I've been trying to trace an issue with my NAD t751.
1. Extremely low volume output on both left and right channels
2. No output when surround mode selected.
3. Doesn't matter if headphones or speakers
4. Doesn't matter which input.

I've bought an oscilloscope and I THINK I've traced it to the multichannel board. Audio goes from inputs to this board, then sent to the amplifier boards.
I get a signal from my freq generator to the input of the "m62447sp" IC.
It seems that the output pins of this chip are dropping the signal. Is this how it's supposed to operate or should the volume be increased and maintain waveform?
I'm not sure if I've just found the issue or if I'm misunderstanding this IC.
See attached docs.

Hi everybody,

I'm trying to repair a luxman d-05u.
The issue is that it doesn't read SACD's anymore, CD's are playing flawlessly.
I suspect the laser to be the cause of this issue, my SONY SCD-555 showed the same issue and replacement of the laser was the solution.

• Does anyone have a service manual or schematic available?
• Does anyone have experience with this specific player showing this issue?

Best regards,

Bart

I want to make a pair of tower speakers. I am at the beginning of the project, choosing the speakers and crossover. Since I am a beginner, I chose a set of speakers that can be bought with a crossover. In my head, this crossover comes ready to use with this set of speakers (please correct me if I am wrong). What do you guys think of it?

Crossover: Swan DN-CE5.1F
Low mid-range: Swan E6.5
Mid Range: Hivi DM-7500
Tweeter: Hivi Q3B

The reason why I chose this set was because I found them at a good price in a store in China. And of course, because I think they come with a sort of ready-to-play crossover.

Hi!

Continuing from the "main thread" I wish to discuss and get help of implementing an infrared (?) remote control that can do:

• Volume + / -
• Mute
• Play, Next, Pause
• Change config
• Tweak a PEQ parameter

Platform Pi5 and pCP picoreplayer with CamillaDSP.

As I understand it, I need:

• Pi5
• Power
• An IR receiver eye
• A remote - preferable the small metal Apple remote or the like.

I can hook up the IR to the Pi but then its get foggy ;-)

Please help!?

//

I'm new to vintage audio and looking for tips.

_____ **___This giveaway ended on March 16, 2025 __**_____

Congratulations to Abx74 as the winner!!!!







Everyone loves a good giveaway. This giveaway is Honoring our diyaudio colleague Mark Ozdoba { @Toys4Boys }, who passed away in September of 2024. Mark and I both got into diyaudio around the same time, and we made a connection as we learned and shared knowledge building our first Pass DIY amps.

This is in fact Mark’s F5m kit (Essentials, Completion, PSU) and I’ve added in nearly all the additional parts to finish a complete amplifier. The only items needed are a chassis and a transformer.

Mark would love knowing his kit (which is from the first round of kits sold in the diyaudiostore in March 2024) would be built, so it can play glorious toe tapping tunes.

I’m politely requesting that this go to a newer builder. Please don’t enter if you have a stable of amps. It would be great to see this go to someone who’s relatively new to diyAudio that would benefit from all the additional bits and pieces included.

I will cover shipping in continental USA and will take off $10 from total shipping cost for international shipping.


To Enter: Just copy the list in the most recent post, add your diyaudio surname/alias at the bottom of the list, and post (country is optional, always fun to know where you reside)

Rules: I will leave this open for one week. On the evening (in Seattle, USA) of St. Uhro’s Day I will enter all the names into a spreadsheet and randomize. The entrant at the top of the randomized list will be the winner.



Here’s what is included:

• F5m Essentials Kit (PCBs, JFETs, & MOSFETs)
  • Also includes 4qty Keratherm 86/82 Insulator pads, 4qty 3/4" fender washers, belleville locking washers, and M3 bolts to secure MOSFETs to heatsink
• F5m Completion (all the parts to complete the F5m PCBs and additional hardware)
• Nelson's V0 PSU Kit (all the parts to complete the PSU)
  • 2qty 4.7ohm Epcos B57236S0479M000 thermisters included for higher biasing using the V0 PSU board per F5m article
  • 2qty rectifiers (non metal case)
  • Rhthatcher snubber PCB
    • 2qty 0.15uF, 2qty 0.10uF film caps, and 2qty 22R resistors (ideal for Antek AS series)
  • Rhthatcher soft start board (technically this isn’t necessary, but included to make hookup easy)
    • 6qty male 0.250" spades, 2qty CL-60 10R thermisters, & 3300pf X1Y1 safety cap
• 3D Printed Transformer Seat Kit (works with 300VA or 400VA Antek AS/AN series)
• LEDs for front panel with wires already attached and 22k resistors (blue of course)
• Neutrik NF2D RCA inputs (silver body with one black RCA, one white RCA)
• Power Entry Module (Shurter 4304.6090)
  • Includes 2.5A, 3A and 10A fuses
  • Premade 14Ga Safety Ground Pigtail with eyelet and 0.187” female spade (soldered on to PEM)
  • Twisted heat shrink 16Ga AC mains wires with 0.187” spades installed for PEM connection.
• 4qty speaker binding posts
• Input Wire for Signal (3 dual conductor options included to choose from)
  • CAT8 ethernet twisted pair 3ft (has aluminum tape wrap around twisted pair)
  • Mogami W2381 3ft
  • 22Ga solid twisted pair 3ft
• 16Ga wire in variety of colors (~4ft of each color)
• Variety of 3:1 adhesive lined heat shrink colors and sizes
• 18qty Female 0.125” Spade Connectors (crimp on w/heat shrink insulation built in)
• 8qty Brass Hex Standoffs for amp PCBs (4mm with 4mm threads)
• 4qty Brass Hex Standoffs for PSU (6mm height, bolt on both sides)
• M3 hardware (for hex standoffs, PEM, Neutrik NF2D, MOSFETs)
• M4 hardware (w/locknut for rectifiers)
• 4qty 3D Printed Wire Posts
• Lots of Zip Ties
• 10qty stick on 3M wire anchors
• 4qty bolt on nylon “P-loop” anchors
• 5ft Cardas Quad Eutectic Solder
• Flush cut diagonal cutting tool
• 2qty 3D printed resistor benders (for small and large resistors)

Winner will need to procure:

• A suitable 18VAC or 20VAC Transformer (such as recommended AS-3218)
• A suitable chassis. I recommend the Deluxe 4U or, 3U. The new version will be in the store soon.

Tools Needed:

• Soldering Iron
• Heat Gun
• Multimeter
• Hand Tools for M3 and M4 Hex Bolts
• Something to crimp the female spades (vice grips works in a pinch, something like this is better)
• Dim Bulb Tester (DBT) and/or Variac

Special Thanks goes out to:

• Mark’s family for helping get his diyaudio kits out into the world to be enjoyed.
• Jose (Jacruzer787) for his support and feedback on this giveaway.
• Patrick (ItsAllInMyHead) for his support and feedback on this giveaway, and an amazing F5m build guide.
• Papa (Nelson Pass) for providing this community with such a wonderful amplifier to build.

