Here is a DIY Modulus 86 amplifier with dual mono SMPS power supplies. The boards, and inductors were all purchased from Tom's website, the chassis is a Modushop Dissipante and the rest DigiKey/Mouser. The amp sounds great! See Tom's site for more info: https://neurochrome.com/products/modulus-86

Asking $400 to your door in CONUS

NOTE: The hole on the IEC and power switch are elongated since I mis-measured the height! 🤦‍♂️

Seeing some stones turned lately , I simply couldn't resist Babelfishing urge......

Though , as I already did some mild Babelfishing of our dear and beloved J2 , logically that this time I needed to do something ...... completely different

due to constant demand and popularity mainly on Far and less Far East , schematic of original FW J2 is still generally unknown or - better said - none of circulating DIY schematics weren't blessed by Mighty Pa (pleonasm here , Pa is Mighty by 42)

few things we all know , and these few things are good and plenty enough for basic postulates of variation of Jazz Standard 🙂

Basic premises :

1. possibility of incorporating less critical ( for acquire) JFets for input LTP, by choice and must possible use of 1+1 , or 2+2 in same ;

2. possibility of incorporating various output devices , of lesser and bigger rarity and/or price

2a. possibility to avoid tearfully matched parts (outputs and other ) , while still easy settable both output offset and OS Iq in broad range of values

I got it all ........ how:

1.easy peasy - use N channel JFets (choice is waste!) , lead them (currents) back to lower output gate via simple and effective current mirror ..... put few cascodes here and there to pet both JFets and fine CM parts (tiny JFets are always grateful for that, but high beta small BJTs like that too) ....... and while we are there - why not using fine emiter follower between CM final end and lower output's gate .......

2. OK - trimpot in front of lower output's gate is trivial ; second part is feeding Optocoupler with CCS , with some current spare , and routing the same in loop around ( in parallel practically) said optocoupler , so we can set Iq of upper mosfet with ease and in broad range

2a.partly already covered above , just to add that output devices can be plain old IRFP150 , same as any boutique part you already have , value of Ugs is irrelevant - easily covered with change of ,say, two resistors


'nuff talking , time for schm (read notes on left side):

new member from California can fix amps and have electronic experience

Went through my inventory and found some "good" old 2N3055´s. Got a little nostalgic thinking of the JLH 69 that I built -69.

Have never seen a compound mosfet/bipolar Darlington before, so I thought I would give it a try. Sims great at 1W/8ohm and outputs over 10W, so I will build a mono pair for my midbass speakers(60-350Hz), when the heatsinks arrive. The upper registers will be fed with IRFP240 FOMO´s. The 193U that I already have are not optimal due to their high DCR, but they will do. Thermally the circuit sims OK, if mounting the IXT on the heatsink.

But is there a catch using an ancient bipolar output device 😉 ?

What I don´t understand is why the IRFP240-version falls off earlier when loaded harder? The sims show the 240 should have a Zout in the ballpark of 0.2ohm and the 3055 0.4ohm. At nominal 8ohm bass response is close to equal. Screenshot with 2ohm load.

Note the sims are not telling it all and are very basic, but indications look good.

Hello there,

Just joined the forum to see if I can find a bit of help with a repair of a CD player, which I'll post about in due course. I'm semi-competent with DIY electronics, but mainly from tinkering with guitars/guitar pedals.

Looking forward to interacting more!

Sam

Hello everyone. I am George from Greece. I am here to learn a few things about piezo speakers.
I owned and still own a few amplifiers, including some from the 80s and 90s and speakers for my home audio system, but it seems that piezo speakers are a totally different topic when it comes to speakers.

Glad to meet you all.

What amplifier do you use for taking your measurements when designing a system?

I tried researching what to use but didn't find much. I am wondering if some amplifiers color the sound enough to actually affect the measurements. I couldn't find anything definitive.

I will probably try a couple different amplifiers next time I am taking measurements just to see if there is any different in response at all. My guess is there probably isn't. If there is, I would hazard to guess its either at the far high or far low end of the frequency spectrum.

Currently I use this cheap class D mono amp. Its actually very clean sounding. I use one of these in my bedroom with better sound than I think you'd get anywhere else for $30.


I found a couple places and also heard from A4e that I maybe should be using a class AB. I do not currently have one of those. I had one in my car but it died years ago. Class AB and hot summers don't mix well. I am wondering if I should pick one of these up or a cheaper car audio 2 channel class AB.


The logical part of my brain says to use the same amplifier that I plan on using with the system. My current project I will be running this amplifier as I already own it and have upgraded the tubes. BTW, if you have one of these, upgrade the tubes and it will bring a world of clarify to the high end.

I bought two pairs of these boards to play around with and was hoping to get confirmation on some mods I saw on a thread in the attached picture.

Do these mods look correct to implement?

I just had questions:

- why the output is attached to ground via a 10R resistor and 68N capacitor

- is the larger .15 ohm 5W resistor bypassed here?

- is my star ground attached to chassis or floating?

- Finally, where is the best location to cut the trace on the board after the ground input? I understand I am just trying to remove the signal input ground from the PSU ground.

Thank you. Any other recommendations or modifications are appreciated.

I am trying to build a mac-based A/V system, and got really confused with the behavior of a few S/W and macOS(CoreAudio?).

I finally made the Leawo S/W BD player play the 4K UHD on my Mac Mini M1(2020), but quickly got embarrassed that the HTP-1 connected to it plays audio with center and subwoofer swapped! I tried to change the speaker config of HTP-1, but no luck. Then I found that AppleMusic playing Atmos track also has them swapped, but changing speaker config got center and subwoofer unswapped. So I assumed Apple Music was doing the right thing to use the speaker config info for output channel mapping, but Leawo BD player was stupidly ignoring it. Email with Leawo support also strengthened my conviction. Leawo guy didn't seem to have any idea what speaker config is.

