WTB:

Twisted Pear: Legato v3.1 PCB or a working one fully populated 🙂

I can pay with Paypal.

Thanks in advance!

Hi all, I've got projects coming up that require adding additional opamp stages to existing equipment. Thus I am on the hunt for a good pre-made PCB breadboard that can hold one or two 8-pin dual opamps & the usual supporting parts.

I haven't bought any of these since Radio Shack led the way lol. Who makes decent ones these days? Many thanks...

my current system is using an macbook usb output to 3x MiniDSP HD to run a 6 way speaker system (each with their own amp).

I would like to upgrade to a DSP with analogue outs or a DSP and a multichannel DAC because I am worried about timing jitter between 3 different DSPs/DACs.

Does anyone know of a DSP or DAC combo that can take a digital input and output 12 (or more) channels? I am thinking this would be pro audio gear?

Hello.
If I use an ecc83, I want it to amplify less than mu, I can't load it too much because it will skew the waveform.
I can't also limit the mA because it will cold bias it, and shift the waveform too.

so what can I do if I don't need all the gain (noise) ?

Thank you.

Anyone have a clue on where to obtain the Via VT1731 chip, and a data sheet? I’m interested to see what it will take to get together a dac with that chip!

Peerless by Tymphany SDS-160F25PR01-08 6-1/2" Paper Cone Woofer Speaker

Anyone used these recently or ?

I was thinking:

4 of these as two small subs in a office/small shop? With a pair of ‘MtM mains’ (hivi m4n or dayton rs100 and tweeters.

Or as a W in a pair of WMtMW?

Or 4 seperates as TMW?

Im Kind of a 2 channel and subwoofer listener but that isn't really important... rs100s/hivi/peerless parts in hand(currently in other speakers.

I’m just posting to see if anyone here would be interested in a beogram 8000. I have one that I would like to sell. It doesn’t have a working cartridge unfortunately ,the Mmc 20cl is with it but appears to be broken. The turntable runs and changes from 33-45. The arm runs back and forth smoothly. It doesn’t have the cable with it, it only has the power cable. It will need some work but it is in nice shape generally. I’ve looked at other examples on eBay etc and I’m asking $475 which I think is very fair. I would like this to go to a good home as this was owned by my aunt and run in a system with Macintosh amps. If no one wants it, can someone recommend a good place to list it as I’m not a fan of eBay.

I have a transformer from an NAD C370. There are no specs/values written on it and I haven't been able to find any on the web. I'd like to use it for another project but have no idea what the VA rating is. Is there a way to measure it?

I have studied ohms law and Kirchoffs law but hadn't come across the equi-potential theory before.
https://www.eevblog.com/2022/05/09/eevblog-1472-resistor-cube-problem-solved/

So I was giving my surrounds a renewal on a very old set of woofers and I noticed that one of the spiders was pretty concave down while the other was flat. I'm wondering which one these woofers is the "correct" one and which might be problematic? Is there any way to fix it that doesn't require replacing the spider?

From an educational perspective I'm also wondering what effects the out of place spider would have on the sound.

Thanks!

Woofer #1


Woofer #2

Hello!
Between MDF, HDF and Bamboo plywood, which one is more suitable for building the cabinet of dipole subwoofer?

Thanks!

Hi;

I am looking for proper pcb layout for my 20x 2200uF cap bank smooting pcb for my Class-AB amplifier.

There are 3 main design i saw on the samples;
A) 2 LAYER PCB - Power plane over Ground plane.
B) 2 LAYER PCB - Power taces over ground plane.
C) 1 LAYER PCB - Seperatred power and ground traces and they do not overlap each other.

I am glad if you can explain which one is the right way to go? And Why?

Hi All,
I fancy a dig around in my little dot MK2 headphone amp. I'm pretty new to this but think the obvious place to start a bit of modding may be the coupling caps.
According this schematic I found, it seems to be a 220ufd bypassed by a 0.68ufd - both electrolytics.
What type of caps would be suitable as a replacement do you think? Space is at a premium in there so massive Russian cans aren't an option.

Thanks in advance

Hi🙂
I want to buy DAC chip Ad1865

Any advantage to gain using Non-Magnetic over metal film Resistors on next amplifier project.

I am looking for some recommendations as to what kind and brand of caps to use in a tube phono-stage's RIAA circuit. I've had recommendations from REL-TFTs to Charcroft's Silver/Mica to Copper foil and propylene. Looking for help in selecting these.

Thanks in advance

Soekris dam1121-01 R2R DAC module, the highest quality 0.01% version. New €365 including VAT, bought from Soekris on January 14, 2021. Asking price €295 275 excluding shipping from The Netherlands.

As good as new and with the latest stock firmware and filters, at the moment configured for the soft filter and easily changeable using a TTL serial connection.





It comes with two "helping headers" that are stackable on the 2 mm headers. These helping headers make it effortless to connect I2S using jumper wires and audio out with signal cables. I got too close to one of the Molex-terminals, but that's cosmetic only and working fine.



Besides these helping headers, I'm also including an unfinished PCB for easy connection to a Twisted Pear Cronus reclocker or Amanero USB-to-I2S module.



I have enormously enjoyed this module, but got DAC fever and bought a Denafrips, and this module is much to good to sit on the shelves unused.

There are a lot of custom filters available too on this very forum (or you can build them yourself) to experiment to your hearts desire. For me, it were the quasi-NOS filters that really brought this module to life. Others swear by the linear filters. Your choice!

Manual: http://www.soekris.dk/download/dam1121/dam1121_manual.pdf

hi guys,

since a few of you already know; I am working on my ATC SCM100 clone
(SCM100ASL Pro | ATC Loudspeakers)

It uses a 12" ATC bass in a ~100L cabinet and a 10cm dia port tuned to 30Hz.
Now I am wondering about the cabinets damping.

