oxyde (sourced from AliX as well), hold it with two fingers, heat it on the far side with a lighter. With alumina it was 15s until I couldn't stand the heat, with those "cheap" Chinese aluminium nitride I had to let go after 5s.

Best,
Markus

This is brand new. Box is a bit knackered but I will reinforce.

I'm trying to solve a small problem with my BEANS amplifier: https://www.diyaudio.com/community/threads/b-e-a-n-s-amplifier.423552/ , namely slight 'sticking' when coming out of clipping. It's only very slight but I would like to try and resolve it. One approach that looks promising is to use an opto-coupler, so that when the drive from the VAS nears the power rail, this causes the opto to start to conduct and that in turn can reduce the drive for the VAS. I've done a few experiments in LTSpice and it looks promising, but looking at the specs of standard devices like the 4N25, it seems they are a bit slow.

Any suggestions?

Hi

I have a Thule Audio PA350B. The amp has a network port (JR45) that is used to control the amp from the Thule Audio preamp. The port may be used to turn the amp on/off and to select between 2-channel or multichannel mode.

I need to control the amp. My idea is to make an simple aurdino bord with a JR45 jack and software that controls the amp. For example based on a 12v trigger from my prosessor (not Thule Audio).

My problem is that I do not know how to wire the JR45 to the Aurdino (what wire to ground and so on) and I do not know the commands.

Anyone that has some knowledge, or even ideas about how to move on to make this work?
I have the service manual for the amp (attached). Thule Audio is gone long time ago, so no help there.

PS: I have aurdiono boards and anything needed to start testing.

For sale is a project that didn't quite make it to the finish line, for a number of reasons...

This is a DAC project based on the Soekris DAM1021 R2R ladder DAC (0.02%), and was eventually meant to be housed in a beautiful custom made case, together with its power supply and USB converter. Maybe have a look at the images first, you literally get the picture.

The project includes the DAC board, the complete power supply (with two Jan Didden super regulators for the board and two TPS7A4700 regulators for the converter and isolator), two transformers with a rectifier and prefilter board, a DIYINHK USB converter and matching isolator, and the custom made case (precision cut from a block of ureol). The components are all mounted on an anodized aluminum plate that is to be mounted bottom up into the case.

The power supply is fully working and can be configured for 115V and 230V mains voltage. It just needs a bit of fiddling around the isolator to play music, all boards are fully functional! I am doing my listening from a modified SD card player hence the sale.

I will ship to everywhere in the world.

Asking price is 280$ (a steal, the case alone is....dada dada 😉), open for reasonable offers.

I have bass bins that contain two 8" woofers in each enclosure. Drivers are mounted one above the other. When I measure response with REW, the phase remains flat at -150 degrees from appx 200 Hz up to appx 1500 Hz. The FR also measures very flat in this entire range, which I guess is a good thing!. The microphone is six inches from the baffle at a point directly between the drivers. Is this normal, good, bad? Am I measuring incorrectly? How do I match that phase to the midranges in their own enclosure, which show a "typical" slope of phase angle in that frequency range? I would attach the graph, but I'm such a rookie that I don't know how to do that, so please include instructions in your response if you would like to see it.

Hi,
I have finished assembling the EL84 push pull lamp amplifier. The schematic and a photo of my amp are attached. The amp works fine with 8 ohm speakers. However, when we connect a 4 ohm speaker to the amp, there is an audio feedback high-pitched noise continius loop. I could not find a solution.

I'm trying out some driver tubes for my 300b SE amp. Currently listening to the EL84 in triode which is sounding much better than I expected. Setup is a LL1660/18mA used as a plate choke with 0.2uF Russian FT-2 teflon caps. My first try out has 14.5mA current, -5.2 bias, 155v a-k. using a 360R cathode resistor unbypassed. I'm sure this can be improved with some further experiments. Take the current up to 18mA and look at different a-k voltages. I can also try SIC diode bias.

Present tubes are Sovtek EL84 which is probably same as 6P14P. So I'm now wondering if I'd get any better sound out of a SV83 or 6P15P or other close cousins. I'm also intending to try the EL33.

I'd appreciate plenty of useful feedback on this!