Then I thought that Dirac Live Processor which I was planning to install anyway could give me the remedy. Written by a renowned S/W company, it was likely to do the output channel mapping of HTP-1 at the HTP-1 speaker config correctly, so the channel swap issue for both player S/W would be resolved. I seem to prove wrong!

The Leawo player and Apple Music are set to play into DLP, and DLP output is set to HTP-1. Changing the speaker config at HTP-1 doesn't work for Leawo player, the same result, though it should impact DLP output channel mapping, not Leawo's. Weirdly enough, changing HTP-1 speaker config doesn't change Apple Music playback case, either!
So, I tried DL virtual device speaker config: it works only for Apple Music like earlier case of changing HTP-1 speaker config without DLP involved!. And unfortunately, this doesn't work either for Leawo!

I am very confused with these behaviors. Is my assumption wrong that the speaker config change of an output device is 'supposed' to impact the operation of a S/W outputting into it? How can these behaviors be explained, and the channel swap issue fixed?

Got a Yamaha AX-900U that wont come out of protection. If I measure the idle voltage i get -38vdc on the right channel and 0vdc on the left channel and neither side will adjust but I think thats because it is in protection mode. Wondering if anyone could take a quick look at the schematic and give some direction on where to start looking.

Thanks,
Phil

Just a silly thought, but given that second breakdown is usually an issue with difficult loads, is there maybe something to be said for operating in class G but with the inner rail set to zero V?

The idea is that you could have the output stage run with only say 5V across it, and hence get away with only say 2 pairs of transistors, with the steering diodes connected to 0V so that when in third quadrant the transistors would not see a large supply voltage, the outer transistors then also only need to handle half the total supply (and will be the ones dissipating all the power, but a transistor that only ever sees 70V across it has way more SOA margin then one seeing 140V.

When in first quadrant the outer transistors will of course be burning essentially the same power they would in a conventional class AB stage, the savings come in Q3 when the output is supplying current while trying to pull the terminal voltage the other way,

Just a thought.

Hello all, I am building some custom output transformers from old iron. It is slightly rusty, is it worth removing, and if so, any recommendations on best way. Preferably without sanding.

Thanks for any feed back.
Jason

This is a general question. I used my last Ksc1815 and was thinking of ordering more for my stash. I have over 100 ksc1845s as I use them a lot. It looks like the 1845 is just a higher voltage version of the 1815. Is this correct?
I was thinking about passing on more Ksc1815s and using 1845s if I need an 1815.

Any battery out there can do +/- 24v?

And this is for my old linestage. Mine has Belleson regulated power supply there, and would to try Salas low voltage supply for that, in case no battery is available for this application.

I have a pair of Sequerra Ribbon tweeters for sale. I bought these from the audio shop I worked at in NY 20 yrs ago but the project never went anywhere.
These were apparently used in one of the Sequerra ribbon systems but I do not have any other details except that they are supposed to reach 40k.
They have the matching laminated core transformers that are obviously very over specd. Also have a spare set of ribbons.
Not sure of the current value however I am open to offers.

Here's for sale a couple of 417A / 5842 triodes tested in my calibrated TV7-D/U:

First unit is a Western Electric 417A, presumed NOS. Tests 120%. Production date code: 5739. Printing excellent.
Second unit is an Amperex 5842, presumed used but testing 110%. Production code is smeared, but reads something like *2A

They come in original Philips boxes as shown, but flaps are partly torn off.

55 USD for the pair, plus 15 USD for registered priority shipping anywhere in the world. If bought in Europe, I would accept payment in Euros at the spot exchange rate.
Paypal Friends & Family or bank transfer.

Cheers

hello.

I live in Korea.

I'm trying to design an entire turntable
I'm thinking of using a synchronous motor, but I have a few questions.

1. According to the results of my search, the only synchronous motor that I can purchase online is the Premotec 110v motor.(9904 111 81318)
Can you recommend another motor? (I hope it is of good quality and has less vibration.)

2. rega uses 24V, project audio uses 16V, 230v, linn uses 110V synchronous motor.
Assuming the same load and RPM (same number of poles and supply frequency), what effect does the difference in voltage have?
I am worried that if the voltage is high, there will be a lot of vibration.

Thank you.

Buongiorno, mi chiamo Giorgio e sono in attesa dall'Italia (Savona). Sono un appassionato dilettante. Ho un lettore CD MARANTZ 17 con il seguente problema: con il volume impostato al massimo sul telecomando l'uscita RCA è "bassa" su entrambi i canali
Checked the muting "signal" when the CD Is playing and It Is -11.5 volt. I read that 2sc2878 transistors used as Muting, could easily get destroyed/damage under certain conditions. It Is possibile that despite the signal NO MUTE (-11.5 V) the transistors (2sc2878) perhaps damage conduct a part of the sound to ground and therefore the output Is low ? Where could the fault be ? I don't have and oscilloscope. Sorry for my bad English. Thanks in advance tò anyone Who wants to help me. I am attach the cicuit diagram of the muting marantz CD 17. Hi Giorgio

Hi,

I am selling 4 2 pcs new TX2575 100k 0.1% resistors.
Purchased directly from the factory.

60 30 EUR, buyer pays fees, shipping from Maastricht, the Netherlands.

PostNL pricing

Thanks!
Daniil

Goodmorning,mu name Is Giorgio and j am waiting from Italy (Savona) . J am and amateur enthusiast of hi fi (vintage)and j would be honored If j can "enter" your magnificente Forum. Thanks

Does anyone have 3v9 zener ltspice model?
Thanks.

Hi - I purchased these regulator boards and additional components to use in a 211 amplifier. They are still in the packet and I will never get around to using them so for sale.

Hello! My name is Deha.
I live in Istanbul, and I work as a mechanical engineer. I have a strong interest in technology and problem-solving, which aligns perfectly with my profession.
In addition to my work, I have a hobby of repairing electronic devices. This hobby allows me to combine my technical skills with hands-on experience, and I find it both challenging and rewarding. I enjoy exploring new opportunities for learning and development, and I am passionate about developing myself both personally and professionally.