I have some Basotect over laying around and was wondering if thats a suitable material for damping a cabinet?
I know it's brilliant for acoustic treatment in rooms but not sure about cabinet and speaker design?

Any experience and/or suggestions?

Hi, Tube folks,

Currently there are 2 major flavors of audio output transformers (both SE and PP) - with silicon steel and amorphous cores.

Amorphous cores are ferromagnetic alloys based on iron (73.5%), silicon (13.5%), boron (9%), niobium (3%) and copper (1%)). Depending on the type of heat treatment after quenching they may have a rectangular (Br/Bs = 0,2-0,9), linear or circular hysteresis loop. They allow to build smaller transformers with given power rating with lower losses, high saturation flux (up to 1.56 Tesla), etc.

The question is - which one would you suggest? Different people state different things - some say only silicon steel (because of higher distortions of amorphous cores - IMHO a somewhat unproven statement), other say "I DON’T EVER WANT TO GO BACK to silicon steel".

Any suggestion(s) are greatly appreciated.

Hi , bought an A100 spares & repair from ebay. It switched on fan run and power light was on but no sound. With lid off i found R1 & R2 OC and one channel op transistors short and a dj on the volume pot. It was clear it had been worked on before as the op tranny's were MJ15003/4 types and the smoothing caps and a few other components had been changed.
I changed R1 & R2 0.47 ohm 2w and the pair of shorted transistors checked around the circuit for other obvious stuff and switched on. I now have +- 35v at R13/14 R113 / R114 on the 35v rail side. But i have anywhere between 12.5v -13v on the Zener side The voltage gradually ramps up, i switch off before letting it go any further. This is the same for all the 12 v Zener rails +ve -ve. I am not sure exactly what's going on here but would assume whatever is wrong is common to all the 12v rails? I am assuming the zener's hold the rails at bang on 12v? I have also noticed that voltages around pin 11 and 4 on IC1 also ramp and are not a the voltages suggested by the cct diagram on Mark Hennessey web site. ZD3 does not reach 5.2v either. I have checked most resistors and diodes in the power amp circuit and i also changed 12v Zener just to check. The diode that came out was fine and the new one i fitted exhibited the same fault condition. Any thoughts /help welcome. I have read the Hennessey website and most of the threads on here and find nothing relevant to this so far. Oh one more thing for interest my board is marked A100 ver5 .
For background , i was a TV & Radio service engineer back when these were new but left that side of engineering a long time ago. More than a bit rusty now in more ways than one.

SOLD

Hello, I would first like to thank all of the contributors to this forum. Without you I wouldn't have gotten this far into the design process whatsoever.

So I'm building some compact-ish bookshelf speakers and some input on my crossover design would be very much appreciated.

I get a deep null but there is phase overlap only on one side. Would that be a problem? Is there any way to fix this and make the phase responses match better? I've played around with the components, changing values, adding or removing parts, but nothing so far has fixed it. Am I overlooking something?

Speaker drivers that I'm using:
Dayton Audio AMT Mini-8
Dayton Audio DS135-8 5"

Hey All,

Here I am again, looking for a schematic for a piece of vintage audio gear...

Seems I keep coming up with old stuff that I can't find info on with a simple internet search.

Now, I'm looking for a schematic for a 80's/90's vintage DOD 1642 XLR II, 16 channel rackmount mixer.

Digitech/DOD did not freely distribute schematics, unless you were an authorized repair center.
Now, they are pretty much defunct...
So, I'm hoping someone here has this archived...

Can anyone out there help?

Regards,
JohnR

Hello People, I am repairing a Crown model CSL800 power amplifier, it uses a 100Vdc power supply with floating ground. I can't get data on the original output transistors (4 per rail), although I saw on some forums that they have used MJ15025 and MJ15025 as replacements. Unfortunately, in my country, it is very difficult to obtain original transistors, I decided to buy some and when I received them, visually they already seemed like bad copies. I measured the breaking Vce and they barely reach 140V. My query is as follows, I have a sufficient quantity of MJ15003 and 15004, of good and proven origin, and although these are 140V against the 200V of the 15024/25, as I see it, in the SOA curves it could work well, what's more, the 15003/4 looks a bit better. If I consider an increase in VCC of 20%, I still have a safety margin. Any suggestion, much appreciated.

I'm unloading most of my driver stock. All drivers are in excellent condition and used very little. All drivers have their original packaging unless noted. Local pick up in Southeast Michigan or can ship at buyers expense. Paypal add 3%.

(Driver Description, Quantity, Asking Price (Ea), Available)

Dayton RS225 8in woofer 2 $40 SOLD
Peerless DA32TX00 1.25” conundrum tweeter 3 $40 SOLD
SB Acoust SB29BAC-C00-4 29mm Be tweeter 2 $200 SOLD
Eton 5-312/C8/25 Hex 5.25” midwoofer 4 $50 SOLD
Audax HM130Z0 5.25” Aerogel midwoofer 2 $40 Sold
Eton 5-212/C8/25 Hex 5.25” midwoofer 1 $50 Yes
Morel MDM55 2-1/8in soft dome mid 4 $35 SOLD
Fountek NeoCd3.5h (missing original packaging) 2.5” horn ribbon 2 $50 SOLD
Tymphany NE315W-08 12in woofer 4 $100 SOLD
Aurum Cantus G3Si Ribbon tweeters 3 $90 2-SOLD, 1-Available
Dayton RSS315HFA-8 12in woofer 1 $100 Yes

Anyone has built a dipole subwoofer with Acoustic Elegance Dipole 18?

Any comments??

