SpeakerSim - speaker simulation software

Hi.

I have made this speaker simulation software.
It works on Windows, Linux, and Mac OS X (requires Java 8 or newer).
Goal was/is to make simple all in one speaker simulator.

It currently has Bass Reflex, Closed box, Aperiodic, and Open Baffle simulator, baffle diffraction, passive filters, active filters, room simulation, power response, listening window response ...

I hope it is useful. Any suggestions, wishes, or ideas are welcome.

Download

In upstate New York, and getting back to my love of higher-end stereo after 25+ years away. Have had much of my gear from the 80's repaired at a local audio-repair shop. Probably spending more the some new gear might cost. Upgraded my Fourier 6 2 way speakers with a pair of 21" subwoofers to Martin Logan EM ESL's with the subs. This looks like this is a good place to share the passion and get questions answered. Looking forward to exchanging ideas with other members. Bob.D

Can anyone help me?
Cheers

Does anyone know if a decent shaftless trimmer pot than can fit onto a d-shaft pot like this? Just need something reliable I can use for pot position feedback.

I was recently looking at writing a book (to be published on-demand/online--like Kindle Direct Publishing, etc.), and was thinking about how I would afford to enlist the services of a copyeditor to clean up the manuscript. It turns out that independent copyeditors serving micro-published authors are apparently just about to be "out of business", to be replaced by ChatGPT:

https://thejohnfox.com/2023/04/how-to-use-chatgpt-to-copyedit-your-book/

I have to say I'm glad I'm not an independent copyeditor. C'est la vie!

But for those that have been harboring secret thoughts of publishing a book, the costs and logistics are now much lower/easier...and interactive.

Chris

Hi everyone,


I'm working on a 2-way passive speaker build using the JBL 8PW8 8” woofer and I'm running into some trouble designing the right enclosure. I'm simulating everything in WinISD, and would love some guidance from the DIY audio community.

Woofer specs:​

• Fs: 81.4 Hz
• Qts: 0.76
• Xmax: 3.2 mm
• Xlim: 8 mm (from datasheet)
• Sensitivity: ~93 dB (1W/1m)

Design goals:​

• A natural and smooth frequency response (flat if possible)
• No DSP or subsonic filtering
• Avoiding over-excursion in the bass region
• Medium-sized cabinet (ideally under 50L)
• Simple, passive design I can build and learn from

The issue:​

In typical reflex alignments (e.g., 45–50L tuned to 50–60 Hz), I'm seeing severe cone excursion at moderate power (30–50W), especially in the 40–50 Hz range, well beyond Xmax.



To mitigate this, I tried:

• Increasing Fb to 90–100 Hz
• Keeping box volume at around 50 L

This significantly improves cone excursion control (stays well under Xlim), and even makes the port extremely short or almost unnecessary. Mechanically, the woofer is much safer.


But a new problem appears:

• The SPL curve now shows a sharp peak near 100 Hz, followed by a dip and slow roll-off.
• The response is no longer flat or natural, and I worry it might sound “boomy” or boxy.

My questions:​

1. Is it valid to tune Fb > Fs with this kind of woofer, especially considering it doesn’t reproduce much below 70 Hz anyway?
2. Is there a known “sweet spot” for tuning high-Qts midwoofers like this?
3. Would going sealed (~12L) be a better compromise? I simulated one and excursion is perfect, but there's little usable output below 100 Hz.
4. Should I accept the SPL ripple and tame it with EQ? Or is this a sign that the design is mismatched?
5. Has anyone here worked with this woofer or similar pro midbass drivers in home reflex enclosures?

Any help, examples, or tuning advice would be amazing. I’d like to keep this build educational and as clean as possible—something I can trust and possibly upgrade later with a dedicated sub.


Thanks so much in advance!

I found a few NOS Raytheon transistors at an estate sale.
They are labeled as ts59248.
Has anyone heard of this designation style? Maybe military?

It sounds like a weird thing to do, I know. The setup is like this: I have a computer with J.River Media Center feeding both a Yamaha receiver and a car amp running on a 12V psu to a set of speakers on the patio. When I use the speakers that are always there, a set of Polk Atrium 8, I run them on the car amp because there I have a high pass filter set so the bass won't distort. When we have a party I take out a pair of Wharfedale Titan 12" PA speakers made for troubadours and small bands, which can take a LOT more bass and a LOT more volume, so they run on the Yamha receiver (a ten year old top model with lots of power). There is are boxes outside with two relays, switching the speaker plus to either the Polk or the Whartedale pair, so they can never work at the same time. A switch sends 12V to the relays, switching between the terminals. The minus is always on for each speaker terminal.

The problem is switching inside. I could of course use four relays, one pair for each channel on plus and one pair for each channel on minus, but something tells me that's overkill, and that I only need to switch on plus and collect the minus from both amp's left and right channel to a common left and right minus to the speakers. They do have a common ground because the line in is fed to them both. Am I right? Am I even making sense?

Hi everyone. I am one of those guys who really wanted to lean electronics properly but never managed to get by the basics in school. I therefor need a second opinion about some alternations I have made to a Luxman L-215.

I really like the look and the sound of this little amplifier but the one I managed to pick up had the same problem with overheated zener diode as many other have had. Just take a look at the attached images of the heated area around the original zener D112 (HZ20-3) and the back of the board. I also attached a part of the Luxman L-215 schematic (purple = 24V pilot lamp, yellow = zener diode D112, red = resistor R153 and green = capacitor C133)

I followed the advice at this page and replaced the blown 24V pilot lamp with a LED but there are a couple of things I am not 100% certain about.

I measured 23.9V, 112.4 mA before removing the zener and original resistor R153 (300-3) and 44.3V, 15.6 mA when the zener was removed and the resistor R153 (300Ω 3W) was replaced by a 2.7kΩ 2W resistor. That was before inserting the LED (rated 2V 16mA) so I guess there is about 42V over the capacitor C133 (47µF 35V). The guide I was following state:

“When the light bulbs are replaced by leds (that I prefer), the zenerdiode D112 is obsolete and can be removed, the 300 Ohm resistor R153, must be replaced by a 1,5 to 5,6 KOhm 2W type as on the photo, depending on the type leds you use, and then you have the correct power design.”

The zener D112 is gone and the resistor R153 replace by a 2.7kΩ 2W resistor but the text does not mention the capacitor C133 rated at 35V. My guess is that it mainly serve as a stabilizer for the pilot lamp and that it is not really needed for the LED (but this is me guessing). So I desoldered it and the amplifier seems to work perfect without it and the LED also seems unaffected by the removal of the capacitor C133, but I really don't know if its good or bad to keep it or remove it from the circuit.

So this is really my question, should I put the capacitor back in and what about the 42V in that case? Or should I keep it removed and not worry about it? Or should I do something different like add a new zener diode but I guess I then have to replace the 2.7kΩ 2W resistor and put another resistor in series with the LED…

Any second opinions are welcome.

Thanks in advance / Rob

Given all the speakers I'm currently building, I need adjustable speaker stands so I can quickly put them at the proper height for auditioning. Any ideas regarding material, design, construction methods? Structure damping? Isolate the stands from the speaker only, or speaker and floor? (I currently use sorbothane buttons between my stands and speaker, and ordinary rubber feet between stands and floor). Let's hear your ideas!

So this has been a 10+ year project in the making. Kids, moving and other hobbies got in the way but it's back now.

The long and short of it is as follows,

12" dayton horn with 2 sb10pgc21-4 drivers and a sb26 Tweeter per side.
The enclosure is egg shaped, sort of and will have active cardioid dispersion via a single side vented vifa ne265 driver. How you ask? More details to come but I think it's a unique configuration, at least one I have never seen before. Driver mounting plates cut out of aluminium and hot glued on.