This looks interesting, especially if like me you're a measurement newb and already have a Digilent Analog Discovery.

Anyone here give it a whirl yet?

Audio Analyzer Suite for Analog Discovery 1 & 2

- THD+N vs Frequency
- THD+N vs Power
- Intermodulation Distortion
- Frequency Response
- Input Impedance
- Output Impedance
- Spectrum Analyzer w/function gen
- Oscilloscope w/function gen

BK

Does anybody know why the CAD drawing for the Dissipante inner baseplate is showing the mounting holes on a 10 mm x 12 mm grid, rather than the specified 10 mm (square)? Not sure if all the files are that way, but definitely for the current version uploaded for the 3U 300.

Really threw me for a loop when I tried duplicating the hole pattern on that thing.

I plan to build a gainclone, but i want to use SMD as much as possible. ( just for fun and learning soldering at the same time, nothing else )
I have both caps and resistors as 0805, but i wonder if thats enough ?
Do i need some 3 or 5W resistor as anywhere except the one on the output ?

Ahh, it's a LM3875, but that's already in the header.

I've been lurking on this forum for a while but only recently made an account. I've been building speakers for about five years now - intially simple boxes, then a large 3-way open baffle system around some Wild Burro Betsy drivers, then Frugel Horn XLs, a self-designed curved line array, some Cornucopya spiral horns, and most recently some Karlsonators that I will post about in that thread once this intro gets approved.

If an enclosure is hung on a wall is there a width and depth size that makes the speaker behave as if it is in-wall?

For example, if you have and enclosure that is 6.75 inches deep (1/4 wavelength for 500Hz) can you make it a 27 inch wide baffle (500Hz wavelength) to make it behave as if it was installed in-wall? In other words, whatever depth your enclosure is you need to make it as wide or wider than the full wavelength that corresponds with the 1/4 wavelength depth of the cabinet if you want it to behave as if it is in-wall. Assuming driver generating that frequency range in the center of that 27 inch wide/tall baffle, although, maybe that isn't necessary.

So here's the argument: vinyl is best, because it's really actually a physical transcription of audio. Others say CDs - they're clearer. And then reel to reel, cassette, 8 track, and those, I'm not totally sure what all the advantages are there. And now we have streaming, YouTube, Mp3, etc. I guess because it's easier.
So I'll let you take your pick in this poll. What do you think is best?

I have a small collection of audio equipment is various conditions. A search engine directed me here for some help with an Acoustat amplifier, but after poking around a bit I see there much, much more. Looking forward to learning and contributing if at all possible.
Phil

The Aune X1s dac uses 2 NE5532 for I/V converter and 1 NE5532 for LPF/buffer and I want to change the NE5532s to newer and better opamps.

2 things I have noted from looking at the circuit board so far:

1. The power supply coupling is close to the opamp but not the best practice. The 2 coupling caps are located near pin 8, so the negative supply pin with not get the best coupling. (Please refer to the image i found on the internet below).

2. There is no ground plane or any traces on the bottom layer below the opamp.

I'm thinking of LME4562 and OPA1612 which are unity gain stable, not to high band width, decent slew rate (>20V/uS).

I have 3 questions/topics to discuss as follows:

1. Will OPA1612 or LM4562 be a big improvement or the NE5532 is good enough?
2. Will the OPA1612 or LM4652 be stable in this circuit?
3. Is there any better opamp that suits this circuit. I'm also thinking of something fast like LT1469 or LT1358.

Thank you!

I'm looking for replacement ribbones and or specs for the metranome 3s by dick sequerra.
If anyone can help with any information I Wana learn

Hi,

I was looking for a display for my DAC project and found 256x48 VFD displays sold in bulk. They looked good so I bought some and made a PCB with everything needed to power and control it.



Module size is 170x46 mm (display itself is 150x40)


To control it I put a STM32 MCU and since the MCU is already there, it makes it logical to make it useful for process all other front panel knobs: encoders, buttons, leds, potentiometers etc. Of course for a specific build it is better to just put everything on one board but at the moment exact set of controls needed is unknown so I've tried to make it somewhat universal by putting two FFC connector on both sides for expansion modules:




On each of these expansion boards there are 2xI2C buses, one MCU ADC input and 6 gpios (unique for both sides).
Main 12pin header has supply input (5V), and MCU GPIOs. Pins are chosen so that I2C, SPI and UART peripherals are available here. So again, pretty universal.
Schematic is nothing special, it is attached.

I do not have the side expansion modules yet but for my purposes I'm going to have encoder with some LEDs+buttons.

Regarding the firmware: the display is supported by u8g2 library which makes it really easy to do some sketches with lopaka app:


I'm sharing this because I have more such modules assembled that I really need and consider selling these in future, the firmware for MCU is also going to be published.
But I have two questions:
1. Maybe it makes sense to create some 'default' firmware for those who don't want to deal with MCU coding? For example, firmware which receives I2S WCK and prints current sampling rate etc.
2. What kind of expansion modules are needed? Of course it is not possible to make it 100% universal.

Anyone have any info on this ? Still sounds great

Hello, This is a behringer ultradrive dcx2496 pro bought around year 2011. It has been in use for approximately 5 years in that timespan.
Perfectly working. Comes with two long cables . Asking $175.
Shipping to canada at buyers expense.
Regards

Hi all -

I have a pair of Rogers LS4a's that I dug out of storage and have finally decided to resurrect. One tweeter is blown.

The original tweeter is a 19 mm aluminum type manufactured by Seas - Model H414 TAF/G. They are no longer available. In my research, about a decade ago, it seems like the accurate replacement became the Model H0532.

However, now it seems that this model is no longer readily available.

Before I reach out to Seas directly, I figured thatI would post on the forum to see if anyone knows of an alternative tweeter that would work well or a source for either of the Seas recommended ones.

Thanks!