Hi everyone and regards from Paris (misleading pseudonym I know). Long time lurker here whom never bothered to register as I didn't feel I had anything to contribute, especially being an audio newbie that found a sudden interest (or rather, urge) to come in possession of a good sounding mic (for work), then excellent headphones and finally drifted into vintage amps due to an obsessive nature for anything unknown and intellectually arousing. This tendancy to propel myself head first into any rabbit hole I come across has previously led me to build a DIY joystick from a hacked Xbox pad and Japanase hardware (Sanwa stick! Seimitsu buttons!), a mechanical keyboard with an obscure 72% PCB produced by a Korean amateur with some vintage-looking double-shot keycaps ordered as part of a group buy that took 18 months to produce (R5 anyone?) and an oak-tanned bull leather belt among other things. I am also bad with punctuation with an obnoxious tendancy to write unnecessarily long sentences, which I was repeatedly told was mentally exhausting. Coming to think of it this would probably my defining characteristic and should any mod venture this deep into my intro thread please feel free to rename my profile to "ExhaustingPhil".

Anyway I still don't have anything to contribute, but having recently purchased my first vintage amp (yay!) that has experienced a rather critical capacitor failure (booo) I come to thee in dire need of help 'cause I don't have the faintest idea of what I'm doing.
I'm already thinking about making an amp and obviously the lure of DIY resonates strongly within this one, but since I have found the one in a thousand WAF-compliant amp I'd like to fix what I have first, plus I figure it'll be good practice.

TL;DR: French dude, happy to be here.

I bought this for parts from ebay.

Like seller told me, it damaged by opposite power polarity or by power polarity bridge, probably.

After power on, nothing is happening!
Because we have not any circuit diagram, I am looking with the continuity of multimeter the paths after power switch.

It is a searching in blind, sure! Maybe the best solution is to find the appropriate flex connector for working with the both parts open, not closed like now.

After that, I found some electronics to have a relation with the power paths. At the attachment photo I have mark some of these.
I have changed 2 of these (by yellow circles) and now lights on the green led (power on led) above headphone level, but no any other led.

1) Any suggestions?
2) Can someone find to me the appropriate code (farnell, mouser) for extra flex connector? I want to work, with both sides open.

i read on ebay: https://www.ebay.it/itm/22444294322...3220.N36.S1.typeWATCH_ITEM_ENDING_SOON.R1.TR5
"KSA50 and KSA80 are praised as beautiful Krell power amplifiers by all walks of life. Among them, KSA50 is a Krell power amplifier, and it is also its own work (in terms of timbre). To this day, Nelson Pass, the designer of the American audio PASS and the founder of another audio Threshold, also said that the KSA50 circuit is better than the current 95% HI-END amplifier!"
I'd like to know if Nelson Pass really said that, thank you.

I needed some AD9201ARSZ a2d converters for a scope project which I have used before.
Out of interest looked around usual vendors for a price. Prices ranged from around £10 upwards.
I looked on Ali Express and they were 52p each !
The last batch I got a couple of years back from Ali and they worked fine.

Looked for some 4700uf 35v caps on RS and they were £2 + VAT.
Looked on ebay and they were 60p each including p+p

I have some crossover parts from a Lampizator p17 build as I've decided to use active crossovers with bi or tri amping due to a change of drivers. I'm not sure how to price these so please tell me if I'm asking for too much...

I have the following available - item, quantity, price per item:

Mundorf MCap MKP Classic 82uF, 250V / 2 / £20
Mundorf L200 Air core 2mm 0.39mH / 4 / £15
4.7mH Jantzen C-Coil 0.07 ohm / 2 / £40

Based in Bristol, UK but can post.

Heya. I am taking some time to peek inside the driver efficiency and implications of that. While here and on AVS, there is lots of knowledgeable people, this topic is still not general knowledge. Firstly, high efficiency means low Qts, which is big no-no for oldschool people and hi-fi people. Then there are other compromises to be made, and then, there are details of speaker manufacturers approach to this, that I would like to know.

This graph below is just a starter, work in progress, and will show 1Watt SPL output (kind of efficiency in decibels)of some known drivers, which I will add. Just from seeing the outcome, a lot of implications were understood immediately. Compromise is being made by setting the reference box volume and a port. I will try to add closed box comparison of the same driver to see, what that one does to the system efficiency. Looking at ported graphs, it looks like the port doesn't do a thing.

https://ibb.co/DfXXnG3

I wonder why high end driver manufacturers decide to use stiffer suspension, to lose on both sensitivity and efficiency, especially in the upper range of bass. Any ideas?
Yes, high end high excursion drivers with narrow magnetic gap prolly need to solve rocking modes, but is that it, or there is more to it?

OK...first of all let me say this....


For years before I was even considering DIY audio, I bought a pair of ACI (Audio Concepts Inc) Sapphire III's from my little brother.

Probably the most impressive thing about these speakers were the cabinets, they were made from 1 inch HDF! (High Density Fiber board.) The knock test on these makes everything else seem amateur!

To make a long story short when I decided to build my own speakers, naturally I wanted HDF! But we had huge problems there.

The problem wasn't just not being able to find it, nobody even knows what it is!!!! But with a diligent internet search and a LOT of CREATIVITY I found the hands down solution to building speaker cabinets with HDF !!! No JOKE!


Let me clarify right here I am working out some details but my first test seems like it will work WITHOUT improving anything from my first trial.


Okay so here goes.


I am currently building the popular Elsinores project. And in one post Joe mentioned one of the biggest improvements you could make to the cabinet was to build just the front panel out of HDF!

"But the thing that I believe would improve the box most is the most simple (and yet difficult at the same time), take a look at the newer Dynaudio designs, that baffle of theirs made of high density fibre board. I have heard a pair of Lenehan ML-1 speakers in both standard and 'Signature' versions and this was the only difference. Make the front part of the box structure out of this material and I believe the improvement would be greater than anything I have covered so far, no kidding!" (http://www.diyaudio.com/forums/multi-way/97043-elsinore-project-thread-15.html)

So I have spent the last several weeks...not to mention several years trying to source HDF! But it wasn't happening! You can get it but you have to buy a few thousand dollars worth of inventory!


