I got to hear that T25S sounds very good and wanted to try myself. I like waveguided tweeters so I started making experiments and this is the 1st version that measures reasonably ok. WG is quite shallow, 20mm, with overall diameter ~160mm. WG was 3D printed, low quality, so it may cause some irregularities. In this stage it is just about finding the direction. I do not use any advanced methods to design WG.
Distortion measurements is excellent. FR irregularities ~9kHz somewhat copies native tweeter FR measurements.

And as I have 18W/8542-10 around, I tried to measure it as well to model 2way crossover. This looks definitely good.

This thread is a follow-on to my thread last year on getting TDA1521 to play nicely in parallel with lower gain. In short, it wouldn't cooperate so I decided to switch the design over to TDA7294. Yesterday we got the first in-a-box prototype up and running. Here's a pic to whet your appetite :



Probably the most unusual thing about this amp is its power supply, a hybrid of linear (a standard toroid) with a high powered buck regulator. The reason the power supply isn't an off-the-shelf switching brick is because I wanted to avoid common-mode noise which comes as standard with such a choice. I did much of the development work on the buck regulator last year but its still not quite optimized - you may note the buck regulator's output inductor isn't tied down to the PCB because its very much a work in progress. Some of the back story to the PSU is told in last year's thread. I've attached the amp board schematic, there's nothing much out of the ordinary there except perhaps for it being a single rail design and the provision for an external bank of supply rail caps. This prototype has about 85,000uF of rail capacitance per channel by virtue of its two out-board cap banks. Having a buck reg means the soft start is built in so with this amp there can't be such a thing as too much rail capacitance.... 😎

(More to come later)

Hi, what you guys use as insulators for transistors on heatsink ..
Is Mica better then Silicone ( Google says. as W/m-K , some silicone has 1.1 and Mica 0.5. )
Are these good from old power supplies. .?.

I am building a speaker with curved sides using a couple layers of bendable 3/8" birch ply (wiggleboard).

Question #1: What glue is best under tension to attach the bent sides to the skeleton frame? There will be front, back, and 5 pieces horizontal crosspieces, all 3/4" ply. I was planning to use titebond 3 along each skeleton edge to attach to the bent ply, and some screws down each end to hold in place while it dried.

Q#2: for the second layer, i intend to coat the entire first bent panel with glue, and then wrap the second panel. Is the same titebond 3 a good choice for this as well?

Increasing distance to the source of sound can, of course, attenuate SPL. e.g. a doubling of the distance might lose 6dB depending on the environment.

However, I've frequently seen this principle applied to subwoofers in small rooms, and I'm not sure this is correct - certainly it doesn't seem to tally with my past experience. I presume this is because at low frequencies, the room's modes start to dominate; the louder areas are more random and may not even be nearer the subwoofers. Even with multiple distributed subwoofers, the peaks and troughs may be less pronounced but the aim is for more evenness throughout the room.

Am I correct in my belief that listening distance in a small room (say in the order of 5m/15feet square) is largely unimportant, or should I still factor in some distance attenuation when choosing what SPL to design for?

Thanks,
Kev

Hi, does anyone know the bias current for this power amp?
One channel is not hot, the other is very hot

I recently picked up this integrated amp and am planning a full restore. I know the SM is available to download, but taking a shot to see if someone has an original with the bigger fold out pages they don't need anymore.

If anyone has one of these they don't need at a reasonable price please let me know. Thanks!

Hello, I am from Tehran
My setup includes:
Jamo c109
dussun v8i
teac ud301
imac
pcocc speaker cable
diy occ interconnect

I am looking for information to make TDA1541 over sampling with usb to i2s input

I am making plans to bring the plasma tweeters to BAF! I already have a friend in SF who can bring a helium bottle.

I have a number of 'smoldering' questions:

• where will it take place
• need a pair of fast (planar) speakers to provide mids and lows (x-over is at 1kHz) to go with them
• need an amp to drive said fast speakers (gosh. who might have that, I wonder 😏 @Nelson Pass )
• need a good quality music source - either digital or analog as my x-over accepts both

I know it's way early for a venue to be chosen, but I am itching to go!

Tony

Hello there,

I would like to measure the THD, Frequency response, Output Level etc of a preamp and DI that I have made with the help of an Oscilloscope.
Please can you help me how to do it?

Thank you very much.
George

I have a friend that runs a photography class and uses these power supply timers dark room lighting. Apparently they’re quite important to him and he has had some failures of the power supplies. I’ve seen that many others have as well. It looks like the common part to fail is a little switching triac, a solid state relay.




He knows that I am into electronics and that I etch my own boards. he asked if I could build him some new boards for his power supplies using a different device since they are no longer available. You can get them from for China for fairly cheaply, but he knows other photographers that have gone this route and the devices from China are pretty poor I guess. So he was hoping I could redesign it. I see no reason to redesign it, just put in a suitable part. My thought is that they are failing because they use such a pathetically small heat sink for the device. I’m trying to figure out the exact load on these power supplies. I was hoping to get some of the lighting back to my house, but it would require removing the lighting from the dark rooms, which she was hoping not to do. Regardless, it is ready for 12 A at 250 Vac, I would think it would benefit from heat sink bigger than this.



At first, I was thinking a standard physical relay, but if the load was immediate, the arching on the contacts would not be great. so I’m back to a solid state. I’m thinking about just getting pretty much exact same device from a different company rated for either the same or more current and mounting it to an appropriate heat sink. There is plenty of room in the power supply case for a substantial heat sink. I don’t want to mount it to the case of the heat sink since it has line voltage, but it’s easy enough to isolate the heat sink from the rest of the chassis.

Similar to this
https://www.digikey.com/en/products...nduYfIIAt9b30ioSpvswMA3aq_YbhqdRoCQPsQAvD_BwE

But being $37 I was hoping to find something a bit less expensive. We were hoping to repair a total of 15 to 20 of these power supplies that are used between him and a couple of his other photography friends. so kind of just reaching out to see if maybe anybody is familiar with these types of devices and can point me in the right direction.

Thank you,
Dan

Looking to source original/real AD1862s times two. If I can find them I'm considering a build of Miro1360's DAC.