Currently designing and 3d printing my own open baffle speakers with ATH horns and SB audience / Eminence drivers.

Hi everybody! I'm Neurofunky. As someone who would read through the forums but never joined until now, I'm excited to be a part of this community. My passion for audio equipment (more specifically hi-fi speakers) started when I was about 12. I was reading through a magazine which showcased a pair of Definitive Technology floor-standing speakers (the one with the large side-firing sub), and fell in love with them. Over the years, I've dedicated a lot of time in trying to design and build my own "perfect" speakers. I've learned more than I thought was possible (or necessary) when it comes to speaker design, but there is still so much more to learn, which is why I'm here. I look forward to learning as much as I can from those more knowledgeable than I, and if I can impart any knowledge that I've gathered over the years, even better. Thank you for reading my post.

Part of my clear out. I am selling above but the amps have been scratched up a fair bit. I could upload a lot of pics but I would want these collected from Reading so why not pop down and have a look. Just tested, used for less than a year, I went through a lot of gear chasing rainbows a few years ago, I dont do music anymore. The drivers have been covered with sound deadening as these are designed to be open baffle and talks with Darryl from Hawthorn determined it was very benificial. These are priced to sell cheap at £200 for the lot due to condition but are in excellent working order and hardley broke in. These drivers and sub amps open baffle produced the best bass I have ever heard, unfortunately I hated the tweeter that Hawthorn used and I just couldnt listen to the system. I did try using the subs with my bastadised Townsend Glastenburry's but Im not a designer and I couldnt get the system to gel so I moved on and kept this for a day that I now know is NEVER going to happen.

Sorry I forgot to say I cant remember the sub amp make but I am searching now. It was something like xyz. Will update.

They are XTZ Sub Amp 1's.
300w into 4
400w into 2
Variable control from 40Hz to 250Hz provides (-
3dB) optimum setting of subwoofer crossover
frequency to match crossover frequency of Home
Theatre components.
EQ 1: Increases 7dB @ 25Hz
EQ2: Increases 7dB @ 50Hz

The last one i could find sold for £175 with marks on AOS
https://theartofsound.net/forum/showthread.php?64227-Xtz-sub-amp-1

Hello forum. I am going to attempt a 3 channel Icepower build. I bought a 300AS1 and two 300A1 modules. They will be mounted in a Ghent 3 channel xlr chassis.
The intended use for the amplifier is to power my 3 front speakers in my hometheater. Speakers are Jamo D500 LCR THX.
I just received the icepower modules today. I still cant believe how tiny they are for 150watt/8 ohm amplifiers.😲 Components are of excellent quality….Panasonic FC and Nichicon caps.
I will post some pictures as I go along. If any of you have some great input and advice, please feel free to post here.

Normally I’m not into DIY stuff because what I do is geared toward studio stuff and making music, but lately I’m starting to realize that I have an itch to do more tinkering to get results that may cost upwards of $30k otherwise.

What I want to accomplish is an active system that has digital crossovers taken care of by Trinnov Nova.

What I don’t want to have happen is “bi or tri-amping”, into a speaker that already has passive crossovers which defeats the purpose as I understand.

Here are some options I’ve come across to make this happen, and they are not reasonable. Maybe I’m not looking in the right spots.

XTZ alpha divine speakers allow you completely take out the passive crossover network. I don’t see many speakers like this.

Linn Akurate Exaktbox: these allow for active crossovers upstream of power amps, but is that really necessary? The cost is ridiculous.

Can I take a speaker like the KEF 11r and just direct wire to the drives and essentially “convert” these speakers true actives by using something like the Trinnov Nova to safely take care of crossovers?

Just curious what options are there for this from a DIY approach.

I own and use nine or so $100 and under Class D amps and a couple A/B amps.

I’ve never upgraded the power supply on any of them….but on a couple of them (most notably the Aiyima A07max), they significantly benefitted from increasing the RCA line level input/pregain with an RCA line level booster.

Been using a $40 Douk Audio L1 with no noticeable added distortion/humming/etc.

Am I accomplishing the same goal with a line level amp vs purchasing more powerful power supply? If it’s different, please explain.

Thank you.

