fs. BPA 150/300 PCB boards

I have for sale 4 BPA 150/300 PCB boards, with all the SMD parts already soldered, added also the required trim pots.

30eur for all + paypall fee + shipping.

Interested in a trade with some BA3 or M2X boards.

im new to amp repair as far as getting into reading component values and undersanding how it actually works.. i have an cheap oscope but not sure how to really use it..

so i have a hifonics brutus 2016.1d that powers up but has no sound except a loud pop when i turn off the power.. thinking about it this it might be cuz im just cutting the power supply and not turning off the remote first.. ill try that next time..

1 side of output fets read 77.5 volts on the drain and the other side reads 77.5 volts on the gate and source is that normal?

i found a chip on the driverboard was burnt so i ordered a new one based on what i found online was chip lm211 and it was a bit larger than the one on the board.. i put it on anyway.. i know not the right move im sure but what should i be checking and whats the correct part to order?

Has anyone tried running one of these drivers down to 600 Hz in an appropriately sized horn with a steep electronic filter?
BMS themselves actually rate it from 500-20 000 Hz.

Seems to handle even 110 db at 600 Hz on the Dayton H812 so I can't imagine it being an issue in a domestic setting:

https://www.justdiyit.com/grand-comparatif-de-compressions-1-pouce/5/



In fact, all of the ones in the above test seems to be fine (with the odd exception of the ND350)

I'm and old audio repair guy from Norway.
I seek people that might be able to help me repair burned car amplifiers.

HB-1 Amp - An EF184 + 25L6 2.2W guitar tube amp

I forgot that I had posted an old version of this scheme here, in the The Hundred-Buck Amp Challenge thread, until an user of a Brazilian forum reminded me of it today. Coincidentally, the first name of this amp was 100Buck Amp.
It is a 2.2W amp, EF184 + 25L6 tubes, with a really good sound. The power transformer is a ordinary 30+30V 30VA. The output transformer is a 1.7K - 8 ohms SE .
Here you can find a review of this amp (in portuguese): Crow | The 100 Buck Amp | REVIEW por Zarbinatti - YouTube
You can build it for less than $100...


And here the last scheme:



*If anyone wants, I can update the PTP layout of this amp and post it here.

Years ago I bought a set of TPA kits, then forgot then in a closet. Just found them and I don't need them any more.
Seems like they are soldered by a beginner, not me. On some of the boards there are parts missing and cut or shorted, refer to pictures. Some are unsoldered kits.
I will prefer to sell them all at once. Price for the complete lot is 70€ + shipping.
See photos for details.
-2x Counterpoint
-2x Sidecar
-IVY 2.0
-IVY III sold
-S/PDIF module CS8416
-4-channel S/PDIF level converter
-CMP1 v1. 0
-OTTO II

I've got 3 of these boards for sale made by JLC pcb, it's Hicocos version of the H9KPXG soft start, which is described in this post 545 here https://www.diyaudio.com/community/...soft-start-h9kpxg.354971/page-28#post-6947574

The Pcbs are 1.6mm thickness with 1oz copper and HASL finish

Just want my costs covering £18 with UK postage included

Hi there,
Driver is 5,5 C 1,5 CP 8+8Ω coax.
https://sica.it/wp-content/uploads/2023/12/Z002810.pdf
According to specification it is 120W AES and 240W Continuous Program Power speaker combo. AES is measured with 6dB crest factor as per manufacturer info.

Crossover:


If I do use VirtuixCAD Power dissipation tool with 240W on 8Ohm with "Flat" settings, I get so ridiculous results, that there seem to be no such resistors in the market. 25-40W of power dissipation for single component seems too much for a 5 inch woofer and 1 inch dome tweeter. But If I use "M-noise" setting - everything seems the other way around - too little power going through components.

Now the speaker in on the active crossover and powered by the Class D TPA3250 ~40W/8Ohm per channel amp, so 40W for woofer and 40W for tweeter (24V 4A power supply). The exact numbers are not important and probably not correct anyway, but lets assume it has at least 30W per channel.

So, the thing is - I cannot fully crank volume signal, it seems that this small amp can melt this speaker on the spot(~-2dB attenuation on PC global, with 100% volume, Presonus 26c as soundcard/preamp, max gain on mechanical gain knob). It is not 240W or even 120W driver. NO WAY!

The question is: which settings should I use for simulations on VirtuixCAD?
On the normal listening conditions I would use 5W resistors and call it a day, but I now I have doubts...
R4 is ~26W on 900Hz, R5 is ~41W on 20kHz(!). My guts say that 20W for R4 and the same 20W for R5 is more than enough. Right?

Screenshots attached

I have a problem with these pairs. Every 3 months I have to replace them because I find Chinese material that at the slightest discharge even just touching a connected rca they burn out. I was thinking of replacing with 4 transistors. Has anyone already done a test?

Hi,
I'd be looking for 2 boards phonoclone 4 or 7. If already populated it's better (no matter if no OP27, I have some) otherwise only PCB boards. Shipping in EU.

Thanks.

Hi everyone!

I’ve been lurking around this forum for quite some time and finally decided to register.

There’s not much to share about myself in terms of experience—I'm a rookie in the audio scene—but I’m eager to learn and excited to dive deeper into this fascinating world.

