I'm thinking about upgrading my surround system to Atmos so have a need for in-ceiling speakers. In my search I came across these:

https://www.crutchfield.com/S-bYgFC...c2IpAbYCHpZzlSha3oc8dEza696tvhZYaAhdoEALw_wcB

This got me to thinking... these use a single full range driver shoved in a can which seems doable with a 3d printer and a few hours in Fusion 360. Can anyone think why this wouldn't be a good idea? If this isn't a completely dumb idea what drivers should make my short list? I think my starting qualifier would be that they have to get loud enough to be used at reference volume without notable distortion.

There are SMD parts, electronic relays, for audio signal. What kind of relays are these ?

Please bear with me. I do not have a strong grasp of the complex interactions of my audio equipment. I have never designed or built a new circuit from scratch.

I have been considering adding a tube output to my Philips CD880 for about 10 years now. I have spent a many, many hours trying to learn the technical requirements of I/V conversion and how to build a working tube output. Today, I ran across Regal's thread from 2011 https://www.diyaudio.com/community/threads/new-look-at-tube-analog-for-tda1541.194134/ and a light went on.

Why has everyone focused on building line level outputs instead of MC phono level outputs? I have never seen any discussion of a MC cartridge level output. My Ortofon Cadenza Black cartridge only has an output of 0.3mv and my CAT preamp and ARC D70 MkII have no problem driving my Martin Logan Sequel speakers to good volumes.

It seems to me that there would be more options to build a low level I/V conversion output that outputs 0.3V than 2.0V. What are the technical barriers to converting the TDA1541A's 0.4ma PP to 0.3mv and outputting that to the phono in of my preamp? Is there an insurmountable impedance mismatch problem between the chip and a preamps phono in? Even if I cannot eliminate the tube output, wouldn't I have more options for which tubes I use and which amplification cuirt I use if I am trying to build a phono level output?

I hope someone who has the knowledge will help me with this.

I’ll go first. Which one of you guys did this?

I need 4 of 2SC2682-P or C2682-Y
If someone has spare please pm me

Hey all,

I've started going down the DIY rabbit hole a little deeper and find myself in the need of additional testing equipment than I've been using for tube builds. Currently in my toolbox are a few cheap-o DMM's, a Fluke 117, Peak LCR45 and a Velleman DCA55 Semiconductor Analyzer. Last summer I saw an old Conar 255 oscilloscope for $20 at a garage sale but now I'm convinced I should just get something modern instead of doing a restoration and questioning everything it spits out. Maybe a fun future project but for now I'd just like to get up and going. Something modern-ish but am Ok with used if its a good bit of kit.

What do you guys recommend for a good testing / electronical / audio bench testing rig? I don't need to spend 10k but would like to start putting together a decent set up that will go for the long haul. Appreciate any recommendations!

Hi everyone,


I'd like to share my latest project — a fully custom digital audio processing platform built around an FPGA. The system accepts multiple digital audio inputs (I2S/SPDIF), applies jitter reduction and fixed-point filtering, and outputs a balanced signal through a discrete R-2R DAC.


The goal was to achieve low-jitter, low-distortion output using hardware-domain techniques, while maintaining maximum flexibility in digital audio processing.

---

🔧 Hardware Specs:​

• FPGA: Altera Cyclone IV EP4CE115
• Inputs: I2S (from XMOS, HDMI, STM32), SPDIF (optical & coax)
• Output: Balanced R-2R DAC (via 74LVC595 shift registers, isolated with SI8660)
• Clocks: External 22.5792 MHz & 24.576 MHz oscillators, dual PLLs with dynamic reconfiguration

---

🧠 Signal Processing Chain:​

• ✅ Sample rate detection: 44.1 kHz to 384 kHz (auto-detect)
• ✅ Bit depth detection: 16-bit / 24-bit
• ✅ I2S Reclocking: FIFO-based low-jitter BCLK generation
• ✅ Fixed-point FIR Filter: Linear phase, group-delay-aware, designed for steep roll-off and minimal ripple
• ✅ ASRC (Asynchronous Sample Rate Converter): Linear interpolation based, upsampling to fixed 192 kHz / 24-bit output

---

🔊 Analog Output Path:​

• DAC type: Discrete R-2R, balanced
• Output filter: Passive RC (887 Ω + 3.3 nF → fc ≈ 54 kHz), optimized via REW tests
• Preamp: OPA627, gain x2, input RC filter (1k + 470 pF)

---

🧪 Measurement Results (REW):​

• SNR: 81 dB
• ENOB: 12.6–12.8 bits
• THD+N: ~0.018% @ 1 kHz, -1 dBFS
• Tested Scenarios:
  
  • FIR only
  • Reclock only
  • FIR + Reclock
  • Raw (flat path)
• Interesting Findings:
  
  • THD increases at 44.1 kHz compared to 192 kHz due to increased jitter sensitivity
  • RCA measurements underreport performance due to lack of CMRR; balanced output performs better

---

🚧 Current & Future Work:​

• ASRC output working on (fixed 192 kHz)
• Next step: porting design to Xilinx Artix-7 (100T)
• Native DSD passthrough & PCM-to-DSD conversion under development
• DSD dac by upper PCB

---

🎶 Subjectively, the system sounds clean, fast, and airy — with a notably improved low-end and clarity after FIR+ASRC stages. THD harmonics are drastically reduced when reclocking and passive output filters are tuned properly.


📎 I'm later to share code, VHDL modules, schematics, and REW test plots if anyone’s interested. Feedback, suggestions, and collaboration are very welcome!


Best regards,
Erdal

If anybody has a surplus pcb for pcm63 dac, please let me know.
From Miro for example, the ordinary one, or some other.

It can be empty, half finished or finished and with or without dac chips.

Tnx. 🙂

By popular demand, here is a new thread devoted to PETTaLS flat panel speaker simulation software, developed by Dr. David Anderson. Flat panel speakers may also be referred to as bending wave speakers, or DML speakers.
Let's use this thread to discuss topics specific to the use of and improvement of this great new tool. Topics could include, but are not limited to:

• new release announcements
• questions about how to use it
• features you'd like to see
• possible bugs
• interpretation of results
• other....

The free version of the software is available here:

PETTaLSFree

Some videos about the software are here:

PETTaLS Videos

Eric

I've been given a bunch of Caps that the giver was using for experimenting crossovers.
Unfortunately they appear to have been liberally coated with some sort of bitumen type compound and a strange sticky grey blu-tak like goo. (possibly to damp vibration ?)
Alcohol based solvents dissolve the goo but so far only Turpentine will remove the "bitumen"

Is it ok to soak the caps in Turps followed by Meths to clean ? or have you any other suggestions ?

I have the following phase splitter designed for a 12AU7.





What components would I need to change for it to use a 12AX7 so it can drive a quad of 6V6 in push pull parallel unless with feedback I can get a 1V input sensitivity for 25 watts out with the 12AU7?

The 6V6 has a max grid resistance of 100k when operated fixed bias so the load on each output of the phase inverter will be 50k unless it's ok to use a single 100k grid resistor for two 6V6 in parallel.

Hi,

I just bought two pieces of Aiyima 07 TPA3255 amplifiers and also bought 48V SMPS for them. But later learnt that the manufacturer advises not to use SMPS for it but use power adapter instead. Well, first of all, what's the difference between them, technically both are SMPS only?
Click this link for the actual listing

Thanks and Regards,
WonderfulAudio

When I was young, we spent hours on end playing what we called word game. Same rules but it was always 4 letter words.
I was introduced recently to this new sensation and tried it today. Now I know it's beginners luck, but first time out I got it in 3 words.
I think I'll try again and let it bring me back to earth.
Who else is doing this?

for a "multi-path" DAC - but will it really do 162 dB N when level is, say -44 dBfs?

I say: no.

I call bogus 😎

https://audioxpress.com/news/imersi...analog-converter-completes-32-bit-audio-chain

You?


PS: Practically this is of course the same as just shutting off the output signal at say -110 dBfs... if you have control of the current noise in the output stage...

//

TU-8850SE KT170 SEP AMP 16W X 2​

Available in September 15, 2023

$1,185 with stock OPT​

$1,750 with Lundahl LL3727/90ma​

​

Audio Note Tantalum Resistor set is available 26 x 2 pcs = $286 singnal path only ​

Folks,

Over in the TDA1541 Meta Thread we had a lot of input to analyse the TDA1541, what makes it tick and how.

https://www.diyaudio.com/community/threads/building-the-ultimate-nos-dac-using-tda1541a.79452/

What I would like to do here is extract the practical part and propose a complete DAC design that may be realised as open source group project.

I would first propose a basic structure.

There will be a main board for the TDA1541 with a super capacitor based "stacked" 20V supply, optimised layout for the various decoupling capacitors needed as discussed in the other thread.

There will be attenuator/slew rate limiter circuits and a set of Flip-Flip's for reclocking and / or division of BCK & LE/WCK as well as a DEM Clock divider from a 512X MCK. The aim is to run a continuous BCK with the lowest frequency possible, so the default option will be I2S with 32X FS BCK, as the lowest sensible without FPGA/CPLD/MCU etc.

There will be embedded clock generation with 22.5792 & 24.576MHz clocks and dividers that allow full slave operation of a frontend at either 32X FS or 16X FS. It will also accept two external 512X MCK from (for example) an SPDIF receiver or USB Board with embedded MCK out that cannot be slave clocked from our on board clocks. Super capacitor based 5V supply.

Space for an analogue stage "plug in" to keep the choice open. My own intention is to use a SuperSziklai Pair based design detailed in the original thread.