Regards,
Dan

Hi all:

I recently came across a Nakamichi Sound Space 12 sub and satellites. I want to test the sub to see if it works. However, it has a 12v DC jack on the rear to get it turn on, and I don't have a receiver or any other component with a 12V trigger jack function.

What's the easiest safe way to trigger that thing to turn on? I've read that you can't go beyond a certain current limit on a trigger circuit, or you could damage the components.

Let's assume I have extremely little understanding of electronics.

hello all just acquired a yamaha b-2 no sound. i am trying to sell it as i dont have a tech near me i am including a 1000w step down transofmer i wish i could get it fixed but no knowledge nor techs in my area of florida. will ship. turns on. im in the florida panhandle area. looking to break even at $500 for all.

Proud owner here, as of last week. I threw them up onto a pair of table leg stands, just to be sure they're OK after shipping, as a Saturday morning effort. They are.

I'm quite happy with the sound. Now, I need to mount them on an OB design of some sort. Any assistance would be much appreciated!

I was casually thinking I might replicate Decware's "Betsy" design and would like to understand why the "barrel" shape works. Caintuck Audio, the originator of the Betsy, also offers "tombstone" style baffle boards with parallel sides.

Lucky for me, there's a Washington state surplus store very near to where I live, which has tables, desks and other MDF based bench-tops at very inexpensive prices. My plan is to pick something up and start cutting. If I'm lucky, there'll be two of something I could cut into a Betsy, or something with parallel sides I can simply trim to height.

The typical desk or workbench top laminate - my worry is how to get a clean edged, say, 16" circular cut in something that may be 2" thick. I like the standing mass of a baffle like that, but I dread trying to make such a cutout with something like a Sawzall. The Decware speaker mounting is flush with the baffle surface - looks really nice - However I assume the only way to do that is with a router...

Hopefully I'll be choosing a couple of hunks of material to work with this coming week. I could have got a pair of matching 6' diameter 2" thick tables - which would have easily yielded a pair of Decware style Betsy Baffles - for $5 each. I couldnt have lifted them atop my Subaru forrester if I wanted to. What practical width should I be setting my sights on for this 15" and its free air of ~50 Hz?

Thanks!

I’ve ordered my Pluvia 7.2 HD drivers and came across an interesting speaker design. Does the design seem viable? Has anyone built it?

In most of the new cars many of the displays and controls have been moved to a large touch screen and the traditional items removed. In the Telsa Cybertruck that has been taken to an extreme and except for a few things on the steering wheel everything has been moved to the large display. Here is a picture:

https://www.motortrend.com/reviews/2024-tesla-cybertruck-foundation-series-interior-review/photos/

Instead of being able to control things like heater, air conditioner, radio, etc., with a single button and motion you now have to first manipulate several steps on the touch screen to get to the item you want to change.

So are the new designs for the better, or do they in some way compromise safety?

Hi folks!

I am fooling around with Altec speakers, and trying to run the 808 8a + 511b horns with 416a / b style woofers. At the present time I do not have any questions regarding the HPF and horn correction circuit; I am hoping for some basic design input in the spirit of "look this direction".

At the encouragement of an engineer friend, I am learning to use LTspice. The following screenshot shows the Z19 / Altec Model 19 LPF. Top models use TS parameters associated with the 416Z (0.567 mH VC inductance / 11.6ohm series resistance) -- bottom models use the 416B (2.5mH / 6.5ohm series resistance).

In both screenshots, the bottom model represents the LPF circuit with the intended 8 ohm woofer. My intent is to create a model for a 16 ohm woofer which corresponds to the frequency filter response with the 8 ohm woofer.

First model, with matching crossover values:


With matching XO values, I get:
Top: 416 Z (16 ohm nominal): -6db @ 1.130 kHz
Bottom: 416 B (8 ohm nominal): -6db @ 1.330 kHz

With capacitor value doubled and inductor halved for the 16 ohm nominal speaker, I get this:


Top: 416 Z (16 ohm nominal): -6db @ 1.180 kHz
Bottom: 416 B (8 ohm nominal): -6db @ 1.330 kHz (unchanged)

I realize that I am a newbie and generally speaker crossovers are regarded as EXTREMELY complex, so I am not looking for a silver bullet. Does anyone have some math or anecdotal suggestions? What could I try next?

EDIT to add: I realize I am only using two parameters to define an inductor and there must be significantly more sophisticated ways to do this, and I'm learning as I go!

Hi everyone!
I am an audio enthusiast, and this last year I have been getting more and more into this world, specifically in box design. I don't have many tools to measure different things, such as the Thiele-Small parameters, which I was able to measure on my own with a circuit I made. But over time, I have realized that I need more tools to be able to reach the objectives I want, such as a calibration microphone. The problem is that I do not dedicate myself to this, nor do I plan to do so, at least not for the next few years, so I am not going to buy tools as expensive as a UMIK-1 or UMIK-2, or the Dayton Audio DATS V3 , since I don't have the ability to buy things at that price either.

My question is if there are cheaper options, specifically for the calibration microphone, I would like to have one. And if someone recommends other tools that could be useful to me, and that are not very expensive, I would appreciate it.

Hello,
Following Bonsai constructive comments and advises,

Ref.:

1. https://www.diyaudio.com/community/...as-a-small-sizzling-sound.411503/post-7659500
2. https://www.diyaudio.com/community/...as-a-small-sizzling-sound.411503/post-7660158

I redesigned my DIY Amplifier PCB. This is the same schematics as threads :

• A Lateral MOSFET Power Amplifier Design (second try)
• My DIY Amplifier has a small sizzling sound

with the HBR resistor added, and a totally new traces strategy.

• I removed all tests points except TP3, now renamed TP1
• I moved the DC Servo closer to the IPS.
• I made Rails connectors closer to each other.
• The BIAS Spreader is closer to the VAS
• I minimized the ground loop area at the IPS
• I passed the +Rails and -Rails in folder view with their respective own ground traces under them, on the other side of the PCB
• I kept the Signal ground return track close to the feedback track to minimize the possible ground loop, I also kept it without nothing connected to it.
• I added the 4.7 Ohms HBR resistor, close to the input.
• I put the speaker output at the very end of the traces.