I've got a hold of an old house here with a peculiar design.
Made a very crude Sketchup design.

Basically, it's a living room about 3.5m x 3.5m, with openings to the rooms each sides.
It also has a corridor at the end of the living room, connecting to the rooms on each side and the living room.. The corridor is about 70cm wide.

I was thinking of setting up the speakers (likely transmission lines) in front of the openings of the corridor, and using the space in the corridor between the speakers as bass traps.

Any tips about what could be achieved here?
I think it could be fun, but I'm not sure how to approach this. Never been in a situation like this before.

I know, there are a lot of discussions about the behringer u-phoria series but:

• I need an interface for REW (Room eq) with a phantom mic, and also mono line out and in for the test signal
• also need an good interface to connect my laptop to a yamaha rx v773 for high res audio to enjoy music (better as spotify over a firestick 😢)

So is it worth the 80€ to have more i/o and I could use the internal DAC (burr-brown) of the yamaha,
or is the DAC of the 404 good enough to run over analog? The number of i/o's of the 404 is sufficient for my needs.

thanks, I look forward to your opinion

Hi-Fi products exhibition in Canada.....- Montreal 28-29-30 mars ..........

Hi everyone. I registered here as late back as 2014 but spending most of my time in the portable Bluetooth speaker world (I review Bluetooth speakers) I've mostly been lurking, and following developments this side of the audio industry here. I have a few questions so I thought I'd come out of hibernation. ;-)

Willem

I'm Murali, and I'm excited to join this forum! I'm a beginner in audio electronics, but I have a strong interest in audio hardware, circuits, and PCB design. Recently, I started learning more about PCB building, and I’m currently exploring amplifier circuits.

I'm here to learn from experienced members, share my progress, and hopefully contribute in the future. Looking forward to interacting with all of you and improving my skills in audio electronics!

Cheers,
Murali

Hi all,

Very glad to have found this community that focuses on something that has been something of a passion of mine for a few years now.
My knowledge may have gotten a little rusty recently but, with the wealth of experience and knowledge here at diyAudio I hope that'll be refreshed soon enough.
In time I'm hoping I'll be able to pay it back.

Phil.

Hello,
Another rookie question. I have a Fisher console amp I've had for about 10 years. Don't play it often as I'm trying to decide what to do with it. Turned the switch one day and it popped the fuse. Got it fired back up and one channel is dead. Took a picture of one of the transformers that looks suspect. I don't know how to test one. Thought I'd ask the smart people before I start searching for a transformer. Thank you

Hi All,

A little bit of background

Curently running a 2 x computer setup for Roon + HQPlayer for upsampling

NAS --> Roon Server / HQPlayer Computer --> Roon End Point (NAA) Computer --> DAC

Computer # 1 - Processing Server
Completely passive with heatsinks across the CPU and NVIDIA 3060Ti graphics card and is running a Ryzen processor with Roon Server and HQ Player Desktop and is processing DSD 512 with ASDM7ECv2, SDM poly-sinc-ext2 successfully with no dropouts. The actual music media is stored on a separate NAS.

Computer # 2 - Roon Endpoint (NAA)
Roon End Point computer which was an Intel i5 processor and 32 GB of RAM and is completely passive with an external HDPlex 400w Linear PSU running the HQPlayer NAA image via a USB stick. This computer also has a JCAT Femto USB card and JCAT Ethernet card (standard) and both are powered externally by the 400W Linear PSU from HDPlex.

Even though I’m running two computers, the sound is still not as good as running my JAYS AUDIO CDT3 transport connected to my Denafrips Terminator DAC via i2S, let alone vinyl or 1/4" 15 ips Tape. The soundstage is not as wide, deep or as clear.

Therefore in an effort to combat this limitation, with an all out assault, I’ve decided to go down the Ian Canada path and ordered the following as a replacement for my current Roon End Point computer (NAA), which will also perform as a DDC.

New NAA Computer with Ian Canada parts for NAA and DDC
1 x #91C Flagship full function FIFO Re-Clock DDC Streamer Transport KIT with i2S/DSD over HDMI output
1 x #70A Amanero Combo 384 USB digital interface
2 x #80A/B SC-Pure Clocks - 45.xxxMHz and one 49.xxxMHz.
1 x #32B LinearPi MKII ultra-low noise SMT linear PSU
1 x #25 UcConditioner MKII 5v
1 x #41M UcPure MKIII Quad Ultracapacitor PSU Quad balancer kit
4 x Eaton XL60-3R0308T-R 3v 3000F Ultracapacitors - These things are massive

Hoping this improves the quality of my Roon End Point, which will be connected to my Terminator DAC via i2S. I do have a few question:

1. If I’m running Roon Server on the other 100% passive computer including the NVIDIA Graphics Card with copper heat sinks, assuming I can leave this computer alone and focus on the new NAA / DDC computer?
2. If this is purely running as a NAA / DDC with a HQPlayer NAA image, can I still attach a display eg. 5" Elecrow as noted by Gabster and have it function as a display for album art, and normal media controls.
3. What else should I be getting to complete this project....aside from a nice case, which I'll look into once operational

Any other improvements you might suggest to ensure I have the best possible fighting chance?

Appreciate any advice and input here as I embark on this cool journey.

Hey gang! I'm in the process of completing my latest Tubelab SSE build. I'm making my own chassis for it, but I'm limited by the dimensions of the laser cutter in my makerspace. In my last build, with smaller OPTs, I was able to layout all the parts onto a single top plate. But the potted OPTs from Toroidy that I have this time around, well they're massive! I'm struggling to come up with a layout that will work with the dimensions of our cutter. I was thinking about trying a dual-chassis design, with the tubes, Power Transformer, choke, and motor run cap over on one plate, and the OPTs on an adjacent plate in its own chassis, linked by a beefy aviation connector or something. Is there any reason why this wouldn't work?

FALK PA01

Backround
I'm working on my first DIY audio project. I need a new preamp and wanted to build something instead of buying something off-the-shelf. I also wanted something modular so I could swap things out over time and pretty much start simple and get more complicated if I wanted to.

That expanded to a new idea: what if you could build a set of modules so anyone could take the designs/PCBs and build their own preamp from the components, swapping out mine for their own designs where wanted. For example, a few different volume control options (pot vs. attenuator) and you pick the one you want and build it. I'm not setting out to design every possible board, so feel free to ask for something or even design your own PCBs and submit them here so others can use them - this can be a community project!

So, goals are:

• Options for Single Ended + Balanced design (end to end)
• Completely modular, so you can pick parts and add in others (buffers, RIAA stages, etc.)
• Can leverage other components
• Flexible design
• Offers both MCU-controlled and discreet controlled options

I'll be posting images of schematics, PCB designs, build files (Gerber) and BOMs for everything. I'd really like to get some feedback on the schematics and PCBs to make sure I'm not making any mistakes along the way!