I also have a small project coming up. It’s not an advanced one, but it’s something to help me get started and explore a hobby I’ve been interested in since I was a kid.

From starting out with a Panasonic portable cassette player, I’ve slowly been exploring and experimenting with audio equipment. While I still consider myself a beginner I’ve owned and experienced a variety of Hi-Fi gear, though nothing audiophile-grade. I’m not really into expensive or exotic equipment—what excites me more is finding affordable, easy-to-maintain gear that delivers a quality musical experience.

Looking forward to learning from all of you and contributing where I can!

Cheers!

I need a simple diagram of a volume controller, using a double sliding potentiometer. I need to connect the headphone output of a computer to its input. It is important that the output is balanced, to be connected to 2 active speakers with XLR input.
I don't know if it is possible to make this circuit in passive mode. This would be perfect.

Looking forward to learning more about this hobby. Currently needing help with a bumpboxx upgrade. Can't wait to interact with everyone!

Hello!
I'm interested in the ER Audio Acorn MKII and looking for someone build it for me.

I can supply frame and base that made by any material such as delrin, ebony, bamboo plywood etc.

As long as someone is able to put it together for me.

Any suggestions?

Thanks!

So let’s consider another option…..say a 2” mid compression driver that can load down to 500hz and play up to 8.5k or so……not a hard task. But what to do about the top octaves? Has anyone considered a surrounding multiple tweeter approach?…….something like say the Dayton ND20fb?……4 units flush mounted in the throat very close to the mid exit? 4 of these little guys in series parallel should be a good efficiency match to a mid compression driver.

While browsing loudspeakerdatabase I noticed bass drivers have wildly different step response. At 60hz most long and medium throw drivers don't even remotely track the input signal.

The cheap Goldwood with only 2mm xmax does a lot better



The only driver I could find doing slightly better than the Goldwood is the insane 31.5" Fostex


If we disregard the practicality of it, would 4 Goldwood drivers sound better than one driver with 4x the xmax and 4x the price in the low bass region (30-120hz)?

How important is step response and which driver parameters are important for good step response?

Great to be here! Looking forward to sharing and learning about audio projects with everyone

Just wanted to say hello, seems like an interesting site , just learning how to repair car audio amplifiers, anything I do know is self taught, so hopefully I get to meet a lot of you and learn a lot from you , thanks

Hello Everyone!

You might remember that about half a year ago I built a hybrid opamp MOSFET fully symmetrical headphone amp that I call M4:
https://www.diyaudio.com/community/...ial-hybrid-opamp-mosfet-headphone-amp.409976/

It's working quite well although I cannot say anything about noise figures or THD+N.
This amp was always meant to be a stepping stone up to the big leagues of something high-end. This is where I am seeking guidance from the community. These are my ideas for future upgrades:

- Raise the PSU voltage to +-15V, upgrade the opamp to OPA1633 and cascode the MOSFETs like in the AMB Beta22 amp with the same topology except for driving the MOSFETs. That would be identical to the current version (2 JFET CCS bias of the OPAMP through the + and - rails). I believe that this setup would provide optimal noise (OPAMP VAS with -132dB noise) and THD+N (cascoded output stage)

- Use the fully discreet design of the beta24 (https://www.amb.org/audio/beta24/) with the output stage of the beta22 (https://www.amb.org/audio/beta22/) with a single regulated PSU (sigma 22). This could be the ultimate headphone amp if done right. The problem with it is that it needs matched components. I could source the input JFETs from diyaudiostore for about 100USD (quite a bit for 8 JFETs but still better than no JFETs), but I am having trouble in locating a good source for the BC550 BC560 BJTs. Especially, that I need 24 of each of them. I could get them through ebay (questionable) or dig through the entire internet. I could also use some better complementary BJT pairs based on the Horowitz book, although, I couldn't find obvious ones to use. I could also use SMD JFETs and BJTs but then I would need to redesign the circuit and the PCB completely.

Here is what I have for this amp:

Schematic:

PCB:


Do you see any potential upgrades in either of these projects? Which one would you recommend pursuing (if any)?

Happy Sunday!
Cheers!

Looking for:
(9) pairs of Sanken 2sa1295/2sc3264
(1) pair of Sunken 2SA1358 and 2SC3421
(1) Sanken 2SC2240.

Found this 2005 article from Skeptic magazine:

https://ethanwiner.com/audiophoolery.html

You might think that a science-based field like audio engineering would be immune to the kind of magical thinking we skeptics see in other fields. Unfortunately, you would be wrong. In my 35 years as a professional audio engineer and musician, I've seen some of the most outrageous pseudo-science sold to consumers, and even to other audio pros who should know better. Not unlike claims for alternative medicine, nonsense is shrouded in scientific-sounding jargon to confuse the uneducated. Or a sales pitch will cite science that is legitimate but irrelevant, such as the molecular structure of a wire without considering whether an affect is actually audible. The result is endless arguments among audiophiles over basic scientific principles that have been fully understood for fifty years or longer.

Click to expand...

As a consumerist, it galls me to see people pay thousands of dollars for fancy looking wire that's no better than heavy lamp cord they can buy at any hardware store. Or magic isolation pads and little discs made from exotic hardwood that purport to "improve clarity and reduce listening fatigue," among other surprising claims. The number of scams based on ignorance of basic audio science grows every day. Surely some of these vendors know they're selling snake oil, but I'm certain that just as many believe their own hype. I'd respect these people more if I thought they knew they were conning people!