Space for a SAA7220 socket that could be filled with an SAA7220 or any PCB holding any FPGA, CPLD, ASRC or whatever. Space will be be left around for a larger PCB to fit this socket. Again, this leaves the choice what goes into this socket (including nothing) to the builder. For my own setup an SRC4190/AD1896 will be fitted to operate as 64X FS to 32X FS I2C converter and as optional dejiiterer for jittery SPDIF Receivers and sources that otherwise sound worse than ASRC engaged.

Anything else will go. Pick your poison. If the 74ACT2226/28 returns from "active but zero stock deads" it may become the FIFO based I2S 2 SIM converter discussed here, otherwise SRC4190 in bypass makes a swell FIFO & format converter with a bonus ASRC):

https://www.diyaudio.com/community/...g-discrete-logic-collaborators-wanted.424459/

Input choices will include standard (Amanero) footprint for USB Boards (mostly XMOS) with isolation via SPDIF (no I2S digital isolators allowed, why will be discussed in good time) and a clock feedback from our crystal clocks with 44.1/48 base selection via opt-isolated pin, probably at least two selectable options.

SPDIF Inputs with SE BNC, XLR AES and Optical plus USB. The SPDIF Receiver position gets a CS8412 DIP socket that accommodate any number of SPDIF RX Solutions, all the way to "roll your own" with FPGA/CPLD/CPU.

I'd draw a block diagram if needed... is it?

So, if anyone is interested in making this a reality as an open source project, join into the discussion.

This is not a channel to debate fundamentals, redebate stuff from other threads or "can you make it into this thing?". If you choose to actively contribute time, effort or money to the project you can of raise suggestions.

I expect to hear crickets, cicadas and the occasional lizard chitering on this thread, but G*d love's a trier.

Thor

PS. As an additional note, all real PCB work will be in Altium, not Kicad or similar educational toys. All simulations and initial schematics capture in TINA-TI. This is non-negotiable.

If you need help with Altium Designer, we can talk in private how to use the free download with full functionality for evaluation and educational purposes beyond the eval time limit. TINA-TI, download at TI.

Hi
the base of this amp is the huge thread about :

100W Ultimate Fidelity Amplifier​

these is the thread for all fans of the Vertical brother of APEX FX8 done by XRK and prasi:
the amp was modified by XRK and others and use no Lateral MOSFET --> therefore well known IRFP240 and IRF9240 are used.

here are some examples and comments:
here
here:

Hi guys, as tittle said "Building BA-3 as analog output stage of noDac", well the noDac outputs 0,19Vrms so I was looking for something with a gain x10 to get near the standard 2Vrms, helping me to take the BA-3 option because I own original SK170BL, SJ74BL, K2013 & J313 from when I used Erno Borbely stuff, also it's not complicated to do it and adjust (very similar to Borbely), don't take to much room inside noDac box and is a lot of more easy and a lot of less money than make a DHT 4P1L with the same gain of course I don't expect the same SQ.

I read with attention NP BA-3 article, it seems with standard resistors values BA-3 fits nicely the x10 gain I'm looking for.

Attached NP BA-3 article to know if it's the latest or there is other new and also B.O.M. for a balanced unit that I will not do because all my system is SE.

I read Jfets have to be "matched if possible" at 10mA Idss, I have on hand:

SK170BL
9.48mA x 2

SJ74BL
9.02mA x 1
9.03mA x 1
or
10.11mA x 1
10.24mA x 1
What's best pair to use with the SK170BL?

I guess with these values P1 & P2 will remain 500R, right?

With the input voltage of +-25V can reach the x10 gain?

I will post pics of my work in progress.

TIA
Felipe

N.B. Big thanks to Jim aka 6L6 to give me a couple of PCB.

I have for sale 2 sets of components for building the Miro AD1862 DAC. Each set consists of 1 x AD1862 SMD DAC board, 1 x Miro PSU1 board, and 1 pair of AD1862 IC's. AD1862 IC are genuine (from Paddy & zoom777) Each set is priced at 40 usd plus shipping. Please see the attached pic.

Regards,
MM

It has been a Long time after the DDDAC1543 saw the light and the world moved on, especially if we look at available sound track material. So much great soundtracks with high Resolution. Red book is not dead of course, but if I spend money on sound tracks, I look for 96/24 or even better 192/24, or the SACD equivalents 88.2 and 176.4...

In the past year I have been working on my new project: designing a DAC which will play up to 192kHz / 24bit material from a PC (or Mac...) There are many DACs who can do this, but I wanted to design a NOS version, as so far, every listening test I did, this led to a more open, natural and detailed sound.

I found this to be possible by using the well-known PCM1794 and avoiding the digital filtering built into the chip. This proved to be quite tricky, but I managed to find the key to do it. It has been a great adventure with much to learn and a fantastic result at the end....

To feed the DAC, I kind of integrated the WaveIO USB Receiver from Lucian. Great design and better sounding than all others I tried (see my website for this as well); I give a very detailed report on www.dddac.com

You can download the circuits here: dddac1794_nos_ver30.pdf



The Images below show:
The Mainboard with I/O and I2S to right justified conversion
The actual dual mono DAC Module (can be stacked parallel)
Built up with 4 modules and two power supplies (5 and 12 Volt)
Wired up in Chassis (Mundorf Gold silver oil output and optional Sowter 1:2
The DAC in my Audio rack
Another view inside
Block diagram


I opened this thread to share my design and experience and give a platform for questions, feedback, remarks and/or discussion...

USSA-5 build and review:

Amplifier Design/layout: Fab (The Great and Powerful Ape)

Amplifer PCB Layout: Alex

PSU Design/Layout: Project16

PSU PCB Production: Prasi


I couldn't stop thinking about this amplifier. The obsession began with a few fleeting traces of it's existence. The few members that have actually completed it were mostly silenced by its greatness. When I had enquired about it, people simply said "Oh, the USSA-5? It's the best amp I've ever heard."

I had to build it. But, the great mind that designed the amp wasn't going to just give me the boards. I offered to build a children's wing at his nearest hospital in his name. He said no. I said I would make huge donations to wildlife preserves around the world. He still said no. He was like talking to Willy Wonka and I was Charlie Bucket. I needed a golden ticket....

In the end, what worked was honesty and a promise to do two things: to build the amplifier and write a review.

So, here it is.

Hi all,

Talk me out of this? I'm just enamored with the idea of a small foot print "tower" that is taller with lots of 8" drivers in it. Instead of a big box, a tall skinny tower. The small foot print is just easier to place in various rooms. Visually it's fun to see. It allows the use of lots of inexpensive drivers. And generally doesn't need much power to get loud. But would it need to be a sealed enclosure? Or ported? All the subs sharing one volume? Or make groups of 2 in their own cubbies in the enclosure? 4 to 8 drivers so that wiring loads is easier?

I tried modeling some options in WinISD but I'm not sure if it handles real world what happens with multiple drivers in one volume or not? Any other options that are more realistic?

Overall bad idea? Better to just build two 10's and stack them instead?

Purpose would be music mostly.

Very best,

Hello, I'm currently trying to repair a Luxman L-3 that I bought at a thrift store to make it mine and enjoy! For now I've read all the previous posts made on this forum and though I found the issue when I changed a resistor that was problematic for someone else (mine also was bad). Replaced the resistor with one that was good (Amazon) and tried to turn it back on... ohoh the dim light tester stays on.

That was my initial try at repairing it, since then, I tried to find the short, but I can't seem to find anything promising. I used a thermal camera to identify hot spots on the power board and found to spots, one around the D403 and D404 diodes and the Q408a area. Since then I pulled all the components to test them outside the circuit, but they all seem to be good from my understanding.

I'm kinda lost and don't know what I could check before starting to resolder all the components back on the board, do you guys have any wisdom to share that could help me with my project! Thanks. There seems to be a good amount of info on this site about the amplifier so if you want something specific let me know and I'll share it with you (schematic, components list, voltage drop of the components I pulled, etc.).

Have no idea in which forum this question belongs, but for the time being the subwoofer forum seems most appropriate.
Is there a DIY technique to measure the BL curve of a woofer?

Some pics of a prototype general purpose DAC Clock board, for which I plan to post the Kicad project. First pic is driving a Andrea Mori FIFO Buffer board; second pic is driving a @MarcelvdG RTZ FIRDAC with asynchronous USB, and reclocking before the dac board (clock board prototype is outlined in red).





The original premise was that the clock board would use 45/49MHz clock modules (or external clocks, including sine wave oscillators using suitable squaring adapters). The 45/49MHz frequencies can be used to externally clock an I2SoverUSB board. The clock frequencies are then divided by two to produce 22/24MHz clocks for driving dacs. Both continuous and switched 22/24MHz outputs are available (USB board usually controls the switching). All outputs are buffered with high performance buffers. Very clean +3.3 power distribution and bypassing is also used. That's the short story.

The board design evolved to also support 22/24MHz clocks (or even 11/12MHz), then use a frequency multiplier to drive the USB board (as an option).


So far with the prototype and some pretty good clocks, it does raise the DACs in the pics into what I would consider to be a higher sound quality performance league as compared to what they would sound like with off the shelf NDK SDA, Accusilicon, and or Crystek (although the clock board can make those clocks sound better too), and or especially better if compared to having the master clocks internal to the USB board.

Of course, all the above having been said, there are commercial solutions out there too. Some may be essentially SOA, but they may be more costly and possibly less adaptable than the clock board of this project.

----------------------------------------------------------------------------------------
Clock board v2.1 files attached below.

Interconnect Board open source project for connecting I2SoverUSB and PCM2DSD to the clock board and reclocker board is at (#68):
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7702293

Reclocker Board open source project files available at (#157):
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729422

Some comments on using the clock board with very high performance dacs in #144:
https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7729060
----------------------------------------------------------------------------------------


NOTE: Clock board schematic was found to have wrong part number (now removed) for the Omron relays. Please see the clock board notes document for more information on part numbers.