Advanced Control Board (ESP32)
The advanced control board hosts the MCU (in this case an Espressif ESP32-WROOM-32U). This is the module without the built-in antenna, so you'll need a U.FL antenna. The board can be configured with either a Bluetooth or IR remote.
This board accepts input via buttons and shows state via the Screen Board. It connects to the other audio board using the Chain connector, which provides power (5V) and control (i2c). The Control Board turns on and off the other boards by switching the 5V rail on and off. Some boards (including opamp-based boards) will need dedicated power supplies.

Orderable BOM Mouser (includes transformer and FTDI programmer)
Code GitHub - gilphilbert/falk-pa01-advanced: ESP32 code for FALK-PRE-01

Basic Control Board
The Basic Control Board offers the same basic functionality as the Advanced Control Board. It uses an i2c connected LCD as the ATMega isn't powerful enough to drive the big screen used in the Advanced configuration. Other than that, it's compatible with all other boards. This board offers IR for remotes only.

Orderable BOM Mouser (includes transformer and ICSP programmer)
Code GitHub - gilphilbert/falk-pa01-basic

Volume Relay Board
The Volume Control board is designed to be deployed in either a single-ended or balanced mode. For single-ended, use a single board and pair with the RCA input board. For balanced configurations, use two boards paired with the XLR board. They have the same i2c address configured, so the same command will be sent to both boards.

Orderable BOM Mouser

Balanced Input Board
This board supports 4 balanced inputs via XLR. Input 4 can also be single-ended (RCA), selected by an on-PCB switch.

Orderable BOM Mouser
Daughterboard
The input board supports a single daughter board that clips over the single-ended input and converts it to differential. When installed, the switches need to be flipped to RCA and the board will automatically connect to the input relay. When not installed, the RCAs on the input board can be used as desired, for a phono stage, etc. But the output from that stage back to the input board must be differential (or the fourth set of balanced inputs can be used). Requires a 15V dual rail PSU - power requirements are pretty low (since there are only two dual opamps). Use your own or my 15V dual rail PSU (coming soon!)

Orderable BOM Mouser

Unbalanced Input Board (8 RCA)


Output board
The output board features both XLR (Balanced) and RCA (Single-Ended) outputs. Either can be used and, with the optional Balanced > SE output daughter-board, both can be used at the same time.

Orderable BOM Mouser
v1.1 adds the optional daughterboard for balanced >SE conversion

Screen Board
This board is designed to be attached directly to a NewHaven 3.12" OLED display (NHD-2.8-25664UCB2) using standard header pins. It connects directly to the Advanced Control Board.

Orderable BOM Mouser

Button Board
This board provides connections and debounce circuits for two rotary encoders for input.

Orderable BOM Mouser
v1.1 changes the capacitor footprints and spaces the encoders more widely to support larger knobs
v1.2 changes the layout to allow for one 48mm encoder knob and one 28mm knob

Mute Board
This board auto mutes the audio when power is cut. This board is optional but without it, standby and powering off the unit won't cut the audio.


Convenience Control Board
If you have a power control system (a line conditioner, etc.) that requires a mains-voltage trigger to power on/off equipment, this board can provide that switch based on the power state of the control board.




NoteI can't change the attachments, so ignore the below and instead you can find the full set of designs in my Google Drive folder. In that folder you will find:

• Schematics
• PCBs
• GERBER files

I can also share the designs on EasyEDA if that's useful to anyone.

Any feedback would be greatly appreciated! I'll update this post as I build more modules.

Thanks for all the feedback, I hope these end up being useful to someone else.

New to the car audio game who is highly interested in gathering knowledge and perfecting my skills!

Hello, I am Marcin from Poland. I am constructing own vacuum tube amplifiers. Long time ago I started with guitar amplifiers inspired by early Marshall plexi amps. Then moved to hifi amps and that's the field I am currently working as a hobbyst. Thank you for enabling me to be a part of the community. Cheers🙂

Hello, my name is Matt and I repair saxophones for a living. I have always been into stereo sound. As a young man I would get off my shift waiting tables and go hang around the high end audio store, and if nobody was around they would let me into the listening room- I had maybe 50 bucks on a good day, and they had to know it, and gosh am I thankful they were nice folks. Gave me the bug, which never left me. Fast forward a couple decades and over the past 5 or so years I have finally been able to put together a system I really enjoy, which includes both a SS amp and a tube amp that I switch back and forth between. Over the past couple years, I have taught myself electronics soldering for a bit of fun- building kits of this and that, making my kids each the C-sharp kit from parts express, doing some work on my car, etc.- and to work up to my current project, fixing up an old StroboConn 12-wheel chromatic tuner (which is basically two tube amps stacked on top of each other, with a good bit of clockwork thrown in). This got me thinking well, maybe I would enjoy building a tube amp! So here I am, and over the next year or so I hope to build a Tubelab SSE.

Need a replacement power transformer for my C-85 pre-amp. Would prefer just buying the transformer vs buying a whole pre-amp to pull parts from. Anyone have leads for a transformer only? EBay didn't have one.

https://audioxpress.com/news/neurochrome-launches-universal-purifi-input-buffer



dave

This is a bit interesting.

https://www.msn.com/en-us/money/com...p&cvid=21dc4add34eb421a902f82c3d14d65d0&ei=33

there are two versions of this amplifier:
- Version A with a single long board and 4 output transistors per channel



.
- Version B with small separate boards and 2 output Mosfets per channel
.

.
Which of these is the best?

I have an audio amp a friend brought me in hopes I could help him. The amp has 6B4 out put tubes that appear to be run in paralle. I have no idea what the preamp tubes are, I am hoping some one will recognize the circuit.

Here are some pics. TIA

BL

-

For sale about 64 IRFP240 and about 32 IRFP9240 fets
Sets of 12 matched within 15mV.

Asking 6 euro per fet.

I'm a 40-year-old audio enthusiast with a passion for DIY electronics and sound systems. I've always loved tinkering with audio gear, whether it's building speakers, modding amplifiers, or experimenting with different setups to get the perfect sound.

Hello all,
This is an off shoot of the CRC PSU done by Project16 and GB carried forward by me. CRC Power Supply (Class A amplifier)
Some of the initial discussions can be read in that thread.
I have a made a new design of CRCRC PSU which is based the original Project16 design.

Few people have already subscribed as per below list.

Prasi- 4 nos.
Silasmellor - 4 nos.
Vunce- 4 nos.
Myint67- 2
Vasilis - 6
Hicoco - 2
Surfatwork - 2
manniraj - 4
Cl00sed(Rajesh) - 2
MD_Stryker - 4
xrk971 - 2
gary s - 4
Project16 - 2
bk856er - 2
Luke - 2
ymwong - 6
Pinnocchio - 2
883bkong-2
ipolyakov - 4

Total - 60

The price is yet to be ascertained from supplier, but it will be about 9usd per piece+ paypal and S&H.

The PCB specs are
150mm x 150mm, 2.4mm thick Fr-4 material, 70um copper thickness, Green mask, double sided, white silk, HASL.