I'd like to share the schematics and the new PCB captures for your comments. I am very open to any comments or advises from every ones...

My bests regards and, thanks in advance...
P.S.: Schematic attached below in PDF format.

01-Ground Components Side highlighted



02-Ground Solder Side highlighted



03-Rails Traces over respective grounds (grounds highlighted)



04-Ground Loop Area



05-Silkscreen on top

06-Silkscreen and Ground Loop Area

07-3D View-Top

08-3D View- Iso

Hi Guys,

I've built a P3A using Rod's boards, standard parts etc.
https://sound-au.com/project3a.htm

+/- 34Vdc rails
2SA1973/2SC5200 output transistors
KSA1220/KSC2690 drivers and Q4
BC546 Q1,2,3 and Q9.

The right channel is behaving normally.
The left channel isn't.

My dummy load is 4x 16R 100w resistors in parallel for 4.3R as per my DMM.
My scope is a Instrustar ISDS205B cheap and nasty USB jobbie.

My first test on the problematic left channel had 3Vrms on the output of the amp. After something like 30-60s the 3A fuses on the supply rails blew.
And the heatsink was pretty darn warm.

The 2nd test was going ok, same signal, same 3Vrms on the ouput, the supply rail fuses didnt blow. After probably 60s I saw a little puff of smoke come from somewhere around Q6/Q9. I didn't see any damage, I think it was the cable tie coupling q6 and q9 together beginning to melt.

After this I learned that I can only do short bursts of testing if I dont want to start replacing transistors.

I performed a few more short tests and took some screen shots to digest whats going on.


Right side 1kHz sine wave

Left side 1kHz sine wave.


Right side 1kHz square wave.

Left side 1kHz square wave.

There was also another square wave test on the left side that I did not get a screen shot of, that looked like this.

Forgive my crude MS Paint work. With my limited understanding this would be full scale oscillation.

This was a purely resistive 4R load, no capacitance in parallel.

So if I am not imagining things, I have a rather unstable amplifier that needs some love to get happy.

My first step is going to be to remove the board from the heatsink and give it a damn thorough eyeball to check for any mistakes, bad joints etc.

Assuming I don't find any construction errors, it seems to me that the next step would be to perform the same square wave test and do some probing around to see if I can find where the oscillation starts.

I'm looking at building a DAC based around the 8-channel ES9039. One of the features to boost performance is combining the channels, which I would do after the output stage i.e. the op amps.

I'd like the flexibility of having all 8 channels, but there could be occasions where 4 channels would be enough, in which case I could make use of the unused channels by combining pairs of channels together.

Some of the ESS evaluation boards achieve this effect using headers and jumpers, but to be useful to me I'd want to be able to use a switch/relay of some sort. I am, however, cautious of adding anything in the way of the signal path. Would the performance improvement of combining channels be reduced by adding something like a relay to the signal path?

Hi all,

I made a separate PCB for the Delta Sigma Modulator by MarcelvdG shown in the
https://www.diyaudio.com/community/threads/valve-dac-from-linear-audio-volume-13.308860/

Thanks to Marcel for this project.

It is intended for Trenz TE0630 LX45 and LX75 FPGA modules.
This module is easy to program via USB and the Trenz application:
https://wiki.trenz-electronic.de/pages/viewpage.action?pageId=10620253
This module must be configured by shorting R102 pads on the FPGA board.

Actual LX45 configuration file see:
https://www.diyaudio.com/community/...r-audio-volume-13.308860/page-76#post-6569767

Actual LX75 configuration file see:
https://linearaudio.net/sites/linearaudio.net/files/additionaldatavalveDACversion2p1.zip

The FPGA code contains a sigma-delta modulator that has three modes selectable by switches.
Similarly, we can choose a filter.
You can read a lot of information about this modulator in the document:
https://linearaudio.net/sites/linearaudio.net/files/03 Didden LA V13 mvdg.pdf

Additionally, I included some information in the schematic.

This version has only I2S input/output.






I put schematic, boom and gerber files.

Hello world from Belgium.

I was graduated in digital technologies in 1982 and worked in Information Technologies. I'm now retired and as an audio enthusiast, i plan to discover the Tubes world.

My knowledge is only about transistors and Ic's ! I've made and repair some solid state amplifiers, mixers and speakers.

I subscribed a long time ago to find informations. Thank's to all

Greetings

I have an ESI 250-DA Impedance Bridge for sale. Great condition and functions perfectly. I picked a different Impedance Bridge and do not need two. Has a newnpower cord and new 9V battery connector. Heavy, but will package well. See photos.

Asking $50.00.

PM if interested.

Thanks

I have one Tektronix TM504 housing that I am no longer using. Very nice shape and works properly. Heavy, but will ship and pack well. Ships from Zip 17404. See photos.

Asking $75.00

Please send me a PM if interested. Thanks

I’m thinking of a 165w rms per channel amp for midbass. Mid bass specs narrowed down to either 100w rms to 200 peak or 120w to 170w peak. So pretty similar. Does an amp usually have more power? So 165rms means it can burst 200w no problem at all. Just wandering about a general rule of thumb might be when looking at amps. That a 165w rms amp channel can burst to 1.5x power no problem. So need to match amp rms to peak speaker handling. Thanks.

I been working for the past 2 days on this amp, I found 2 op amp circled with red in my photo that does not have power supply. It is in the front of the drive circuit. All op amps are all supplied except on these 2. If I can make it working then I believed output will.come. Furthermore because of its thick brown coating tracing backwards is very hard, for the traces are not visible. I did not find any diffective diode or parts either in the power supply section. Does anybody encountered this issue or does somebody can share an schematics diag , I will appreciate it much.

Hi all, I have a newbie question about the power supply for Purifi amp module.

I am thinking of building a linear power supply for the amp as I have a spare toroid transformer lying around (removed from a dead amp).

Now the issue is that the transformer has 4 x 50V (6A each) secondaries instead of 65V. Are there any issues with using 50V instead of 65V for the power supply?