Click to expand...

Few of us have unlimited budgets and must spend what funds we have wisely. Therefore, the purpose of this article is to help you distinguish truth from fiction, so you can determine what is and is not worthwhile. Experience has shown that it's futile to claim I know what someone else can or cannot hear. Therefore, I will relate only those things that matter to my experienced ears, and explain what makes sense from the perspective of science and logic. You don't need a college degree to understand the explanations that follow, though I'll assume you've played with a stereo receiver and CD player or cassette deck a few times. I'll begin by defining the four basic audio parameters. Then when I describe some common audiophile scams later on, you'll understand why they are scams.

Click to expand...

Hi I got a Sony ES amp with some bad scratches on top of te front panel is there a way to fix this?

Attached is a LP section of either a 2.5 ways or a 3.5 ways speaker. To calculate for L3, I’m curious whether the speaker W1 could be considered as a capacitor, so the calculation can follow standard third-order formula.

Or are there any means to calculate L3 except using simulation softwares, i.e., VituixCAD, REW, etc.? (I can use them but just curious if there’s an alternative method, even hand calculation, available.)

I'm watching this guy on YouTube that repairs all kinds of audio stuff, and came across this:

Login to view embedded media
I'll let the video speak for itself, but I must say I'm shocked by what shoddy circuits anyone can put together and sell for ridiculous price tags.

... I was lost in a new (to me) forum. Just looking for now.

I used to enjoy playing with affordable low end stereo stuff in the '80s. Since then I gave all my vinyl away and re purchased some of it on CDs and today play ripped copies on my laptop. None of the old hardware exists. Not sure where my re awakened interest will take me.

Cheers, Russ

Hello Ive been learning allot about healing frequencies. 432hz. 528hz etc

But Im really confused by all the youtube videos with "earth frequency" 8Hz

No speakers can play this low. Whats up with all the videos?


How do I make a speaker play this?




Thanks

The post that I started last Wednesday on current drone sightings has been shut down by the Moderators. I assume that was done due to the rather silly and somewhat derogatory comments that were being made by some posters.

But this is an important and timely subject. And it is completely nonpolitical. People on all sides of the political spectrum are concerned about it.

So, I would like to continue a serious discussion here and ask that it not be corrupted by unnecessary silly comments.

========================================================

As of now there are still no definitive answers by the government or anyone else.

More sightings continue at a high rate and in new places not previously heard from.

The sheer number of drones that exist in the US alone, almost a million accounted for and probably an equal number unaccounted for, makes this a very serious matter. I don't think people realized until now exactly how many of these drones exist. And more are being manufactured every day.

This issue is not likely to go away soon and seems to be certainly worthy of a respectable discussion here.

Hi Guys,

I'm trying to build a phase splitter for a tube push pull amp, i only need about 2v p2p swing from this and I plan to run it off the negative bias supply, thus NPN rather than PNP. Any advice how I can improve this circuit? Priorities are PSRR, symmetry then distortion.


Cheers!

I have a broken Sony GTK-XB5 speaker, the electronics are broken and one of its woofers too, my idea is to use a woofer and a fullrange to make a smaller self-powered Bluetooth speaker.

I thought that if I took the volume of the box and split it in half and did the same with the length of the bass reflex tube I would get a box that sounded the same but smaller but trying in WinISD I have seen that this is not the case, and I do not have the thielle-small parameters of the speaker.
I have a 3D printer and a calibrated microphone. My idea was to make a box with half the volume and try different bass reflex measurements until I got the desired response, but I don't know whether to start with the same diameter or a smaller one.

How would you do it?

Hi all,

I have this amplifier in protection. I have noticed the power supply caps are leaking.

what are the correct mosfets for the psu / output sections?

the amplifier was previously repaired

Hello,

I have a Rudistor RPX-33MK2 headphone amp which is producing noise in the left channel. The noise comes on a few minutes after the amp is turned on. The channel still works, but the static noise is just there along with whatever is playing. I've recorded a sample of that, which can be heard here - https://app.box.com/s/7htgpg3ieiuytt61qwhsd5ux05i3b0bf

I wanted to ask for some advice on how to go about resolving the issue. I can see the trimpots, maybe need to adjust those but have little idea where I would point my multimeter to..

Any tips are most appreciated, would like to put this dude back in use 🙂.

Thanks,
-Art

Hello All,

Very much new to understanding this program.

I'm trying to understand how to get loaded B+ measurements at output transformer with using the Vta st70 as a template. Mine is the same power supply section besides transformer to the Dynaco ST70 attached schematic.
transformer is 360VAC @350mA
output transformer is 4.5K
I'm running 6l6gc output tubes and 6ns7's on the driver board.

When loaded With a multimeter its got about 440vac at C1, 430vdc on the plates of 6l6 with 40mA bias and 375vac on the driver board B+ which is correct to the Octal schematic

Attached is a screen shot what i have so far which seems like Ive done something wrong
So, Is the B+ voltage for output transformer read from the V(R1) RMS? C1 voltage isn't 440v

Help is much welcomed 🙂

Wayne

I'm planning to build a speaker, but I want to build something different - thinking outside the box (pun intended). I'm planning to build it out of either 12mm or 1/2" birch wood plywood. Maybe you guys have better ideas on construction materials. I drew a rough sketch of what I thought might work good (open side-view attached), but I need you professionals to give me the exact dimensions that would work best - or just tell me if the design just plain won't work.