But I did find something called "hardboard". And as it turns out it is the same thing as HDF, but it's just come is thin sheets.


So I got the idea of laminating several sheets together to make the thickness needed to build a cabinet!


So I bought a sheet of it, ripped the sizes I needed and this afternoon laminated them together...and all I can say is WOW!


WOW, WOW, WOW!!!!

On a single 9" X 4' panel the knock test hurts your knuckles! I am not kidding! It is like concrete, without any bracing of even a structure! For speaker building I think it was the smartest move I've made!


I used 7 total 1"x 4"s with braces behind them and my test piece is not as straight as I'd like. Which I am sure once even thing is put together would not be a problem, but tomorrow I'm going to get a half sheet (4' x 4') of 1/2" hardwood plywood and make a "former" to keep the rest of the laminations straighter!



I'll update when I have more to tell...and pictures.

I got another Cyrus Two that blows mains fuse. I suspect that the transformer is fried because the copper leads to the preamp rectifier are melted away and diodes are shorted. Most likely the secondary has some melts as well.
I consider my options:
1. get similar new transformer - 2x30V 300W = expensive
2. get two 30V 10.5A transformers, wire these in series and keep these outside in a box = 4 times cheaper
3. get smaller(less than 100W and maybe 2x12-15V - I don't think it has to be 30V - preamp needs 18V DC) transformer just for the preamp and build PSX with these 300W trannies(total 600W?) for the main amp

For me the third option sounds the most interesting since the original PSX(not the PSX-R) seems to be very simple device.
What do you think and what is the best way doing it(what parts to use and what improvements I could include)?

Interesting article about a new analogue physical music format. Claimed to be the pinnacle of sound.
https://www.whathifi.com/news/there...ound?msclkid=bc92236ed0ff11ecacd9588a99097e37

What are the changes of survival? For starters the name of the format (Ionic Original) does not stir me. Looks like these Ionic Original discs can be played on a DVD player. This part confuses me a bit – playing an analogue format on a digital disc player. The disc looks rather pie shaped on the photo. Are DVD players still available?

Anyway, it certainly sounds amazing, and I hope it survives longer and is more successful than Neil Young’s attempt a few years back.
https://www.noise11.com/news/r-i-p-...0423?msclkid=a21bc70dd0fe11eca0abc9b5d7da8044

Looking for wireless HDMI transmitter/receivers relatively affordable (<$200) unless a little more gets a lot more performance.
The distance between the receiver/transmitter would only be around 20ft and would be mostly without obstruction other than a bedroom door. Also would need it to be remote/IR capable.
Thanks for any direct recommendations as the reviews for the ones I’ve seen are all over the place unless you get into systems in the big money category.

Sansui BA-F1 schematic

Would anyone happen to have this diagram?

Much obliged.

/Hugo

Hello,
I want to build full range stereo loudspeakers with Visaton BG20 speaker. Can you help me please what will be the good volume for the sealed cabinets?
I saw that it was given as 1,06 ft3 and 1,66 ft3 and i am confused.
Thanks a lot for your help
Noyan

https://www.visaton.de/sites/default/files/dd_product/BG 20.pdf
https://www.visaton.de/en/products/drivers/fullrange-systems/bg-20-8-ohm
https://www.visaton.de/en/products/drivers/fullrange-systems/bg-20-8-ohm
https://www.parts-express.com/Visaton-BG20-8-8-Full-Range-Speaker-with-Whizzer-Cone-292-548

1x Morel MSW144 New - $75 shipped
1x Morel CAW538 New - $110 shipped
CSS powered MTM bookshelf monitors with Aurum Cantus ribbons, WR125 mids and Parts Express active 2-channel plate amps Used/Good - $350 shipped
Anthem MRX-500 w/remote Used/Good - $425 shipped
Rotel RDV-1045 w/remote Used/Good - $125 shipped

Looking to identify the center IC on this YEUM1007A output driver card. Card is from a Sundown SAX-125.4 but the same card is common on many of the class D 4-ch zenon board amplifiers.

So I salvaged two large Peavey CS800 power amps. They are old school class A/B quasi complimentary output with a 50lb power transformer.
I kept blowing transistors until I realized the speaker protection crowbar triac had gone dead short permanently.
This is the second time this triac has gone short circuit. I think what happens is it get's triggered on power up because one power rail rises quicker than the other.
As usual, like any semiconductor, it's failure mode is short circuit.
I really question the value of a crowbar. I guess the philosophy is save the speakers by sacrificing the amp.
One thing I noticed is the filter circuit for firing the triac has a capacitor half the value of what is listed on the schematic. I speculate I could easily triple or quadrupole that value as listed on the schematic and still save speakers.
Maybe I'll just nix the crowbar.
Thoughts?

If I measured my own drive units with REW and then used Xsim to model a crossover, how close would the finished speaker be to the model?

Hi all!
I found a nice older Shure 545 (Series 2 - "pistol grip") microphone that needed some work, at a garage sale.
One of the challenges is that I would like to find one of the adapters that Switchcraft used to make (#L3MN), that would adapt the 4 pin 'Amphenol' connector on the mic base to the now more standard 3 pin 'XLR'.
It looks like Switchcraft doesn't make that L3MN adapter anymore, but I just thought I'd put out feelers to see if any of you have seen anything like that or may know of a good alternative?

Thanks for your help and leads,
Buck

Hi all, wasn't sure where to post this.

Have done a bit of googling but was hoping on some direct opinions and advice....

I bought a job lot of 6 JBL 2226s, second hand, for a decent price. The guy seemed honest, was doing me a deal on a bunch of stuff, said he had tested them etc. Consumer advice not neccesary, Im aware I did take a minor leap of faith.