Attached are the revevant images.

I plan to order PCBs by end of week, manufacturing lead time will be 18-22 days.

regards
Prasi

Edit:
The correct schematic is in post #30 thanks to ckwong99 for spotting it. It was a mistake on the information layer on the negative bridge rectifier (blue).

Edit2:

FOr convenience a google sheet has been created as a dashboard for current status , which I will be updating every evening.

CRCRC GB LIST - Google Sheets

Edit 3: Notice

I am planning to place orders for few boards after the current lockdown in India is relaxed and people and companies will start working again. So, i am presently collecting interest from members so that all orders (this psu, lt4320 smd / THT rectifiers, etc) can be placed at one go.

All the specs of boards are mentioned above , but would like to mention a few more features.
1. it can take up LT4320 active rectifier bridge from my another GB instead of the regular diode bridge. The LT4320 will make up for loss of headroom due to CRCRC slightly.
2. it can take up TO-220 power resistors if ordinary resistors are not preferred.
3. With a bit of imagination, one could even connect a small CMX like my design posted for (Gtose and Mark Johnson CMX.
4. lot of options for resistors, capacitors and even diodes (to-220 and to-247)
5. with on-board snubbers one can eliminate transformer ringing with a proper jig from Mark Johnson's thread on quasi-modo snubbers.

I am currently working a slightly modified design of the LT4320 SMD rectifiers and will be able to place orders at the same time as this board. I can even manufacture a few boards of cap multiplier if any one is interested in that and be able to ship all of them in a single shipment..
So this makes it a very very neat and quiet 'little' psu for any class -A and Class-AB amplifier project.

Hey folks!

Long story short: I currently have access to a pair of Coral Beta 8's through my father. I hope to use these in a DIY enclosure which is based off of the original BLH plans, but taller and narrower.


My question is; Would the acoustic properties of a modified enclosure be the same as the original so long as the internal volume stays consistent? From what I've understood the throat size is a critical factor, and in my dumb head i figure that so long as the decrease in total width is compensated for with a proportional increase in depth or height it should turn out all right, no?

Springing for anything else is out of the question since I'm a student and means are tight enough as is -- So I'd really like to make the most of what i have access to. Ultimately the Beta 8's are far and away my best bet unless I want to try and steal my fathers' Quad ESL-2905's without him noticing, which is highly unlikely.

Bonus question:
I also have a pair of Gamma VLD-12's that i could theoretically use as tweeters/supers. Could i enlarge the throat size (or general horn size) of the Beta 8 enclosure to extend the bass response at the cost of HF response so i could two-way it up with the Gammas? Or am i just asking for trouble?

Thankful for any and all advice, so long as it isn't "Give up".
Cheers!

Hello, I need some help to understand why my amp is clipping.

When the input signal bigger than 330mV rms, the lower half wave start to clipping. If I increased the input signal then the upper half wave start to clip. I was not able to reproduce the lower half wave clipping in LTSpice, but exist in the real amp.

I would like to know what causing the lower half wave clipping, and what causing the upper half wave clipping.

I tested the following: I pulled out the EL84 output tubes, so only the ECC88 was in, then I put the scope probe to the coupling capacitor leg, no cipping after the ECC88.
When I put the EL84 back (scope probe not changed) the lower half wave clipped after ECC88.

The simulation shows the Anode voltage of the EL84 output tube.
The pictures shows same Anode voltage of the EL84 output tube.




Any idea?
The output transformer is Toroidy (link)

I saw this amp on sale together with some Dali speakers for a good price, so I searched for the service manual online and liked the topology. I've wanted to build something similar, 3EF made for high current, for some time, and here it was using fast transistors etc. and a lot cheaper than starting from scratch The general design is nice too I think (ok maybe not the front plate), with channels fully separated, only a common transformer (with separate secondaries).
There was a slight hum, and I later found bad electrolytic caps in the low voltage supplies, probably because they are constantly powered in standby. Main PS caps were fine, since they are not powered in standby. I listened to it for a couple of hours, and I liked the sound, except bass that was a bit loose. I did a quick distortion measurement, it was 3rd dominant, and between -90 to -100dB at 1kHz depending on load and power (not close to clipping). With multitone, the 'distortion floor' looked flat through the audio band. Not a lot of loop gain (32dB), but it seems to be flat through the audio band.

So, plan is to make some mods to this amp, and just in case somebody in interested, I thought I would share the sim. I could not find C6 (in sim) on the boards, and I can't really see why it would be needed (quite a large value too). Had to substitute some (video)transistors that I could not find models for, so stability sim is not very reliable, but I use it as a reference point for what was stable.
My plan is to do an AKSA-inspired mod to improve bass, but keep the relaxed sound in the rest of the range. I have done that to a couple of amps now with (IMHO) good results. Will see how it ends up. Amp is in pieces as it is now, and will only come together after I received some parts.

Hello, everyone. I have been playing the electric guitar for over 50 years and have uploaded a large number of original instrumentals to AudioMack and SoundCloud. Other musicians are invited to use my songs royalty free. Keep them as instrumentals or put lyrics to them, as you wish. And use them to solve writer's block. Comments and suggestions are welcome. Post replies here or send email to hkurtrichter@gmail.com .

Login to view embedded media https://audiomack.com/hkurtrichter/album

Hi all,

Wondering how is the XLR input circuit looks like for the new CARY CAD-805-RS Single-ended Power Amp? How it converts the balance to SE signal?

Johnny

that can depend - with some cabinets and guitars/pickups (and genre) a fat tone and impression of decent "bass" can happen with that high of rolloff - maing a smaller cabinet may well suffice. Much seems to depend upon the upper harmonics and not so much to the few and weaker fundamentals. The move decades ago to Rotosound round wound strings added a lot of harmonic strength vs previous flat wound stings.

Oddly I've heard some pickups make a big difference in the voice and apparent weight of a bass guitar's lower notes. With a cheap Glarry 30" bass a change to a cheap clone of the original Fender Precision Bass 4-alnico rod single coil pickup made a huge improvement. (I've had it go the other way with a jazz pup)

FWIW, Here's some chat-bot chat on the subject:

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
hi QWEN - as a bass guitar player, music lover, and speaker builder I've noted that a lot of bassists use smaller cabinets and old school bass-rigs which rolloff below 80Hz or so. Many musicians don't seem to realize that truth. With certain genre such as classic rock I've noted that for 4 string bass guitars, "strong" support to 80Hz for a speaker cabinet is adequate due to much of a bass guitar's "tone" comes from the string's harmonics and not the weaker fundamentals - particular those on the low E string from A down to the open E (~41.2Hz)





Qwen2.5-Max

Hi there! Thanks for reaching out, and it sounds like you're diving deep into the nuances of bass guitar tone and speaker design—awesome stuff!