I am a professional amplifier engineer, and my goal is to accelerate the transition of audio to green.

Hi.

Dave here.

I lurked on here to build a headphone amp a long time ago, and have been back lately as life changes a bit.

I just built some of the redux amp camp amps. They came out really nice- using them to drive some speakers in my shop. Not the most powerful but sound alright, and it keeps the neighbors from getting too upset about volumes and my lack of control. 🙂

Main listening is currently a simple system; Bluesound Node as streamer / DAC, Naim Nait XS, with ProAc 2.5 Response out the end, with Naim cables throughout.

I'm thinking about building more because it brings me joy, so I'm now posting and getting started. (And learning is such a great thing.)

So, thanks for such a great forum.

Dave.

New to this forum, I tinker with electronics and audio crap, I collect cassette tapes and players, and I dabble in vinyl.

I thank you very much for lettin’me in.
I am an audio aficionado and also a reviewer in two Italian Magazines called AudioReview and AudioGallery.
I pretty much follow electrostatics threads as this kind of loudspeakers mean so much to my passion for music and audio.
Thanks again.

Hi all, I've already learned a lot from this forum, but I'm now out of my depth and hoping to get learning again.

Just have a few questions on wiring sub to amp. And sub enclosure recommendations for home audio. First off I have a Skar EVL-12 DVC 4ohm and a BASH 500 plate amp, I don't know how to correctly wire these . Being a dual voice coil sub I don't want to wire it wrong and damage my amp. And yes I know this is not the best speaker for home audio but it's what I have. Also is a car audio enclosure different than home audio? Finally any recommendations for a box builder program that works with mac.

Hello everyone, 🙂

I’m currently training as a cabinetmaker, and I’m working on a project to build a Leslie/Doppola speaker inspired by Dürer’s Solid (https://en.wikipedia.org/wiki/Polyhedron_of_Dürer). I also plan to design an electric guitar to match this amp. This post focuses primarily on the technical/electronic aspect of the amp (the guitar being a separate project). My goal is to create a Doppler-effect amp for electric guitar.

After some research, I’ve encountered a few dilemmas:

• Should I go for 1 or 2 speakers in my amp? Would this improve the sound quality?
• Should I faithfully replicate a Leslie cabinet, or consider a simplified design that might be less expensive and easier to build?
• What would be the best setup for guitar? Should I be inspired by David Gilmour’s Doppola, or go with a single-speaker configuration and rotating baffle? It seems to me that the Doppola has a less pronounced effect compared to the Leslie cabinet.
• Where can I find all the parts needed for this project? (My idea is to start with a tube DIY amp kit that I can assemble myself.)
• Where can I find schematics or plans for similar projects? Or even other specialized forums for this kind of project, perhaps?

I’m a beginner in electronics, but I’m passionate about this subject, and this project seems perfect to start learning. I will surely post updates if the community is interested (about both the amp and the guitar).

For now, I think a simplified version, like the Doppola or a design with a single speaker and rotating baffle, would be the most coherent, although the original Leslie cabinets are legendary… 😍

Thank you in advance for your advice and suggestions. I’m open to any resources or feedback on similar projects!

P.S. I’m French, so I apologize in advance if I make any mistakes in English!

For sale, a pair of Altec 902-8B compression drivers with original 34647 aluminum diaphragms, 8 ohms. Also includes gaskets. Great Plains sells these for $850 each or $1700 for a pair. Asking $400 net, plus shipping. Please see my ads for Altec items.|

For sale, a pair of Altec 816As loaded with 515-8LF woofers, 8 ohms. Only driven on Sundays - they came out of a church in Ft. Wayne, Indiana. Asking $1,000 net, plus shipping that you must arrange or pick up from the Cincinnati, Ohio area. Please see my ads for Altec items.

Hey DIYAudio!

I've been a long time lurker of the forums for over a year now - I've caught the speaker-bug & it's consumed most of my free time. Dreaming of a big stack of speakers - putting on unique events & connecting people through sound.

I met my wife on the dancefloor at a unique bass music event in Canada - music has always been a core part of our relationship. We talk about how the event we met at is no more - & where would we meet today of we were that age again?

The desire to curate high quality events surrounding connection through art & sound, quality food & non-alcoholic beverage has me seeking the best possible sound I can possibly create.

Im a builder & do everything myself to the highest quality possible. The level of professionalism here has me excited to be a part of this community.

Recently I've assembled a Maslow4 CNC - working out the kinks to be able to consistently & reliably cut cabs & delve into scenograhy is the goal.

The works of Tom Danley & Tony Andrews are inspiring & how they continue to move the sound world forward is incredible.

Located in the Okanagan area, BC Canada. Very keen to bring something good to the sound world.

Look forward to collaborating with the lot of you!