They then sat around for a while in my (nice and dry) workshop waiting for some cabs to go in, which I have finally built a couple of. And now I have a job for two of them, so i loaded one into each cab, and was excited to hear.... nothing. Spent ages troubleshooting the amp and cables, but turns out the drivers show an open circuit on the multimeter. Tested the rest and 4 out of 6 are showing open circuit! Cones all move freely and without crunch, terminals all look ok and generally they are in decent enough shape. So, whats likely to be going on here? Broken connections to the voice coil? What can I check and repair?

Apologies if its a basic question but im hoping they can be salvaged
Many thanks!
Fen

Hi looking to buy one of these to replace one I have that has gone faulty in a specific physical configuration (so I am not able to use later versions). It has to be a III version and not the IIIse. If you have one for sale can you send me a reply or PM. I am located in the UK but happy to pay worldwide shipping. Thanks.

Hi there,

I'm looking at an alternative EU source (Other than Farnell, RS, Mouser, digikey) for 'medium' quantities of passive components, let's say typically quantities of 1000 resistors or caps.
Usually I find low quantities at a very high price or all-in on 100.000 at the price I can afford. I understand this is how it works but I wonder if some of you have found the resistor heaven. Also curious about every source I'm not aware of. I remember 10 years ago buying 100 pcs from farnell very cheap, this is not the case anymore and I need to address it.

I can buy as private or company, around 90% through hole, website with datasheets only.

Direct from manufacturer with low moq and an online store or reactive support would be perfect.

Tried the search function as I'm pretty sure this has been posted before but got no luck. Do not hesitate to link other recent threads.

Thanks!

Trying to sort out production dates for some Hitachi 2SJ49 MOSFETs... marked 5C1, but no luck so far..

This is an offshoot from the Alpha Nirvana amp thread here:

https://www.diyaudio.com/community/...8ohm-class-a-amp.344540/page-110#post-6949783
@minek123 adapted @AKSA ’s 39W Class A amp to use a JFET input opamp as the input stage.

This has several advantages as explained by Minek including lower distortion, etc usual things opamps offer.



I wanted to move the discussion to a new thread as it really is a different and new amp. This will keep discussion of the original Alpha Nirvana amp less confusing for those looking for info on the base amp.

Thank you to Hugh Dean for the original Alpha Nirvana and to Minek for the new modern opamp variant.

Every year I try to do something a little crazy. Last year I built two 15" guitar cabs based on my own design which apparently had a lot in common with the old Forte 3D guitar cabs. They turned out fantastic, so looking to build something crazier now. The 15" cabs turned out great, but there wasn't a lot of trial-n-error. I guess I just happened to guess well on dimensions and such. Looking to be a bit more scientific in this next build.

So what I'm looking to do this year is build another guitar cab. This one would have an 18" driver in a spherical enclosure with a 12" driver in a teardrop shaped enclosure. See attached pic below (not to scale obviously).

Can anyone school me on what I need to know to get the dimensions for this design right?

A few things to note:

The "cone" shaped thing behind the drivers is for rear deflection from the driver. For the 12" cab, this will be screwed into the backside of the cab. For the 15" cab, I will likely need to suspend it inside the cab so it is centered behind the driver. This should add a little bracing and will be closer to the center of the sphere (scale way off on that one).

I was planning to make the walls 1" thick but can be thicker or thinner based on advice here. How thick should the walls be?

I live in South America and wood species are different here. I don't have access to Baltic Birch ply here believe it or not. I used some local pine for my last cabs and it was fine. I will likely veneer these cabs, so I don't care what the wood looks like. But I do need to know what qualities of wood to look for here as any specific wood species suggestion isn't gonna be helpful unless you know how the wood strength/density varies by species here. I know most folks say to look for voidless marine grade wood. Anything else?

My plan is for the 18" cab to be sealed. How can I calculate the cab resonance pre-build to see if I will likely need to add a tuned port?

In my 15" cabs, I spent a bunch of time focused on eliminating standing waves in the cab. Other than the rear cone deflector, I also cut grooves all over the interior of the cab.

For these spherical and teardrop shaped cabs, do I want the inside surfaces to be silky smooth or should I add a bunch of half-dome wood dimples of various sizes inside to create more diffusion?

For the 18" cab, is a sphere going to be better than say slightly stretching the design out into more of an oval?

Any guidance on how to design the curves & proportions of the 12" cab?

For the 12" cab, my idea was to have the piece at the rear with the rear deflector attached have openings to vent from the backside, so this is kinda open back. Any advantage to cutting some slits at the skinny part of the cab to make it even more open or is venting out that backside all I need?

Here was one of the final designs for my 15" cab. I didn't end up doing the rear or side deflectors and used a wood dome rear reflector instead. Design also doesn't show all the details of what I did inside the cab, but you get the idea.

Login to view embedded media

Hi all,

Anyone have schematics for a Dynacord L2400 that includes the output
pc board ? The copy I have does not include the output board.

Thanks so much 🙂

I have several DP3T (ON-ON-ON) switches. Instructions indicate "jumper needed to achieve triple throw", but no drawing of this on the datasheet.
Can anyone explain or show me how this would be achieved?

Hi! I know that this one has been asked before (even on other forums).

I am currently servicing a Tapco 4400 for a friend of mine and have the following issues:

1. Sticky Faders which have improved after cleaning with alcohol
2. Channel 1 reverb randomly drops out sometimes and takes a while to start working again
   1. Perhaps there is a cold joint?
3. Channel 2 Reverb/EQ has a very low output - perhaps a bad op-amp or capacitor?

Thanks! I look forward to hearing your suggestions. I'm obviously going to have a look at the service manual to identify the signal paths.

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

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

Enjoy!

I've just starting looking and researching ribbon speakers and am interested in making one and experimenting with them as well as Magnepan style speakers.

I've read a few threads talking about transformers to run a ribbon speakers, but can't really find any definite answer or guide on how to build them.