8/11/24 - Clock Board Notes document updated to v1.1 (some changes to recommendations for regulator load resistors)

I originally made a similar post in the Room Acoustics forum; however, there appears to be a lot more discussion of CLD in this forum. (Pretend the room is a big speaker enclosure – just kidding.)

I am remodeling my family room and want to make it a better “listening” environment for stereo and future multichannel. About ten years ago I read Earl Geddes excellent book “Premium Home Theater” and one of my big takeaways was his recommendation to use CLD in a listening room to absorb bass while preserving midrange and treble liveliness. Although Geddes also recommends CLD for sound isolation - that is not my objective, since one corner of the room has an open ½ flight of stairs up to the middle level of our home with no good way to enclose it.

Tentative plan is to incorporate CLD into the ceiling, the front wall and one sidewall of the 8 x 14 x 24ft room. Sound isolation clips would be attached to studs/ joists with 7/8” steel hat channel attached a maximum 4’oc and spaced a maximum 2’ apart. Two layers of lightweight ½” drywall separated by a suitable damping compound (Green Glue?) would be attached to the hat channel.

Is this a worthwhile endeavor to hopefully preclude the need for standalone bass absorbers, multiple subwoofers, room correction software, trial & error measurements, etc?
Is this a good design? Am I on the right track with the following design assumptions?

Increase the flexing of the constraining layers (and thus energy absorption via CLD) by decreasing the stiffness and mass of the constraining layers.

Reduce the strength of reflections into the “listening” room by decreasing the stiffness and mass of the constraining layers.

The damping compound that is used between the constraining layers should have very good adhesion and be more viscous than elastic so that energy is absorbed rather than returned to layers.

Minimize the Resonance Frequency of constraining layers by increasing mass and decreasing stiffness.

Greetings.

I present the DIY FRONT END 2022.




EDIT: For current boards marked "V0R1" please find the changes and additional information in post #686 of this thread
https://www.diyaudio.com/community/threads/diy-front-end-2022.394339/page-35#post-7323986

I have this cheap little class AB amplifier. I am getting a hiss through any speaker I connect it to. Both channels. I'm thinking bad transformer but I will run through my troubleshooting steps. It is HIGHLY likely it is a just a bad design and there is noise between signal and power on these boards, however, many have used this amplifier without this issue. BOTH channels hiss.

I do not have the schematic

Findings:

1. When it is whole and you power it up you can hear the power supply transformer hum. The soft start relays kick on once the caps are charged and then you start to hear the hiss. The sound from the transformer isn't that different from the sound through the speakers which is why this is suspect #1. The transformer makes no noise unless it is hooked up to one of the boards. I know class AB is always on and pulling some power even at rest so this makes sense.
2. The hiss seems less noisy with the 120V input ground disconnected which is strange. If you scratch the 120V input ground on the chassis you can hear the scratching come through the speakers. This seems to point to a grounding issue in the design. This ground only goes to the chassis. This is suspect #2
3. There is a 3 pin volume pot for each channel. If I spin the volume pot with my head up to the speaker I can hear the sound of the pot turning coming through the speaker. I do not know how to bypass a 3 lead volume pot. I have disconnected the pot from the boards which seems to default it to the lowest volume level. The hiss is still present.

Things I have tried:

1. Disconnecting the volume pot - no difference
2. Separating the boards and moving them far from the transformer - no difference
3. Attaching the incoming 120V ground straight to the chassis and then to the building's conduit. I know the buildings conduit is a good ground as we have had to test this for other things we have built in the shop.
4. I soaked the transformer in polyurethane. I was hoping to quiet the actual mechanical noise of the transfomer. This also did not help.
5. I took a pencil and started tapping all of the components while it was powered and I could hear the hiss. Touching the components had zero effect on the hiss. I was hoping it might have been a badly seated/soldered component but that does not seem to be the case.

I open to try any suggestions at all. I have hooked this up in both my shop and my house and I get the same noise. I don't think its DC on the AC line since I have another class A amplifier that uses a toroidal transformer and I hear zero hiss coming out of that one. That one is about half the power but it has abosolutely no hiss at all.

The transformer is outputting 12v as well as two 35V leads to the board. Right now I am thinking its the transformer. Could be a bad batch of these cheap filter caps. I really do not have enough experience with class AB amplifiers to give any type of informed guess. Thoughts?

I'm really looking forward to this -

Designing Audio Power Amplifiers: Amazon.co.uk: Bob Cordell: Books

After reading about the AudioKinesis "Swarm" sub system and the Geddes paper on loudspeakers, I am fairly convinced that 3-4 randomly placed small subs are well worth trying in both 2-channel and HT rooms. Geddes specifically recommends multiple and different (not matching) subs to force more randomness (and I assume averaging) of room modes. The Swarms are matched drivers/cabinets.

My question is which small commercial subs would be appropriate for this theory? There are hundreds of small 8, 10, and 12 inch subs that are sealed, ported, etc. Has anyone tried this approach and can anyone recommend a combination of subs? I would like to use the smallest possible subs given the need for 3 or 4 or them in my room.

Roederstein draloric 0.60w resistor

Today I bought 🙂 (pics are not mine)

Harman Kardon Citation 11


Yamaha B-2


Nakamichi 480


Philips CD-104


Yamaha CT-610


Philips CDR-765


CEC DD-8200 with Shure V15 type IV


Grundig Fine Arts T-903 MKII


Next 😀

Oops! Almost forgot yesterdays goodie 🙂

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

Hi

Long story, but I’ll make it short.

Picked up a pair of used Lowther EX4’s in really good condition.

While testing them, in Martin Kings MLTL enclosure, and swapping out amps, they were both turned into smoke machines. Not my best moment…

They are in their way to Lowther for repair, and I will have the option of having either silver or aluminium voice coils installed.

As I didn’t get to finish getting the filter networks installed, parts had not arrived by the time I ruined them, I didn’t get to hear them “properly” with their original aluminium coils

Any thoughts/experiences with the differences between the coils would be greatly appreciated!

Thanks

P

Just got them delivered from the UK. Doing up a Lowther Acousta Enclosure for them pretty soon

Premium Drivers information sheet​

Standard specifications: Many misleading terms have been used to describe the paper preparation of the Lowther diaphragms, doping, age-conditioning, curing, varnishing, etc., leading to discussions & myths around old preparations, similar to the legend of Stradivari’s varnish. There is no magic formula. The standard process, used for many years, is to apply freshly prepared 'special pale' French polish to the made-up cone/voice coil sub-assembly prior to fitting to the motor. This soaks through the paper leaving pure shellac distributed through the paper fibres as the spirits dry. Sugar-like crystals can be seen on the surface of a freshly treated cone. A few months sees a uniform yellowing of the diaphragm due to the reaction of light & air with the shellac. The paper fibres are locked with the shellac to be stiff yet flexible; It is generally accepted that the driver performs optimally after this point, though the foam suspensions co-incidentally loosen up over this period, and this has more of an influence at the early 'break-in' period. Older drivers (pre-Thornton) mostly exhibit a dirty, patchy yellow appearance due to poorly prepared lower grade shellac, which does not cure well over time. Controlling the quality & preparation of the shellac is an all-round long-term improvement, but due to the cleaner appearance, some still think we do not shellac the cones. Standard spec. drivers will continue to be available as usual.

Premium Specifications: The main difference over the standard range is the treatment of the paper. In this process the paper is impregnated with our own in-house formular before cutting, forming & assembling. The 'curing' process is mostly complete by the time the unit is tested & packed, though improvements will still be noticed over the 'break-in' period. The new treatment reacts with the paper fibres differently to the shellac process, resulting in a more stable, consistent & dimensionally accurate cone. The impregnation formular, however, can only be made in small batches in our own workshop and will not scale up to industrial preparation. This limits production to the ‘premium-hand-made' scale,
with the inevitable expense involved. The premium diaphragms are also fitted with the new back centre, replacing the foam standard. The entire set of components is laser-cut, enabling greater control of consistency & accuracy over the die-cut standards. Laser cutting also allows us to make small detail modifications like rounding the points of the 'pips' that hold the voice coil to the inner cone, cut elliptical 'pressure-relief' holes to control the dual cone phase errors, adapt the turned edge of the inner cone to a more suitable paper weight & composition and re-design the assembly relationship of the inner / outer cone / back centre / voice coil - most of which
would have been adopted before, but not possible because of the limitations of the old die cutting. The result of all these adaptations is a diaphragm which excels in all areas, including appearance, with the Lowther logos, radial embossing, and consistency of paper surface & colour. The legendary hand-crafted double-wound speech coil and overall <>10.5g moving mass of the assembly are retained. Foam surround suspension is the same as standard.

Sound: Initially developed for use in the Edilia, testing in all driver models & cabinets showed a marked improvement in all areas. Diaphragms prepared straight-out-of-the box for our most critical 'test bed' - the Lowther-Hegeman with field coils - were received by everyone with amazement; described by various judges as 'game-changer', 'most significant positive step for Lowther in years', 'improvement in all areas of presentation of natural sound'. We are confident that the premium 'upgrade' easily justifies the enhanced price, and all customers are encouraged to hear the difference at our studio showroom. All of our top range handmade cabinets (TP2, Almira/Edilia, LHSR, Audiovector) will be fitted premium regardless of driver type. The premium diaphragms can be fitted to almost all existing Lowthers as an enhanced Re-cone, or LFL trade in.

Premium diaphragms: Key points - Changes / Improvements

Paper gsm weight & fibre type
Laser cutting & CAD design.
Lowther's own paper treatment impregnation process
Inner Cone improved, so:
Enhanced choice of phase plug /centre pole treatment
Aluminum or Silver voice coil
Radial embossing
Logos printed onto cones.
New back centre & assembly
Improvements in quality consistency, appearance, longevity.
Significant improvement in all aspects of sound presentation.​

Click to expand...