Ready to fill the gaps with construction adhesive, i bought the wrong one but it seems to be sticking ok. Horn has been dampened with rubber base tile glue, its a rough job and im not proud but it will be fixed, sort of..Next pics are a jig i used to cut the throat to height and the drivers mocked up in position. I modified the tweter faceplate and am about to glue it to the horn. It will still just guve me access to remove the tweeter if need be.

Hey all,
I’m building a mic preamp to interface a dynamic microphone with handheld radios and smartphone TRRS inputs. I’ve designed the following circuit to buffer the mic and improve audio quality while protecting from RF interference.

Use Case:

• Works with dynamic mics
• Designed for radio mic inputs that supply 2-5V bias through ~2k-4.7kΩ (like Yaesu, Icom HTs)
• Also hoping it’ll work with smartphone TRRS jacks, which typically provide a similar bias voltage

Key justification:
2N5088 NPN transistor for buffering/amplification

• Ferrite beads (FB1, FB2) for RF filtering
• Bypass and AC coupling capacitors (C1–C5)
• No external power supply — powered only by bias voltage from device input
• I am using a M-87 5Ω dynamic mic, outputs around 0.05–0.11 mV @ 103 dB SPL

Questions:
Will this work reliably with radio and phone inputs that provide ~5V through 2.2kΩ?
Is the transistor biased correctly with this setup, or does it need tweaking?
Is the signal level likely to be too low or too high for typical radio/smartphone mic inputs?
Any improvements for RF robustness or audio performance?
Can this safely be plugged into both radios and phones without harming either device?

Planning to build it on a prototyping board. I’d appreciate any feedback, especially from people who’ve built something similar!

Complete kits are now available on my website

What is it?

• The F5m by Nelson Pass in a different form factor
  • Monoblock design, each measures 140mm wide, 160mm deep, and 125mm tall (5.5” x 6.5” x 5”)
  • This design borrows objectives, ideas, and some parts from my ACA Redux development. In short, ease of assembly and cost reduction are the primary focus. You can read more about that here.
• Dual switching supplies for each monoblock creates +/- 24VDC
  • No mains voltage present. +/- 24V is just under the 50V threshold for what is considered touch safe.
• Two of Mark Johnson’s AmyAlice power supply filters are integrated on board to clean up switching noise
  • AmyAlice uses surface mount components, but the pads are large, parts are well spaced, and it’s designed to be soldered by hand with a regular iron. Tweezers are a must, but even something from the dollar store will work.
• An inaudible, slow moving fan keeps the heatsink cool and the design compact
  • Thermal switch for safety in case of fan failure. Fans are rated 80,000 hours (over 9 years of continuous operation)
  • Reduced thermal mass means the amp gets to a stable temperature more quickly.
• All connectors are on the PCB. The only wiring is shortening the fan leads if you choose to do so.
  • Upgraded RCA jack and power switch compared to the ACA Redux.

This kit is for you if:

Complete kits are in the works which will be available on my website, reduxkits.com, and with any luck, at Burning Amp Festival 2024. If you'd like to be notified when the kit goes live, there's an email list sign up on the website, or you can just follow this thread.
I’ve built a few prototypes, sent out a pre-production kit, and am currently working on sourcing the last few items to be able to make kits reliably. The BOM will be posted once sourcing is complete.

Pricing is not yet finalized, but $480 is my best estimate at this time. That’s around $100 less than building an F5m in the 4U chassis with a linear supply.

Thank you to Nelson Pass, Mark Johnson, and all others at diyAudio who share their excellent designs and ideas. I built an F5 many years ago when I was in high school and it's proven to be an excellent and reliable amp, maybe the best I own. So I knew I had to build an F5m when it was presented at Burning Amp last year. I am extremely pleased to be working on my own version and hope I can help bring the joy to even more builders.

A video build guide is now available!
Login to view embedded media

I have built a fair number of tube amps and always used EI OPTs. I seen that Antek sells toroidal OPTs, both SE and PP.

Do they work as well as EI OPTs?

See attached audio file. I recorded this directly in front of the tweeter on my speakers. It's the same in both speakers. Amplifier is an Audio Research D-70 MkII. It does this intermittently. At the time of this recording the amp had been on for maybe 45 minutes. The tubes are all at least 25 years old.

I plan to change from FOSTEX FF85WK+BH to MarkAudio CHN50P+TQWT for TV.
If I use it for a while and don't like it, there will be no change.

in this thread https://www.diyaudio.com/community/...stion-for-integrated-amp.427820/#post-8016107 post 5 by rayma and post 6 by me have disappeared.....

I've posted an evaluation of the J-Box III speaker measurement system if anyone is interested:
https://www.htguide.com/forum/missi...ment-tools-techniques/957531-j-box-iii-review

I picked up this used Bose Acoustimass 10 IV speaker system. Speakers seem to work fine, but the subwoofer does not make any noise. So I took apart the unit and found some obviously failed (burnt) components:

• 1x 3.14 A @ 250V main circuit fuse
• 1x bridge rectifier GBU601. there's actually two of these on the board, one is obviously burnt and the other does not seem to have any anomalies like shorts. However I figure may as well replace both.
• 2x diode. This is tricky because the only markings I see on it are: "617 402". No current rating or anything else. How do I figure what to replace this with?

There are also transistors SGSD200 (PNP) and SGSD100 (NPN). Couldn't seem to do the typical diode test on these, maybe due to how they are wired on the board. There's no obvious shorts, but I wouldn't mind replacing these just to be safe. One of these does seem slightly darkened. The part numbers show up as obsolete on Digikey. What do I look for in order to source a suitable replacement?

So plan is to just replace the components listed above, help identifying what diode and transistor to use appreciated. Everything else on the board otherwise looks fine. If there's other thoughts, let me know? Thanks!

See attached picture.

EDIT: I also just discovered that the small SMD resistor below the "O" in Bose may also be blow. See my post #15 below.

Hi, Quick question regarding the volume pot , using it after the pre amp will make better S/N but you may overrdrive the pre amp if the signal source is potent.
So I'm thinking to use it before the circuit. In this case a 4th order low pass filter for a sub amp . two 6.8k in series so 13.6k for the resistors makes it easy to use 100nF caps , and two in parallel for 200nF so I get 82Hz freq cut point.
Is this the way I should be doing it ? . What about a small cap 47p or so on the op-amps inputs ?. NE5532 for now. There will be decoupling caps for the op-amps.
Sorry for the bad quality drawing , made in Paint .

I have a PCM1704 on a pcb that is distorting, is this a known kind of chip failure or do they usually die completely with no more output ?

All surrounding caps are changed already, all pins confirmed to share signals and supply with other working chips, also connected for test to another I/V.

I sell 8 kt77 JJ, matches, I don't have the boxes, they are new from Tubestore, 300, or 410 in Canada+ shipping

Hi All. Sadly, my KT-5020 tuner has developed an intermittent fault. It works perfectly but every so often, it has started to produce no audio at all. This presumably is because something in the "front-end" is failing as the display shows zero signal strength when the sound disappears. If I leave it switched on, it will suddenly work normally again after a few seconds of making a rustling sound in the output, then normal clear audio. Sometimes switching off after the fault appears occasionally gets it working again normally when switching back on. Could someone help me here please?. I could fix it but have no hands on with tuner fault finding at all. I attach the circuit diagram. Many thanks for reading. The file is safe to open.