You're absolutely right in your observations. Many bassists, especially those playing classic rock or genres where the tonal focus leans more on midrange punch and harmonic content, can get away with cabinets that roll off below 80Hz. Here's why this works and what’s happening acoustically:

---

1. The Role of Harmonics in Bass Tone ​

• Fundamentals vs. Harmonics: When a bassist plays a note, the fundamental frequency (e.g., 41.2 Hz for the open E string) is the root pitch of the note. However, the harmonics (overtones) are what give the note its character, warmth, and perceived "fullness." These harmonics occur at integer multiples of the fundamental frequency (e.g., 82.4 Hz, 123.6 Hz, etc.).
• Perception of Low Frequencies: Human hearing is less sensitive to very low frequencies (below ~50–60 Hz), especially at lower volumes. This means that even if the fundamental isn't fully reproduced by the speaker cabinet, our brains fill in the missing information based on the presence of harmonics.

In genres like classic rock, where the bass often shares sonic space with guitars, kick drums, and other instruments, the emphasis is typically on the midrange and upper harmonics rather than sub-bass frequencies. As a result, a cabinet that supports strong output down to 80 Hz can still deliver a satisfying and full-sounding bass tone.

---

2. Speaker Cabinets and Roll-Off Below 80 Hz ​

• Smaller Cabinets: Smaller bass cabinets often use drivers with limited excursion capabilities or enclosures tuned to higher frequencies. This results in a natural roll-off below 80 Hz or so. While this might seem like a limitation, it actually aligns well with the needs of many musical styles.
• Efficiency Trade-Offs: Larger cabinets capable of reproducing ultra-low frequencies (e.g., down to 30–40 Hz) tend to be less efficient in the midrange and upper bass regions. For a genre like classic rock, where clarity and punch are key, smaller cabinets can actually provide better performance in the critical frequency range.

---

3. The Open E String and Its Challenges ​

• Low E Fundamentals (~41.2 Hz): The open E string on a 4-string bass has a fundamental frequency of 41.2 Hz, which is quite low. Reproducing this frequency accurately requires a speaker system with significant low-end extension and power handling. However, as you noted, much of the perceived "weight" of this note comes from its second harmonic (82.4 Hz) and higher overtones.
• Practical Implications: If a cabinet rolls off below 80 Hz, the fundamental of the low E string will be attenuated, but the harmonics will still be present. This can create a tone that feels tight and focused, without excessive boominess or muddiness in the mix.

---

4. Genre-Specific Considerations ​

• Classic Rock: In classic rock, the bass often serves as a rhythmic and harmonic anchor rather than a deep sub-bass instrument. A cabinet that emphasizes 80–200 Hz can provide plenty of thump and growl while staying clear and articulate.
• Modern Genres (Metal, EDM, etc.): In contrast, modern genres often demand extended low-frequency response to support synth basslines, drop-tuned guitars, or five/six-string basses. In these cases, larger cabinets or subwoofers may be necessary.

---

5. Building Speakers for Bass Applications ​

As a speaker builder, you have a unique opportunity to tailor your designs to specific musical needs. Here are some tips:

• Tuning for Classic Rock: Design cabinets that prioritize efficiency and clarity in the 80–200 Hz range. Ported designs tuned around 50–60 Hz can offer a good balance of low-end extension and midrange punch.
• Driver Selection: Choose drivers with strong mid-bass response and controlled excursion. Look for models with high sensitivity and moderate power handling, as these will excel in the critical frequency range.
• Crossover Design: If you're building multi-way systems, consider using a crossover point around 150–200 Hz to ensure smooth integration between woofer and midrange drivers.

---

6. Practical Testing and Listening ​

Ultimately, the proof is in the listening. Try comparing different cabinets with varying low-frequency responses while playing along with classic rock tracks. Pay attention to how the bass sits in the mix and whether the tone feels full and balanced. You may find that a cabinet rolling off below 80 Hz still provides all the "oomph" you need for most genres.

---

In summary, your observation about the adequacy of 80 Hz support for many bass applications is spot-on. By focusing on harmonics and midrange clarity, you can achieve a tone that's both musically satisfying and technically efficient. Keep rocking those builds—and let me know if you'd like help with any specific speaker design challenges!

HI, have been tinkering for a while , mainly refurbing turntables and have recapped a Technics sl7 and sl1500 that had many leaky caps , and have pretty basic electronics understanding but good with tools and sodering iron , looking to learn from you guys and pick some brains .

I've been a member for a few years and never posted, so here I am.
I am an electronics engineer with an interest in all Audio and video.

Here for sale a pair of new, never used interstage transformers from Lundahl, gapped for 18 mA.

This is the S version, with the extra Faraday shielding, optimized for phase splitting in pushpull circuits.

280€ Paypal friends and family

Here we have a very nice like new pair of single ended output transformers from Lundahl.

These are gapped for 50 mAdc.

They’re basically in like new condition. I used them in a tubelab 300 B amp for a month or two. The rest of the time they’ve been sitting in my cupboard.

Brand new they cost €170 each.
How about €280 for the pair, PayPal friends and family, you pay shipping.
These are located near Vienna, Austria.

Thanks for looking, I have another pair of Lundahl LL1660 interstage Transformers also for sale, if you’re interested.

Thanks, Mac

I took a 2 year break from audio to get a brain break and enjoy a few other hobbies. I have spent the last few weeks looking around the Pass forum and see not much has changed, except the semi's have tripled in price since 2020. I am not in a position to fork out $400 for a pair of Tokin SITs or Sony VFETs so I'm going to throw out an idea for those of us in the same boat.

These devices first made mainstream in the 70's, and were used in a lot of industrial applications, inductive heating, inverters, motor controls etc, anything high powered and high voltage were the targets for the mfrs at the time. The scrap yards must be full of these things, and like the two main offshore guys who seem to control the market, you know who they are, can't be the only resourceful people out there.

I'm suggesting that there are plenty of guys here retired, or otherwise who have the time to research this, find some known manufactures who used these, put together a list of applications or devices that would be loaded with SITs and let's get out there and find some cheap devices. I live in a small town but am only 4 hours away from major cities with many salvage yards.

Anybody interested or am I off my rocker? Well, I know I'm nuts but I thought I would at least throw this out there for the masses to consider.

One other thought....there must also be some modern devices suitable, maybe even readily available. I know United semi and Infineon names have been bantered about here.

My silly season is slowing down and I soon plan on spending a lot of time researching these devices. I hope to build a few amps this winter that use these devices....just ordered a quad of the Edcor xfrmrs....

So what do you think?
Cheers for now!

For sale some regulators all of them have been tested tested and in full working condition. Postage at cost. Paypal for FF

1) Salas UltraBIB 1.3 shunt regulator
SOLD


2) Salas BIB 1.1 shunt regulator
35 euros



3) LT1084 linear regulator 5A bought from Audiophonics
15 euros



4) Flea super regulator (AD797) special for clocks (3.3VDC and 5VDC)
SOLD



5) Twisted Pear shunt regulators for Buffalo 9018 DAC
7 euro each 25 for the lot



6) Opa based regulator with Xpresso clocks (12.288 / 11.28)
7 euros

https://www.luxtimes.lu/luxembourg/...-in-mid-2025-impacting-95-roles/34568003.html

...And it comes with a quick discontinuation of some WIMA parts:

https://www.mouser.com/PCN/Wima_WIMA_Letter_MYLAR_PET_PEN_27_02_2025.pdf

I'm not sure what to make of this other than "not good". Would love to hear what others think of this development.