-Scott

Hi.
I'm working on this GAS PSP2500.2DF amplifier (made by A/D/S, model APA21700DFB. http://www.adsaudio.cc/webs/carAudio/detail?id=1000111 )
The amplifier always turns on in protection mode.
On first start, a PWM pulse is given in the power supply, which charges the rail capacitors to +/- 50VDC. If you disconnect the remote and reconnect it, the PWM pulse in the power supply does not appear until the rails are discharged. I have checked both channels and they are correct, I have even replaced the 2092 ICs. I have also checked the power supply control board and everything seems to be in order.
Has anyone had a similar problem?I hope I have explained myself well.

Thanks.

Hello,
For my new project 4 channel amplifier SA2015 (Bi-Amping) I will also make speakers protection with large mosfets in (TO247). These protections are usable up to 400W.

They work reliably in my SA2014 amplifier (400W/ 4Ohm).


schematic:


pcb layout:


PCB colour: blue
Thickness of copper: 2 oz

Closing on Sunday (24.11)

Hi.
Anyone got a scematic for this excellent Sub amplifier?
I have No sound, relay do not turn on, No voltage to relay. No DC on output either. All opamps looks ok when tested separately.

.

I have 10 of the mentioned driver at home and planning to build enclosures for them for a movie theater system. I can't however find any parameters for them or really any info at all apart from that they have been available in a diy build kit from now bankrupt Finnish audiostore HIFITALO.

I tried contacting the peerless company but got no answer. Does anyone have anymore info on these or a clue how I could get the parameters I need to design and build a enclosure for them

Is Curcio Audio still around? Any where to get the ST70 and power supply regulator boards? Have some made?

As per title, and like these please from hifi collective.
Thanks.

Hi,
I recently got these 3 way tower speakers from my godfather and when I connect It to my amplifier only the middle was working, I've tried it with a Technics SA-EX310. I've tried it also with a Kenwood KRF-A4030 and the issue stayed the same. All I know about these speakers they were used long time ago.

also here all the specs that I could read of the speakers:

• Long term power: 100w
• short term power: 170w
• frequency range: 50hz - 20.000hz
• impedance: 4 - 8 ohm

I also know about the technics amplifier It can be used with because it supports 8 ohm speakers.
I also heard that these speaker have a poor crossover and It might need a better one. I really don't know how I can replace it by myself and what kind of circuit bord do i need to buy, but the speakers worked before without the crossover change so I don't think It's necessary.
Sorry If the answer is really clear but I only got this far

Adam
Odorheiu-secuiesc

I saw an amp I've been looking for some time... it's on Mercari.

Has anyone bought anything on that site?

Gautier Capucon played Shostakowitch's Cello-Concerto N° 1.
We (wife & I) were right in front of him, ~4 m away. Wow.
It reminded me of a concert of the Who (never saw them live though), he kinda wreaked havoc on his instrument, unbelievable.
Near the end, the 2nd string gave up and jumped off the board, but even this didn't stop him. (A cellist from the orchestra wanted to help out and gave his cello and the conductor had to keep it until the end)
Had no time and no occasion to take a picture.

I'm looking to build myself a good set of speakers to replace my Focal floorstanders.

I do a lot of joinery work including bespoke cabinetry so building the cabinet from scratch is not a problem, hence why I don't want to waste money on pre-cut cabinets that come with some kits. I want all of my outlay/investment to be on drivers and crossovers.

Amp wise I am currently running a Michi X3 which has a max output in class AB of 350w/ch into 4ohm and 200w/ch continuous into 8ohm. At some point I will no doubt start to experiment with pre and power amps and no doubt tube amplification.

My musical tastes are eclectic but I would say mostly - Alternative, Prog, Kraut, Psych, Electronic, Folk, Reggae & Dub, Hip Hop/Rap, Rock some Jazz and Classical.

A member recently introduced me to SEAS kits and their drivers do seem impressive. Has anyone built any of their speaker kits or could anyone recommend one?

I am interested in the Delling, Thor, Acuity and Aphel from the quick read I have had....any thoughts?

Hi ! watching some videos on Youtube about high priced small speakers in the comments often someone points out the fact that they use songs with limited frequency response i.e. little bass
for example, one asked why in the demos of small two-way speakers they never use songs like Bach's Toccata and Fugue, if anything, by raising the volume a bit
One answered because otherwise they destroy the speakers
I wonder first of all if this is possible
after all a speaker should be able to reproduce all the music at a decent level with good quality
Does this mean that these small speakers have strong intrinsic limitations ?
I saw a small monitor that costs as much as 100 kusd/pair
If someone puts Bach on and raises the volume, does he risk making it smoke ?
is it possible? if so they should warning the customers

New here, just sharing some info, repairing audio gear/etc

Hello everyone!!!
I am writing to you from Italy, and finally after a long time, I am about to start the construction of my final audio system (at least for a while)!

I would like to present the project, and ask you as well as your opinions, some advice...

Ready, go!