After many years of using Windows laptops I intend to transition to a current model Macbook Air as my digital music source. I now play WAV files from my Windows laptop to a DAC then into an amplifier. I have a few questions for anyone with experience using a Macbook Air as a source:

1. If you play local files, what format do you use? I’m thinking about converting my WAV files to FLAC which would reduce my current total file size from 116gb to around or 70gb.

2. What music player app do you use for local files and streaming? I have used Foobar2000 and Jriver Media Center 31 & 32 and with Windows and have been happy with both. Just wondering if there are any other players for Mac OSX to consider.

3. Can the DAC/headphone out be set up to use as a DAC with line output? I have read elsewhere that the current Macbook have a very good DAC/headphone output. I’m just wondering if I could do away with a component here.

4. Does the Macbook have a Bluetooth output comparable to something like Aptx HD?

That is all I can think of for now, I may have more questions as comments come in. As always, thank you in advance for your advice!

Rick

Macbook Air

Beginner question for a schematic. I'd like to make a variable constant current sink so I can simply dial-in milliamp loads from 10mA to 100mA on the bench when testing power supplies for tube amps. I think in the industry they call this device an "active load" or something like that, anyway they are very expensive. In PSUD you can load your simulation with either a resistor or a CCS (in diagram below), that CCS (in yellow) is the thing I want to build for my bench. It should handle voltages from 90 to 450 volts and sink whatever current you select from 10mA to 200mA. I know I can simply use big resistors on the bench, but to land at the load you want you have to have that resistor on hand for the voltage you are targeting, then you have to do ohms law with all your spare big resistors you do have to get close to the mA you want. So I thought there must be a way to simply build a current sink where I can dial in (or rotary switch) to the amount of current I want to draw from the power supply under test. Can I simply do this with a MOSFET and a 500 ohm rheostat wired source to gate to self bias the FET as a CCS? Then make a paper vernier dial of the currents I can dial into, put it in a box and done. Or is this a bigger project? Has anyone built such a device here that will cover the voltages and amount of constant current I want to present to the PS DUT? Thx.

Estoy en un proyecto de un sistema de audio DIY con altavoces reutilizados, por lo que he tenido que medir todos los parámetros de los altavoces por mi cuenta, pero hay un parámetro que no he podido medir... Watts.
Los watts máximos que soportan mis woofers, y es un gran dato que necesito saber con qué fuente amplificar el sistema sin quemar mis woofers.
Entonces estoy buscando una manera de medir esto, por eso vine aquí, para ver si alguien me puede dar una respuesta o recomendación.

Moderation Edit. Please post in English.

I'm in a DIY audio system project with repurposed speakers, so I've had to measure all the speaker parameters on my own, but there's one parameter I haven't been able to measure... Watts.
The maximum watts my woofers support, and it's a big fact that I need to know which source to amplify the system with without burning out my woofers.
So I'm looking for a way to measure this, that's why I came here, to see if someone can give me an answer or recommendation.

Click to expand...

Hello everyone,

I am making a trial 12V DC power supply with a transformer, and choke I already had and some salvaged capacitors from an old defunct project - so no investment apart from some diodes, really mostly for learning.

I have not yet got back my old 15V transformer that a friend is using so I found an old one wall wart 15v to start to understand and explore.
Well this is the current circuit I am 'comparing' simulation from measured

(for my real 12VDC I am going to build I will use the twin 0-15 transformer I have in series to give 30vAC I think to be able to get the noise down, according to simulations)

The current draw is 340mA Anyway this is the circuit and below is the measurements from an oscilloscope on DC and AC coupling.
The crazy thing is in actual measurement that last filter ADDS NOISE!! and the overall noise is way off e.. VC2 27mV predicted and 232mV measured?


Any thoughts?

VC1 17.1V DC and 5.3v p2p
VC2 13.5V DC and 232mV p2p
VC3 8.86V DC and 720mv p2p

I'm getting close to having my system dialed in, which brings me to the final frontier: tuning my room.


my listening room is in a smallish, 1500 sf condo and comprises my kitchen, living room and dining area. The room itself is about 16" x 24", the seating area where my system and sofa are is about 12w x 10" deep, with the dining area directly behind it and the kitchen to the left, as well as the main entry. I don't hear any prominent echoes when I clap my hands or snap my fingers, but the spectrogram tells a different story.

further complicating matters, the blank space above the credenza is a projector screen, so it can't be easily treated and the wall to the right is irregular and approximately 60-70% windows, with sheer curtains and blackout shades. how may I best treat my room to reduce reflections? my speakers, which resemble Klipsch LaScala, have passive radiators mounted on the back of the upper horn enclosures, extending the bass to 23Hz- intuitively, I'm thinking bass traps and diffusers behind and above the speakers and heavy rugs in front of the speakers; am I on the right track?

would mounting diffusers in the RH corner and above the L speaker, such as the one below, help?

I could also install bass traps directly behind the speakers. Unfortunately, we rent, so treating the ceiling is not an option and WAF is also a consideration, as are budgetary constraints. That being said, what are the best bang for the buck options, assuming I have more than adequate woodworking skills (I'm a master carpenter and former cabinetmaker; I engineered and constructed my speakers and make my own furniture).

Hello. I have already Bliesma T34B-4 and my brother have SB MW19TX-8. Can I do an interesting project? I need suggestion about enclosure, crossover, crossover point? I'm asking for advice. Konrad

Amp powers up and idles at 20 amps of current .

Amp works besides the idle current is way to high .

Any ideas on this ? Do I need to adjust the bias or idle current ?

Dave Sanborn, one of my favorite saxophonists , passed away.
This NPR writeup does a very good job talking about him.
RIP Dave, you will be missed ...
😢

Hi all,

I want to make simple speakers or install existing speakers for a garage. The garage may be 30 feet by 300 feet with high ceeling.

Any recomendations it will be used for a bluetooth source.

If cheap I would like to try large woofers.

Thanks,

Walter

hi

i am looking for CHEAP and powerful amps.

most seem to be WAY more expensive than car audio amps. i need the amp to handle 1-2 ohm impedance and built in hp filter would be absolutely great since i will run subs on it.

i can get a 12v fullrange mono amp for 290 euros with 3000wrms in 2 ohm impedance, for example. can you match this with a 230v amp?