Looking at this website... http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/refload.html I can see the equation for reflected impedance (resistance) at the bottom which says.... R x (number primary turns/secondary turns) squared. So a 20:1 transformer with a 0.01 ohm ribbon gives a reflected impedance of 4 ohms. Am I right so far?

If so, a transformer would need to be made with a 20:1 winding. So you could do 20 on the primary and 1 on the secondary or 40 and 2 or 60 and 3 or 80 and 4 etc. The primary winding would be a very low impedance I would imagine, so does the high pass capacitor need to be calculated on the resistance of the primary winding or the reflected impedance that will be 'seen' by the amp.

Thanks in advance for any help.

Restoring a rather tortured but alive Sony TA-5650 v-fet amp, I found these. First I thought... well well.. quality parts....

Just carrying out some preliminary bench testing of PCB's while waiting for chassis to arrive.

Power supplies are fine, however when testing amp board i cannot set offset and bias according to the guidance notes.

Adjusting r27 seems to have no effect at all, but by adjusting r7 i can set voltage to required value (anywhere upto 400mV).

Q7 and Q8 get hot while Q5 and Q6 stay relatively cool.

However as i understand r7 is for adjusting offset, but when i measure voltage across signal output/gnd i get full +ve rail voltage ie aprox +26v, and does not change when i twiddle trimmers.

any advice appreciated

Hello!

So i just found out about tweaking esi juli@ and in general audio cards from here: https://www.diyaudio.com/community/threads/tweaking-an-esi-juli-xte-card.238451/

As this thread is quite old and i can't see any pics available on the given links i would like to know which is the best tweaking for an ESI juli@ in 2022.

What should i do with my microsoldering guy to make it better? I have one card laying arround that i am not using and i would like to see if i can make the digital in+out better.

ps: i know that this card is not different from others and i could try other mods on it but as i am not experienced with this stuff i would like some help. should i change the OP amps and OS CONs? if so which ones should i choose? Am i going to get better sound with a modification using digital coax or am i wasting my time as digital is digital and it can't get any better (like analog)..?

Thanks!

Greetings all,

I'm not very experienced in DIY Audio, but man I'm loving it!

I'm currently working on a design of a small lecture room, media will be displayed via laser projector to a 150" screen. the design of the space utilizes 4 in-ceiling 8" full-range drives. A laptop will be connected to the projector via HDMI, for ease of use, in which the projector will send the audio signal to an amp powering the speakers.
Audio doesn't have to be top-notch high-end immersive, but it needs to be much better than a standard tv speaker. (budget is very limited)

so the plan is to have a 2 channel amp where two speakers would be wired in parallel to one channel, here are more details

Room dimensions: 7.5m × 4.5m
Audio drives: Dayton Audio ME820C 8" 8-Ohm 45W RMS (×4)
Amplifier: not yet decided, maybe (Fosi Audio BT20A100W + 100W)

I've been reading about parallel vs series connections, Parallel seems fine but there is always a warning about the risk of running it due to increased voltage which can damage equipment. I've searched how voltage is calculated and how to compare it to the amp and speakers specs but couldn't find anything useful. So, what is the procedure and calculation necessary to avoid damaging equipment when connecting speakers in parallel?

I would be grateful for any explanations or comments in general.

Cheers.

Hello,
I just got the third note that "one of my" accounts is going to expire/has expired.
There is "something wrong in the state of denmark" as I've already transfered the money
on April 18th.
Secondly, I do not know of any more accounts than one.
Since I've been already slightly irritated by the rise in "taxes" for this service
I'd suggest we quickly settle this one. I'm not getting more patient with time.
And yes, my answers to these (your) postings have not been answered yet.

Greez

Siggi

Dear members,

I need your advice, I want to add a standard vintage graphic equalizer to my Turntable and active speaker setup please advice would it work before I assume and spend on the speakers.
Planned setup is:

TT -> Phono PreAmp -> Graphic Equalizer -> Active Speakers

Would the above work in a situation where the equalizer function as expected?


Thanks in advance.

Hello all,

I would love to see more discussion about single box stereo solutions.
Here's my case, but I am interested in the subject in general:

I've been thinking for a while about how to approach a speaker for casual music listening in our difficult living room.
Clearly this would be very different from a "critical listening in the sweet spot in a treated room" kind of thing.

A few considerations:

• I want to make it a one box solution. This room doesn't give you an option to put a second speaker in a sensible location without some crazy cable stretches. And with two rambunctious kittens in the house, I'd like to minimize cable runs, ideally to the point where it's only one cable going to the box - the power cable (I generally use Apple Airplay for music, so an Apple Airport Express would sit inside the speaker, along with a power amp).
• The room is a long, somewhat reverberant living room, TV room, kitchen, dining area, staircase all-in-one monstrosity. The listening would primarily happen in the living room section.
• The speaker has to sit off towards one side wall, otherwise it would end up in the middle of the floor. Wall mounting is not an option in this case. A floor-sitting column or stand mount is the way to go here.
• I'd like to have some semblance of stereo imaging. Or at least a vague feeling of stereo depth.
• I generally enjoy full-range speakers, but multi way, or sub-supported designs are fine too.

I've played around with Mid-Side techniques. I most recently put together a simple line-level contraption encoding L/R into M/S using 1:1 audio transformers, and while it works very well in my small workshop, once I bring it up to the living room the whole thing falls apart (not physically, mind you, but sonically). Because of the neccesary placement of the speaker, the required walls for successful sound bouncing are too asymmetrical: on the left side the nearest surface (a staircase) is 15 feet away, while on the right side there's a large window surface only 2-3 feet away.

So now I'm wondering about making an omnidirectional speaker, using multiple (probably 8) full range speakers wrapped horizontally around a flat cylinder (a bit like a flying saucer). But instead of making it an mono-omni speaker, split it 4+4 into left and right halves. Sure, asymmetric reflections would still make things uneven left-to-right, but at least you'll spread the reflections more widely across the room rather than relying on two particular reflective walls, and you'll also get a small degree of stereo separation from the mostly front-facing pair of speakers (as well as some much needed unreflected sound for clarity).