Jon

My recent upgrade from a Raspberry Pi 4 to a Pi 5 left me without a convenient audio out. So I thought I would get a HDMI audio extractor. We'll I did, and I am disappointed. I thought with this device I could replace my Windows 10 Dell all-in-one that I use only for streaming Pandora. I feed the PCs headphone out to my little 6BM8 tube amp and small near field speakers. I really dig the sound from this,but when I switched to the HDMI extractor the sound quality diminished.

The device I bought is supposed to handle 4k at 60Hz, so I thought it would do a good job. Anyone have experience with extracting audio from the HDMI output? I know it's not ideal, but really, should there be that much difference between these two ways of playing audio from say Pandora?

Thanks in advance,
Roger

Does anyone have a Monacor WG-300 they are willing to sell?

Thanks

Been a minute since I posted here. I have enjoyed my previous project for years. That project was some modified Polk T50s using a Dayton DAS 175-8 and morel MDT29. I fell in Love with the things I heard from that Morel tweeter, but in some respects the DAS175 has left me wanting for a more full sound. Or maybe it was just the overall path I took. I really should have gone 3 way instead of 2. So now I am going for Really 3 way. You see I came across some enclosures I had to have. Like Vintage solid wood. I think it is Walnut. I am including pictures and would like to hear what path you would take for a 3 way. But 1 st let me tell you the path I am heading into. I am leaning towards a Woofer & MidRange in the vintage enclosure and topping that with an articulating Tweeter enclosure on the top. And I will be at some point upgrading to a better subwoofer system. I want to make the sub system to stand these vintage boxes on for a some tall towers> These vintage boxes are currently 16.875 W x 23.750H x 18D internally. I have looked for weeks now trying to choose a proper midrange to work with the Morel MDT29 and the SB34NRX75-6. I also looked at the 10" SB woofer but this particular 12 can work well in a sealed box. Since I will use a subwoofer system I like the idea of faster transient response from a sealed woofer & sealed midrange. I would make the Tweeter box adjustable for depth and cant and also include the Xovr within that enclosure to the back. So an easy to get to crossover I could play with. Your thoughts and ideas? Would you be more apt to build something like the Gema? ???

SB34NRX75-6 + Undecided MidRange + Morel MDT29 ( or one with slightly higher SPL)

Hi, I have a SA15S1 that is not taking cds anymore. It does but it can refuse 10-20 cds then take one. Been like this for a while.
Also mention that it has extern clock/powersupply, so when it works it sound real good.
I change the lacer 4-5 years ago.

So, now I think maybe its time for a new one, how does the CD50N sound compare to a original SA15S1?

Must step up to SACD30N to sound as good?

Frank

Hi All! I’m new here, but I posted this on Head-Fi and Audiophile Style, and I haven’t gotten much traction. I’m curious if folks here have any ideas on how to make this work.
_____

It’s 2025, people, and the world needs a plug and play, headless, “it just works,” Raspberry Pi (or other SBC) running HQPlayer Embedded locally. I know, HQPlayer is supposed to need a small nuclear reactor to crank DSD 2048 with unspeakably complex filters and noise shapers, and I am 100% for that at home, but what about on the road? Hear me out…

The Vision:

I think a lot of us have wandered into the HQPlayer conversation after encountering a product from Chord, realizing that handling of digital signals is absolutely crucial to sound quality, getting addicted to the detail and musicality, finding out about the M Scaler, seeing the price, throwing up a little, and then thinking - “there’s got to be a better way” and landing on HQPlayer. Besides giving Jussi a bit of an ulcer with constant comparisons to the M Scaler and its legendary million taps, this process has also had the side effect of Mojo / Mojo 2 ownership among a large portion of the HQPlayer audience.

The Mojo is in an interesting spot in the audio device stack. It’s certainly capable of competing with most modest to moderate desktop stacks in terms of sound quality, yet it is portable. We have seen a significant rise in quality (and prices) of high end dongles that also compete in this space. Of course, DAPs are also reaching ever loftier heights of technical prowess. We can enjoy incredibly high quality audio on the go, and now that we have heard the benefits of HQPlayer, why are we depriving our portable systems of this essential upgrade. It might have seemed crazy in the past to spend almost $300 on software to upgrade the sound of a portable system, but that’s the going price for a battery base for the Woo Audio Tube Mini, and it’s less than half of what people will pay for a Chord Poly just to act as a streaming endpoint with no upscaling at all for the Mojo.

I travel a lot for work, and when I do, it’s with an iPad and iPhone and either my Mojo 2 or Tube Mini depending on how I’m feeling before heading to the airport. I don’t have a laptop, but I do have Roon Arc with Qobuz and a bunch of DSD and Hi-Res PCM files on my Roon server with my favorites saved locally on my phone. So, HQPlayer on a laptop is not really a practical solution, and a VPN would be fine when I have a great internet connection and everything works perfectly and I don’t have to reset my desktop, but it seems janky and redundant when I’m already effortlessly playing my newest MoFi and Analogue Productions SACDs that I’ve ripped to my Roon server through Arc to my portable DACs.

All that is missing is a little box that sits between the phone / iPad and DAC and magically makes the music from Roon Arc sound even better - no screen, no settings, just switch it on, plug it in, and benefit. Think of it almost like a mini M Scaler or a mobile DDC or a Poly-ternative. It would be perfect in the hotel, at Head-Fi meetups / Can Jam, when auditioning gear at a store, and on planes - Rob Watts has said he listens to his M Scaler + TT2 on planes, which is a totally baller move that I would like to replicate at a smaller scale. There are so many situations where this would be useful, and I think it is possible now. I don’t think this is something that we will need to hassle Jussi to do. As a community, I think we can build it, grow it, evolve it, and share it.