A full set of 8 Ohm tweeters and 4 Ohm midrange from the Optimus range of speakers from Tandy/RadioShack from the 1970s.

Optimus were Tandy top of the line speakers, as most of you would know this combination was used in both the Optimus 5B and the Nova 8.

The Midrange are 4 Ohms and must be used in a series connection, this is the green wire

Complete with back cups and all the original wires with crimp connectors. Also included is the original polyester fibre damping material and as a bonus some long fibre reprocessed wool. Postage extra at cost

Speakers have been tested and all work. But they are vintage so I cannot guarantee them long term. Being small voice coils power handling is limited; especially if you use first order crossovers
Just listing for interests sake

Advertised elsewhere for $100- feel free to make me a more Realistic offer
Postage at cost only but pick-up in Geelong OK for forum members
Box will weigh 3 kilos with all the padding and packing

Just sold on eBay for the asking price

Brand new Sure Electronics Wondom class D and T amp modules. Never used.

2500 watt @2 ohm $150 for the pair

Two 2x150 modules $65each

Two 2x100 modules $50each

Shipping included in the usa. Will ship worldwide, contact me for details

Hey everyone.
I’m the new proud owner of a nice NOS set of 806-8A, 811B horns, and 416-8A Altec’s. So now I need the Brain Trusts help in deciding on what cabinet to build for them.
I’d like to keep these in the 4-6cuft range and also would like to run the horns free air exposed sitting on top. So what would you guys do? Iconic style or Valencia with the horn on top?

As far as crossovers should I just grab a pair of the GPA N1200-8c and call it a day or is something else needed.
Amp power isn’t a problem from my Yamaha AS2200. I’ll also use digital room correction to extend and smooth out the frequency response.
Should I plan on adding super tweeters?

Basically if these showed up at your door what would you do?

Thanks.

Hello, I need to limit the input signal voltage in my TPA313 amplifier within the range of 0V to 5V, and since the input has an offset of 2.5V, a 4.7V zener is perfect for cutting off signal peaks almost symmetrically beyond ~5V and ~-0.7V. In practice, it works, but the TPA seems to enter some kind of loop every 2 seconds: with no signal applied, it works correctly for 1s, the next second there is a snap, where the speaker membrane remains tense and still at its maximum height without any sound, including noise.

Where am I going wrong? Or alternatively to a zener, what could I use for the same purpose?

The zener is placed with the cathode to RIN+ and anode to GND. There is a 100R resistor between the input cap and the preamplifier.

Grazie.

FS: TOS 2SK2013/2SJ313 and Renesas K1058/J162

I have for sale Toshiba 2SK2013/2SJ313. I ordered these from a supplier in Japan. They were made in late 2011, probably last production run by Toshiba.

Price is US$4.5 per pair (K2013/J313: 1 piece each)
Shipping is flat at $6 by registered airmail from Bangkok, Thailand.
Payment is by Paypal only.

Sorry, no matching service at this time.

this is a power traffo using a 2inch center leg stacked to 3 1/4 inch DEECO silicon steel (noss) irons..
specs are as follows:
primary: 220 volts 60hz.
secondary1: 250volts at 2amps.
secondary2: 100volts at 0.5amps
secondary3: 12.6volts at 10 amps
secondary5&6: 6.3 volts at 3 amps






completed, there are 3 chokes sitting on top, 1/2inch, 5/8 inch, aqnd 3/4 inch.


testing prior to dipping in polyuretahne varnish


line voltage:


magnetizing current:


unloaded core apparent power:


actual unloaded power in watts:


power factor:

Hi everyone,
I’m a new member but I’ve been lurking for a while just reading. I started out here wanting to do a wolverine build and ran short of time and the necessary equipment to get started (no bench power supply, scope died), so decided to start rebuilding an old NAD C372 to get into the groove of things and give me time to accumulate the right tools and improve my general knowledge, before tackling the wolverine in the near future… I’ve now got the bench supply on the way and was thinking about posting a rebuild thread for the NAD amp… hope to enjoy my time here and contribute something useful if possible. Thanks for the great forum!

Hey All,

Have been lurking here for a long time usually just absorbing info on 2ch audio. Currently looking to share ideas on component matching and good value setups.

Cheers
Dan

Greetings and glad to find this Forum.

Im in the middle of a project, renewing a pair of MB Quart 1002 S from the ground up.

Just finished the new Crossovers and its ging good but maybe there will come a point were im glad to discuss or need a little help.

Cheers

An old audiophile friend of mine, who is somewhat extreme in audio occultism lol loves to pot everything. Anyway let's not get into that(!).

I'm in the process of soaking this preamp he gave me in a chemical bath for a week or so. Just because I wanted it clean and ready for future projects.

The only way of reversing this potting solution mess is chemical baths followed by tiny holes drilled into the potted layer then a final soak in super glue remover for 78 hours.
Sadly some damage is inevitable, the odd snapped resistor or diode here and there.





My question is does anyone recognise this board? It has a Chinese phone number and "designed by Wu Gang" on the board. I want to find photos of the original board online so I can get a better idea of the component list (board scratches sigh...).



A schematic would be amazing however just some products photos would suffice.



I know this one is a real longshot but I would be extremely grateful for any help with this preamp.

There's some Muse caps here, it came pre-built from eBay (eBay I think), and with a blue potted/cased tranny on a small power supply board with single fuse holder.

Happy to be here.

For graduation I bought my son a Yamaha HTR 3063 receiver and two Tannoy pbm 6.5 speakers for $100 and added to them a mint Kenwood KD 2000 turntable I got for free from someone at work and ever since have become obsessed with building my own budget system that sounds just as good...

Schitt Audio has a preamp that is intriguing the FREYA+. It uses 4 6SN7 tubes. But here's the kicker... you can optionally purchase 4 "solid state" tubes. What are these? Well I assume they would have to be solid state circuits, in a bottle, with an octal base, that simulates the transfer function, curves, mu, rp, etc of a 6SN7 tube? So the circuit still thinks a tube is in the socket. Is this cool or what? Has anyone seen this concept used before with anything other than the old silicon rectifier substitute's?