A 12" woofer that I've never seen measured in the @Hificompass.com way (sine sweep, 20mm, low self noise, high SPL capable microphones)


Manufacturer page:
https://www.products-peerless.com/en/transducer/207
Here's one view:



If we change the view of the website, it can look like this:


Lesson 1:
Scale matters!

Here's the VituixCAD2 Enclosure simulation:



Here it is in my actual cabinet, a 1cu foot sealed cabinet with medium fiberglass filling. Note the close correlation at 100Hz, but slightly more output at 20Hz due to the fiberglass filling.

Here is the log chip / exponential sine sweep at 2.83V drive:



Lesson 2: VituixCAD2 Enclosure simulation is very close to practice!

Now at 8.95V (+10dB)




Now at 28.3V (+20dB)



Yes yes, you say. But how can we compare to other woofers?

We'll need to equalize for the same SPL, surely! Here it is at ~85dB, between 40Hz and 262Hz.



There is a low pass filter for an acoustic LR4 @380Hz, which is how it was used in my system, hence the drooping high end.

Here it is again, with harmonics shown: -20 to -100dB down between 40Hz and 262Hz:










What happens when one doesn't do their homework properly*, and decides to install two into a 100L cabinet?
Part 2: *as implemented during COVID-19:

Simulation:
Two 12" woofers in 100L with 2.83V (~2W into 4 ohm)
vs
One 10" little engine that could in 22L with 9V: (~10W into 8 ohm)




What the upper 2 lines show is a 8dB advantage for excursion limited maximum SPL for the pair of 12" woofers...
On the other hand, the two lines are almost superimposed- the 10” in 22L plays with virtually the same frequency response as the pair of 12" woofers in a 100L box, ut it needs more voltage/power to do so- 9V into 8 ohms (~10W) vs 2.83V into 4 ohms (~2W)

Here's the measurement comparison:



Lesson 3: this David vs Goliath battle to bend Hoffman's Iron Law is interesting to this author...

Conflict of Interest Disclaimer:
I hereby declare that I have no financial, personal, or professional conflicts of interest that could influence the content, opinions, or decisions expressed in this post. My views and statements are made without external influence.

Edit: April 29, 2025:
Standard twin vs Double reverse inverted

This thread is for people to discuss their builds, build issues, and parts for the DIY Class A/B "Wolverine" Power Amplifier.
The boards are currently available through group buy's when they are held.
@jjs is servicing the USA and Canada regions.
@stuartmp is servicing the other regions.

Main Thread:

Wolverine 57v & 64v Schematic:
Please see the attached PDF files. These schematic show.
The Wolverine IPS - V3.7 (1st Group Buy) & V3.8 (2nd Group Buy)
The Precision EF3 - Both

BOM and Build Guide documentation:
Currently only available to group buy members.
In time will all be posted publicly once the group buy members have had time to order parts.

YouTube Build Link

Google Photos - Wolverine Build Album

Review Attached by @fireanimal 30-06-22
Review Attached by @richbandit 05-08-23 or at post #2,493

Posts of Interest
#

There is also a distortion sweep plot of the Wolverine below with the values listed for 1K, 10K and 20K.
A big thank you to Andy for taking this measurement for us. 🙏

17-3-23
we finally have 20k distortion measurements.
0.000095% THD 80 watts 8 ohm load.
Thanks again Andy for providing these amazing results
More test results can be found at the end of the build guide.

-------------------------------------------------------------------------------------

Announcing the Wolverine 5th Group Buy - Pre Order Open Now!​

Register for the Wolverine 5th group buy

Hello, I'm a new member from the USA. I'm currently building a 2 way speaker. I have interest in building a power amp.

Hey Guys, I have found this forum invaluable in helping me evaluate which sub I want to build to start my mini rig. In particular the Xoc1 TH18 thread has me sold thats the way i want to go. Thanks for having me!

Hi guys, new to the "business" and trying to build a wifi speaker 😀 will be fun

Light fantastic​

“The P1 power amplifier requires a super clean high current power supply to turn the low voltage line level music signal into hundreds of watts of output power. To do this, Siltech designed the Apollo Light Drive. A super-strong AC-powered light source is used to drive a photo-electric cell, giving a totally noise-free, galvanically isolated DC output. This then drives the amplifier’s output stage, keeping it absolutely immune from mains-born distortion. The idea behind this is not new, but its execution in a high powered amplifier is extremely challenging. The result is ultra-clean, low distortion power – and lots of it.”

Has anyone tried DIYing this concept?



https://www.siltechcables.com/saga-amplifier-system/

I heard these speakers by someone who tried to build Dunlavy SC V1 clone type speakers. They used two Focal Audiom 15 inch woofers. The model number for the woofers were 15VX. These were top of the line Focal Audio 15 inch woofers, 2 Focal Polyglass midbases. The model number for the midbase was 7K6411 and a Raven R2 ribbon tweeter.
The speakers were about 6 feet tall and weighed 335 pounds.

They speakers had a nice soundstage and the bass was tight with good extension. These woofers were very impressive.
Now, he couldn't do a crossover like Dunlavy. Dunlavy could make speakers that used ok drivers, but make the speakers sound great.

I remember i heard the Dunlavy SC-IV speakers that used all Vifa drivers. These speakers had an amazing soundstage and sounded very layered and the bass was fast and tight. I always though what could Dunlavy have designed using top of the line drivers like Focal at the time or Scanspeak.

Here's a pic of the speakers he designed.

Hello everyone, I'm new to the audio world. This is my first practical assignment for my courses so i want to improve it more. Since English is not my mother language and this is my first question so maybe there are some mistakes.
The requirement of the circuit:

• The bandwidth: 15-50Khz
• Output power on load should > 30W
• The efficiency η > 45%
• Distortion < 1% at 1Khz
• Input signal is in range 50mV - 100mV.
• The input resistance: Rin > 20k

This circuit i adapted from Audio power amplifier design handbook of Douglas. However, when i tried to simulate this, i met some problem:

• The quiescence current is too high, about 130mA through Q15 when a load is attached (if no load, floating, the ide current is much lower). I changed the bias voltage with Vbe Multiplier (Q10) but it didn't help.
• The gain to fulfill input 100mV and output 30W which make it become tremendous ~ R8/R9. So i think i need a preamplifier before feed the signal into power amplifier.

Could you suggest me some improvement to the circuit?






thank you verry muchh.

Yeah so i bought a sub on a whim. Its a skar vxf 15 d4.
T/S Parameters
Bl 39.1 n/a
Fs 35.4 Hz
Re Dual 4 Ω
Sd 779.3 cm2
Cms 0.05 mm/N
Mms 384.3 gr
Qes 0.43
Qms 4.78
Qts 0.40
Vas 47.7 L
Nref 0.47%
Xmax 30 mm (one-way)
Sensitvity
88.7 dB
I plan on attempting to build an hroar box for it. So far i have modeled it in a roar box with very nice response from 26hz-80hz. I havent figured out how to translate bp8s function in hornresp to hroar, but i have a good idea what will work without modeling it. Ill post a hornresp response later today. I really have no particular need for this, i just want to build it and see what it does. Ill probably try it in my ht but inevitably it needs to be in an suv or something, so ill probably sell it haha. What would you do with it?

I've been trying to find a reliable formula to calculate the total group sensitivity of a relatively odd configuration and number of LF drivers. They would be arranged as close as possible to each other.

In my own personal scenario ->

- 3 identical 12" LF drivers, wired in parallel, individual base sensitivity of 87 dB/2.8V/1M per driver, arranged in a triangle.

- what would the total sensitivity be of all 3 drivers playing together at frequencies lower than the equivalent of 1/2 WL?

With an even number of 4 drivers connected 2 in series, then the 2 groups paralleled, we'd theoretically observe a 3dB gain from doubling the driver count and another 3dB from doubling the cone area, but lose 3dB from cutting the drive voltage to each woofer of the series connections. That leaves us with a total net gain of only 3 dB if we only count the frequency range that falls in the 1/2 WL CTC driver spacing.

With an abnormal quantity of drivers, CTC spacing and adding in series.resistance from a thinner awg, it becomes a bit more complicated to figure all this out. Short of putting it in a software sim, which isn't always accurate, there has to be a better way to get a closer answer.

V-FET lottery amp #038 P-channel from first lottery
Original, unmodified, perfect condition
In addition: 2 Bulwark FE and 1 Tuba filter
Asking price: 700CHF + Paypal Fees and Shipping

Do i need to worry about baffel step correction if i measure all my drivers in the finished speaker cabinet or will that measurement already account for it? Thanks! Travis

This thread is intended to discuss the preparation and construction phase of building an F5 Turbo. A thread already exists for the circuit boards, so I'm guessing we will see a lot of activity here!

I have a ported sub which lives outside. The rear-facing port would seem to be an open invitation for mice, wasps, or small birds to set up home inside the cabinet. I plan to cover the inside aperture of the vent with speaker grill cloth but it stands to reason this will have some affect on airflow.

Thoughts?

Use this link for more details:
https://electrodac.blogspot.com/p/dac-ad1862-almost-tht-i2s-input-nos-r.html
Note: 8th pin on the I2S input header is missing connection with the GND (on some of my PCBs this pin is unconnected, if you are going to use it, solder it with the nearest GND pin on the header)


People who are selling brand new unused AD1862 or AD1865 chips:

• Paddy Garcia new group buy
• https://www.diyaudio.com/community/threads/ad1862n-j-dac-chips-for-sale.405922/
• https://www.diyaudio.com/community/threads/ad1862n-d.417897/

I want to thank @Paddy Garcia for the whole happy DIY community. He did very honorable work: Group Buy #92



Special tested DACs:
DAC702BH/CH (Glue logic - I2S data input) (result: audible digital noise on the output, not good for audio use)
DAC8811 (CPLD data input) (result: audible digital noise on the output, sound far away from very good audio, don't waste time and money on such DACs)
...

