about the German Forum
Theorien und Literatur über Lautsprecher - Verstärker, Lautsprecher, Zubehör - Analog-Forum
you will find a good overview.
here on diyaudio I have found only this:
DIY Loudspeaker Books - diyAudio
loudspeaker books - diyAudio
about
www.hornlautsprecher.de - solutions in sound
a lot of datasheets and the complete book (in German) "Dichtung und Wahrheit" you will find as PDF file

Magazines:
Voicecoil:
audioXpress | audioXpress Magazine. Advancing the Evolution of Audio Technology - Since 1970 - test example:
http://www.moreleurope.com/data/mediablocks/ST 728 Voicecoil reprint.pdf

More books and magazines (also from other countries) wanted - thank you for additional advices.

post #15 under
https://www.diyaudio.com/forums/everything-else/196492-recommended-books-2.html#post6749607
shows a very interesting book concerning horn constructions

Hi everyone,

Thanks for reading - I hope this is the right spot to post this.

I have a Nakamichi PA7 and the power just flickered on and off a few times - and now it won’t turn on. It’s plugged into a surge bar.

I was wondering if anyone could shine some light on what could have happened to it, I would like to try and repair it myself if it’s doable.

Appreciate any input, hope you’re all having a good day.

Thanks

Two C64, old floppy disks and gaffer tape:
https://linusakesson.net/commodordion/index.php

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The world is not lost yet.

Hi everyone hope some one can help with my naim nap110 as it got a fault where the dc off set is showing 36v from spk terminals have checked outputs and driver both seem ok there is 37v from psu and both boards shows the 34/36v from spk terminals they both drawing 15ma and 4.2 mv bias which don't seem to adjust i must be missing some thing but not sure where

For sale an Audio Precision SYS-2322 with additional USB interface. The unit can be used with Windows 10 and 11 in a Desktop or with a laptop and the PCM card (I was using it with Bootcamp in an iMac without any issues). The unit works perfectly and passes all the tests, it only has a small dent on the front which was there when I bought the unit. It has been used in a clean laboratory (not in production lines or the likes) and it is well taken care of.

The bundle includes:

• SYS-2322 unit with CCIR2k, CC468-3, A-Weighting and 20kHz filters
• APIB USB adaptor, www.s1usb.com (worth 290$ + shipping)
• APIB PCM card with cable (cable not in the pictures)

The unit is in Hong Kong, asking for 3,800USD including shipping to anywhere in the world or a reasonable offer.

Thank you

Introduction
As an audio enthusiast, I like to use some creativity building speaker systems. But also using nice vintage audio products, upgrade them and extend their lifespan in a fun and useful way.

This time I took two speakers from the 60's: B&O BeoVox 1200. Traditionally built wooden casings, no top class but just nice speakers that fit well into many interiors because of acceptable size (W x H x D 50 x 20 x 24 cm) and nice natural wood looks.

Originally, these are passive speakers, so they would need an external amplifier. But in this case I transferred them into active speakers, each with its own amplifier, wireless + DAC module and power supply.

The setup I created looks like this:



Wireless transformation
The wireless magic has been added by using the products of Arylic: www.arylic.com

As I had PSU's and amplifier modules laying around, I choose to use Arylic's Up2Stream Mini module. Great module for this use, small and easy to install. The wireless antenna is easy to be put inside the casing of the BeoVox. The signal strenght is strong enough to do so. And it keeps the speaker in its original looks, with this 'invisible' antenna.

An alternative could be the Up2Stream Mono, which has a built-in mono amplifier.


Build

I took of the front grills and then removed the two speakers to create access to the inside of the casing. And put all components in place. Only for the Power socket, I created a square hole in the back side of the wooden casing, to put that in.


Conclusion
It is a great build and gives a lot of fun using these old vintage speakers, as if they are Sonos. The 4Stream App that comes with the Arylic products is great and easy to use. And has very similar functionality and ease of use as Sonos.