Does anyone have a schematic of what solid state circuit might be fitted into an octal bottle to precisely impersonate a 6SN7? I'd really be interested in such a circuit that can be a plug in replacement of a tube, for study and interest.

https://www.schiit.com/products/freya-n

Looking to recap this amp. Anyone got recommendations for better replacements? Thanks 🙏

Hey there everybody,

Curious who ended up with the stock of RCA MI-9449 cones that auctioned a few years back? They were selling in lots of 60 cones at 4.5k, I'm not that loaded so I just watched 'um sell... I need a pair - but if I can afford it would like to buy 4 or 5 pair and have a lifetime-ish supply. Idk what's a good offer, you tell me:



I'd also like to find a pair of this style of binding post, for restoring an RCA woofer which is missing them:





I would also like to identify any other manufacturers that used this piece of hardware, so if you recognize them & their cleanly-machined square slots, and would like to share the knowledge of the other possible sources (I.E. I'd like to part them out of a cheaper driver), I'd greatly appreciate that information... I could try to info-trade, I sourced a replacement basket from a cheaper driver as the donor...

Please excuse the cat hair visible in all three photos. The culprit:



Cat hair yes, but mouse poo, no. Everything in life is a balance of positives and negatives...

I am trying to make a power supply for a microphone preamp.
I have a transformer with a 12V AC winding and I would like to obtain 48V for phantom power and something around 12V to power relays, LEDs and a vu meter buffer.

The first approach I tried uses a voltage multiplier which produces effectively the desired 48V, and a bog standard 7812 section for the other rail.
The two circuits work well independently, but not if they are connected together to the same transformer winding.
It looks like the diodes in the multiplier and the ones in the bridge rectifier are interacting between each other creating some undesired current paths.

I have tried another circuit borrowed from a JLM power supply and in this case the two sections work well together (I guess it's because C1 and C2 provide isolation between the two rectifier sections) however despite the schematic claiming you can get 48V from a 15V AC transformer winding, my transformer which in fact outputs 14.5V AC (it's rated at 1A so the voltage is increased with no load) can only produce max 36V DC on the output.

I am looking for any suggestions on how to modify any of these two versions to meet my requirements, or by all means if you have an alternative circuit to suggest for this application.

So after my TDA7294 amp finally getting done with all the mods and options. I am now moving onto my P3A design. Full credit to Rod for his contribution to the DIY community.
So I purchased a few PCBs that are available to me in my country. Some are better than others. But all work.

My problem now is do I follow the values provided with these PCBs. Or do I follow the original design.
So far I have listed out the key areas of difference. I have then started to try each change one by one and see what sounds better and measures better.
But this is taking way too much time. Ideally I would like to just create a Simulation model. And keep changing values and seeing the results. Being new to Spice I can create the modell. But where I get lost is what parameters or commands would I need to monitor in the simulator.
If a spice expert could give me a starting point or list off commands to give spice.

I am attaching both schematics. The OG Rod vs the one I got with my local PCB.
In particular I'm curious about the value difference.
(When I first built this I kept blowing transistors. Then I had a lot of distortion).
All these problems were caused by fake components. The BD139 BD140 and main drivers were fake. One batch just failed. The other had a lot of distortion. No matter how bad the PCB is with the right components. This design just works.
The key areas where there is a huge difference in recommended values.
1. R3 / R39 = 470 ohms on Rods R6/R7=560 Ohms (I used 505.12 Ohms).
2. C2/C4 220uf/47uf on Rods C3/C5 100uf/100uf
3. R11/R12 = 220ohms on Rods R11/R12 100 ohms.
4. BC547 vs BC546 the implications. And I landed up using 2n2222 why because it sounded the best of all the ones I had on hand. Maybe psychological. lol.

There are a few other differences between the two schematics But I want to get to grips and understanding these 3 to start with.
If nobody responds. My backup plan is to just try both options measure noise and power output and just pick the one that sounds better to me. Im just curious were these values changed because they proved to work better or for some other reason.

pick up only in 91320 California.
misc heat sinks, electronics, pcb's. nothing special, but excellent material for someone that is into Pass diy.

i have set the bias on both Channels to 600mv
and set dc offset on Channel 1 to 0 mv

problem when offset stays at 267 mv when the trim pot is turned to maximum on Channel 2 ?

Mr Ohashi's Blog July 1, 2024​

Translated by Google translator...

Silent Majority​

July 1, 2024
It has long been said that a ramen shop that 5 out of 10 people think is delicious is a very successful shop. In other words, it is impossible for 10 out of 10 people to think that the ramen is delicious.

I happened to be talking to a colleague today, and he told me that he was very depressed after seeing some nasty comments online. In this day and age, it's said that everyone is a critic, and if you do an ego search on social media, you'll find a lot of nasty, negative comments, but personally, while I accept those opinions, I don't pay much attention to them.

The reason we have been able to continue this work for 26 years is because of the presence of the silent majority (the majority of people who do not like to speak up) who support us, and because of the trust and gratitude we have from our users.

For example, there may be some customers who say "I don't like the taste of this restaurant" at the register before leaving. However, worrying about that and losing your individuality is a bigger loss. You can just look forward, knowing that your restaurant can continue today because there are customers who come to your restaurant without you having to say anything because they "like the taste of this restaurant."

Just as other people's faces are different, the taste of ramen and the sound of audio equipment are also infinitely different. Since they are made by different people, there is no way that the taste (sound) will be the same. Moreover, with audio, multiple devices interact in complex ways to create the final sound, so even if the device you happened to choose doesn't produce the sound you like, we should understand that there are various factors and backgrounds behind this.

For example, a customer came to listen to the headphones today. He brought his beloved Marantz 7 original and McIntosh MC240 in the rain. Both are in very good condition and in perfect condition.

Using the 4344 listening room, the demo units SV-310 and SV-8800SE were used for comparison, and by changing the order and combination,
a total of four different sounds were enjoyed.