This thread is about all ways to use OpAmp as input stage in power amplifiers.
Let us see your way to do this.
There are many ways to make an opamp control a power amplifier.
There are good ways, I am sure - and less good ways.

I have one way up my sleeve now, but I also have Choctaw in another thread.

Hi all, a while ago I purchased a very lightly used set of, all Morel, ET 338, CAW 538 and CAW 938. My intention was and still hopefully is to pack these drivers into a nice 3 way speaker.

I have been learning VituixCAD but am a bit stumped with designing an enclosure for the CAW 938. I have a few questions about this regarding simulated SPL, Xmax and overall rules around these topics.

• • What SPL should these speakers be able to play up to, as in max db SPL for loud listening in a medium to large lounge at between 3-5m listening distance? Or if there is a standard for general high end home audio speaker I would be happy to aim for that.
  • In terms of woofer roll off at what point do you not need to worry about cone excursion, weather that's referencing the SPL roll off, the power dip at the impedance spike, cone force or velocity. I have looked around but cannot find any solid information on what is safe in terms of Xmax, everything from sealed enclosure to bass reflex and band pass all pass the rated Xmax of driver even at fairly low wattage, why is this not a big concern. What are some good rules or parameters to follow in terms of this while getting the desired SPL output.
  • I really want to do a nice job with these speaker as it will be the first I have designed myself and will be my daily drivers. Keeping this in mind they will be mainly used for music and watching movies. I would ideally like the qtc to be reasonably balance around 0.707 to avoid sloppiness or compression.
  • I have built and done some measurement on some test enclosures. The volumes and dimensions are listed below:
  • CAW 938: 320mm x 730mm x 436mm, built in 18mm OBS, the volume is 76.5L with a qtc around 0.71.
  • CAW 538: 260mm x 320mm x 210mm built with the same 18mm OBS, the volume is 10.5L giving a qtc of 0.5 to hopefully keep the mids nice and dynamic.
  • Finally, is the CAW 938 not suited for a low range woofer, my initial goal was anywhere from 500 to 250Hz down to the driver roll off with no HPF. If this does not seem viable I could definitely use it for a 2 way using it with a beyma compression driver.

Please correct me if I'm wrong with anything above. Please see some enclosure simulations below and also some nearfield measurements of the CAW 938 and 538 test enclosures, these measurements are also gated from memory.

Hopefully this data is enough to go on, let me know if not or you need any more info. All measurements in REW have 1/24th smoothing applied.

Thank you!

US patent 5,612,646 (PDF version) discusses Berning's ZOTL circuitry (there are actually commercial amplifiers), where instead of using a regular output transformer, the output tube is fed through a high frequency ferrite transformer by the load and MOSFET bridge. Begning claims significant improvements in performance as the high frequency transformer supposedly has little impact on audio frequencies (the switching frequency is suggested around 250 kHz).

A diyaudio member, hifizen, suggested to me that a better design would, instead of having a switching bridge in the signal path, use AM modulation, thus still allowing the use of a high frequency transformer instead of a regular OTL.

I'd like to get some opinions and discussion on the pros and cons of these two suggestions, as well as implementation caveats to watch out for (I actually intend to build one or the other, and have procured appropriate ferrite cores).

Hello everyone,
I have for sale pair of DIY finished boards of B&K st 140 amplifier built on the original exactly schematics.
Construction with components of absolute audio quality and definitely superior to the original:

• Nichicon Fine Gold audio capacitors
• Nichicon MUSE audio on the signal path (green)
• MKP bypass capacitors (Polypropylene)
• Cornell Dubilier silver mica capacitors
• ORIGINAL HITACHI K135 and J50 final MOSFETS
• Construction with Cardas tin.

Calibration as service manual 200ma @ 20kHz and zero DC offset (see photo) and absolutely perfect measurements in terms of bias, DC offset and THD (see measurements).
Power supply required dual 60V DC to have the nominal power of 105Watt/channel on 8 ohms.
Sound very well and powerful with NO hum and perfectly stable in temperature and elecrtical parameters.
Big heat sinks is not included.
Price request 80 Euro plus shipping (From ITALY).
Consider that the Hitachi mosfets alone are worth the asking price.
Some pics:

The TDA7293 series are underrated gems in the DIY world. This chipamp, with its modular structure, clip detector, mute-stby functions, low noise and low distortion, produced with DMOS technology, actually has the potential to compete perfectly with National/TI's LM3886. On the other hand, it is common practice to use chipamps with a buffer due to low source impedance demands and relatively high input bias currents. Likewise, with composite feedback applications, both the noise and distortion efficiency of chipamps can increase significantly. In our implementation, two matched N-channel JFETs, together with the PNP transistor, operate as a complementary feedback pair as a high-impedance, high-CMRR differential input buffer for the TDA7293. The JFE2140 / LSK389 LSK489 dual JFET combination used provides significant improvement in THD and noise compared to the use of the chipamp alone, thanks to its extremely low noise. The composite feedback rate is 26dB (20x). In this way, ~1.25v RMS input signal is sufficient for full power. On the other hand, thanks to the DC servo circuit established with TI's low-noise, low-offset opamp OPA277, the DC offset remains below 1mv.

Our inspiration for our design was Bob Cordell's LSK489 application notes and JFE2145 datasheet.
https://www.cordellaudio.com/JFETs/LSK489appnote.pdf
https://www.ti.com/lit/ds/symlink/jfe2140.pdf?ts=1717672324923&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2FJFE2140
https://www.st.com/resource/en/datasheet/tda7293.pdf
https://www.ti.com/lit/ds/symlink/tps7a49.pdf?ts=1717660447218&ref_url=https%3A%2F%2Fwww.google.com%2F
https://www.ti.com/lit/ds/symlink/tps7a3001-ep.pdf?ts=1717738722969&ref_url=https%3A%2F%2Fwww.google.com%2F


The ancient 78xx 79xx series regulators, which are well known in the electronics community, have been used in audio circuits for years thanks to their stable structure, high PSRR rates and relatively low noise(?).
Measurements of 78xx-79xx ICs (even though noise values such as "0.003% Vo" are given in their datasheets) have been found to reach noise values of 500uV - 1mV in the audio band, which may disturb sensitive ears, regardless of the input noise. Of course, such a supply noise is meaningless for modern audio opamps whose PSRR is around 120dB.
However, especially in discrete applications (since PSRR efficiencies are quite low), this level of noise will be disturbing.
Although complex, discrete, parallel-hybrid low-noise solutions have been produced to solve this problem, these applications remain a troublesome alternative due to application difficulties, additional noise due to the area covered by the regulator, and the necessity of matching components in some applications.
Our application provides a good and affordable alternative to all these difficulties. TI's low-noise regulators TPS7A4901 for + rail and TPS7A3001 for – rail form the heart of our application. The effective noise amounts of these regulators in the audio band are below 15uV (RMS) level. In addition, while PSRR rates are 60dB in the 78/79 series for 100-120Hz, they are around 70dB in the TPS7As. On the other hand, load and line regulation rates and transition responses are significantly higher than the 78/79 series.
Although the input voltage of these regulators is limited to a maximum of +/-36v, input up to +/-60v can be applied thanks to the input voltage limiter used in our application.
Since the pinout of the 78/79 series is used directly, they can be used as a one-to-one replacement in applications where these regulators are used.

EPIC S

EPIC S


Positive Regulator Schematic


Negative Regulator Schematic


Final prototype measurement of EPIC S.
1K-1NF input filter
47K-4.7K NFB Resistors
4.7mA Input bias
Power: 78W 8ohm (2x42V)
Input sensivity: 1.25V
Slew Rate: 8V/uS 8ohm/1nf (JFE2140)
Slew Rate: 9V/uS 8ohm/1nf (LSK489)
Bandwidth: 5-75khz -3db
DC Offset: <500uV



EPIC S Output Noise

Hello,
I'm building a P3A amp that will be paired with the ESP tone control preamp. The pre already has an output cap so I'm wondering if there is any reason to keep the input cap on the P3A, and if not, could I also eliminate R1, R2, & C2?

This Error-Correction/Composite Combo amp is based on Mr Evil "Unnamed feedback method explored" and Nickolay Shvydky "My ZD-50 ultralow distortion chipamp"

Output power at +/-29.5V: 8 ohms clip at 42W, 4 ohm clip at 65W. It is very stable in both EC and Comp mode. Ans it behaves very well after clipping.

I could only measure its THD+N very roughly using Focusrite Solo 3rd, which has a minimal line-out and line-in THD+N of 0.002%.

U1 is OPA1655 and U2 is OPA828. For error-correction(EC) mode, RV1 was set at 330ohm. For composite (Comp) mode, RV1 was set at 680 ohms.

Only looking for the SuperCables Cookbook now. The Vacuum State site is no longer available, so hoping to find someone who wants to part with their book.

Well, origin thread is here : Iron Pumpkin(s) and other smaller vegetable animals

If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.

This one having two purposes :

-placing all necessary info about final iteration,

-trying to layout clearer picture of what's fuss about,

-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread

(3 purposes then , not two )

edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:

do not connect buffer output to Turtle

maximize trimpot R36 (measure across R39 to confirm max value)

R37 position is irrelevant for now

if you're sure that you connected everything properly, just power it on

set positive and negative rails to +/-12Vdc , with trimpots R9 and R10

power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output


do everything the same with other channel, connect outputs of buffers to Turtle, enjoy

Earlier in the Le Monstre Preamp thread, we posted schematics and spice files for 3 different line level buffers.
www.diyaudio.com/community/threads/preamp-for-hiraga-le-monstr-2024.421562/

They all have JFET inputs and use 4 complementary transistors in total.
We have now built and measured them all, as shown in the pdf attached.