The room is 4,3x10mt big, the system will be placed on the narrowest wall.
At the end of the room there are stairs going down, so it is not enclosed. The roof is built with wooden beams placed crosswise, relative to the placement of the system.
The thermal insulation of the house was made cork, which could also help with the sound.
This Is the room:



I have always been fascinated by the sound of horn loaded systems, and after much thinking and many doubts, I am finally coming to a concrete final idea:

Three way, fully horn loaded, multi amplified system.
Bass with Radian 2216 neo driver, loaded in spiral box as designed by inlowsound:
https://inlowsound.weebly.com/spiral-bass-horn.html
Double mid-bass with b&c 8pe21 driver, again based on inlow design:
https://inlowsound.weebly.com/135-hz-mid-bass-horn.html
Mid-high with Radian 950pb driver, loaded on Arai 290 horn:
https://www.araihorn.com/p/arai-290.html?m=1

As a preamplifier I have my eye on a model from Black eyes audio, tube with integrated dac:
https://blackiceaudio.com/daccd-pla...p_mzEsxKOnnsQ6TQI1Z-rqfXn0mVFk4z7O3LGaK6aC_vI
For the crossover I like the dbmark series:
https://dbmark.co.uk/products.php?i=XCAX
For the power amps I wanted to install class d amps made by IcePower, models and power ratings to be determined.

Indicative cutoff frequencies 130Hz/600Hz...

You will carry out the construction by me, and calibration together with a friend....

I am looking for a very dynamic and very exciting sound, but one that does not fatigue the ear....
I would like the frequency response to be as even as possible throughout the room....
I would like to have great quality both very low and at very high volumes...

Here is a picture of the possible arrangement...



Let's move on to the questions:
My first idea was to make a four way system, and supplement the Radian driver with a tweeter higher up...
Given the problem of the distance of the emission centers, I decided to let the Radian driver do all the work up to 20KHz, but I have no idea how it will behave on the higher frequencies, like above 12Khz...
The changes introduced by Arai on its horn, compared to the Tad one, should give me a good off-axis frequency response even for the higher frequencies...
Has anyone had a chance to test this aspect of this driver? How do you think it will perform combined with this horn?

Also regarding the Radian driver, is the 8ohm version or the 16ohm version preferable?
Also the issue of dual mid-bass is to be able to have the most consistent frequency response possible across the width of the room, and so I should match 2+2 horns...
The designer told me that this horn has great punch and matches the bass very well, and that's exactly what I'm looking for....
The problem is the off-axis response, and I was thinking of solving it by doubling the horns....

How would you amplify the horns? Drivers in series?
Given the stability of the 4ohm amps, also parallel drivers?
Or even better, get the crossover with 4 outputs and put in two power amps?

I'm also a bit worried about tube preamplification....
Let's say I would like to give some warmth to the sound with preamplification, but then I would like to have the sharpness and control of a class d on the power amps...
I wonder how much sense this would make?
My friend who will help me with the calibration claims that we can use the crossover to create the kind of sound I want....
If this is feasible, I could easily opt for another non-valve preamplifier....
What do you think?

All opinions are welcome, thank you all very much, and Sorry for the english

Top pair of basmid units in verry good condition. Verry good T&S parameters. In 40L netto volumen enclosure - 3dB 34Hz.I sell only zhe drivers, no enclosure included!!! Shipping worldwide but the price for 200 euro for this pair is including shipping price only to EU countrys. Payment is Paypal for friends.

I'm building class-G amplifiers (which I mistakenly labelled as class-H on the silkscreen - sacre-bleau!), which stretches my lab supply capabilities.

Normally I use an pair of old Thurlby PL320 supplies (nominally 0-32V, 0-2A), which I tweaked ages ago to do 0-40V, 0-2A. They don't do enough current to actually start testing amps though, so once I've done the initial setup and smoke testing I generally substitute a +/-40V or +/-56V unregulated supply.

It's not ideal. I'd like a lab supply that's capable of driving a typical 100Wish power amp to the limits of it's capabilities, so something like 60V, 5A.

So ages ago, I lashed up the circuit shown. The idea is to use half a dozen N-channel lateral MOSFETs in parallel to do something like 60V, 6A. It never made it past the schematic stage.

Until now, when I need another couple of lab supplies to test my class-G amplifiers.

So I've spent the last couple of days doing layout, and come up with a reasonably simple 235mm x 65mm PCB, that has everything bar the transformer (actually 2, as I need a 2x12VAC low current supply to drive this), plus pots and panel meters.

Please see attached LTspice simulation, KiCad schematic, and PCB.

Alas I won't be ordering this PCB for a couple of weeks, as I've spent my play money on amplifier PCBs and I don't want to get into trouble.

New aluminum top plate for AR. Size 13 x 13 x 1/8". Drilled for AR T-bar and on/off switch. Cork damping on underside. New, still has protective plastic sheet on top, no marks or scratches. Purchased and built for customer who backed out of the deal. Motor and switch not included. Holes for spring bolts are not visable when platter is installed. Designed to use a side armboard like the Linn.

$30.00 plus shipping.

Hi
Here I am again with a new project.
This time I bought a radio from the 50s, the Ever Ready Super King.
These battery powered radios usef powered a 90V battery.
I will use either 10 9v batteries or some li-ion cells and a boost instead. Using a boost will allow the batteries to be recharged.
The filaments’ current is 25mA or 50mA at 1.5V.