Even with the same combination of vacuum tube preamplifier + multi-electrode tube preamplifier, the sound output is completely different. With the

Marantz + MC240, the mid-bass region is emphasized, giving the sound a full-range sound with a large grain. With classical Tutti, the sound is a little rough, but it is very attractive in terms of density. With the Marantz + SV-8800SE, the high-frequency overtones are added, giving the sound a sense of spaciousness and fine grain, but depending on how you listen, you could even say that the Marantz feel has been diluted. The frequency response of the power amplifier is more than three times different, so the balance of the sound's dominance has changed significantly.

Next, with the SV-310 + MC240, the elasticity and bounciness of the low frequencies add to the dynamism of the music. If you don't mind a somewhat monochrome, sour sound, this may be the best combination for old jazz.

The last combination we listened to was the SV-310 + SV-8800SE, which many people actually use, and the customer said, "This is the best match." To put it in a positive way, you could say that the richness of the SV-310's sound and the flexibility of the SV-8800SE are well blended, but some people may find it too straightforward and uninteresting (sound source).

...As with anything, there are two sides to the same coin. Where there is light, there is always shadow, so it is only natural that evaluations will be completely opposite depending on where you focus and how you feel. Chefs and audio retailers like us do not follow recipes written in a recipe book, but rather believe in our own sensibilities and techniques, so I told them that there is no need to be overly confused by the rare loud minority (a minority that wants to loudly express negative opinions).

It's okay if there are people you don't like... but rather, please take care of the fans of your amplifiers, I felt like I was telling myself that today. We just have to quietly believe in the majority of people (=Silent Majority) who don't like to speak out and continue to make things honestly today... that's all we can do in the end.

I hope im not breaking any rules posting this here. But i wanted to let people know. I know fakes on Ebay are common but my seller feedback will confirm that i have genuine Toshiba parts.



https://www.ebay.com/sch/i.html?item=126478127702&rt=nc&_trksid=p4429486.m145687.l2562&_ssn=jsaarl

Edit: i made a mistake in the post title. 2389V should be 2sk389V. I also have some 2sk146V for sale

Hi all, I want to build a tape delay unit from scratch. I was just wondering if anyone could suggest a simplish circuit to generate and inject the 100khz signal to the record head.

I would like to use transistors but if there is a much simpler way to do it with an IC I am all ears. Any suggestions appreciated!

Just joined today (7/1/2024). High end audio has been a hobby of mine for many years as well as restoring older equipment. Mostly just plan to see what people are doing in this area these days.

hi what changes can i expect if i increase the cab size of a sealed speaker - cabs are built the same ?

I used to be an EE, then became a dentist, and as of last year, I'm retired. I used be do a lot of DIY and looking to get back into it.
Current system is older stuff- a TEAC VRDS-20 CD player, Squeezebox Touch, Krell KAV300i amp, SVS 3000 Micro sub, and Kanton Ergo 22 DC speakers.

I recently recapped the Canton speakers, and I'm 95% done with a recap of the Krell amp.

Blog page on the Kantons here: https://drmrehorst.blogspot.com/2024/06/another-recapping-project-canton-ergo.html

There will soon be a blog page on the Krell recap - waiting for a few more parts to come in.

I've been out of pocket for health reasons for a while but all good now. I finally got around to swapping out the resistors that were overheating in my stereo version and swapped out the PS caps with new mallorys.
The amp performs like a champ except for one thing that was also an issue with my universal tiger mono versions back in 1975, a faint 60 cycle buzz that can be heard in between tunes if preamp volume is at a relatively loud volume. Is there any grounding changes that could/should be made to the amp that might help in this respect? It's still got the original no-ground non-polarized cord cap but I'm assuming with the inputs and outputs being grounded to chassis that going to a earth grounded cord to chassis may not be advised?

Hi, I'm Ron, from Interlude Audio. We've recently launched an analog HAT for raspberry pi and we're about to launch our digital HAT. We plan on making more mainstream commercial products as well, like DACs and smart amplifiers. We like the diy space and are wanting to create for the diy audiophiles out there too.

Let me know if you're interested in our brand. I'll be posting info about our two HATs in the Vendor Bazaar.

PA150 LM3886 pcb with all components to complete now with Jantzen input capacitor for sale:87€
IC's are new and are not applied on the pcb,like main capacitors,power connectors and SMD output resistors
the other components are already assembled, with genuine components,like on the second picture.
Machined Heatsink with the machined copper hardware and ceramic pads can be supplied the cost is 68€,
It is available for purchase in another listing.
DRV134 and gold plated pcb can be supplied if requested cost is 16€
I have also power supply pcb's for who want one model the power supply can be used for powers up to 400watt
and the other for powers up to 800watt, power supply partial assembled as example.
More than one set available
Tracked shipment to European union
Skematics sended together with articles.
If you are interested in this kind of stuff check here:
https://www.ebay.de/usr/dialedinmusic?_trksid=p4429486.m3561.l2559

Hi everyone,

Over the past 10 years I have learned much from DIYAUDIO.com and it's members. You have been great and I truly appreciate your support. Special call out to Frank, Andy, Bela, Alexander and the gentleman of hi-fi, Rod Coleman. Your support has been nothing short of great.

I am changing my life and as such, selling off my remaining DIY audio inventory. Hoping to find good homes for these products. All products come with a 5 day return policy (less shipping).

Here is what I have available. Let me know if you have questions or need photos. Accepting reasonable offers. Prices listed below, with the exception of the Muse Coil products (please email for pricing - banpuku@mac.com)

Thanks, Pat


Muse Coil Transformers and Chokes Minotaur Series (used unless otherwise noted)

2 x power transformer: 0-120-125Vac primary; 550-440-275-165-0-165-275-440-550 @ 50mA (10mA extra headroom). (please email for pricing - banpuku@mac.com)
2 x power transformer: 0-120-125Vac primary; 800-654-580-0-580-654-800 150mA & 130-0-0-130V secondary #2. (please email for pricing - banpuku@mac.com)
2 x L1 choke 30H 25mA 250Vac 23Rdc. (please email for pricing - banpuku@mac.com)
2 x L2 choke 16H 25mA 125Vac 27Rdc. (please email for pricing - banpuku@mac.com)
2 x L1 choke 12H 150mA 400Vac 25Rdc. (please email for pricing - banpuku@mac.com)
2 x L2 choke 7H 150mA 150Vac 23Rdc. (please email for pricing - banpuku@mac.com)
2 x Interstage Transformer 120H 30mA (new). (please email for pricing - banpuku@mac.com)
2 x Muse Coil OPTs: 9.1K - 4/9/16 ohm, OCC + OFC. (please email for pricing - banpuku@mac.com)