Patrick

.

In the last few days off, I have been somewhat confused and have tried to collect enough reasonable data for a possible replacement circuit using the usual home remedies. I don't know whether I succeeded or whether I was able to develop a common thread; the more diagrams one plot, the more confused the scenario becomes. I deliberately left out the interesting mechanical side, because how can one approach it reasonably well with home remedies? Of course one can think about the elastic side between the cantilever and tip and the plastic disk, but on average we always come to a conclusion, reso fo is always less than 35kHz and the cutoff fc moves from 61kHz to 32kHz ... outside to inside.

Perhaps we can develop a test procedure, a common thread, together at this point.

Hi

The big thread of "100W Ultimate Fidelity Amplifier" is a chaos.
i need time to search through all the page and mark all i can find.
pcb is done in yellow by jlcpcb.

Gerber and all other documents are in post 13908: here
input BJT i use the recommended KSC1845, driver are 1381 and 3503, power mosfets are the renesas 1058/J162
as C4 it is written 220µF, and XRK use a polymer elco with 330µF. I use a orange 1000/16VµF by epcos
for C9,C16, C12, C15 i use Panasonic 680µF/50V
input cap is a red polymer panasonic 2,2µF/400V instead of 10µF
i use the lower gain setting R11, R12--> 550R and 20k
i did my first output coil...its not nice done but it has about 0,9µH the resistor is under the pcb

bias setting:
post 6686 bias at 100ma-170mA, wrote about goldmund amps--> bias 200-300mA
my bias is set according to the hint of post 7753 by bimo to 400mA. the amp is working fine.
post 6971 test by XRK as an Class A amp with 1,3A works fine...big heat sink is needed!

i used for the first test a 0,65K heat sink.
i plan to use a 4U/300 case by modushop with a 300VA 2x24V sec. transformer

i will just check the other channel.
psu voltage is 31 per rail and bias is after 2 hours 420mA stable. no heat problems, no smoke..

Gain is about 31dB, at 8ohm load about 29WATT.

if you have any hints , let me know.

edit:
Apex directory - done by XRK ..thx:
here:

edit: 26.8.2024: set bias current back to 400mA #post 104
edit: 25.03.2025: post 123 latest PCB Gerber by Peter(Kleinhorn) - thank you!
post 123

kr
chris

I have a distortion in one of my tweeters on my 3-way. The distortion occurs only at certain frequencies and above a certain volume. The distortion is pretty deterministic, I can reproduce it. They are old 3 ways energy speakers from the 2000. I managed to isolate the distortion problem : it is only one side, and because I can bi-wire it, I can confirm that the distortion is coming from the tweeter and not from the mid or bass (because mid and bass share the connector).

I also swapped sides of the amplifier, so I know it is the tweeter on the speaker and not the amplifier that is problematic.

The screw to remove the drivers are not accessible (see: https://rvb-img.reverb.com/image/up...,t_large/v1639605839/olidljagmyhg8zmbkcx4.jpg), so I would like do the debugging and part sourcing before taking them apart.

Is there something I can do to pinpoint where the problems, i.e. crossover, dome, magnet, voice coil? And the potential solution?

Thanks

I don't really post up here as often as I should, but I have been posting as tarior on AudioKarma for over 20 years now.
At any rate I have a ton of obsolete chip amplifiers and some excess small signal transistors. I would like to trade them for parts I can use, or, I can sell them outright.
All of the transistors were sourced from Digi-Key, Arrow, or Mouser. I'll start with parts I don't have enough of:
KSA1381, 2SC2240/A970, 2SA1370/C3467, KSC1845/A992 with a gain range higher than F, KSA1220A, through hole versions of 2SC4207/A1552, 2SC1904/A899, 2SC1885/A912, 2SB568, 2SB718, and TDA7109P. If you have interest in any of the parts, and have some of the ones listed, I'll let you determine the trade ratio, within reason. If you would like to buy any outright, we can also talk about that.
First up, we have a few transistor part numbers.

KSC3503D 200-300 available.
KSC1815GR 2000 available
KSA1015GR 500 available, maybe more in the future.
KSD1616A(L) 2000 available
KSB1116A(L) 2000 available.
MJ2901 NOS 9 available.
SGSD00034 6 pieces
SGSD00032 2 pieces
SK3009 3 new, one used. I'll throw in any used ones for free.
SK3014 1 new, two used. ""
Tektronix 151-0337 One piece
SK3113 Germanium damper diode One
2SC3976 3
2SC3982 2
2SD1441 1
2SD1453 1
SGSD00042 3
SGSP321 2
SGSP579 2

Next is the long list of obsolete chip amps.

(Rohm) BA511 9 pieces BA511A 3 pieces BA521 1 piece BA532 4 pieces

Sanyo LA4430 7 pieces LA4420 9 pieces LA4400 3 pieces LA4422 2 pieces LA4100 4 pieces LA4032 2 pieces LA4122 4 pieces LA4220 8 pieces
LA4140 4pieces LA4102 1 piece LA4182 1 piece

Hitachi HA1338 3 pieces HA1308 7 pieces HA1339A 5 pieces HA1306W 10 pieces HA1306P 2 pieces FA6013 2 pieces HA1366W 2 pieces
HA1366WR 2 pieces HA1368 1 piece HA1377 4 pieces

Panasonic AN7120 6 pieces AN315 6 pieces AN214Q 2 pieces AN7147N 1 piece AN630 1 piece MN2114 2 pieces M5115P 1 piece M5115PR 1 piece
M5109P 1 piece

Delco DA101 2 pieces DM31 1 piece DM11 1 piece DM44 1 piece DM32 4 pieces

Dolby NE545B 2 pieces

NEC upc1230H2 8 pieces upc1182H 4 pieces upc1181H 3 pieces upc1181H (board pulls) 4 pieces upc1025H 6 pieces upc1185H 4 pieces
upc575C2 11 pieces upc577H1 1 piece upc555H 1 piece upc554C 1 piece

ST Micro TDA1170N
TFK TDA1170N

Toshiba TA7205P 10 pieces TA7209P 2 pieces TA7201P 2 pieces TA7203P 1 piece

Fujitsu MB3731 1 piece

Mitsubishi M51513BL 3 pieces MB51514AL 7 pieces MB51515BL 3 pieces M51102L 1 piece

Few years ago I build Seas based speakers. (T25-001 and W17E-002). Speakers was my own design, even filter.

I was quite satisfied speakers sound to the moment when I get chance to listen original Jamo Concert 8 speakers. After that I was not satisfied anymore


So my question is that, does anybody have Jamo Concert 8 (Jamo D830) crossover schematic?

I have seen some pictures taken from that crossover board, but component values are not clear to me.

Picture shows how components are placed to board.
Red are capacitors, white are resistor and black circles are coils.

To answer various instigations from forum members in the polemic of 'does THD..' I re-open this subject by submitting samples of audio recorded through the ADC of the Emu0404 to try to hear any differences in the various outputs of :
1. Dac of computer
2. Dac Ak4396 through ecc88 tube of Broskie unbalancer
3. Through Ak4396 + 6BL7 8 Watt tube amp.
4. Through Ak4396 + SS JLH modified amplifier
5. Through computer + SS JLH modified amplifier

Everything will be done at optimal levels for fairness and quality, (amps same power, dacs same output voltage, ADC same gain)

I got the proto of the s.e. trafo with multi tap
5 kohm, 43% and 20% UL
5 ohm single secondary
around 20H
primary wire 0,28 mm diam - Rdc 140 ohm
max Ia around 200mA
Pmax around 10 watt, column 40x45,
M3 - 0,3 mm. o.g.
4,4 kg




This is not available.

To play in the real world not in virtual
Testing some circuit.
Unfortunately I have to service now my Sofia ( some hard problem) then I can test the tube that will play in the circuit
proposed


Walter

The Iron Pre is now listed in the diyAudio store for anyone to purchase.

Until the 'Build Guide / Build Thread' is created, this post will contain all current schematics and notes for the Iron Pre sold through the diyAudio store. Check back frequently to ensure you have the latest files.

Sep 14 2023 - Below is what you're waiting for! See some awesome information and help from 6L6 on the SE build. A new thread and the guide using the web interface will be posted ... soon. Post #2291

Background

Hello Happy DIYers / Greedy Boyz!

I am thrilled to announce that Zen Mod's Iron Pre essentials kits will be offered in the DIYAudio store. This is not a group buy. You can learn more about the project in the thread linked below.

https://www.diyaudio.com/community/threads/whats-wrong-with-the-kiss-boy.293169/

Highlights include matched Toshiba JFETs from Nelson Pass and high-nickel CineMag transformers. 6L6 has volunteered to post one of his incredible build guides also.

If you're a Smiths fan, you may ask, How Soon Is Now? They should be available for order before the end of the year. At this time, we have enough parts sourced for 100 SE and 50 balanced kits.

The next obvious question is, how much? Costing is not final yet, but the goal is $100 for the SE kits and $125 for the balanced kits; a tremendous bargain. We have contingencies for all the parts, and we hope that this will be a permanent addition to the store. However, for now, we can only promise what we've got. Get 'em while you can.

Click the link below to see what will be included in the kit, answer a few questions about what you might like to see in the future, and get on the list.

Note - The n-channel JFETs will be 2SK370.

Quick and Dirty Startup Process

This happens after: the boards are stuffed, the AC supply is verified and connected properly, and I/O has been connected. Nothing needs to be shorted. Note the additional step for the V4 SMD version.

1. Set V+ and V-
   
   Adjust P1 and P2 for each board until V+ is +15V0 and V- is -15V0
   
   GND, V+ and V- pads are clearly marked on PCBs.
   Do not move forward if you cannot adjust the voltages to within 0V1 or if the voltage seems unstable.
   