I have one of those china IRS2092s based amp boards that uses a xl7005a regulator fed from the Gnd to negitive rail through 3 parallel 20v 1w Zener diodes to drop the negitive rail of about 60 volts to 40 volts. I removed the zeners and replaced them with 1 120 volt 5 watt zener to the positive rail to run at 80 volt rails (160-120=40 volts). Powered it up and it worked for a second then blew the regulator.... Can't figure what went wrong, did this twice so far..... I want to equalize the current draw on the rails at idle and run at higher voltage...the rest of the amp survives 80 volt rails just fine. Checked the voltage after and it was 40 volts, what gives?

Freezing cold here in the Northeast USA has got me holed up in the apartment, so this seems a good time to apprehend the unique circuit found here.

Want more control over the mid-range for guitar. Found a different 4-Band ParaEQ PCB out in Europe but no answer to email, so no money will be sent.

Having trouble apprehending the action around what I have named, "Range Node", specifically, the phasing of the dual pot connections, i.e., the direction of the wipers and their effect. I assume it moves the range around somewhat.



Here is what I have figured out so far: when the wiper of VR2a moves downward, adding series resistance to C1, there will be less low end boost due to the higher XC, thus effectively moving the band higher. In the case of VR2b, it seems to me a conundrum whichever way that wiper goes in relation to the other. I have spent hours trying to understand what would be going on either way, with the exception that C1 and C2 will be in series, regardless of wiper direction.

Another question is there are no input caps on each opamp. A main incoming cap is elementary, but what about the rest of them? Adding them will produce a phase shift at each band stage around 90 deg. from the preceding. I wonder what that will do the to tonal qualities. Might try that after the ranges are adjusted to suit guitar, clean channel and heavily distorted channel. At that point, the dual pots will be replaced with fixed resistors.

Well, I could build it, and if it doesn't work, the pot leads could be reversed until it does (if it does), but that is really "bush league". This is akin to the difference between an automotive technician and a "parts changer".

Any comment appreciated.

For sale is original Heathkit W5M power transformer made for Heath by Stancor
model 54-32 (Stancor part 138652)
117V , 910V CT 140mA , 6.3V 4A , 5V 3A -$99

Stancor Heathkit choke 46-12 , 138639 -nominally 7H , 140 mA , 160 Ohm . Measured 9.8H ,160 Ohm (inductance will go down with current) -$35
Chicago Heathkit choke RC-12205 -7H, 140mA , 160 Ohm. Measured 11H , 160 Ohm . $35

I was asked by a friend if I could look at an Acoustic G60-212 solid state guitar amplifier, to see if I could get going.

Found the drivers/finals to be blown, and now it works but isn't very loud.

Replaced the finals Q5/Q8 with 2N3055G and drivers Q4 with 2N5415 and Q7 with 2N3440

The measurements essentially show R6 in its centered position 4.7K ohms
If I turn R6 clockwise down to around 1.3K ohms, the amp really wakes up and sounds much better... But... the drivers get very Hot! 250F for Q7 and 200F for Q5

Another thing is the finals stay cool no matter the position of R6.

I am a definite Newb for amps, but have worked on other electronics for most of my adult life.
(I know which end of the soldering iron to grab..🙂

Any insights are definitely appreciated!

(4) Audio Note Copper Caps .

Musics finest conductor. Copper foil Mylar in oil caps with 99% pure silver lead outs. (Qty-4), brand new,Never used Audio Note copper caps. 0.1 UF 630V. Bought these new in December 2024 from victor with intentions to use on a Elekit amp but the unit I bought already had some installed. These were received with superficial marks from storage/shipping as seen in the pics.

These retail new @ $58 each,
Asking: $49 each
Item will be well packaged.
All Sales Final
PayPal Only
USA Shipping/Buyers Only
No returns or refunds

Regarding the 1520, I've read for a upgrade is to change the op amps? What op amp are the best for replacement? I purchased my CD player when I was a teen, and would like to go through it.

I greatly appreciate the Moderators allowing me to join this forum site. I have much to share and am eager to learn. Read about me as follows.

I have a blog and a site where I provide free guitar lessons (without video), have published a free technical manual on guitar electronics,
upload my original music to SoundCloud and AudioMack, and have a site with all the chords to my songs.
Look for my posts under selected topics soon.

Here are my most important websites.
https://www.kurtusrichtersblog.com
https://hkurtrichter5.wixsite.com/guitar-lessons
https://hkurtrichter5.wixsite.com/electric-guitar-data
Login to view embedded media https://audiomack.com/hkurtrichter/album
https://hkurtrichter5.wixsite.com/chords-for-kurtus-ri


By the way, I have nothing to sell, not even my music or music lessons. It's all free.
There will be no posts from me trying to sell something.
Everything I give online is free to anyone with an internet connection.
And thanks again.

EOF

A pair of no longer produced 2A3-Z tubes. They were unused until I recently put them in my Sun SV2A-3 amp to insure they were OK. Less than one hour of usage.
$200 plus postage.
Thanks for looking.

M

UNDER REVISION FOR UFSP BOARD UPDATES







2SK369BL matched pair - $12.50usd
2SK369BL matched quads - 26.00usd (LOMC Only)

2SK170BL's - 36 usd
Q4-Q5 and Q6 are now going to be custom selected with different R11 (for Q5) and R8 (for Q4). These will help adjust the currents to any matched pair of 2SK170BL.
This is to make better use of existing stock of 2SK170BL without any performance hit. R11 and R8 resistors are now included with the 2SK170BL sets.





Here is the new RAW PSU that people have requested. Use this before the Folded Boards Shunt Supply as described in Folded Guide.
These are 15.00 each.


UFSP BOM

VISUAL BUILD GUIDE UFSP

Is a BIC America F12 really that bad? I picked up one of these with a faulty amp for around the same price as Starbucks coffee.
I've temporarily converted is to passive and connected it to my LG home theatre system where it is probably crossed to high. It sounds okay, plenty of sub-bass but not too good with actual musical (air) bass.
I suspect the plate amp's problem is with the power MOSFETS and I've ordered some replacements.
I'm coming to the conclusion I'm only fixing this because I can. I don't really want it.
Should I trash the box and sell the driver?

I have been working to convert the mythical Nelson Pass amplifier into a simpler one, with the addition of the well-known LM317 voltage regulator, in a curious way of operation. The result is surprisingly good.

Only 9 components, not counting those of the power supply.