I picked up this dead subwoofer at the weekend mainly to harvest the drivers for a DIY speaker project. (They're pretty mighty things)!
I hadn't realised the PV1D has a Hypex amplifier and I thought it would be good to try to make the thing work. Looking online seems that the OEM Hypex with the onboard SMPS are pretty problematic.
Once I'd got it off the heatsinks board I could see an area that looks like has had some intervention before. (C3 and C6). I measure 240v into these.
Also T6 looks suspect, or atleast it's soldering.
I haven't probed much beyond that area, other than various electrolytic caps, and they aren't charging. So the mains AC isn't getting far into the circuit, which I hope narrows a few things down.
Obviously we can't get a scheme for these but is there anyone with SMPS knowledge that might hazard a guess where this could have failed and possible replacement parts. Or where to do some meaningful probing;I'm struggling to see the identity of T6.
Thanks

Hello to all fellow members and friends. Sony ST-SA5ES tuner came to my hands with poor sensitivity issue and after a re-alignment seems to corrected but still signal strength reports low levels. Looking around front-end circuit, I realized that IF level is too low and not clean 10.7 MHz wave. Unfortunately, SONY doesn't provide schematics of this Front End can. Is anybody from you faced same problem or has this schematic in order to investigate deeper? The P/N is 1-693-289-11. Also it is not available any more in known market places. Maybe someone of you has this available for purchasing.
Thanks in advance for your kind attention and help.
Regards,
John

This amp is in protect.Its like two amplifiers on one board.It has two 494s with 13v on pin 1 of both ICs.

Any suggestions?

Simple Hobby Circuits For Guitar

We start with some basic volume and tone-control circuits easily implemented, with input and output jacks shown in case separate project-boxes are desired.



Volume controls can be used to make splitters and mixers.



Note that you could, but should not, use a splitter backwards to create a mixer. Rather, rewire the splitter circuit, as shown below, to keep the potentiometers oriented properly. In such cases the correct wiring of a potentiometer has the signal going in at one end of the resistive element with the other end grounded, while the signal is taken out from the wiper. That is how a potentiometer is meant to be used with audio signals. There are cases where the signal goes into the wiper, such as balance controls, but which means the ends of the element are two separate outputs, or where two signals are given at the element ends and their balance is taken from the wiper. But here, we want the element acting as a standard voltage-divider with the wiper providing the output signal.





Next is a simple tone-control with selectable high-end cutoff. Larger capacitor values affect highs more drastically. Comparisons between different switch settings will provide the best understanding of how different caps affect tonality as the Tone pot’s position is changed. This circuit is typical of on-board passive electric-guitar tone-controls except that the rotary switch allows for selecting different bleeder capacitors.



The most common and cheapest capacitors used in guitars are the ceramic disk types. However, they tend to impart a thin sound to the guitar signal. A better capacitor type is the polypropylene film-type capacitor, also called an “orange-drop” capacitor because of its looks. These always sound good and are of high quality, and are more reliable than other capacitor types, but do not cost much more than ceramic-disk types. The most expensive capacitors are the paper-in-oil electrolytic capacitors, and if you want vintage sound, especially if your guitar has humbucker pickups, these are often chosen for that purpose. There are even NOS paper-in-oil capacitors available online, but which often command extreme prices. Therefore, for the most bang or the buck, use polypropylene orange-drops instead. Electronics parts are available at www.stewmac.com , and metal project-boxes at www.parts-express.com . Other electronics sources include www.mouser.com, www.digikey.com, and www.newark.com.

For any project in this post, or effect or effects-line, here is a bypass circuit, if such a circuit is desired.



If you get an annoying 60 Hz line buzz from your guitar or effects device, the notch filter below will cut it out. This is called a “Twin-T” notch filter and cuts the frequency to be notched by -12 dB. The formula for part values is provided in case some other notched frequency is to be addressed with the same kind of circuit. I do not recommend using potentiometers to make this a variable notch filter, accepting experimentation.



The wah pedal involves a circuit where a single potentiometer sets the frequency of a notch filter, but the adjustable wah effect cannot be implemented passively. All wah-pedal circuits involve active circuitry using either transistors or op-amps, or both. Note, however, that wah-pedal circuits are easily looked up by searching the phrase "wah pedal circuits", or similar.

These days SMPSUs are so ubiquitous and cheap that there really isn't another economical solution to powering a modest power-level amp. However they're all CM noise generators which leads to potential SQ issues with SE input connections as the noise current from the SMPSU travels down the shield of the input cable. An input transformer through providing galvanic isolation helps reduce the noise current substantially and thus reduces SQ degradation.

In this design the input transformer also provides signal attenuation seeing as the TDA8932 in BTL mode has way too high gain (36dB). Added to attenuation there's also SE-bal conversion and the final element is the creation of an input low-pass filter by virtue of the trafo's leakage inductance. The trafo thus realizes four design goals in a single component.

The other point of interest in this design is the use of two regulators - one for the signal supply and a second for the output power supply. Subjectively the regulators make a significant improvement in dynamics - an earlier iteration of this amp used an LC filter to derive the signal supply and there's no doubt that the SQ with the regulator was more enjoyable.

PCBs are due back in about 5 days. I estimate the BOM cost using parts from Taobao to be under $6 but there is the business of winding the transformer to be taken care of. Once I have the PCB working as expected, if there's interest I plan to open a thread in the Bazaar to make kits and finished/tested boards available.


<Update> I've already received interest so here is the thread where the kits are offered for sale : https://www.diyaudio.com/forums/ven...ed-tda8932-25w-8r-mono-amp-kits-new-post.html

Hi I want to build a buffer preamp, point to point, looking for a simple project to drive a power amp. (I don't have the power amp yet). I am in the process of learning basic electronics, amps, tubes and circuitry but I'm very green and have done very little circuit building other than a bit of soldering. But I want to give it a crack and hopefully for under $400 AUD.

One of my options was to buy the bottle head moreplay but it's about $1000 AUD delivered and I would prefer learn more about what is actually going on in the circuit than just follow instructions and in time keep building and modifying as I get better.

I have 2 options so far, the first one is from the wtfamps website called the Muchedumbre buffer preamp
https://wtfamps.com/muchedumbre-3/

The 2nd is the colour preamp from Skunkie designs
https://www.skunkiedesigns.com/colorpreamp

Looking for advice on which would seem the better option or if you have any other suggestions. I chose these 2 because they both have fairly clear build instructions that I think I can follow. As currently I can't simply look at a circuit alone and work out how to physically build it yet, I really need pictures/video. So open to any other options along those lines.

Thanks heaps for your help.

Mike.

hello everyone,I bought a used ATS-2, but the machine lacks a fuse holder. I found a way to install an external fuse on the machine, but now I have a few problems. When I soldered the fuse and tried to power on the machine, the fuse blew immediately, even if I unplugged the secondary line of the transformer from the motherboard. I have confirmed that the voltage jumper has jumped to the voltage I use. Can anyone who has an ATS-2 take some photos of the power input terminal inside the machine and the transformer harness? I want to confirm that the transformer multi-voltage jumper is plugged in the correct position. Thank you

R21 is power supply add-on module that replaces resistor between two capacitors in a standard CRC power supply and transforms it in to the regulated power supply. It has high PSRR and output current, low dropout voltage, output impedance, and noise. Transient response is good and module dimensions are small.
It works, as is without any changes, from 10 to 65 V output voltage and load up to 10 A, with dropout voltage of 0.15 V for 10 A load, PSRR greater than 100 dB @ 100/120 Hz and total noise less than 3 uV. Headroom voltage is 0.5V for 10 A load.
Single rail module dimensions, including heatsink, are 70 x 60 x 38 mm.



Why I made and published this is explained here:
https://www.diyaudio.com/forums/pass-labs/376002-amplifier-extension-power-supply.html#post6759478

As I see it, the most favorable property of this regulator module is that it can be used as an upgrade on wide variety of existing power supplies and that it can be easily utilized on one DIY project and then repurposed for another one. With this add-on regulator, single power supply is upgraded to the level above dual mono PS configuration.