I will try to re-use as many parts as possible.
As this is a single ended amp, the schematic should similar to the fender champ.
I will be posting as I move along.
Cheers
Pedro

hi all,

first 3 way crossover design here so im looking for guidance

the tweeter is 1x beyma cp21/f which is 8 ohms - 105dB 1/@1m
the midrange drivers are 2x B&C 6nsm51-8 in parallel for a 4 ohm load "100 dB, Applied RMS Voltage is set to 2.83 V for 8 ohms Nominal Impedance"
the mid bass drivers are 2x faital 10pr320-8 in parallel for a 4 ohm load 95dB 1w @1m

in practice these are some of my favorite drivers.. but I've always run them with active crossovers. I was thinking maybe I could try this and save on amp channels and DSP..

now im noticing the sensitivity is a little spread out, so maybe some L pads needed? that's fine if required..

for the HF I'd like to low pass it @20kHz @24dB / octave
mids x over to HF I'd like to hand off @4kHz with a 12dB / octave slope
Mid range to mid bass X I'd like to hand off @500Hz with a 12dB / octave slope
Low cut I'd like to roll off @45Hz with a 24dB / octave slope

and somehow, I'd like to gain match it all!

not saying I can't just go online and look up a 3 way calculator and how to make a bunch of L pads and filter circuits but im sure there are people here with much more experience doing this that I can ping off of

appreciate it " tips hat "

Apparently there is a gaping hole in my understanding of negative feedback! Normally when you apply voltage feedback, the output impedance will fall by the same factor as the gain reduction.

Yesterday I was testing a simple 6L6 PP amp, and measured the output impedance to be 170 ohms. Then I applied about 6dB feedback. THD fell by half as you would expect, but the output impedance fell to 16 ohms!

So I created a very simple circuit model to see if I was going mad, and sure enough I get basically the same result. What is happening here? Why is the output impedance changing by a factor of ten? I feel like I'm missing something very obvious!

Frequency response shown below, indicating 6dB of feedback. 6L6s are biased to 42mA cathode current.

Hi

I am working on this JCM 2000 DSL100 which a friend sent to me for checking. Upon opening the amp, I realise that a " JCM 2000 stable Bias Mod" has already been installed earlier. I plugged in a CD player and turned on the amp. At first the amp was working as normal, After a while, there was a slight buzzing and it startd to get louder, at the same time the music started to get softer. This contiued , the buzz getting louder while the music fading, After about an hour the buzz was much louder and the music could hardly be heard. The bias reading is stable and was not drifting. What could be the cause? Could it be due to the B+ voltage leaking into the preamp tubes or could it be a problem with the the Output Transformer. Please assist.

Thanks

I got small issue with my Denon pma 510 are.
After turning on you are able to change inputs for short time. Later on switch no response at all.
Remote control stopped working as well.
After replacing ir sensor, remote control works fine, and input selector switch as well.
But after hour or so, IR sensor diode blown again and everything stops working again.
Any advice? Please don't write about selector switch cleaning because it is not the case, switch it's brand new, old one was wobbly.

These are five variations on a simple SE. Small differences, but which one would you go for in the real world? It is mostly about 2H wrt 3H.

There have been a lot of nighttime large drone sightings recently in the NY and NJ areas. No one seems to know what these are, or if they do know they are not saying what it is.

One theory is that they are foreign based and coming from a ship just offshore.

The fact that no one in government can provide any sort of answer is particularly disturbing.

https://www.foxnews.com/video/6365887118112

Hi everyone,

I'm new to DIY and joined this community to meet with other diyers.

I'm an audiophile and am starting to get into speaker designing. Looking to start with small affordable builds and eventually build high quality speakers. I would love to build everything from scratch (even the drivers) and some day start my own company if it makes sense to do so.

Three x MC-616C (2-way L/C/R)
6.5" woofers, 1" tweeter 180 watts, 6 ohms, 89dB sensitivity
191/2"W x 7 3/4"H x 9"D
Weight: 24 lbs.
MSRP: $579 each

Also one RBH MCS-88 dual subwoofer as per picture. MSRP $500 each

Total MSRP over $2000

£250 for all four items. Can ship for extra. UK only. Sorry no can demo. Pick up from west yorkshire available

selling a Pair of RCF 850ND 2inch ; perfect state like new 450€ .
shipping to E.U only.

Hi everyone,

I’ve started putting together a small collection of vacuum tubes, but I’m realizing I could use some advice on how to better organize them. I’ve taken some pictures and uploaded them here: Vakuum Tubes

I’d appreciate any tips or ideas on how to sort and store them—whether by type, brand, function, or something else entirely. I’m also curious about any labeling systems or storage solutions you’ve found helpful.

Thanks in advance for your help!

Good morning to Everyone
Being interested in vintage loudspeakers I understand that TS parameters of a driver can vary with its age
I wonder why and what type of drivers can be more critical in this regard
Any suggestion and advice would be very welcome and precious
Thank you very much indeed

I need to pipe audio from uneBlade on a virtual machine on my server to a few separate Pi's with ShairPort. The reason is that the physical server/host is on another network segment, and a double-headed server is just as ill-tempered as a double headed troll.

The only reliable way to do that is to use one of the sound card outputs from the host (I have a bunch that feeds both these PI's and regular amps with cables, 14, if I'm not mistaken) and then the input of a USB sound card that is mapped to the virtual machine. I could use several USB sound cards, but that easily becomes a mess and creates problems on startup of the VM. So is there a sound card where I can use that has several line inputs, preferably RCA or 3.5 mm Jack, so I won't have to use any extra adapters? The TuneBlade works by capturing audio from any input on any sound card, but of course mic inputs easily gets distorted, even if they are set up in software as a line input. Here is a screenshot from TuneBlade:



It's the line in from the el cheapo USB sound card I'm using at the moment for one zone, but I want something better. Reasonably priced is up to $200, maybe 300 if there are many inputs.