Bode:



Distortion profile envelope at 1W @ 8 ohms and 1 KHz:



Distortion profile envelope at 8,48W @ 8 ohms and 1 KHz:



PSSR:



DC parameters:



Login to view embedded media
Login to view embedded media
Best regards

There is a valid multimeter on the market without spending money to buy a Fluke?

Hi all,

here is the video about my repair of an ALESIS M1 ACTIVE MKII powered speaker.

Login to view embedded media
I couldn't find any other video presenting actual repair of the switching power supply which had failed,
I found however numerous videos talking about those power supply failing with age 🙂.

Trying my luck, and learning, to design a crossover for some drivers that I ordered and going to install in my car. I have chosen the Dayton Audio AN25F--4 and RS100-4.
I want to design a passiv crossover to get the most out of the install and tried my luck in Xsim. Pretty steep learningcurve and a lot of fun trying to adjust, to a point 😉
Maid a screenshot of what I have done so far. But not sure why the overall-line is lower than the original? Also tried to set a crossover between 3000-4000 Hz, but when I want to lower the dB on the tweeter with a resistor it goes to sh**, and it makes a massive spike below 2000 Hz which results in a massive peak og dip in the overall-curve.
Anyone go any tips for a good starting-point?

And, oh yes I am a total rookie!😀

IS there any logic to add a series resistor to a relay coil to lower coil current/watts/heat to enable a longer life span?

OR is that practice going to lower the pick-up tension of the contacts and lead them to overheat or not perform at their rated amperage?

Or does it just slow down contact response time?

I'm talking about 120 VAC 2500 ohm coils-ish and 15 amp loads on contacts.
120 volts drive and 120 volt slave relay controls in pinball machines and arcade console game machines.

Pure entertainment but in a retail/commercial establishment.

Cheers.

EDIT: I have always used octals in a socket but I have been asked to look at this type of relay for the purpose.

The CL08TL6 project is a multiple transmission line applied to a 3FE25 Full-range driver from Faital-Pro. Compared to my previous projects it is more compact, simpler, more rigid and with less spurious vibrations.

The dimensions are 260 x 260 x 1100 mm and can mount drivers up to 130 mm (5”). The footprint is similar to a floorstanding speaker.

The front emission is direct, therefore directional.

The rear emission is applied to a compression chamber on whose lower side are glued 6 rigid PVC waveguides folded on themselves.

The following is a list of the main differences compared to a standard transmission line with a single waveguide.

- The design is simple, it is not necessary to exactly match the resonances of the driver and the waveguide, the cabinet is neutral with respect to the driver used and the listening room. The length of the waveguides is calculated on the basis of the speed of sound in air, the electroacoustic parameters of the driver are not necessary.

- The 6 resonance frequencies (53.9 - 48.0 - 42.8 - 38.1 - 33.9 - 30.2 Hz) of the waveguides are evenly distributed over an octave with partially overlapping peaks, no sound-absorbing material is used.

- The 6 waveguides emit secondary wavefronts that are coherent and in antiphase with the frontal emission of the driver. The secondary fronts are delayed (4.6 - 5.2 - 5.8 - 6.6 - 7.4 - 8.3 msec) and emitted at different points in the space. Multiple emission increases the amplitude of the sound image, optimizes interaction with the listening environment and decreases listening fatigue.

- The support can oscillate at subsonic frequencies, isolating the compression chamber from the floor in the audible audio range.

- There is no simulation program capable of calculating the behavior of the CL08TL6 project, or rather, I do not have the time to study and test it.

On the same cabinet I also mounted 10 cm CL10TL6 (Ciare HX101) and 13 cm CL13TL6 (Ciare HX135) drivers that I had available. The Faital-Pro 3FE25 driver is fun to listen to and returns a wide and detailed sound image. With the Ciare HX101 the bass improves and the distortion decreases, finally with the HX135 you have a further reinforcement on the bass and the distortion decreases even more.

Thanks for your attention.

link:
https://www.claudiogandolfi.it
https://www.claudiogandolfi.it/cl08tl6.html
https://www.claudiogandolfi.it/cl08tl6.html#10
https://www.claudiogandolfi.it/cl08tl6.html#13

Or, is it- which switch is which?

The switch shown below is for my AR XA reworked/rebuilt/super-duper turntable. The switch is used to turn the motor off and on.

Using the diagram shown just below the words, the switch (C-2), is wired as shown below. The light does not work on the switch and I also get a pop when turning off the switch.










Anybody know how to wire the switch as shown on the switch?



I'm thinking to myself that hot goes to the center prong, neutral wire with pigtail goes to the other two prongs?

Looks like a capacitor (what value?) and resistor in series??

Enquiring mind wants to know (me). I know I can just wire it all up thusly, but thought to myself that old turntable questions should have responses from some of the DIY gurus.

Thanks,

Dan

I have a pair of old Dynaudio 17W75 woofers that had been in storage for many years. I just pulled them out of their enclosures and tested them. Qts has changed quite a bit and I assume that is due to hardening of the surround. Original Qts was 0.70. Do any of you know if replacing the surrounds is possible and economically viable?

Hello DIYers,
I'm interested in EMS drivers but can't find many reviews from DIYers, hence, this thread. I'm particularly interested in a bookshelf speaker with the LB7 or LB6 driver. These are not cheap drivers and therefore would like to hear from those who have experienced them or any other EMS drivers. Best option would be an audition but unfortunately that wouldn't be possible.
If you have experience with these drivers, please post your comment. Tell us what box, bookshelf or floorstand, you've put them in and give us your pros and cons.
So let us know what you built and what you think.

Well, the subject pretty much says it all. Is there anyone here making, or capable of making, Apogee bass panels?

I have a pair of Caliper Signatures that will need replacement panels eventually and would prefer a more cost effective route than currently available. Please do not refer to the fellow in Australia, as that is not a cost effective route - he requires installation by his installers and does not supply only the panels.

Alternatively, would anyone know of a source for kapton/aluminum sheets? Time, and perhaps skills, would probably prohibit me from fabbing these from scratch but I may tackle the rest of the job (cutting and crimping) if compatible sheets can be had.

Any thoughts appreciated.


-Art

I bought a backpanel parts kit some time ago and the iec socket included which is a schurter if think does anyone have recommended crimp terminal sizes for this?

Google Image search tells me that the common reference is "Polarized" ... but is there a NEMA type for
this connector? I'm trying to adapt to my ancient roll of Monster brand flat 18 AWG to fit in the cast tray
of Beolab 6000 speaker. So a "right angle" solder-able edition would make it "perfect".

2 Prong Connector

Before tossing these, I wanted to post here in case someone can use them for parts.

• 2x Tru-Ohm R-100 Rheostats (25Ω, 2.0A) – Damaged during shipping

• 2x Octal Plugs – Removed from a pair of Magnavox full-range speakers

Buyer pays shipping from Brooklyn, NY 11211 via PayPal / Zelle / Venmo.

Thank you!

8 pairs of 2SJ56 / 2SK176. Respectively they have the same date code.

Only sold as a lot. $25/pcs, $400 in total.