Tools and Challenges:

Frankly, when I started looking at HQPlayer about a year ago, I just assumed that someone had already come up with an implementation like this, and you can see my confused posts on the HQPlayer settings thread from late March 2024 just assuming I was tweaking some setting wrong. After doing a bit more digging, I don’t think this has been done yet. I think the parts are all there, but we just haven’t pulled them together into a coherent package. I have enthusiasm and patience for messing around with things like this for way too long. I have a couple of Pi 4s and many of the necessary adapters, accessories, etc. to tweak and test implementations. I have been building, tweaking, and overclocking computers since about 2001, but I don’t know much about programming, formal computer science, or Linux, though I’m certainly willing to learn some bits and pieces if people can explain a problem to me like I’m five and point me in the direction of the necessary info and wind me up.

Raspberry Pi

To me, this seems like an obvious choice. It’s relatively cheap, it has strong HQPlayer support already, Pi 4 is powerful enough for most anything we would want to do with PCM, and with ultra light modulators, Pi 5 might be able to do meaningful DSD. Pi also has USB OTG support built into HQPlayer OS through its USB-C port. There are numerous HATs like Pi Juice that could be used to provide power through the GPIO pins as well as some limited battery and a separate charging port (suitable for a power bank as well).

We have Pi 4 and Pi 5 to choose from, and for a first run at this, I think we will need to pick a lane here. Open to suggestions, but Pi 4 seems like it will be the more mature system with more manageable power draw and thermals, but I could also understand if people feel that this wouldn’t be worth doing if it doesn’t do DSD, which would be more of a Pi 5 thing, if it is feasible at all at this stage.

HQPlayer OS / Embedded vs HQPlayerd

This is where I am out of my depth. I don’t feel like I have a good understanding of the options here, and I am not sure there is a single place to get a straightforward comparison of the possible implementations. This is a question for a person with significant Linux and / or HQPlayer experience I think.

I nearly have a Raspberry Pi 4 with HQPlayerOS working in this use case, but the jankiness level is extreme. It has played from my iPhone Roon Arc app > USB C OTG > Pi4 HQPE > Mojo 2 a couple of times using the USB C into the Pi4 and the USB A out and the Pi Juice HAT with or without a battery (can just be plugged into the wall for full power through its own micro USB port). It requires access to web interface to start playback from the USB port, however, and this would not be feasible for the intended use case.

I think it is reasonable to configure the settings for filters, shapers, modulators, etc. using the web interface once on a home network. It might also be nice to have a few different SD cards that can be used with different DACs, if, say you want PCM for your Mojo but an AK4499EX DAP might do better with DSD. You could just configure each installation the way you like and drop in the card that corresponds to the DAC / Dongle / DAP you want to use that day.

It is totally not reasonable for this use case to have to log into the web interface and enter a URI just to start the music playing. This seems like the biggest hurdle we face on the software side from my novice perspective. Given the level of sophistication of even relatively cheap dongles using UAC 2.0, I have to think that this problem has a solution, it just needs to be implemented.

In my vision, there is no need for a screen, options, or really any level of configuration while out and about. If we are successful in this first iteration, then I could see it expanding into something much more DAP-like. It could have a screen with options, it could replace the phone and act as a streamer, or it could replace the DAC/AMP with a fancy HAT or possibly some version of DSC-1.

3D Printing:

I’m planning to get into 3D Printing in the near future (I have a Bambu Labs A1 on the way), though I have no experience so far. My wife is extremely crafty and would be interested in helping. I already have a number of ideas for different audio-related bits and bobbles, and I could definitely see making a case for the Raspberry Pi and Mojo 2 together. This could obviously be adjusted to accommodate other dongles / portable DAC/AMPs. We could make the CAD files available for people to edit for themselves.

Future:

A couple of interesting thoughts have crossed my mind here as well. I wonder how long it will be before we have something like a Pi Zero 3 with hardware that could come close to Pi 4 performance. I also wonder if solid state cooling will make it possible to run a Pi 5 fast at relatively high power and performance in a small form-factor case (there will be new demos of solid state cooling chips at CES this year). If we get started imagining together, it’s hard to tell what awesome ideas and use cases we could come up with!

Next steps:

First and foremost, I would love to hear feedback and others’ ideas for how to proceed. Is there a possible direction or solution I haven’t thought of? Is it even remotely feasible to configure HQPlayer Embedded / OS / other version to behave in the way I’m envisioning with no need for user input after initial configuration? If so, can you do it or tell me how to do it (preferably like I’m five)?

I think we need to pick a device to be the heart of this thing and prove that the software can work. If it does, then I think we’re off to the races with testing potential accessories for power, I/O, case designs, performance / temp / battery life optimization / electromagnetic interference management / etc. (these are areas where I believe I can be of great service, more so than with the software).

This project also needs a clever name…

Thanks for reading, and I can’t wait to hear your ideas!

Mods, please remove if discussion about capacitors is not allowed.

I have built some three way speakers with a DSP crossover (Nanodigi) and got them to a point where I like the sound and have decent nulls (good phase alignment). So the next step is to try my hand at a passive crossover.

I have used my measurements and Vituixcad to design a passive crossover which gives a similar response to the DSP crossover I like. However, I do not have a stock of parts so will be buying from scratch. For capacitors, and to mock up a first try, is it acceptable to use MKT (Jantzen Compact MKT Metalized 5% Polyester Film Capacitors) for the woofer low pass and mid low/high pass and MKP (Jantzen Standard) for the Tweeter High pass filters. This would half the price of the parts as a first mock up (compared to using Jantzen MKP Cross Caps).

Thanks in advance for responses.

I've recently sent my NAD 614 cassette deck to a repairer as it was not receiving any power. He replaced the motor and drive belt and has now found that the solenoid controlling the lift/dop of the playing head is faulty. Unfortunately he can't source a new one. He has asked NAD but no luck there. On the NAD schematic it is called Ref 83 Solenoid Assembly and has a parts no. 0000P01030. Does anyone by chance know where such a thing can be had or whether an alternative part exists. Thanks in advance.

Is anybody familiar with Chris Found’s VDAC designs please?

Over the coming days I will post more versions of various chassis feet here for anyone who has access to a 3D printer to download and try out.

Here are some posts I've made previously for 3D printed chassis feet.