Greetings friends. I'm seeking recommendations on a good 2-way kit, possibly from Madisound.com, that would pair well with my DIY 2A3 Single-Ended amp. Room is 12x25'(4x6m) and I'm down at one end, 6-8' (1.5-2m) from the speakers when sitting on the couch. Budget is under $2k or so.

I have an eye for the SEAS A26 kit but the datasheet has the Sensitivity as only 88db/m, a bit low for a low-watt amp, unless it isn't. And the classic A25 was paired with higher-output Push-Pull amps in its heyday. So maybe I need something more efficient. But I like the simple crossover.

What do you think?

w

Hello, I have been a regular visitor to the forum for several years, and I can always say that I have gained knowledge and audio news from here. But this time I would like to share a discovery with you. We are talking about the Chinese R2R dac, or more precisely, a DIY board that allows you to build a fantastic device. For a Chinese product, I must admit that it is a bit expensive, but the quality of workmanship and components is at a very high level. According to the data, it is a 64-bit R2R design, with very precise resistors, and these are controlled by transistors! so each resistor has its own transistor, and this is a very different system from standard designs of this type. The board contains several low-noise, top-class stabilizers and tantalum capacitors. The design is fully thought out, it allows you to connect an i2s source and an external clock, and the dac can operate in master and slave mode. In my case, it works in slave mode where it receives a very good quality i2s signal along with external clocks.I made sure that the DAC equipment was of the highest quality and had a very good power supply. The dac has two outputs, with a capacitor where there is no DC and without, where we have to use our own recognized capacitor, in my case I used v cap tftf which fits this sound perfectly. I struggled for a long time with thoughts about whether to make an analogue output at the DAC output. I finally found and developed a simple analogue with one op per channel that did not spoil what the r2r ladder gave us, and even slightly improves the dynamics. The construction of the entire device is complicated, so I will get to the point. The sound... very rich, dense, deep and saturated. With good, clear treble and punchy bass. I compared the device with several well-known dacs and I don't know what more you could want. There's just music playing..

1. The first question I have should be straightforward…
When using a ground/loop breaker should the return connection go a chassis point near the safety earth chassis point or to the safety earth chassis point itself?

I've read articles stipulating both ways. I was always under the impression that the safety earth connection should be a dedicated point with nothing else connecting to it.


2. In terms of the group/loop breaker itself I have seen various versions of it. I am trying to understand why there are all these variations and which I want to implement, the pros and cons of each.

Attached is:
1. the Pass version from a Pearl 2 phono,
2. the Rod Elliott version (same as pass but with resistor and cap)
3. Merlin Blencowe version
4. not pictured but my F6 uses a thermistor

Looking for advice on speaker building

Here is the schematic for the MX50SE kit by LJM that can be had on Ebay for about $18 USD shipped. I have not really hammered on the board yet so I wont comment on performance but clearly for the cost it is a great deal. The circuit is also interesting looking. I believe it is a rip-off of the Musical Fidelity X-A50? I would be curious to know if it is a clone or of this LJM character contributed some intelligence to the circuit. Someone deserves some credit.



This simulates fine. Note that the schematic posted with the Ebay listings is totally bogus. And the transistor listed as "5551" is not a 2N5551. It has to be a transistor with pinout ECB. Then it makes sense and simulates well.

Anyway, hopefully no one gets bent for posting this. But I would say it only makes Musical Fidelity and / or LJM look good. So either buy some MF gear or make something with the super cheap boards and if someone knows who the real brains are behind the circuit please enlighten us.

I will try to develop and build a multi channel amp for a large 3-way active speaker build.
I have been considering Hypex solutions but before going that path I would like to see what I can create myself. I enjoy the process of learning new things. Have built a couple of active speakers based on ADAU1401/1701 and pretty cheap Class D amps before that I am satisfied with.


The plan is to:

Arylic HD DAC Streamer -> I2S -> ADAU1467 (DSP) -> I2S -> AK4468 DAC -> Differential signal 2V RMS -> OPA1632 -> Differential signal 2.5V RMS -> TPA3255

I have bought 3x2 channels of TPA 3255. (https://www.aliexpress.com/item/100....order_list.order_list_main.60.76611802JUlLBt). They use one TPA3255 chip per channel in PBTL mode. On the input signal path, one TL072 opamp per channel is used. Input connector is single-ended so I assume the TL072 acts as a buffer and inverter to create a differnetial signal for amplification, need to double check that. It says is also has a post feedback loop.