Any other single box stereo tricks? Ceiling-firing speakers? Center cancelling phase trickery?

Hi! I know that this one has been asked before (even on other forums).

I am currently servicing a Tapco 4400 for a friend of mine and have the following issues:

1. Sticky Faders which have improved after cleaning with alcohol
2. Channel 1 reverb randomly drops out sometimes and takes a while to start working again
   1. Perhaps there is a cold joint?
3. Channel 2 Reverb/EQ has a very low output - perhaps a bad op-amp or capacitor?

Thanks! I look forward to hearing your suggestions. I'm obviously going to have a look at the service manual to identify the signal paths.

Hiya,, For my Mac MC30 mono tube amp, w/o taking out a 2nd mortgage, what's the best all around winner?? Amp originally called for 1614 versions.... I'm presently eyeing a set of 7581's for around $100...
Many thnx 🕉🎵🎵

I just finished the Philharmonic BMR speaker kit (the bookshelf version) from Meniscus Audio and thought I would capture a few notes in case it is helpful to someone else building or thinking about building it. I built the cabinets, although flatpacks are available for this kit.

• The biggest challenge in the baffle is that the BMR driver is not round. It has projections for the screws, and so the usual approach with routing using a Jasper circle jig is not adequate. After searching for ideas, I covered a BMR with plastic, screwed it face down on a piece of ¼ plywood, and used a router template kit I had to make a template for the driver. The template kit is designed to compensate for the router bit width when you create and then use the template. Once I had the template, I routed the hole for the body of the driver in the baffle, carefully placed my template on the baffle so it was oriented evenly over the hole and square to the baffle, clamped it down and then routed out those screw projections. As you can see from the picture, it produced a nice, tight fit. As an only moderately skilled woodworker, I was very happy with the results.
• Within the cabinet, there is a small box for the BMR – kind of a cabinet within the cabinet. I had trouble visualizing this from the drawings, but found a video of a flatpack being assembled and that made it clear.
• The inside box for the BMR needs to go right up against the brace – the brace forms one of the walls. I cut slots on the side walls of the cabinet for the brace with multiple passes on the table saw. I made the first pass at the same height as the top of the cutout, then made subsequent cuts until the brace fit into the slots.
• Routing the irregular shape for the BMR, and getting the inside BMR box in the right place were the only aspects that made this a more challenging build than other speakers I have built. (I have done a few, not a lot).
• From other posts, including from Dennis Murphy – the designer of the BMR - I made sure the little BMR box was very well sealed, including the hole for the wires, and stuffed that little box very full of eco-core. Much more stuffed than I would have had I not seen his posts.
• I did not do the fancier joinery which came with the plans. My panels were all straight cuts which I joined with my Festool Domino.
• I made the woofer crossover layout to look like the pictures of the built crossovers Meniscus has on their site. They are a little different from the orientation in the drawings that come with the kit. If I didn’t do this, the woofers were longer than the inside width which would make placing them a good distance from both the mid crossover and the woofer driver a challenge.
• The overview is that the sound stage is large, and I am hearing things I’ve never heard before in songs I have been listening to for a long time. So far, nothing has been disappointing, and I have had multiple moments of sheer joy hearing new things.
• Some song-specific impressions:

• All For You – Sister Hazel – (live version) – The width of the sound stage helped with the “you are there” feeling as the crowd responds to the intro. With a compressed sound stage the two singers can feel on top of each other, but they help distinctly separate spaces.
• I haven’t Been Me – Once Blue – I had never heard her breaths before. So cool.
• Rich Mullins – Sometimes By Step – This is a poor recording which I expected to sound poor because these speakers are revealing. It didn’t, it sounded great. The intro to this song is some moderately fast piano playing. What I had never heard before is that the drummer is hitting his high hat in synch with those notes. Listened to this song a hundred times and never heard that before.
• I’ll take you There – Sapphires – Heard ghost notes from the drummer I had not heard before. It is a much more complex beat he is doing that I ever realized. I enjoyed the song much more hearing that.
• Quanta Qualia – Hayley Westenra – I love this song. It is beautiful. And it’s a good tweeter test as she hits outrageously high notes and I have heard it sound a bit shrill on lesser speakers. No shrillness at all. In addition, my wife remarked that there were a pair of voices in one place where she thought it was single before. In general, as she is singing notes of accompanying instruments, it was much easier to hear to them both separately.
• Songs by Chicago also sounded better than I expected – great music not very well recorded.

• I love these speakers. They sound great to me and I am anxious to finish work each day so I can go downstairs and listen to more music.

My setup

• Raspberry Pi with a Digi SPDIF HAT feeding digital flac into a Topping E30 DAC.
• Dac into an SP14 tube preamp.
• From the SP14 into 2 down-firing Rythmik Audio DS1200 subs.
• And into M-125 tube monoblocks. And out to the wonderful BMR bookshelf speakers.
  
  

Hello every one . due to the lack of valves tubes and in general all this situation that prevailed with the war in Ukraine, I open this topic .. generally looking for a way to replace a valve tube with a transistor… in general I have made several emulators pedals such as: Mesa boogie / soldano / fender / Marshall ,, and all I did was copy exactly like the schematic only I changed the bulbs with jfet (j201) and put a trimpot in the drain and adjusted it 4.5-5.00 volts depending on the occasion, .. now this What I am looking for is to make a replacement of a valve, the only problem is that I do not know what jfet to use for 300+ volts ,,, I have found similar products such as jetcity retro valve and something called fetron…. I know very well that in sound quality it will differ, I just want to have a planB because there are no more valves and the ones that do exist are really very high prices! ..

i think something can be learned by using the rta feature in rew (or similar) to display the sounds that surrounds me, sometimes the response curve suprises me deeply, but i do need to find a easy way to get my measurements with absolute db values, that really would be something

do you also measure your day?