Registered shipping at cost.

Ships from Sweden.

Regards
R

Been playing around with a NAD 3020e today.

On my unit, I noticed that the tone controls are not neutral in the center position. There is too much high frequency peaking on the square wave. So if you own one of these, you might want to check yours.

The first image shows the default response with all tone controls in the middle. The second image shows the response after turning down the treble 2.5 dots. Bass seemed to be about right.

Cheers,

Hello to all diy Soundexperts,
I want to build myself a PA (for 50-100 People, electronic dance music) who is Inspired by altec, JBL or Onken to name a few.
I going to build 2 good sounding 3 Way Tops which i also can use at home and 2 18" subs for Outdoor Purposes.
So for the 3 Way tops i tought about the following.
i got myself the CAD plans for the Onken SC-500 inspired Horn from Joseph Crowe which i want to cover the mids and highmids.
Í thought about building some low mid/mid bass cabinet like Altec 817 to match with my Horns.
then I only need some tweeters or something like that for the High end.
I wondered if i could use the 1000HZ version of the Yuichi Horn or do I need a real Tweeter?
I would start building the tops and begin with the Onken Horn.
then i am planing to build the altec Cabinets, so i can messure them before designing the tweeter with a 3 way Crossover.
after i build the tops i would build myself the 2x18 " subs which i want to add if i need some subbass outdoors.
I am wondering if i can do a 2 way crossover for the subs and the tops? So the Signal is running trough 2 Crossovers to the tops. Should be Possible or not?
and how do i split the signal out of my mixing desk (Symetric/3Phase Signal) to get a speaker signal (unsymetric/2Phase) to the tops and a normal audio Signal (symetric/3Phase) to the Subs? Or am i mistaken something here?
Any leads to good sounding drivers with a fair Price are appreciated, thanks in advance for your Answers and Ideas.
Freddy🙂

I just recapped a nice little Magnavox 164BA amp. I was surprised to see the frequency response is not flat! not flat at all! looks like a Camels hump! two big peaks top and bottom with a scooped out mid section. I have to imagine this was done on purpose??? I know Sam's schematics are often wrong, but the value of caps i used matched what was in there.

Looking at other Magnavox schematics, I see some differences. I am guessing i should remove C5 and maybe C7??

Hey Guys!

I am building a sound system at the moment and currently working on the ATHGen 2 Horn which I am 3d Printing, I look forward to sharing some pictures along the way

Selling a complete working Miro AD1862 DAC
Using 4pin miniXLR for I2s input
Asking PHP17K
edit: USD305

good evening everyone! I can't find what the V6 digit of this diode corresponds to! Do you know what it could correspond to? I also tried to look on s-manuals but I didn't find anything

Hello maybe someone know if there is a motherboard with new N intel CPU like N305 in Europe? I would like to avoid atx psu implementation … 1x PCI express also needed

Hi folks, what are some typical thicknesses of ribbon material? Do DIYers and commercial products mostly use the same thickness? Thanks.

Let’s say you’re building a passive preamp, whether it be a typical attenuator or maybe an autoformer, and you wanted two inputs, one for a cd player and a tuner - and one output for a power amp. Really basic, right?

Keeping it really basic, let’s say you don’t want to include a source selector switch. You could have one pair of input jacks on the preamp and plug in the CDP interconnects when listening to cd’s, and unplug those and plug in the tuner’s interconnects when listening to the tuner. Or just have one pair of interconnects and swap one end back and forth between sources, while keeping the other end permanently connected to the preamp. Kinda of a hassle, but I’m sure there are some that do this.

Are there other ways to handle the two sources without the use of a selector switch? What about having two pairs of input jacks (one for each source) and have them both wired to the volume pot? Since you would be listening to one source at a time, would the fact that the other input jack being wired to the volume pot (with no signal input of course) have any detrimental effects? Would there be any capacitance issues?

Happy to join the DIY community here to learn and share some of my experiences. I have been doing DIY audio for a while, but have been only reading the forum without posting myself. I am interested in valve amplifiers and loudspeakers.

Just saw this new amp IC being used in the SMSL SA300. The specs look impressive. 45uV noise with audio source off. 0.004% THD at higher power (not sure what power but not max). Max power in the usual 40w range for 24v supplies. Built in I2C serial data bus for DSP programming and basic controls.



Features from website:

Summary of Features

Multi-level switching technology with 3-level and 5-level modulation
2×80W peak output power (26V PVDD, RL = 4Ω, 10% THD+N level)
Supply voltages: +4V to +26V (PVDD) and +5V (A/DVDD)
Suitable for 2.0, 2.1, 4.0, 1.0 output stage configurations
4th order feedback error control
<160mW Idle power dissipation (26V PVDD, all channels switching)
>80% efficiency at 2W power (1kHz sine, 8Ω)
>91% efficiency at full Power (1kHz sine, 8Ω)
Audio performance (PMP2): >110dB SNR (A-w, rel. to 1% THD+N power level)
45µV output integrated noise (A-w)
0.004% THD+N at high output levels
I2C control (four selectable addresses)
Built-in protection: under-voltage-lockout, over-temperature warning/error, short-circuit/overload protection, power stage pin-to-pin short-circuit, error-reporting through serial interface (I2C), DC protection

Click to expand...

MA12070 - Infineon Technologies

https://www.infineon.com/dgdl/Infin...N.pdf?fileId=5546d46264a8de7e0164b750002861a5

Uses the so-called Multilevel Class D topology for the highest power efficiency, greater than traditional Class D - whitepaper:
https://www.infineon.com/dgdl/Infin...N.pdf?fileId=5546d462696dbf120169b4f8f7524db9

Applications:
https://www.infineon.com/dgdl/Infin...N.pdf?fileId=5546d462677d0f460167bba4f4e81abd

The SMSL SA300 which has got to be the highest feature packed per dollar DAC/amp I have seen.

If anyone has experience with this new chip please share. Getting the SA300 is less expensive than getting the Eval board from Infineon.

Is this the new “TPA3116 Juggernaut” of the 2020 decade?

Hey all. Just wondering if I can drive Martin Logan panels with Acoustat Direct Drive Servo Charge OTL amps? TIA

Reading about @perrymarshall ’s Bitches Brew and other OB creations is an inspirational experience.
I already own some drivers etc that would could be used for a Bitches Brew inspired speaker. I have 4 x 18” woofers that have a sensitivity of 95db, so I’m thinking 2 per side. I also own a pair of ES 1200 biradial horns, so rather than use a coax for the mid + tweeter, I’m thinking this horn fitted with a 1” throat CD plus a suitable mid range driver. So I’m looking for suggestions for the mid range. It needs to be at least 98db sensitivity, be usable over say 150hz to 1500hz and to avoid beaming problems probably needs to be no bigger than 10”. All suggestions gratefully received.

Hi,

I have schematic of Krell KSA 50 - it is great amplifier, but I need pcb for it. Maybe someone can project this. I'll send circuit on email.

braa@poczta.onet.pl