Bare Board Feet (ACA Mini slide on over Hex)
Bare Board Feet (ACA Mini, or others using M3 bolt/nut)
Bare Board Feet (Zenductor II)
Modushop Feet Risers (fits inside standard Modushop plastic feet)

Here's the latest version I made based on dimensions of a commercial chassis foot for sale. You want to print using soft TPU (Thermal Polyurethane) to get close to the squishiness of rubber. Additionally, TPU has some grip (not as grippy as rubber, but works fine), whereas harder plastics like PLA and PETG are slippery and could scratch more delicate wood surfaces if used on heavy amps.

Suggested TPU Print Settings for Large Chassis Feet:

• Temperature - Depends on your brand of TPU (I use around 220°C for mine)
• Walls - 2, or 3
• Infill - Gyroid, 15-20%
• Top/Bottom - Increase top to 8 layers at 0.2mm/layer. Feel free to do the same with the bottom layer if you don't mind a few extra minutes of print time, but not critical since it's in compression.
• I suggest using a glue stick for the plate adhesion, but if you know what you're doing, it's not critical to use, just a safety blanket for me since I print on flat glass.

Here's a picture of completed "Chassis_Foot_PrtsExrs_Clone" set with one that failed to finish printing showing the internal "gyroid" structure that gives it extra "squishiness".


Here's the dimensions of these large chassis feet mimics from off the shelf rubber options.

Attached you will find a small collection of 3D printable parts I have found useful when building or asembling enclosures. I have a board-mounting block, handy in situations where the PCB mounting holes aren't quite where you want them; a foot (I use peel-and-stick felt dots to cover the hole and prevent scratches), a couple of knob designs, and my version of a coax stripper that uses utility blade cutters. The knobs are a little unusual because I didn't think the plastic would be robust enough to avoid stripping-out the set screw threads. I got around that by using a short length of brass hex stock. It's drilled on one end to accommodate a pot or switch shaft, and drilled/tapped on the side. The hex piece is glued to the knob to fix it in place, and the hex form adds additional strength, in terms of torque. Pots are pretty easy to turn but switch shafts can require more torque to turn them.

I also like the visual appearance of the brass, but it would be easy enough to print a blind hole if you don't want that look. I'll add an STL of one with that feature to this thread.

The only tricky part about assembling the knob is keeping the glue away from the set screw hole. A drop of CA glue will do the trick.

I bought some cheap used compression drivers on ebay. They are the eminence nsd2005-16. i chose them because they have a 2 inch diaphragm, a 1 inch throat and a factory fs of about 578hz. not to mention i bought the pair for $90 shipped. I'm not one to spend a fortune on audio and i figured it was a good place to start. Once ia recieved the drivers, i printed a horn to test them in; the ath a520g2 with extended throat. I also printed a couple metamaterial rear chambers and picked the best of the two. then i added aquaplas to the diaphragm wihich i also purchased from ebay for $23. here are the results.

factory rear chamber, no aquaplas



Metamaterial rear chamber, no aquaplas



metamaterial rear chamber, 1 gram of aquaplas



a lot of this is below the noise floor of my rather noisy ifi zen dac but its what i have at my disposal. i havent listen to music with these but the sweep itself sounded noticeably better. the only problem i see is a deeper/wider notch @ 14k. idk why this is. it could be that i dimpled the diaphragm while applying aquaplas. it popped back but this is a lesson learned. when i get around to the second one i will be more careful and hopefully it wont happen again. then we can see if there is a difference. otherwise i consider this a success.

Several years back I built a pair of ‘child safe’ Seas A26 inspired loudspeakers, in large cheap IKEA cabinets with heavy duty steel grilles to prevent little fingers reaching tweeter domes. Following a house move the time has come to get these out of the house. The drivers are in very good condition, have never been driven hard. The cabinets are functional but not very attractive. I built simple crossovers following the A26 design, but with small / low power inductor etc (intended to get me up and running, but I never went back to do a better job).

Will follow up with photos later today.

Open to any offers for the driver set. Happy to provide the basic crossovers too, but I’d suggest that anyone building an A26 or similar Devore style speaker should plan on redoing these properly.

Collection from Edinburgh would be welcome, but I can ship drivers within the UK if costs are covered.

Ping me if interested. Happy holidays all!

I bought this for the fun of it. It's a bandpass box with 2 x push-pull 8" drivers. The surrounds of both drivers have perished. I have no interest in restoring to its original spec using the Peerless drivers.

Any ideas?

I have for sale 10NOS Epcos now TDK capacitor with screew in terminal, 15000uF 40V. Bouth them from RS years aggo... lets say 100

What is the most euphoric midrange you have heard? So far I have heard KEF Reference, Dynaudio Contour, Accuton, Seas, and B&W Kevlar.

Based on my experience hard materials sound more similar than different. The higher the young modulus the brighter and more revealing the sound. An excellent goal when the source equipment and music is well recorded. Putting a state of the art measuring DAC will be heard on these speakers. But soundstage will not be artificially expanded and nothing will sound better than what it is. If you are in audiophile with refined taste in well recorded music and top of the line equipment then this is for you.

Poly isn't so much euphoric as it presents a softer tone and sounds more expansive. Giving up ultimate resolution, perhaps changes of equipment are less noticeable but it makes most content sound more listenable. I assume most soft materials are like this.

If my personal preferences tend towards the euphoric and not the audiophile. What paper midrange is most likely to please me with a Sonus Faber type sound? Sonus Faber uses Kapok and Kenaf. On the DIY side we have the paper Revelator, Illuminator, Purifi, Satori, Seas Nextel & Acoustic Elegance.

Finally decided to resurrect my old pair of Rogers LS4a's. Have been looking at the same threads for probably over a decade. Decided to join the forum because it seems like the right place to pick the brains of folks in the know.

I looking for a 8” woofer to go into a sealed box app. 45L . I would like to spend $100. Or less per .

What do you think of this power supply for B1K?

https://cpc.farnell.com/tiger-power...000/portable-power-supply-bank-24v/dp/BT06846

Hello common Swedes!