The plan is to develop a PCB with AK4468 and pre amp stage to take the differential signal to 2.5V to get the most out of the TPA3255. If I do so I will also the skip the TL072 op amps on the board and pass the signal straight into the TPA3255 in order to not toch the signal more than needed and to ensure 2.5V RMS.

Is it to overcomplicate things and instead go the extra way into a single-ended signal and keep the TPA3255 pretty much as-is?
Any advice in this conceptual phase of the project?

Hi everyone,
Emendion here. Design and manufactring od high quality microphones för use everywhere.

Hello everyone. I am a new member here. I have been making various audio equipment and loudspeakers as a hobby and most of them are multi-way type. I am on the way to find out my preffered sound and if possible, I like to build it by myself. I know it will be long journey but if I can have advise from here, I believe that I can do it. Thank you very much and have a nice day!

Hi folks. Been away from the scene for a long time and been throwing a lot of money in the bin just to make room. This lot was purchased in 2018. I cant guarentee that i havent used a few of the big caps but I ordered everything as per the parts list from AMB, nothing was subbed. I do remember ordering multiple diodes and resisters to build various output voltage versions, i probably went for 5v 9v and 12v options and i would of thought there will be parts to build 3 of each size. I did only purchase 2 big heat sinks as i wasnt sure what I was going to use. Looking for £50 plus post for the lot. If you would like to collect I live in RG7. Please check my threads, ive sold and posted stuff across the world on here with no probs, I had 2 accounts by mistake so some sales may be under DC2100. I am selling this as 3 supplies, splitting it up would involve an amount of time i dont have working out what 1 supply needs and ive been throwing stuff away to avoid this sort of thing so sorry if your looking for a single supply.

All the best

Alan

https://www.amb.org/audio/sigma11/

Thread split from: Tube amp high-voltage delay


Thanks Mark - never saw that AR amp! Seems like a nice touch.

The controller is really a no-brainer; after switching the HV on it goes to sleep, switching everything off, its clocks, timers, what have you. It just becomes a blob of dead silicon sipping away a few tens of microamps.

In The Netherlands we have a saying that means something like: 'unknown makes unloved' 😎

Here on my bench I have a completed design of a HV regulator for tube amps. Less than 1mV noise, no sagging under load, light, low heat. No need for additional power supply.

A single R sets the output anywhere between 0V and 580V. A single R sets the current limit to anywhere between 5mA and 1A. Fully overload and short-circuit protected. A tube amp's wet dream.

But I am hesitant to publish it because it contains - gasp - an opamp ...

Jan

One pair Lii Song Fast 8 drivers .
Never used . Europe sale only
125 euro for the pair
Shipping not included .

I’ve decided to sell my K209 amplifier.

Very nice build (not by me) with Audio Note Silver/Tantalum resistors, Charcroft Z-foils. V-Cap teflon, Audio Note and Samwha HC PSU capacitors (22,000uF). Latest Avondale Schottky rectifiers. Input and output FETs are all matched.

Compact amp giving 30w in class A/B and variable gain/damping factor.

For sale at £1200 plus shipping at cost. UK sale preferred in the first instance please.

Thanks.

Ian

Hello, into most all electronics. Creating a membership for help on a cd player.

I was having a read around cascodes and came across this 1956 thesis paper on cascodes - the interesting point is figure 1b, where it shows a parallel cascode:

https://scholarworks.montana.edu/xmlui/bitstream/handle/1/5007/31762100133923.pdf?sequence=1

Essentially the parallel cascode passes the signal from the anode to the cathode but decouples the path, unlike a anode-cathode serial connection, so that both run in a lower B+ (as a benefit).

I know of the cascode shunt but I thought that this was interesting as I've never seen another 'parallel cascode' so it may be called something else.

If it's useful and doesn't have any draw backs it may help reduce B+ voltages required for cascodes.