Attached is the simulation of my KT88 tube amplifier. Is it correct to interpret that I have oscillation around 1 Hz area? Do I need to worry about at all since it's way down there in frequency band? Thanks.

Hi guys!
I need help with many things.
I would like to build a LAB horn type subwoofer for my system. I have Dallas II speakers which i made.

https://www.diyaudio.com/community/...stex-fe206en-and-monocor-ht-958-pa-si.365465/

Im lacking of good pounchy bass.Speakers are working hevenly but i miss the power of bass.Idea is to build something to fill that emptyness.
I have 2 10" Eminence Delta 10B and i have lucky and find used,excelent clean digital power amp with active X over,and LR input.
So idea is to make horn woofer,becuose im in love with with horn sound,with this amp.
I want to make double 10 in one big box becuose,if i understand coretley,bigger box,bigger opening of horn,bigger sound stage.

So first what i would ask you to help me is to discuss about this woofers,are they good for this project.
Box will play from 150Hz down.
Here are specification for woofer.

https://eminence.com/products/delta_10b#specifications



Second big thing where i need help is with design.
I would like to make box which is 550mm deep and 1300mm long,and hight is not defined.It can be up to 1000mm.
Mouth is on surface 1300 x hight.
I like this design,in my case just rotate them for 90 degrese and make it double but with one spiral and one mouth.

https://www.hometheatershack.com/threads/my-lab-12-bass-horn-project.85634/

But,i dont have knowledge to calculate and make design by myself.So i humble ask for your help and idea,suggestion...
Is it posible to make design in that limits and what would be performace of this woofer,how low can it go,...

Hey guys, I'm new here. So I bought an Audisse Shokunin work radio on a Dutch auction site. The price was pretty good so good stuff. Because the warranty has already elapsed I took a look inside and the electronics are quite good... for a work radio. The speakers though are something else, cheapo Creative 5 watt RMS "full range" speakers. It's pretty clear they skimped on those. Funny thing is this thing sounds better than other work radios. Anyway, no more warranty so I can stuff in it what I want. I found the Dayton Audio DMA80-8 and the Visaton FRS 8 M. The Dayton is literally a drop in replacement but more expensive, the Visaton will need some minor adjustments. The price isn't an issue. The radio casing is 245mm wide, 150mm deep and 170mm high with a D-class amp, control board and usb/bluetooth board in it. This takes up a good 60% of space of the back half of the radio. Any thoughts on which would be better in this case?

This is the same radio. The Audisse brand was made obsolete and the radio was rebranded as the Rockpro: https://www.perfectpro.eu/product/rockpro-rp2/

What's inside it now 😛

1 Alps 50k RK50 potentiometer

Purchased 5 at once. Have one spare for time being.

Current lead time is 5 months unless they are. Currently stocked.

750usd was (Paid the hard $750)/ a piece. Asking 715 including shipping. Or about 680 after protection fees.

I have earned stellar eBay feedback through audio related records of salles and a perfect Headfi selling record. Of top flight headphones.

Account at Headfi is "Andrew_Seeley" and ebay has nearly 100K in perfect sales and positively above and beyond customer service.

Thanks for participating and reading, cheers! Do not forget Happy listening too, the RK50 turns beautifully and should be enjoyed for many years

What is the best sounding waveguide/horn with a mouth under 6.75x17.75"? I am going to use it in a two-way with a 15" woofer and the closest distance it will be from the edge of the woofer is 2". The 15" is tuned to 65hz and can play up quite high but I do not want it to beam. So the ideal waveguide/horn will allow the driver to play down to the woofers upper end beaming frequency with 2" from the center of the surround and up to at most 20khz (but less would be acceptable, such as 17khz) This is the 8 ohm version.

Hi all
Can anybody tell me what is U20? I tried tl072 but it blowing the outputs. Pin 5 connected straight to the 3rd pin of connecter J8. As I touch that wire the frequency changes alot blowing outputs.

I have been trying for weeks to get in touch with Acoustic Elegance. They aren't answering their phone and when I email them, I get a form letter dated 3 months ago in reply. Anyone? Thanks.

One of my friends have one of these that isnt working

Is it worth investing any time to get it working again? or sell for spares?

Im not a valve man so i wouldn't be repairing it

Hi,
It was so nice to discover this amazing forum.
It is a fantastic place for info for audio guys 😉
Cheers form Portugal,
Pedro

Hi!

I own a stereo multi-channel system (MiniDSP active crossover) with DIY amplifiers :

1. Focal 10L subwoofer powered by one Hypex UCD180
2. Davis 13KLV5MA bass/medium powered by two Hypex UCD180
3. Audax TW025A20Mg powered by one LM4780 gainclone module

All powered by dedicated connexelectronic.com SMPS
Because of some hum, I want to replace LM4780 by a class D integrated SMPS module.

I need your advice about these two boards:

1. MA-TA05 TA2022 SMPS
2. Ice50Asx2

The first one is a certified Tripath chip (old stock).
The second one, I don't know about! We can see it on Ebay, Ali, Amazon...

If someone has tested and listened one of theses?
Any other idea? (same budget)

Hello,

If I downsize the enclosure, do I automatically need more Xmax to get the same volume?

selling some tubes left in my garage : 8x 71A DHT triode ( 6 globe : 2st shapes NOS) 150€
4 type 26 globe DHT 100€
pair of pentode 350B ( 6L6) NOS 100€
pair of pentode MULLARD EL33 NOS 100€
pair of pentode Tungsol 5881 ( 6L6) 60€
pair of RCA 2A3 NOS 150€
pair of rectifier RCA 5R4GY NOS 80€
shipping included for all E.U

thanks.

For sale 2 x hypex NC250MP

Price 400 euro for pair + shiping

Will post pictures later, today or tommorow...