I was planning to stock up on some transistors and audio OPs buy buying from Profusion

https://gb.profusion.uk/uk/#
(use EU side in menu when.going to the store)

Cost of shipping TO Sweden is roughly 300 SEK so if there is any out there interested we could share perhaps.

Drop a DM or write in thread.
I live close to Malmö.

hello,

someone in a recent thread mentionned stk4231. A local store clears stock, claiming to have original sanyo products. I would like to check marking against original sanyo

Any picture ? Tips ?

Hi. Sorry I brought this up earlier, but I've reached the point where I'm almost obsessed with the future of my vintage audio gear, so I'm thinking of buying another set as a backup, to rotate them every 6 months, is that a good solution?

Hey I’m going through a lot of stuff trying to downsize and found this.
A bottom cover from a Modushop (?)
Chassis (400u?)
Anyway,
Yours for the the cost of shipping and maybe a couple bucks for the old guy packing it up,🤣
Excellent condition

Hi everyone,

I'm from Berlin, Germany, and I've been interested in the DIY audio scene for some time now. I enjoy learning about and building custom audio gear, and I'm currently looking into building my own open baffle speakers. I'm excited to join this community and share ideas with like-minded people!

Looking forward to learning from all of you.

I need to replace a bunch of MSS2-1A05 reed relays in a pre amp. Would this relay be suitable EDR201A1 5V. The coil resistance is much higher 500ohm vs 140ohm and the input power is much lower 50mw vs 178mw

I have a schematic One of the inductors has a value of .07mh. Is that a typo. Or are there inductors of the low value?

Hello friends of DIYA,

For the sake of having clues of audio preferences, isolating bad audio devices or both, I always make measurements of the thing I built or take for upgrade or simply listening (borrowed).
Of course, my measurements limit is the Asus Xonar board, but I use it anyway, since things like the AP2 system is outrageously expensive...
Perhaps some clues appears even with some limitations.
I posted here since my idea is to post something about the DAC's, since measuring amps and preamps are far more easy to interpret.
For example, some of my current DACs or equipment having ones:

1 - CS8412>YM3433>AD1860:


2 - DIYINHK USB interface > IanCanada I2s to SIM converter>TDA1541A>passive I/V>tube pre/buffer:


3 - CS8416>DF1704>PCM1704>trafo I/V>tube buffer (Aikido):



4 - DIYNHK USB interface>DIYINHK ES9018K2M voltage mode:



5 - CBHT Audio china micro portable phones DAC:


That are some examples of basic measurements, ans sometimes I'm in doubt about the wheight of the eg. jitter sidebands, but are clear about some unfortunate mains noise pollution in some measurements. Mains noise aside, what I'm need to focus more about things to note?
The idea here is to learn to interpret better these type of graphs.

For some DAC's I measure the amplitude, reducing 20dB each timne until signal is not visible anymore.

True or not, I have preferences for some of these DACs.
For instance, the CBHT audio sounds extermelly metallized/harsh (and the sidebands around the J-test are variables).
The AD1860 sounds also harsh, and normally I culprit it due to it's internal opamp, albeit it "seems" to measure decent.
One of my preferred ones is the TDA1541, using the PC as a digital filter, since it is NOS. At least measures "clean" (considering the tube stage). Sounds ultra open and have a amazing rendering of background echoes of live recordings.
I use regularly the PCM1704 DAC, but these measurements not are so pretty... a little worry about...
The DAC with the ES9018 sounds very "competent", but not have the "air" of any of the multibit DACs I have. And measures bad due to high output impedance due to direct voltage mode use.

i "made" (simulated) an parallel op amp amplifier my idea is to use something like th jrc4556 as the "power" op amps and an ne5532 as the "voltage" op amp
feel free to give sugestions

Hi guys, Yesterday I've finished building the 6336 SET amp based on this website:
https://www.cascadetubes.com/the-6336-set-amp/

After that I did some testing on the amp I found some strange wiggling on 1W output frequency response graph at around 14 - 30 Hz:



What can cause this wiggling? BTW is it even something to get worried about?

Here is some pictures from square wave responses and also power vs. THD if they can help:




Thanks

I have a Buffalo III and Buffalo IIISE that I've had for quite a while. I'm trying to get them running in dual mono mode. Neither DAC has the firmware chip. I believe the hex file is still available on the Twisted Pear website, but I don't know what chip is needed. Any guidance will be most appreciated.

Of course I may be asking a really dumb question. If that's the case, just let me know.

Cheers.

This is a way to use low voltage tube to drive headphones.
Uses 4 transistors for the output.
Is adjusted to give some THD with 2nd harmonic.

Hi,
After some time running (30-40 min), the right channel makes a loud popping noise. Then sometimes the protective circuit switches the amp off.
It's the same problem mentioned here:
http://www.hifi-forum.de/viewthread-185-10129.html (sorry, german language).

The user declared 2SA1309 (AR) , 2SA1370 (D) and 2SD1512 (AR) as problematic and replaced them. After that, the problem went away.
Unfortunately, I'm neither able to find 2SD1512 nor a replacement type. I need at least 6 pieces.
Attached is the circuit of problematic board, the service manual and 2sd1512 datasheet.
I hope a nice user here ist able to help me in this case.

Best regards
Olaf

I like electrical engineering (not an EE), high quality audio (not obsessive), subwoofers and their very low frequencies, computers, biking, healthy food etc.. I come here to expand my knowledge.

good morning everyone
soon I will have a problem

Placing a small speaker on top of a subwoofer

To make a long story short I am looking for a system to mechanically decouple the small speaker from the subwoofer box
For now I have thought about the following options:

1. washing machine feet
2. squash balls held in place by plastic rings that prevent them from rolling
3. small diameter air chamber
4. gymnastics mat
5. marble slab with adhesive rubber underneath

do you have experience with these problems?
thanks everyone

The JLH-like amplifier I designed/built has a nasty turn-on transient. That was an oversight on my part, I didn't simulate that. The problem is caused by the autobias circuit, which requires a ~100uF capacitor to charge to about Vbe before it begins to work. In the meantime the idle current and output voltage go nuts -- see below:


If the low pass filter capacitors are increased to, say, 500uF the problem is even worse.