Measured performance:

• 104 dB PSRR @ 100/120 Hz at 0.3 V headroom and 5 A load
• 2.5 uV total noise @ 5 A DC load or 17 nV/rtHz noise density @ 1 kHz
• 0.01 % load regulation @ delta I = 9.3 A (2 mV output voltage change for the 9.3 A load increase at 30 V output)
• 0.001 %/V line regulation @ delta V = 10 V (1 mV output voltage change for the 10 V input voltage rise)
• 40 uOhm output impedance @ 20 kHz

That's all fine, but there is a catch.
You can't use regulator at 0.3 V voltage drop in the ordinary CRC power supply, as there is a substantial ripple voltage at the first capacitor in the CRC line and there is also some mains voltage variation. In example, usual 30 mF capacity will provide 1 Vpp ripple at 3 A load. Minimum drop that can be used is half the ripple voltage + min. regulator headroom: 0.5 + 0.3 = 0.8 V. Add some headroom for the mains fluctuation/voltage drop at load and, realistically, 1.5 - 2 V drop is what can be used as a minimum on A class power amplifiers.

There was some voltage drop on the resistor in the CRC chain, so only 1.5 V is lost. That shouldn't be a problem, but if you really need every volt, then replace diode rectifier bridge with active rectifier (LT4320). This will provide 1.5 V higher rectified voltage in comparison to diode bridge.
For the new designs, you can order transformer with 2 V higher secondary voltage.

Building
Complete documentation including BOM, one click shopping cart, gerbers and build guide is attached. I've made a reasonable effort to provide documentation that will be sufficient for anyone to build this module, however this project is not suitable for beginners. Design is made with through hole components, as much as possible. There are only two really easy to solder SMD components that require fine soldering tip.

Parts
Recent parts shortages postponed project for 8 months. At any moment, something from the parts list was not available. I had to find and verify suitable replacements. Situation is increasingly frustrating and it is hard to obtain all parts from only one source or at all. I've prepared one click Mouser shopping carts for easy ordering, though you'll certainly need to adjust them.

Mouser Electronics, Inc. Croatia

I have sourced a single driver of the above models, so after another to make a pair:

Supravox 165GMF (Newer model with Black Label)
Goodmans Axiom 201 15Ohm (Later style cast chassis)

Regards, Rob

Used it a couple times. almost brand new. In box. Price beats best ebay completed/sold price.

Each track used 2 to 3 will SA1186 2 SC2837 2.

LAPT power transistors, ultra-high frequency FT, solve the CFP switch distortion.

Tiny hand in the distortion + 0.6 V.

I've been on this site for a few years now and figured I might as well introduce myself.... HI!

Electronics has been an interest of mine since I was very young, it's only within the past five years that I've gotten into vintage electronics, and now it's time to dive into the audio side.

hello.
due to an incorrect purchase I am selling the items listed, all from 18sound. never used and kept in their original box that I opened to check the contents.

• pair: 15W700 Woofer 15", 8 Ohm, 450 W rms
• pair: ND1460 Compression driver, 1.4" throat, 3" coil, 200 Wmax.
• pair: XT1464 Elliptical constant directivity horn, 1.4" throat, 60°H, 50°V, DI18.

in case of selling the entire package the price is €900. if bought new the price is €1250 as a minimum. with the complete package you can build the speakers of the kit of which I attach some photos (for those interested I can provide the entire PDF file with the instructions for construction). the woofer was used by troelsgravesen to build a 3-way http://www.troelsgravesen.dk/The-Loudspeaker-III.htm .

If you are interested for measuring and studying the vibration behavior of any audio component like a loudspeaker driver, a loudspeaker stand or a turntable you could use an accelerometer with a suitable amplifier.
You could find more information in my article in Audioxpress June 2011 which is posted also online here:
Test Your Speakers? Performance with this DIY Measurement System | audioXpress

If you are interested to construct such a system you could find information here:
http://www.diyaudio.com/forums/swap-meet/262944-pcb-anf-front-panel-accelerometer-preamplifier.html

I have a few PCBs (as shown in photo) for the construction of a stereo Line preamplifier as was presented in my article in Audioxpress January 2019.
The preamplifier is based on OPA627 and has three unbalanced stereo inputs and two unbalanced stereo outputs.
Due to copy rights I cannot post the article here.
If someone has access to the article and want to build it, the price for each PCB is 28 Euros (shipping is included).

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

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

CONUS ONLY

Thanks

Why is there a perception (particularly on social media) that antique equipment sounds better than modern audio gear?

I see countless posts from self-proclaimed audiophiles showing a stack of separates that were designed and manufactured in the 70s, like that somehow proves their audiophile credentials. Tubes and vinyl? Really? It's almost 2025!

In my view, even the cheapest Chi-Fi equipment from the current era sounds superior by orders of magnitude to dusty, out-of-date gear from the ancient past.

What is this trend that older is better? The test of time? Visual bias? Vintage chic?



I don't get it 😅

Hello friends!

I'm building an ultrasonic filament supply from cheap chinese "electronic transformers" sold for halogen lamps. These drive a small toroid trafo with a self-oscillating half-bridge topology at about 60 kHz :



The conversion requires inserting a big-ish electrolytic after the diode bridge so one has to limit the inrush current to avoid busting the drivers. The usual method is to replace the on-board fuse FS1 with an NTC thermistor.

Works well enough but I'm designing a replacement for the very cheap stock PCB that uses a self-oscillating half-bridge IC (IR2153). I want the new board to fit in the existing small enclosure so the extra needed parts create a severe board real-estate constraint even when using mostly SMD parts.

So I wonder if I could put the NTC off-board at the secondary output - specifically, thinking about an NTC on each leg to keep balance relative to a center tap to ground. Also note that if there were multiple tubes to be driven in parallel there wouldn't be a pair of NTCs per tube but rather a pair at the start of the heater wiring chain.

Do you see any issues with that? Can this create noise on directly heated tubes?

As always, thanks in advance for any insights,

Joris

Was just servicing my old Comtech 800, adjusted the bias and by mistake shorted momentarily heatsink of one channel to the chassis 🙁
After this when turning the amp on protection circuit comes on and cuts the power off to that channel; other channel works normally.

Symptoms are now, when switched on, right channel behaves normal (yellow IOC light comes on, after few sec it goes off and green ODEP lights turns and stays on).

On bad (shorted) channel the yellow IOC light comes on, after few sec the green ODEP light comes on but it immediately switches off while the yellow IOC remains on; this keeps cycling every few seconds.

I looked inside and could not detect any burned component on the output board; also there was no obvious smell/smoke that something burned when I accidentally shorted heatsink to chassis.

I would really appreciate some tips on how to troubleshoot this; there is obviously a protection circuit that turns power off that channel as soon as gets powered, but could not detect anything getting hot.

What would be the first suspected part to get damaged; I got full schematics and wanted to compare L to R channel but it is hard to do as there is no voltage to the bad chanel (it gets cut by power control protection circuit)?

Do you have a favorite driver that you would like to use in a mass loaded transmission line (MLTL) like a TABAQ, Pensil, or Metronome, but no one has yet run a simulation for it with MJK's software? Sometimes, folks on this forum can be very generous with their time and provide you a simulation if you ask. I have seen Bjohanessen do this many times for me and others. But in case you do not have the fortune of a full-blown simulation in MJK, but would like to hear what your driver sounds like in a MLTL, this thread is for you.

Let me first say that, this is not meant to replace a real simulation, but is rather an observation I have noticed that has worked a few times. I imagine that there are drivers where this will fail. For MLTL's where you want to push the tuning frequency below the natural free space frequency of the driver, choose a driver with a moderately high Qts (> 0.5).

This idea arose out of something I noticed happening on several occasions with a good result. I call it the 'accidental MLTL' technique because it may have been luck or chance but it seems to work a few times now for me (and at least once by others). I originally posted this in Bjohanessens's TABAQ thread but figured it was enough to spin off a new thread. I will repeat that post here...

If you happen to have MJK's MLTL worksheet, give this a try by running a simulation with your driver and running WinISD and calculating the CSA, length, and vent and compare the two. It would be interesting to hear your results.