   
2. For V4 SMD Only- Set current through JFETs
   • Set DMM to DCmV.
   • Place probes across R34 and R37 for SE or R40 and 41 for Balanced. You can also use square pads / test points near resistors.
   • Turn P4 and P6 respectively until DMM reads 14mV +- 0.05mV - See schematic.
3. Null DC offset
   • SE
     • No jumper caps in place for JP1 or JP2
     • Measure at center pin of JP1 and JP2 NOT between those two pins*
     • Turn P3 / P4 (V3 and earlier) or P3 / P5 (V4 SMD) respectively until voltage shows 0V +- 5mV
     • Cap the jumpers for your choice of gain.
   • Balanced
     • No jumper caps on JP+ or JP-
     • Measure at pin 1 of JP+ and JP- NOT between those two pins*
     • Turn P3 / P4 (V3 and earlier) or P3 / P5 (V4 SMD) respectively until voltage shows 0V +- 5mV
     • Cap the jumpers.​

Updates

4-May 2023

Edited 7-Aug 2023. All in-line photos have been removed. Please see attached files for all documentation.

5-May 2023

Updated Single-Ended BoM to correct 330R part notations in the gain stage to R28 and R29.

Attached are the Bill of Materials / Parts Lists - Note File Names for Balanced and SE

26 - May 2023

Updated SE and Balanced Bill of Materials to indicate that snubber components should not be installed.

Balanced BoM Filename - BOM_Store_Iron_Pre_Balanced_Dist_v5.pdf
SE BoM Filename - BOM_Store_Iron_Pre_SE_Dist_v5.pdf

27 - May 2023

Updated SE and Balanced Bill of Materials to correct and clearly note which diodes should be installed for input switching.

Balanced BoM Filename - BOM_Store_Iron_Pre_Balanced_Dist_v6.pdf
SE BoM Filename - BOM_Store_Iron_Pre_SE_Dist_v6.pdf

1 - June 2023

Note - No changes required. However, the packing lists some of you will receive may note LM336-5.0. That was a typo; apologies. The correct parts (as supplied and noted in the BoM) are LM336-2.5.

Removed the link to sign up indicating interest in kits. Those currently on the list will get first priority for the next round of kits. After that, they will be sold through the normal process through the store.

6 - June 2023

There are two gorgeous prototype chassis available; one designed specifically for SE, and one for Balanced. You can find some details in post #431. The depth for both chassis is 280mm. There is additional information sprinkled throughout the thread re: acceptable sizes and some potential part numbers for IECs, input / outputs etc. along with pictures of some examples. Please search first before asking chassis questions, and I'd recommend using the latest posts' information. Again, they are prototype chassis, and anything could change at any time until the design is finalized. The best source of information re: the chassis is directly from Modushop until they are sold in the diyAudio store. Timing TBD.

8 - June 2023

Added parts placement and pcb layouts for those interested.

30 - June 2023

V7 - Minor Updates to BoMs. QTY added. Ensure to check quantity per board against the quantity you need for your project. Added links to a popular online website to show examples of parts that will work for the connection between the main boards and the twister boards for input selection / LED power etc. Added generic descriptions for those that would prefer to select their own parts.

1 - July 2023

V8 - Minor Updates to BoMs. Added heatsinks for M3 if 12V relays are used.

7 - Aug 2023

I'm excited to say that more kits will be available very soon for 'round 2'. Continue checking this post (as always) and the thread overall for up to the minute updates.

In his graciousness, ZM has made some minor running changes. Changes are:

• Updated transformer snubber circuit.
• Easier positioning / mounting of the CineMag transformers in some situations.
• Changes to allow easier use of some logic circuits for input switching.

Boards that include the changes will note "2023" vs. "2021" on the silkscreen. The Twister board accompanying the 2023 boards notes V.3. Both 2021 and 2023 boards are included with 'round 2'. You cannot choose which you will receive, and you will not know which you will receive until they arrive. Do not fret if you get a kit with 2021 boards. If you need to use a particular type logic solution, there is a very easy modification previously noted in the thread, and the snubber is not necessary. The changes made were a kindness from ZM, but all 2021 boards can be made to function just like 2023 boards with a few user-tweaks described in the thread.

Note - The attachments have been packaged and note which files to choose for the respective boards. Previous attachments and in-line thumbnails / photos have been removed for clarity. The BoMs have been updated slightly for clarity.

9 - Aug 2023

There is a minor error on the silkscreen for the boards marked Iron Pre SE Zen Mod Labs 2023. The polarity notation for C11 visible when the cap is installed is incorrect. Ignore it.



13 - Aug 2023

His Mightiness created two graphics for how to wire standard pots for both SE and Balanced. Attached.

29 - Aug 2023

Minor updates to balanced BoMs. Removed reference to D15.

31 - Aug 2023

Added wiring diagram for AVC for SE. See post #2113 for context.

21 - June 2024

All testing for the Super Mega Deluxe version is complete. Kits will be back in the store 'soon'.

25 - September 2024

"Soon" is relative. 🙂. SMD kits are on sale. The schematics and files for the Super Mega Deluxe (SMD) have been attached in their appropriately named .zip files. Enjoy your builds.

26 - September 2024

A few people purchased the "completion" kits for the V3 and earlier boards and were wondering if they could be used for the V4 SMD kits. A lot of the parts are identical, but below is what you'll need in addition and to swap a few parts.

For balanced you will need:
4x additional 825R or 820R resistors - I like these Vishay BC 825R
8x 58R or 62R resistors - I like these Vishay BC 62R
4x 1R resistors - I like these Vishay BC 1R
8x 100R trimmers - I like these Bourns 3296 Series 100R Trimmers
4x 1uF film caps with 5mm or 15mm lead spacing - I like these TDK 1.0uF with 15mm Lead Spacing

For SE you will need:
2x additional 825R or 820R resistors - I like these Vishay BC 825R
4x 58R or 62R resistors - I like these Vishay BC 62R
2x 1R resistors - I like these Vishay BC 1R
4x 100R trimmers - I like these Bourns 3296 Series 100R Trimmers
2x 1uF film caps with 5mm or 15mm lead spacing - I like these TDK 1.0uF with 15mm Lead Spacing

27 - September 2024

Some potentially helpful additional parts in post #3784. If people have more helpful suggestions, I can add them.

3 - February 2025

Added diagrams for setting buffer current in V4 builds.

If a crossover design calls for an 8mH / 0.790 Ohms and the two closest options are 8.2@0.800 ohms (Solen) or 8.0 @ 1.75 ohms (Janzen), which would be better or does it even matter? Actually I've already purchased the 8.0/1.75 Janzen which I suppose I could return. Any issues with either of these? If it matters, this is for a first order XO on the woofer with only a single inductor. Thanks

(For Mechano24 design with Scan Speak drivers click here LINK)
(For Mechano323 3-way design with AMT driver click here LINK)
(For Mechano23 design with Scan Speak and SB Acoustics drivers click here LINK)
(For Mechano325 7l 3-way design with Dayton drivers in "horizontal" arrangement click here LINK)


Mechano22
Not so long ago, I made a small 2-way speaker design with the following goals: f6 around 40Hz with 8 liters BR enclosure, generally balanced on-axis response and close to linear frequency power response.

Experience gathered with that design led me to a conclusion that maybe it could be done better and cheaper. And here is the new version, codemame "Mechano22".

It is based on relatively inexpensive set from Dayton: ND25FW-4 tweeter with waveguide and DS135-8 midwoofer.

Box dimensions: HxWxD: 290x174x260mm, made of 18mm birch plywood. The Box is filled with polyester fiber.

Both drivers are placed in the middle of the front panel, with centers 75mm (tweeter ) and 195mm (woofer ) from the top edge.

The woofer has a flat basket edge, which, according to the manufacturer's note, allows application without flush so it wasn't implemented. On the other hand, woofer mounting hole was chamfered on the inside.

Pic1. System on-axis and power response characteristics in comparison with target lines. For power response calculation +-180deg measurements were taken in H and V planes (10deg step):




Pic2. frequency response for DS135-8 (orange) and ND25FW-4 (gray):



Pic3. Crossover schematic:


Pic4. VituixCad, schematic and 6-pack for double check:



Pic5. Filters assembled on a scrap of plywood (for 1 unit):


Pic6. Units assembled (need sanding and waxing ):


Pic7. Measured on-axis dBspl (both units, 5dB/div). f6=40Hz if I did not messed up the measurements.


Pic8. Measured system impedance (both units).Nominal impedance is 6R (considering 5R minimum at 200Hz):


List of components used (for one unit):

Dayton Audio DMPC4.3 / 4.3 uF / 5% / 250 V / Polypropylene capacitor MKP
Capacitor Jantzen Audio CrossCap 0.47uF / 400VDC / 5% / MKP /
Dayton Audio DMPC8.2 / 8.2 uF / 5% / 250 V / MKP 2 pcs.
Capacitor Jantzen Audio Cross-Cap 9.1uF / 400VDC / 5% / MKP
Dayton Audio DMPC-2.7 / 2.7 uF / 5% / 250 V / MKP polypropylene capacitor /
Ty-Ohm ceramic resistor 22ohm / 22R0 / 20W 5% SQP
Ty-Ohm ceramic resistor 4.7ohm / 4R7 / 5W 5% SQP
Ty-Ohm ceramic resistor 100ohm / 100R0 / 5W 5% SQP
Ty-Ohm 12ohm / 12R0 / 5W 5% SQP
Jantzen Audio core coil 0.68mH / cylindrical / 0.162ohm / dr.1mm Fe 0.021kg / dia.20, length 40mm /
Jantzen Audio core coil 0.82mH / reel / 0.22ohm / dr 0.8mm Fe 0.056kg / dia.24 length 33mm /
Jantzen Audio Air coil 3.7mH / 3.25ohm / dr 0.5mm / dia.33, length 15mm
Jantzen Audio Air coil 2mH / 3.21ohm / dr 0.4mm / dia.31, length 8mm
Jantzen Audio air coil 0.12mH / 0.26ohm / dr 0.7mm / dia.27 length 8mm

Attached files: VituixCAD *.vxp and XMachina *.xmp with spinorama.