The schematic above has my solution (the top half of the amp components are R23, R24 and Q13). It is a current-sensing transistor that turns on when the idle current is too high. The circuit can't completely eliminate the turn-on transient because at some point it could be triggered when playing at higher (but headphone-safe) volume. R23 is set to 1 ohm to illustrate the "nasty" turn-on transient.

When R23 and the corresponding resistor on the negative side are increased to 5K the transient looks like this:

Much better. The transient will still produce a fairly loud "thump" but nowhere near the 300mW max for your typical headphones.

The added circuitry doesn't increase the THD -- it simulates out at .006% for a 1KHz 4.5Vpp signal into 48 ohms, so the limiting circuitry isn't activated by normal-to-loud musical material.

Never used Focusrite Scarlett 4i4 3rd Gen usb audio interface for sale.

$135 includes shipping within USA.
PayPal (F&F)

I am truly confused with this amp right now. Everything appears to be functional yet I have an lm317 where the lm337 is supposed to be. Isn't that the same as having a 7912 where a 7812 should be? How is this amp still working? According to the schematic u4 should be an lm337.

Hello I have a pair of Muse model 300 amplifiers and all the pictures of the back of these amps show that there is a resistor across the xlr jack , can any one enlighten me what this is for and do I need this on my amplifiers?

while looking at OP-amps that I could possibly use to replace the ones in my dac (ad846, used as voltage buffer and not I/V conversion, that part is handled by a resistor) I looked at the ad846 datasheet and noticed it is a "Current-Feedback Op Amp".

how do they work? can you put any OP-amp like the typical voltage feedback ones in its place and it'll be fine (like newclassD, burson, sparkos etc...)? or am I supposed to stay with current feedback amplifiers?

if I need to stay with current feedback op amps, are there some I can simply replace without any modification to the circuit? my dac is not DIY so I would like to upgrade it with making as little changes to the circuity as possible.

looking at op amps like the ad8001,ad811 and lme49713, can you simply replace the ad846 with one of them without any special circuit changes?



thank you in advance!! (the dac I own is the muse model two plus)

A few months ago I'd decided I was ready for a change in my center channel speaker from craigslist. The Acoustech PL-28 was a poor timbre match to the rest of my front stage (currently a pair of Infinity Qb speakers, a large 3-way), and I had the itch to try my hand at a full range speaker with my own crossover design after building a few speaker kits in the past. After some reading and thinking I decided to focus my search for drivers on coaxial drivers for the localized imaging they inherently offer.

Fast forward to December and I'd basically landed on the Satori MT19CP as the driver I was most interested in. Large enough that it should have headroom at higher SPLs, and frequency response modeled down to 60Hz (my desired crossover point) in a reasonably sized vented enclosure. Over Christmas break I noticed that the drivers were on sale through Madisound so I pulled the trigger on three of them (more on how I'll use the other two some time later on) and started working on the enclosure and crossover designs in earnest. I landed on an enclosure that was 9"H x 24"W x 15"D with two front facing ports tuned to around 53Hz. This was also my first experience with VituixCAD and modeling with baffle step in consideration as well. After a few revisions on the crossover and enclosure I ordered the remaining electronics and mapped out my cuts for the enclosure.

I decided to overbuild a bit, and doubled up the 3/4" MDF for the front baffle. Gluing had to be done indoors since the temperature in the garage wasn't high enough:


Cutting was kind of a pain too, with an atmospheric river coming through Portland at the end of December and into January.


Crossover mockups (longer layout for to allow it to pass through the driver opening in case I want to change it up later on):


Bevel in the baffle:



Mocked up with the dowels holding things into place. I'd change my approach to dowel layout and the assembly order if I were to do it again, but they turned out OK:


I finally finished assembly this last weekend. I totally forgot to take pictures of the interior with the egg crate foam installed, but it's in there.



I took some measurements with REW after I got the enclosure together. If you sit off center even slightly you can't hear any of the dip you see at 9K Hz. I was surprised about the dip in the low to mid-200Hz range, then dipping again right below 100Hz and falling off a fair amount under 80Hz. Surprisingly (and missing from these measurements), there seems to be a good amount of room gain down in the 30Hz region, without taxing the driver too hard. I wouldn't leave it to handle those frequencies or anything, but it was not something I ever would have expected.


My impressions listening to it have been very positive so far. Vocals all sound lovely on the test tracks I threw at it, highs are crisp and despite the way the SPL chart the low end was nice as well (though it's definitely lacking under 70Hz or so).

Anyway, that's the project so far. I'm going to let the speaker break in a little more and then measure again. Definitely interested in thoughts from the community. When the weather warms up I'll be learning how to veneer the cabinet and work on the execution of the project that uses the other drivers.

Cheers!

Yesterday I bought a set of KEF 103.2 speakers. Oldies but decent speakers.

When I got home I connected them and everything sounded quite nice. Then I put on a vinyl record by "Nightmares on wax", a quite bass heavy record.
This was all on moderate volume.
After a minute or so the bass became noisy, as like the subbass was made with a noise component.
So I read about the crossfilters needing a recap, so before I ordered a recap set, I did some tests.

Long story short, when I finally connected the speaker out directly to the woofer, i heard the same kind of distortion......so there must be something wrong with the woofers. They don't sound blown to me, but they don't sound right either.

Did I just buy a pair of duds or is there an easy fix for the woofers, so I can order the recap set, instead of throwing this lovely set in the garbage,

Where can I get the battery power supply for low voltage application (preamplifier)?

Simulation requested by another member separately.

FlaCharlie has built several successful amps using 6N6G.
And may find these results interesting.🙂👍

anyone seen this?:
YouTube