Input Transformers
2 x Finemet Input Transformers: SOLD

Slagle Intact Audio filament chokes
2 x 2.5A $90 / pair SOLD
2 x 3.5A. $90 / pair SOLD

Tubes (All NOS unless otherwise noted)
2 x Philips 814. $250 / pair
2 x GM70 graphite plate (100 hours). $200 / pair
1 x Heinz and Kaufman 25T. $75
2 x Eimac 35T. $100 / hapir
8 x 866A. $50 for the lot of 8
2 x EML 20B (200 hours). SOLD
1 x VT-51. $50
3 x Valvo Aa. $150 for all 3

Caps
2 x Duelund Silver/Copper Hybrid PIO 1.0uF. $180 / pair
3 x Russian PIO 50uF. $60 for all 3 SOLD
Many WIMA DC Link. too many to list, email for details
2 x Russian KY-40 0.22uF. $40 / pair
other various

Here is some different measurement equipment, only sale in eu cause of weight
Make an offer..

This must be a noob question but I will ask anyway:

I have an electrolytical capacitor coupled in series. The + side of the capacitor is connected to 6 Volts of a headphone amplifier circuit output.
With a multimeter I measure the other - side of the capacitor: I measure 6 Volts.

I expected to measure a few mV at most, theoretically 0 Volts. Is this normal behavior due to some voltage leakage and the high impedance of the multimeter?

Almost every capicitor I tried shows this. They cannot all be bad can they?

I was unable to identify these boards. Folks in the Tube amplifier forum suggested a Dynaco upgrade kit.
PM me your address. North America only please, to keep mailing cost down.

I'm in need of schematics for a pair of Cello Performance II amplifiers
Thank you

This is the impedance sweep of an inexpensive 8" DVC woofer that was part of a Buyout on Parts Express. Not a bad woofer for only about $10. I am very curious about the apparent resonance peaks so close to the F[s). Here are some pictures of the driver for reference:

Note list. The ANTEKs are NOS. Shipping extra from Atlanta. The 12 lb. Ten Pao is a monster . . .

I started out with this...

https://www.parts-express.com/2.1-A...ooth-LCD-Backlit-Screen-and-IR-Remote-320-636

And I am retro fitting it into the same cabinets as these... basically I am ripping out the original electronics, and upgraded the main speakers to these, https://www.parts-express.com/FaitalPRO-3FE22-3-Neodymium-Professional-Woofer-4-Ohm-294-1100



I got it all working and then started to create a new panel where I will add the display and my own buttons. However, the more I work with the kit, the more I dislike it. The display isn't very good. It's got the string "Music World" hard coded into it, and the bluetooth version is quite low (3.0).

So I started searching for a better solution, and I can't find one. What I am looking for is an amplifier kit with these specs...

• Stereo channels
• Subwoofer
• Decent power (50W a channel into 4 ohm load?)
• Highest quality bluetooth support
• 2 AUX in
• Decent display (i.e. something like https://www.adafruit.com/product/358)
• Remote control

And I can't seem to find anything. So I started thinking... Could I build one? I have pretty good programing skills and have built many a project using ESP32 chips. I've also got good soldering skills and have a basic understanding of electronics. But I need help to fill in the many gaps I have. Do I use an ESP32 as the master controller? I found this (https://github.com/sle118/squeezelite-esp32) that shows the ESP32 is easily usable as an audio controller. But is this going to be high quality? Is it relatively easy to hook the 8-bit DAC built into the ESP32 to an amplifier circuit and will that be of any decent quality? I don't need thousand dollar HiFi, but I don't want poor quality either.

So looking for advice here... anyone want to work with me on this? I was thinking maybe a community project, open source the code and overall design and build it in a way that people could swap in their own amplifier specs or modify the code in creative ways.

Thoughts?

hi,
i just got my hands on four faitalPRO 12fh500 used for 350 euros.
my idea was to build four 15" tapped horns (JBELL SS15) and use my 12fh500 as midrange drivers.

i was wondering, is there any clever design i can do to increase the sensitivity of these? i am running an off grid setup on generators and want it efficient.

my SS15 will have a response curve like this:


some guy sent me this curve a couple of years ago that i saved:


i think he used four 8" car speakers in back of his car. the box looked something like this: https://en.toutlehautparleur.com/midrange-kit-tlhp-tt-112-with-cabinet-kit-and-speaker.html
i feel like that response curve would be perfect for my SS15 setup. is it something similar i can do with my 12fh500 drivers? 1000hz should be high enough to let compression drivers take over the job, right?

Hi Gents, wondering if anyone has some suggestions on a few nice caps for a Bryston BP-25 pre.

It's a lovely preamp! I've sourced the majority of filter caps etc from digikey, but across the signal path there are these 100uF 40v axial bipolar electrolytics. Stock ones are nice, German made, and wondering what I could use to refresh or even improve upon them while doing the rest of the caps.

They measure out 25mm long / 10mm in diameter.

I've been having a heck of a time..

100uF
40v or higher
Axial
Bipolar
25mm x 10mm dia - There is a little wiggle room on sizing / creative positioning but not huge unfortunately..

I was thinking Mundorf E-CAP RAWs. Any of the pros here have thoughts?

Happy new year!

I am selling a clone of the excellent tube amplifier EAR 869. It is characterized by a precise bass foundation with great dynamics/ tested with Sansui AU 111, with excellent results/. Power tubes are PL509 and ECC85 RFT, PCC88 Tesla. All tubes are unused. The input capacitor is from Mundorf. Power 15W in A class. Pl509 are connected Enhanced Triode Mode. Special connection of power tubes. The durability of PL509 is approx. 10,000 hours. Everything is installed in a chassis from Modushop. The 869 includes an input switch and a remote control. Spare tubes are included in the price/I will deliver later/. The price of the original is 7000 USD


Postage included in the EU price

Price 2100€