----

Use WinISD bass reflex software (free) and plug in your driver's T/S params and design a vented bass reflex speaker enclosure using the default optimal case. That will give you the volume of the box and the vent cross sectional area and length.

Now choose a maximum length you are willing to have based on practical size constraints, typically 30 inches to 40 inches long. This will correspond to a quarter wave length that is probably higher than the tuning freq of the bass reflex design that came out of WinISD (circa 60 to 75 Hz).

Calculate the cross sectional area (csa) of the transmission line using volume from WinISD and the length you set. If the csa is bigger than you prefer, you can go off the optimal case by going back to WinISD and adjusting the box volume manually to a smaller value and tweaking the frequency even. You can play with the vent to get it to a diam and length you like. Typically, I do this because the default vent is not very practical. Then use new box volume and vent dimensions to calculate the new csa based in length of the line again.

Now build the enclosure with the csa and length and put a vent with dimensions from WinISD at the distal end. On the closed end, measure 1/3 of distance down and make cutout for driver and mount it there. Put polyfill stuffing from closed end to about half to 2/3 of the way down the line. Adjust this to taste, less stuffing gets more boomy bass. More stuffing gets tighter bass at expense of amplitude. I have found that the position of the driver need not be exactly at 2/3 and indeed can even be at the closed end.

Doing this approach will guarantee that at worst, the speaker will perform as a bass reflex optimized for volume and vent size. But if physics of a MLTL and quarter wave theory kick in, you will end up with a speaker that has deeper bass extension than predicted by WinISD. The speakers that I have built following this recipe have measured very well when I look at what is coming from the bass port - typically, I get the low frequency extended or 'pulled down' by an additional 15 Hz from the plain bass reflex prediction. The speakers also sound great - very balanced when the bass port output integrates with the direct radiation from the driver.

If you want to experiment without investing too much in wood, use foam core to build quick and dirty speaker. Even cardboard can be used as a test speaker for this.

----

Here are the two examples that have worked for me:

http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures-148.html



http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures-109.html



A third example not by me might be Cogitech's "nano tower" speaker with the ubiquitous TB W3-881si. Which I think was also designed as a bass reflex with WinISD but due to its slender aspect ratio and length, happens to have some very nice bass deeper than one would expect based on accounts from builders.

http://www.diyaudio.com/forums/full-range/200912-nanotower-tang-band-w3-881si.html




Update : 4th example is a quad driver bipole with W3-881si http://www.diyaudio.com/forums/full-range/234535-tangband-w3-881-mltl-build.html



Fifth example is a folded AMLTL with a Vifa as wall or bookshelf speaker:
http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique-16.html#post3466655

Regardless of whether you are dealing with the original versions from Sanyo or with various replicas and various fakes - it just remains unreliable after any replace. An incredible amount of wasted time has already been accomplished (alone in my circle of acquaintances) by this bad design of STK front ends (in order to get low thermal stress).

The reason for this is obvious - simply too weak cooling in the voltage amplifier stage. This means, lokal hot spots and thus premature malfunction. The higher the supply voltage, the greater the power loss and the higher the thermal stress.

I still have a large number of defective amp devices equipped with these STK front end resp. pre-driver modules.
In particular, I would like to get the Sony power amplifier TA-N55ES and the Luxman R5030 so as various Marantz models up and running again permanently.

For a replica I would prefer a 3-transistor LTP (differential amplifier with current source without current mirror) and for the VAS-stage only 2 transistors and 2 heat sinks - one for the gain stage and one for the current source (no SMD resp SMT parts). The loss of sound resulting from this simplification should be negligible.

Maybe someone has done it in this kind.

According to the attached images, the solution in image No and under
https://www.diyaudio.com/community/threads/stk3152-stk3102-clone-for-aluminium-back-pcb.380947/
and post #30 under
https://www.diyaudio.com/community/threads/fake-stk3152-stk3102.268473/page-2
seems to me to be the best.
But it's still not good enough from my view, because one can't mount a BCP56 SMD transistor in the SOT223 outline onto a heat sink (disadvantage is the not good thermal conductivity between PCB and metal/aluminium plate).

Maybe there are even better solutions.

some URL's
http://epicbeardquest.blogspot.com/2016/09/exploring-sanyo-stk3122-iii.html
https://www.diyaudio.com/community/threads/fake-stk3152-stk3102.268473/
https://old-fidelity-forum.de/archive/index.php/thread-41061.html

https://www.diyaudio.com/community/threads/any-modification-for-replacing-stk3102-iv.69472/
https://www.diyaudio.com/community/threads/sanyo-chip-amps-v-ii-xi-differences.170525/
https://www.diyaudio.com/community/threads/i-need-a-information-about-stk3152.4607/
https://www.diyaudio.com/community/threads/connecting-stk-hibryds.187226/
https://www.diyaudio.com/community/threads/amp-crackling-sound.338876/
https://www.diyaudio.com/community/...-amp-module-for-marantz-pm80-amplifier.36425/
https://www.diyaudio.com/community/threads/alternative-for-stk3102-iv.177898/
https://www.diyaudio.com/community/threads/stk3102-iv-manantz-pm-80se-amplifier.55376/
https://www.diyaudio.com/community/threads/stk3062iv-substitute.164588/
https://www.diyaudio.com/community/threads/stk-series-type-amp-bias-adjust-how-is-it-done.26710/
https://www.diyaudio.com/community/threads/marantz-pm-52-no-sound-speakers-or-headphones.309626/

These new Brazilian and Chinese clones are using some odd numbered resistors that even tho obtainable, but can they be replaced by the nearest logical types along the mosfet gates on the audio output gate drive circuit without any form of problems?
For example 13ohms can I safely replace 12ohms (replace all for each mosfet) and for Taramps 3.3ohms can I use a 4.7ohms?

I bought a Pink Triangle Cardinal Transport for repair off ebay. The seller said it is powering on but it is not reading CDs properly. I also bought a new Sanyo SF-91 laser pickup. Will swapping the laser heads cure the problem?

Hi,

I was looking for a bit of advice. I have the above receiver where everything works except for the tuner part.

It has an AM and FM section, with both sides just producing white noise. On occasion with the AM (on medium wave) selected I can hear a faint radio station.

I have attached the block diagram and schematic - the service manual is easily downloaded, with the 9MB being better quality.

My thinking is there is a problem with the circuit where both AM and FM come together, and that there is probably no issue with alignment or the oscillators as they both have different ones. I am slightly optimistic that at least the AM is picking up something as I can hear a very faint station in amongst the hiss and crackle. So I think at least one of the front ends must work.

I think both FM and AM first come together on IC201 (AN7273A) - FM/AM IF AMP, DET and AM mixer. AM comes in on pin 3 and FM on pin 1. The output is on pin 13. If I put a 1V 1KHz sinewave on pin 13, I hear the tone amongst the noise, so I assume everything after IC201 is ok. I am wondering if the IC is the problem ? Is there any way to test if that is the case ? I tried bridging pins 1 and 3 to 13 with a 0.3uF capacitor but got nothing, but then the signal would not be 'processed' or amplified. I have got an old analogue scope, which does not pick up much on pins 1 and 3, I am not sure what frequency or what voltage I would expect.

I can pick up a AN7273 (not sure if an 'A' or not) on ebay for £5, but it would be nice to prove the chip is the problem first, or investigate other things on the PCB.

The voltages coming in (15.5V and 5.5V) are there.

This is the first tuner I have attempted to repair, so have spent the last week reading round the subject, but am now looking for a bit of advice from the more experienced.

Cheers !