Here is my measured results from 2 samples and manufacturers spec sheet

Disappointing but is there any real issues that I should be made aware of? Maybe just cross high enough with a small woofer?

Some time ago, I presented a complementary matcher based on a novel principle:
The same principle applies equally well to identical transistors, and it brings the same advantages: direct comparison between the junctions, with the TUT's themselves performing the comparison and a substantial amplification.

To demonstrate the operation, I have chosen a BC547B and a BC847B, which should be identical but aren't in reality (sim)



This time, no cheat is possible regarding the 0.1% tolerance of R1 and R2.
The calculation is the same as for the previous one:

Suppose that for a given collector current, the delta-Vbe is 1mV.
From the junction equation we can infer that the delta-Ic will be Ic*Exp(1mV/26mV)=1.039-1=3.9% for both transistors.
The difference is split between the two transistors, resulting in a 1.95% change. As the collector current is ~1mA, the variation will be ~20µA.
The voltage appearing across the two 3K3 resistors will thus be 6.6*0.02=132mV.
Thus, a theoretical magnification ratio of ~130; not bad for such a simple jig.

Here, the current is 1mA, but it can be changed to any value by scaling all the resistors values in the same proportion; self-heating remarks apply too.

Here are some pics:

I have a Fender 60 Watt Hot Rod DeVille with 2 12 Eminence Speakers and I recapped it not long ago and I changed one cap C1 to 22 uf to add some more tone I remember, Other than that one mod it is stock. 2002 Model Year. I had a nec and ge in it for about a year now and I was testing out some RCA 6L6 GC tubes in it today and individually They were 98% and 100% Emissions with 50 mV and 46.5 mV each. @ 489 plate, 487 grid and -057 bias. Cold Idle I set the bias to 63.5 and when they get hot it goes up to 102-104 mV at idle two tubes, it's Max idle @ 85 % . The tubes sound really good there Hot and I don't have any negative bias adjustment left. I turned the lights off and I was looking for red plates but I didn't find any but I noticed a little bit of blue haze in the tube near the getter and I tested them for shorts and grid leakage with my tube tester. The Amplifier has never sounded better than it does Now. I tried a pair of RCAs in it when I first got it and I didn't like the sound super bassey At 60 through 70 mV idle so I put what I had in it The NEC and GE instead At 63.5 mV idle no signal. It was okay but not really what I was looking for. I have noticed that blue haze before in 6L6 GC and other vintage 6L6 tubes. I was told Year's ago to just ignore it if they sound good. I played it for a few hours and it plays good. Am I worrying about nothing or should I be concerned ? I've heard some people say that 85% is fine with 6L6 GC Vintage tubes. I have 3 other pairs of The RCAs matching, I used to have a Fisher Ambassador that I converted to use 6L6 GC and One of the OTs went bad so I pulled the tubes out and I saved them. I forgot about them and I found them in a bag together the other day and they do match but I had another 5 of them also. I have two 97% @ 30/30 mV , two 97% @ 27/27 mV and two 100% @ 67/67 mV. They don't have any shorts or grid leakage. I'm A little bit afraid of using the two that Are even higher At 67 mV with The limited negative bias voltage and I don't really want to Use the other four because it's a Quad of working good RCA BP tubes. The Amplifier is actually quieter now At 104 idle than it was with the old tubes at 63.5 mV idle. I can run the settings down at 3 now and I have a good balanced room volume, they were up at 5 to 7 before on the clean channel. I don't want to burn up my 1200 dollar amplifier but I don't want to have a crappy sound either. I've got some really good vintage pre amp tubes in it. I know that I could play it safe with two of The other tubes but they probably are not going to sound near as good with 20 less mV idle. I've never really tried pushing the limits before with Guitar Amplifier tubes but it seems to me like the best sounding player's definitely do ! . I remember an old Sovtek MIG 100 lead I had that had 580 volts plate and EL 34 Vintage Mullards it was loud and clear and it would just about strip the paint off the wall. I want something like that but A little less loud. The 60 Watt DeVille seems just about right to me. I can still get good tone but At A lower volume. I play At home now and I just want to have a lot of extra power or headroom in Case I play out with A live drummer sometime. It really sucks when you can't play through the mix because you have a weakling Amplifier. And I tried the Hi power transistor stuff and up loud they didn't cut it for me. I had a custom built Crate Amplifier once that did but it broke down in short order. I'm done with those things. I guess that I'm just looking for opinions about The 6L6 GC RCA black plates and their limitations. The Old RCA tube Data is not really up to par with modern guitar amps with the Big voltage drops between plates and grids of 50 and 100 volts. I don't know exactly how to make sense of it for my application.

Where to connect power transformer screening:

-Direct to chassis ground with nothing more shared?
-Together with signal gnd to GLB (ground loop breaker) to chassis?
-Other?

Just acquired a single one of these - don't suppose anyone knows of another one that can make up the pair?

Hi guys ,
The source selector switch on my Rata amp is looking quite fragile and I did discover some small bits of plastic beneath it so I think it’s on its last legs .
I don’t really want to risk removing in order to identify it for obvious reasons so I’m hoping someone may recognise it ?

The amp is from the 1990’s .