Good morning

I am building a clone of the SUGDEN A21 amp (class A) and want to associate a very good preamp with RIAA, tone control.
That of ELEKTOR 2012 caught my attention. To validate the quality of the PCBs manufactured by JLCPCB, I ordered the tone corrector part from them. Superb quality.

Now that I am sure I can have PCBs, I would like to have feedback from those built or use/used the Elekto Preamp 2012 or want to go in the same adventure than me!
So any feedback from this preampli would be appreciated, going to build it alone with no support is a bit hard.

Please let me/us know

Georges

Have been gifted a pair of Toa Horns. I've no PA experience and looking at current Toa product I assumed these were 70v line drivers...but was told they were used on std home hifi as additional drivers.
Plugged them in to a basic 20watt/ch 3-in-1 home mini system and they seem to play fine. (other than the constrained range of course)
Can anyone explain what may be happening ?

As a continuation of work by Esa Merilainen and Pascal Brunet, as well as my previous work, an approach with a deeper feedback circuitry has been tested. The deeper feedback indeed lowers harmonic distortions by 20dB and more, including the most stubborn 3rd harmonic, in a somewhat unexpected (by me) way.

Introduction​

In the previous experiments, a degree of improvement was reported by applying series resistors 6/12/24 Ohms, which corresponds to the feedback depth of only 6…20dB. The results were promising but it was not clear what you would get with deeper feedback.

Method​

Measuring a driver impedance​

A few drivers from different vendors have been measured using Feeltech FY3200S-20M generator and Rigol DHO802 oscilloscope.



The driver impedance lump was modelled as Zeq = (L+RDC)||C||Rres:



Contrary to the statements of previous researchers, it was found that the p grade of Lp is neither 0.5 nor 0.55 but varies from driver to driver, from 0.6 to 1.0.

Feedback loop structure​

To start with, Dayton Audio SIG150-4 was used. An equivalent of 0.1*Zeq[SIG150] was used as a feedback discriminator, to get a voltage amplifier (LM3886, simplicity’s sake) with a gain in the range between 20 and 30dB. Of course, the feedback network cannot be universal. For SIG150-4:






A reasonable amount of RF care was taken. The amplifier is stable. Measurements were taken by an 12dBA AudioTechnika 4040(Or 2020?) cardiod condenser microphone calibrated by ECM8000 calibrated by AZ8930, at 0.5m from the cone, while being adjusted to 1m loudness (60..85 dB SPL), in a moderately damped living room (RT60 ~= 250ms for f>200Hz). In the signal processing, frequency resolution was traded off to benefit precision and dynamic range (i.e. the curves have been denoised). Dotted lines correspond to the resulting noise floor for the given harmonic and excitation levels. The curves are positioned on the originating frequency, i.e. they correspond to the frequency that produces the harmonic, rather than where it appears, and are properly normalized for the cone frequency response (FR).

Results​

Voltage Drive​

Current Drive​

Discussion​

For LM3886, the depth of feedback is higher due to GBP=200kHz (46 dB on 1kHz). Most decent DIY Class A/B amplifiers have GBP over 1MHz. The depth of feedback can be improved by using second-degree astatizm and/or nested feedback. It is not entirely clear how to implement the current drive with non-self-oscillating Class D amplifiers efficiently.

Note that an open-air inductor serves as an antenna and gets lots of interference, even after turning most of the switching PSUs in the vicinity off. In a real product, the inductor must be shielded.

If seen as necessary, the f<2Fs distortions can be dealt with by motion feedback. However, here the focus of the efforts is on the midrange drivers. Here, you do not need to worry about Fs lump.

90 dB @ 1m is as loud as SIG150 (sensitivity 91.1 dB @ 2.83V / 1m) can get without producing obnoxious distortions, both voltage and current drive. Sig150 is not capable of producing clean sound for f < 2*Fs, and multiple saturated resonances appear all the way through the passband, which is fairly typical for non-professional drivers.

The current sensing network is too sensitive to power and temperature variations. Thicker wire shall be used for the inductor and all resistors must be high-power rated. Satisfying the destruction limit is not sufficient distortion-wise.

It is not clear how far you can get with the current drive because you are limited by the cone distortions.

Conclusion​

More experiments with different drivers, both Fe and Nd, both chirp and music to follow. The effect on Barkhausen noise (non-repeatable-in-details discretization of non-linear de/re-magnetization distortions) is most interesting for magnets that are never fully saturated because of the back current of the magnetizer and some domains are easier to flip than others.

The drivers are implicitly optimized for voltage drive. The current-drive-optimized drivers may turn out to be quite different. It’s a terra incognita, for you to discover.

Waiting for the missing components to be shipped and delivered…

Copyright © Michael Zrull, 2024/09/19. All rights reserved. Released under GPL 3.0. I won't patent it nor restrict DIY by any means.

I have a limited supply of these extremely low distortion NatSem ICs.

Common price, €10/each. + postage. Min 5 pcs, mixed ok.

Ships from Sweden, so no tax in EU.

R

Hi to all,

I just want to make a album for 15 songs time over 16 minutes. It's simple. Each user has to copy and paste adding only one song to the album so in the end it's 12 songs, one per user, and each album has to have a different theme.

Whoever adds the last song of the album gets to say what the the theme for the next album will be and it starts all over again.

Songs over 16 minutes:

1. Pink Floyd - Echoes (23:31)
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.

Hi all
I'm trying to design a 3-way speaker based on mid-range and tweeter I already have (used in a 2 way speaker some years ago).
I decided to add SB26SFCL38-8 to these 2 drivers in bass reflex configuration. The volume for the woofer will be around 88L with a resonant frequency is 27Hz.
I want create a cabinet with hard plywood 19mm with external size WxDxH 38x55x63 (the height is a constraint).
The cabinet will have a "small room" for the mid and tweeter of about 8L.
The port tube will have diameter of 9,2 cm and length of 22,5 cm
I have 2 main doubts now (may be more 🙂)
1. Where put the port tube. I have not enough space below the woofer do I would like to place it upper. Something like this...



I also did a try with 2 port of 6,6 cm and 24,5 cm length below the woofer.



What do you think is the best solution?

2. How many braces, where to place them and how shape them. I'm not so expert about this aspect.

Acoustic Horn Design – The Easy Way (Ath tool)

This is an associated thread for a waveguide generator called Ath (Advanced Transition Horn), version 4.
Ath is a piece of software for designing waveguides and horns. At the same time it makes it possible to easily simulate their acoustic behaviour by means of FEA (BEM) via ABEC/AKABAK tool.

The current Ath release is available at https://at-horns.eu





Thread milestones (last edited 26.12.2020, no longer maintained):

#233 Birth of the OS-SE formula
Acoustic Horn Design – The Easy Way (Ath4)
Acoustic Horn Design – The Easy Way (Ath4)

#375 Measuring driver's exit wavefront
Acoustic Horn Design – The Easy Way (Ath4)

#666 Some of the practical verifications:
Acoustic Horn Design – The Easy Way (Ath4)

#844 Ath 4.4.1 - Introducing superformula
Acoustic Horn Design – The Easy Way (Ath4)

#922 JBL M2 "How-to"
Acoustic Horn Design – The Easy Way (Ath4)

#933 JBL M2 - Ath clone
Acoustic Horn Design – The Easy Way (Ath4)
Acoustic Horn Design – The Easy Way (Ath4)

#1003 Comparison of an OS waveguide and a flat piston
Acoustic Horn Design – The Easy Way (Ath4)

#1117 Ath 4.4.3 released (Fusion 360 import)
Acoustic Horn Design – The Easy Way (Ath4)

#1533 Ath 4.5.0 released (scripts not backward compatible)
Acoustic Horn Design – The Easy Way (Ath4)

#1602 General phase-plug discussion
Acoustic Horn Design – The Easy Way (Ath4)

#2389 Joining profiles of different curvatures
Acoustic Horn Design – The Easy Way (Ath4)

#2494 Tritona Waveguide
Acoustic Horn Design – The Easy Way (Ath4)
Acoustic Horn Design – The Easy Way (Ath4)


Spherical-wave phase plug

#1706 Initial ideas
Acoustic Horn Design – The Easy Way (Ath4)

#1824 Kessito's input
Acoustic Horn Design – The Easy Way (Ath4)
Acoustic Horn Design – The Easy Way (Ath4)

#1892 Compression cavity modal analysis
Acoustic Horn Design – The Easy Way (Ath4)

#2016 Diaphragm suspension analysis
Acoustic Horn Design – The Easy Way (Ath4)


Free standing waveguides

#2600
Acoustic Horn Design – The Easy Way (Ath4)

#2936 Rolling back the profile
Acoustic Horn Design – The Easy Way (Ath4)

#3390 Employing axisymmetric BEM (finally)
Acoustic Horn Design – The Easy Way (Ath4)

#3427 Rollback added
Acoustic Horn Design – The Easy Way (Ath4)

#3532 Source amplitude shading
Acoustic Horn Design – The Easy Way (Ath4)

#3549 OS-SE formula extended: k
Acoustic Horn Design – The Easy Way (Ath4)

#3664 Effect of an enclosure and other parameters
Acoustic Horn Design – The Easy Way (Ath4)

#3822 Compression driver throat plug
Acoustic Horn Design – The Easy Way (Ath4)

#4186 Preferred in-room response and DI target (discussion)
Acoustic Horn Design – The Easy Way (Ath4)

#4503 Incorporating compression driver model
Acoustic Horn Design – The Easy Way (Ath4)