Hi all.
I barely know what I am doing in the world of tuners. I have the above receiver and it has absolutely no FM reception.
When testing, all transistors seem to behave correctly.
I found a chip with some very weird voltages. It's the LA1231 FM IF system chip.
Voltages are:
1) 0.072v
2) 0.06v
3) 0.06V
4) 0v (GND)
5) 0v
6) 0.07v
7) 0.239v
8) 0.237v
9) 0.239v
10 0.237v
11) 13.7 (Supply)
12) 0v
13) 0v
14) 0v (shorted to GND via PCB)
15) 0.017v
16) 0v

According to all info I can find, Including LA1231 datasheet and service manual, all voltages are very off (except pins 11, and 4).
Is this looking like a bad IF chip to anyone? What should I check more/next?
How would you go about restoring the FM receiving abilities of this unit?

BTW:
The receiver had no AM reception and while on FM, the "FM Stereo" indicator was on, permanent. But I found a defective resistor supplying the power supply to KB4431 MPX chip. Now AM seems to work (I think) and the indicator is now null, as it should be.

I got into the theater business in the late 80's. Played with some Voice of the Theater speakers.. and took the amps home.. Ended up doing projection and sound installations in the early 90.. I got to install some incredible equipment.. I kept searching Google for some subs we installed; and a thread here turned up.

Hi trying to get into enclosure design and using programs such as winisd and hornresp to create loudspeaker cabinets.

Here's a link with some pics: Login to view embedded media
This is the amp that made me understand what people meant when they talked about “that tube sound.” It’s not syrupy or veiled—just right. It brought out texture and warmth without ever losing grip. If I didn’t already have a system shift in progress, I’d keep it and not look back.

This Willsenton R35i comes with a freshly biased quad of Mullard EL34s and a full Tung-Sol front end (12AX7 + 12AU7). It’s ready to plug in and go—no tuning, no fuss.

Power section: 45W ultralinear or 25W triode.
Front panel: motorized volume, headphone out, selector knob, no remote.
Rear: 4 RCA inputs, 4Ω and 8Ω speaker taps, proper terminal spacing. Includes a set of -6dB rectifiers for flexibility in voltage drop and tonal response.

Trade-wise, I’m open to something with serious current: Purifi 1ET400A, NC502MP, Nilai, or something equally clean and confident. I’d also entertain a solid-state sleeper or hybrid with real presence.

Happy to talk gear, answer questions, or field interesting offers! Also happy to sell to interested parties!

I have since gotten a cool class D amp, so this is now on sale for 900 plus whatever shipping is!

Hey everyone,

Long-time lurker finally checking in. I’m Alex — civil rights lawyer by trade, audio enthusiast by obsession. I came up through the headphone world but eventually hit the ceiling there and made the leap to speakers once life gave me the space (and forgiveness from the neighbors).

Current setup includes a Cambridge CXN100 streamer, a rebuilt DS-99 amp, and a Willsenton tube integrated — powering a pair of big, beautiful speakers I call the Butch Towers. I’m in an old Virginia home with hardwood floors and big rooms, so getting the acoustics right has been its own adventure.

Lately I’ve been toying with building something a little wild — maybe dual-mono Class D, maybe something else entirely. I’m here to learn, share, and probably ask a few naïve questions about modules I don’t fully understand yet.

Looking forward to getting to know you all!

I have started on building an entirely new system for my living room. Transformers and many parts for my hand built monoblock amps are on back order or delivery dates months out. So I turned to the preamp I am going to use with them.

I bought 2 Audio Research LS1s (same as LS9 minus built in phono stage) for the project. The LS1 is a hybrid FET/MOSFET/Tube design, using a 6922 in the tube role. It's fully regulated on the B+ as well as the heater supply. I know there is huge debate over this, but I am quite fond of the idea.

The black LS1 was in mint condition and the silver LS1 arrived in terrible condition, nothing like the seller described. But my plan was to modify one, compare to stock and decide if I could actally improve the preamp. So I kept it. What that added was a restoration as well as modification.

The goals of this were:

• Replace all the electrolytics with new ones as this pre is pretty old at this point
• Update the audio signal and possibly the power capacitors
• Not break a single connection of the Litz wire anywhere in the preamp which meant try to salvage the RCA jacks

So having the preamps, this is how the Silver LS1 restore and modification went:

• Polish RCA Jacks with Simichrome metal polish and a rotary tool
• Carefully clean front panel and knobs with bleach spray to remove years of dirt and film
• Clean pots and switches with CRC 2-26 spray - an electrical contact cleaner I prefer to Deoxit and it's way cheaper and available at Home Depot
• Cut off hardwired power cable
• Cut and drill aluminum for can capacitor and IEC radio filtered power jack
• Sand top and bottom to bare metal to get rid of corrosion and bad paint
• Soak hardware in white vinegar to neutralize and remove corrossion
• Sand handles of corrosion spots and bad paint
• Respray the top, bottom, handles and hardware with black rust inhibiting paint
• Blow out as much aluminum bits and dirt as possible with canned air
• Sprayed 32 oz white vinegar through out pre and scrubbed with acid brush to neutralize corrosion
• Sprayed with 32oz 91% isopropyl alcohol to work on dirt and oil
• Sprayed with multiple cans of CRC Lectra Clean and Contact Cleaner to work on dirt and oil
• Replace all Rel Cap and Wonder Cap with 630V Solen Fast Caps (metalized polypropylene) in power section and Dayton (film and foil) 250V/400V capacitors in audio path - the film in regulated suppy was bumped from 2.0uf to 4.7uf and the last output cap went from 5.0uf to 6.2uf. All others are same value
• Replaced Sprague 100uf/450V with Illinois Cap 100uf/450V and added a JJ 100 + 100uf/500V can capacitor
• Move the 7815 regulator to the chassis as it gets very hot and it is visible where it darkened the board from heat. It stays very cool in this position.
• Replace the EH6922 with a NOS GE 5670W and added silicone tube dampening rings
  

So the verdict?

Well it looks great and is very clean. The corrosion is removed and halted and hard to even see where it was. The sound is a definite improvement over the stock LS1... there is a slightly darker background, there is definitely more top end and air. The LS1 has exceptional low end by default, but it still tightened up nicely, but then again all of the signal did. It's less harsh with the GE tube as well. Most of the LS1 issues that were critiqued in the press are sins of omission (it's an entry level ARC pre) and these changes remedy them IMO. There was such an improvement in the sound, even my significant other went, it does sound better. And she has 0 interest in audiophilia or electronics.

I am certain any high quality modern capacitor is an improvement over the Rel Cap and Wonder Caps in these old units for those wondering... and this seems to be a popular internet question.

So part 2 is going to be to redo the black LS1 as well, but using premium parts. I am planning on using Auricap XO capacitors and probably will stiffen the power supply even more.

Have a look through the pics to see begin to end progression.

Good morning,
I own a pair of Maranz MA-5 amplifiers. The level indicator LEDs on one amplifier only light up at fairly high volumes. Does anyone know how to adjust the settings? Unfortunately, I don't have a service manual and I couldn't find any information about it. Thank you very much.

Hi,

Im using the parts express dayton ultimaxes diy kit (sealed) in my 2 channel (2.1) setup. Im varying the crossover but sofar the best sounding is around 100hz. Sadly the Daytons seem to not be as tight above 70hz and ive been reading more and more about how they are actually more a home theater sub driver and they are great below 70. Fantastic even.

So im looking at an upgrade driver that goes well 20hz-110hz thereabouts and maybe using in the same cabinet, or make a new one with winIS, or buy a package at GSG. What would your preference be for replacing the daytons? This is regardless my room condition etc. Just purely looking at the driver itself. Ideally Id have a subwoofer with a good quality of the ultimaxes below 50hz and to about 20hz, but also one that gets nice and tight at higher frequencies.

Im using a Behringer 6000dsp, and a minidsp. Been experimenting with MSO and REW, using UMIK1. MSO is nice though it is catering for home theater sub setups more than music usage imo. I have Revel F208 main speakers, driven by a Quad 606mki, and a crown xsl 1502. I aim to have a system capable between 103db spl for some nice techno moments, about 80 for average music and sometimes lower levels for classical or jazz. My budget is anywhere about twice what the dayton ultimaxes are. Im not considering manufacturer subwoofers like SVS (had them, liked them). I want to stay with diy. Thanks!

Hi folks,
My name is Christoph and I`m new here. I live in Austria, I love music and hifi, especially analogue. I joined here because I`m looking for a valve phono amp with a mono switch so I can finally use my Miyajima Spirit Mono hum free 🙂 I`m fairly new to building stuff myself, but had a good time and results with the Nelson Pass Amp Camp Amp. It`s time to step things up a notch and I`m looking forward to friendly exchanges with likeminded people.

Hi,

I've built a 38-liter port speaker to be tuned to 28Hz.

Using default WinISD end port correction of 0.73 I've got a theoretical 16cm port length for a non flared 5cm port diameter (I know it's small but this speaker is for low power levels). Checking the real built box, I've got the tuning well below 28Hz.

Searching the forum, I've got a picture set that indicates that when we share walls with the port, the end port correction increases.
I my case, I have a round port pipe but it is very close to 2 walls - the pipe is only 1cm away from the walls. See pictures below.

Question: should the end port correction be something between 0.73 and 1.7, as shown in the picture set below?
From my tests, I shortened the pipe to 11cm to get the planned tuning. With 11cm the simulation factor should be 1.7.

I'll adjust to my needs, but I just want to understand what happened and if this is really due to the port being very close to the walls.

Thank you!




Pictures of my box port.

It uses the the bias network to do error correction. It is equivalent to CFP with MOSFET output, but it can output from rail to rail, with help of the bootstrapping.
The example below is +-14Vp into 8 Ohm with only +-15V supply voltage. You can see the distortion is low. Note that you could put opamp at the front and wrap NFB around it to reduce distortion farther.




[Edit]Final Version:


The full schematic.

For Sale – Various Hi-Fi Components (Belgium–Luxembourg area)



Hi everyone,



I’m letting go of a few items from my collection. Everything is in working condition and has been well taken care of. Local pickup preferred between Belgium and Luxembourg. Photos available on request.

---

🔹 Mirand USB DAC – built by Sonny with the discrete output stage option.

Currently wired for RCA, but XLR output is possible.

A true AKM dream 😊 – €200



🔹 Tony Gee Twenty Five speakers – beautifully built by another DIYAudio member.

Great sound and craftsmanship – €350



🔹 Linn Keilidh (from the golden 90s D’Appolito era!)

Includes Kustone bases and Linn speaker cables – €350



🔹 Naim NAT 05 – a superb FM tuner, classic Naim sound – €200



🔹 Sony Vintage Combo – ST-5950SD tuner + TA-3650 amplifier

Punchy and musical vintage sound – €250



🔹 Technics SL-10 turntable – linear tracking, iconic design – €350

---

If you’re interested in any of the above, feel free to contact me via PM or reply to this post.

Thanks for looking!
Lot price: 1500 eur

Hello all, I'm new to DIY audio and to aftermarket audio systems. My current system is installed on a motorcycle, it is a Soundigital 400.4 & SounDigital 2400.4 and they're running 4 diamond audio 6.5 speakers and 2 diamond audio 6x9's all are coax speakers. They're being controlled by a Pioneer mvh-ms512bs and Dayton audio 4x8 DSP.

CARY AUDIO HH-1 Class A hybrid headphone amplifier in like new condition and working 100% with no known issues. Includes manual and original box (fair condition). Has been upgraded by Big Sky Audio, LLP with a nice 5-step process to make a terrific sounding amplifier even better. The input capacitors, feedback resistors, power supply capacitors are replaced with better components along with bypassing added to the main power supply caps and a soft recovery bridge rectifier. Finally, Golden Dragon teflon tube ring dampers are added. The parts chosen will not add coloration to the sound but will bring out the best clarity and detail. It sounds spectacular but now that I have been retired for a few years it is time to lessen my load of stuff.

Made in USA and operates on 115-Volt AC USA power. Includes Genalex ECC88 tubes (6922 equivalent) with gold pins. Runs pure Class A at any rated power level.

$995 plus shipping (to be determined). PayPal ok. PM if interested.

Sold "as-is" and sale final. No warranty is expressed or implied. No returns or refunds. Sells and ships to continental USA residents only.

Hi,

I'm building an active subwoofer for my home theatre setup. Please suggest me the best Class-D amplifier to drive the 600W 4Ohm Rockford fosgate P3D4 15 inch subwoofer to its full potential.

For those that are interested in common-mode distortion in JFET-input op amps, and why it is dependent on source impedance for some op amps, I've written an article on this topic: http://www.ti.com/lit/an/slyt595/slyt595.pdf

Full disclosure: I am an applications engineer for TI Precision Analog in Tucson AZ. The article shows measurements on TI op amps, but the principles are applicable to JFET input op amps from most manufacturers.

Enjoy!

Hi guys

I am a 47 yo French guy living in Paris area and being passionate for headphones and headphones amps.

I have / had all kind of headphones from AKG k1000 to hd800 or Grado gs1000.

On amps side, I am using Linear cube or Vincent or little dot mk9.

The source is a computer or phone using a DAC M2Tech young.

Thanks for the acceptation in your group !

So I have just fitted an LED bulb into a mains ceiling light fitting for my bro'.
The bulb glows dimly when the light is switched off indicating a small leakage current.
It is not the wall switches as it happens even if the wires in the switch are pulled.
It's a stair light so on 2 way switches.
Strangely, it only happens with the switches in one orientation.

The bulb is a fake filament type (I probably wouldn't have chosen it for stairs), I don't know if they are particularly sensitive to leakage current.

Any practical suggestions?
I suppose the first is try a different style of LED bulb.

Have one. It was bought 12 March 2025. Today it stopped working after a reboot because of a macOS update. Orange LED blinking.... No recovery possible.

Felt wrong when I got it. A smart phone without display that can't make telephone calls. Half of the weight of the previous one, no USB A ports at all (many many devices are USB A), 3.5 mm audio output at the front (WHY?) but worse of all a power switch at the bottom. This stupid design decision made me wanting to skip it but the flesh is weak. I guess my feelings were right, this seems a cheap knockoff of what the Mac Mini used to be and the power button is spitting regular customers in the mouth. Of course I want the thing to shutdown every day, no normal soul leaves stuff powered on for no reason. Why does it otherwise even have a power on/off switch?

It is (was...) fast but so was the previous one. Well does this prove that it is not of the known Apple quality? No it does not but it is the first Mac that dies on me (except the notorious 27" iMac) in such a short time. Less than a month old. Thankfully the M2 still was here.

Hello everyone.
I'm Ronny. I have known this forum for a long time and have been able to use the information in this forum several times in the past to solve problems in my own projects. Especially references of current transistor models to already discontinued transistors could help me a lot. Now I want to be part of this community to help others with their projects and maybe get some support for my own projects in the future too. I am particularly interested in integrated amplifiers, power amplifiers and tape decks.
In the past I have mainly restored various Harman/Kardon amplifiers. For example, a PM665 where one of the power amplifiers stopped working, or an HK6950R where only the switches and controls needed a good cleaning. I was also able to successfully repair a Harman Citation combo consisting of the 25 and the 22.
A less successful project was a Harman Kardon HK770, where the well-known corrosive glue had unfortunately attacked the circuit boards too much for my skills.
My current project is a power amplifier from Luxman (M-02). Here one of the two channels is defective and generates a DC voltage at the output. Let's see if I can find the fault there...
I hope my presentation didn't bore you too much.🙂
Greetings Ronny

Hi im' Frank from Italy,
since 1975 I began my passion for electronics by dismantling my mother's portable transistor radios and repairing the table lamps at home, then when the technicians of the TV antenna, the washing machine or any other electronic equipment came to my house, I liked to watch their work. From the first half of the 80s I began to be interested in radio transceivers, first on 27Mhz and then also on other higher frequencies. For years I attended the laboratory of a friend who taught me the fundamentals of audio electronics and telecommunications and then in 1986 I obtained the amateur radio license. Now I still have this passion and I like to find original solutions to some electronics problems always putting respect for the environment and sustainable recycling in the foreground. Thanks for welcoming me into the group.

TLDR: I am very new and looking for a gift for my father that I could have ready in the next 2 weeks.

Hi there - super excited to meet the community here,

I am a newbie when it comes to DIY Audio, I do have some limited experience with soldering and 3d printing. My background is heavy in the computing world both from hardware and software (Windows & Linux), but custom writing drivers/firmware would be a line I don't cross. As for audio, I certainly appreciate great quality sound, but I have never worked with custom builds or mods anything. A few examples of what I run at home (nothing really super unique - mostly mainstream):

1. Living Room:
   • Receiver: Onkyo tx-nr696
   • Front: R600F
   • Center: R50C
   • Rear: R40M
   • Sub: R120-SWI
2. Computer (used for DJ, Streaming, Production
   • Focusrite 4th gen 4i4
   • JBL 305P MKII Monitors
   • Shure SM7DB

For those that might be more of the networking/home lab side, I do run my own 42" rack with a 6 node Kubernetes clusters, stacked switching, redundant power, etc. and I also have a fleet of raspberry pi's performing various roles. As for electronics bench, I have a microscope, thermal camera, USB tester, some network and fibre testing equipment, a Weller soldering iron, Greenlee multimeter and a cheap heat gun that I'd really only use for shrink wrap (doesn't have the precision for resolder work). No oscilloscope or logic analyzer yet and would probably like to get better with what I already own first.

As for 3d printing, I have yet to really make any successful print, but I think I overlooked the simplest area and spent too much time (and money) on trying to upgrade/fix known issues with this cheap FDM printer that I bought. I'm think my prints were mostly getting a lot of issues simply due to it not being on a sturdy surface and I took it one step further by using some isoaccoustic pads that I was no longer using (never thought I would find another use for them besides vibration dampening for speakers!), but have yet to go through the setup checklist of Klipper yet to see what kind of a difference these upgrades have made.

Now, here's the thing...I have been casually thinking about a gift for my father for the past 6 months and I know he was very fortunate to have some commercial grade tube amp from his employment back in the early 70s. He nearly cried when he pulled it out to "upgrade" to a Denon for 5.1. This was many years ago. Sorry I don't know the make and model, but I'll try to find out for anyone who might be curious. Initially, I came across these forums as I thought...hey I have a lot of bits and pieces of knowledge to maybe build a tube amp as a birthday gift. However, I have been getting overwhelmed and have no idea where to start + I think this would be something after a number of projects once I have built up skills and saved up money. I have lowered my expectations, but I am still a little lost as to where to proceed or what might be something a little quicker/cheaper to do while still showing that I have put a lot of thought into this. Now, I also got some hard to swallow news yesterday and it's made me bump this up in priority (sorry being vague here, but I am sure some of you can read between the lines).

I'd like to try and have something for him in the next 2 weeks. I live in Toronto, Canada, so here are my loose thoughts and I am totally open to suggestions:

I have a raspberry pi 5 sitting around doing nothing, so perhaps some components from iancanada and some sort of 3d printed case (I don't see any links on iancanada's sites for and models though?) or failing that, I could build something out of wood as my skills with 3d modelling software are 100% limited to very quick remixes and not anything from scratch. Thoughts?

Thanks in advance everyone! Also, please ask me any questions if you need more details to help me out.

Good morning,
I own a pair of Maranz MA-5 amplifiers. The level indicator LEDs on one amplifier only light up at fairly high volumes. Does anyone know how to adjust the settings? Unfortunately, I don't have a service manual and I couldn't find any information about it. Thank you very much.

Have any of you had a chance to run/listen to this Bram Jacobse module for TDA1540?
TDA1540 High Precision Synced TikTak mod

im new to this forum, but I am a big diy guy, mostly in home diy projects, but my love for vintage audio is growing rapidly, so im seeking as much knowledge as I can find

good morning,
I have been interested in the audio world for decades, I own many audio devices and I am always looking for new solutions to improve my systems.
would like to know how to join the diyaudio community, I am also interested in purchasing some members' items.
many thanks
roberto
italy

Cannot run hornresp due to either settings issue or missing MS sans serif. not sure what to do here.

thanks

Hello. I want to implement Quiescent Current meter for current source. The question is - what is the best place to connect? And about the meter - should it be a current meter or volt meter?

We have some nice powered subwoofers from Vera-Fi Audio.

The Caldera series comes in a 10in and a 12in version. Both are thin channel vent slot reflex designs. The 10in comes with a quality Class AB amp with a linear toroidal trafo and the 12in comes with a Class D amp with a linear toroidal trafo. Nice cabinets and class leading powerful motor drivers.

Recent review (and teardown) of the Caldera 10 here.

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We have to fix the power specification. It should be 175w peak power for the Caldera 10. The Caldera 12 should be 250w peak power. Since drivers are very high sensitivity, this is plenty of power.

The review and teardown of the Caldera 12 is here.

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You can order both here:
https://verafiaudiollc.com/collections/speakers

Good morning Everyone. Am looking to get the Tang Band W3-1231SN 3 inch Metal drivers. Am doing a project for my wife. Am looking for new or Gently used. Here is a pair of the drivers am looking at buying. Please E mail me or PM me.
⭐️Am only buying from legitimate diy Audio source members Here. Any outside sources Trying to sell to me will not be answered or replied to. This is due to a Scammer that took a good chuck of money from me not long ago posting on this forum. Have a nice day. Jeff

Neurochrome Modulus-86 DIY Audio Power Amplifier in black

SOLD

$845 Canadian, $605 USD

Cost of parts, before shipping and taxes, was $1429 Canadian.

• Class AB design.
• 40 watts per channel into 8 ohms. 60 watts into 4 ohms.
• Very low Total Harmonic Distortion (THD).
• Balanced input using XLR cables.
• Single ended input also possible using XLR to RCA adapters.
• Linear power supply.

See the link for complete specifications.
https://neurochrome.com/products/modulus-86

Includes:

• Neurochrome Modulus-86 amplifier boards
• Neurochrome Power-86 power supply board
• Neurochrome Intelligent Soft Start board
• Neurochrome Modulus Chassis in black
• Neurochrome Gold plated 5-way binding posts
• AnTek AS-2222 200VA 22V Transformer

Assembled by me. My best work to date. See photos.
No effort was spared to assemble this exceptional power amplifier.
Has a very pleasing warm and full sound.
Kudos to Tom Christiansen for designing a wonderful amplifier.

Components sourced from Neurochrome, Digi-Key, and Mouser.
No counterfeit or unauthorized parts used.
Each component was tested using a Component Tester prior to assembly.
Boards thoroughly cleaned to remove flux residue.

Contact me if you have any questions.

USA: Order totals below $800 USD are not subject to tariffs. Refer to the latest information from US Custom and Border Protections regarding the $800 de minimis limit.

Smoke and pet free home. Thanks for looking.

WARNING: Electricity is dangerous and can cause personal injury or death as well as property damage, or property loss. Do not attempt do-it-yourself electrical work if you are unfamiliar with electricity, or have any doubts what so ever about performing do-it-yourself electrical work. Never work with live mains electricity. Always disconnect the power source before working with electrical circuits. The seller is not responsible for personal injury, death, property damage, or property loss caused by the use or misuse of items in this sale. Please read the "DIY Safety" page at www.diyaudio.com for more information.