Money wise ... The speakers only cost me €25 for the set, the Up2Stream Mini 2x €49, and then a few Euro's for cabling, power socket and amp.

Hope this is inspiration to someone. Enjoy!

Does anyone have a pic of the following area in this amp ?

I got it in for repair and not sure if U1 is missing

The owner said another tech took some chip out of the amp

Hello,
first of all i would like to make two statements
1) i am very ignorant on this subject
2) i feel the mains noise affects more digital equipment than analogue one. I listen only to digital sources so my interest.
I found this video on youtube:

Blue Circle Audio 6X Sillycone Optimum Effectiveness - YouTube

and this is the page on the Manufacturer site

http://www.bluecircle.com/page26.html

Very very impressive isn't it ?
I think that this device acts as a parallel filter or noise trap i do not know.
My question is ... where can i get a schematic for some filter/trap with similar effect ?
It is impressive and handy the fact the reduces also the noise from the power strip to which is connected.
Great product also the sniffer of course.
Thanks a lot and kind regards,
gino

I left my turntable on over night and now it rotates backwards. I tried manually stopping it and forcing the platter to rotate proper, but it will not cooperate. Is the trouble in the power supply? What do you think?

Thanks,
Francis

I purchased these jentzen for a crossover and I found they are awfully light...uncomfortably so.
Shouldn't film caps with comparable voltage and capacitance should have comparable weight?
As anyone opened one of these to see what's inside?

It was reported to me that ignored content was showing during certain posting operations.

On testing I was able to force the situation by simply linking to the post. Shown here, the content is already showing and so are the 'show' buttons.


(Random post and testing account)

* EDIT: Testing thread started here - https://www.diyaudio.com/community/...e-function-not-for-general-discussion.386750/

Hi there.
A friend brought me a Little Mark Tube for repair.

I've asked questions regarding the PSU there: https://www.diyaudio.com/forums/pow...ailure-ir21531-please-help-3.html#post6156903
But I was advised to start a new thread here since last question is not PSU related.

A faulty cabinet blew 2 output transistors and then the 2 power supply transistors. They were the 4 only parts I've diagnosed faulty and replaced.
The amp is working again 🙂
I've replaced the 6 output MOSFETs with Vgs matched trios.
Now...
Does bias has to be adjusted (via TRIM1 pot and if it's its purpose) and how?

There nothing explained in the service manual. Here it is: https://music-electronics-forum.com/attachment.php?attachmentid=37571&d=1453963798
The Little Mark Tube I have shares the same DA510 board. Schematic attached.
I've read on an italian forum that Markbass replied that idle current must be between 40mA and 50mA. But gave no procedure or values. That's all.

Any help would be appreciated 🙂
Thanks!

Long-time listener, first-time caller!

I'm new to this world and only have built a few kits, this is my first build from a schematic and the learning curve is steep.

I'm curious to hear what is the best practice for reducing the voltage of a power transformer's secondary. I'm adapting a Japanese tube preamp design to accommodate US AC power. I've found an Edcor transformer that will put out 18VAC @ 3A - I will wire two 9V secondaries in series - however, the circuit wants 15VAC @ 1.5A. What is the best way to achieve this? A voltage divider? Diodes?

And best practices for reducing the amperage on this and the other secondary... resistors?

I'm sure there are a bunch of approaches and any input would be appreciated.

Thanks!

I am using my Raspberry Pi as a network media player and cannot find a simple solution to feed my Raspberry and HAT DAC with quality power. Finally I made a simple board which can be used as HQ power source for both Raspberry Pi and HAT modules, and can be configured according your requirements.

Mezzanine Power Board can be installed between Raspberry Pi and HAT module and can provide up to 4 outputs to power PI, HAT and other devices which might require quality power source.

Module A – LT3086 Linear Regulator, 5.5VDC 2.1A, used as pre-regulator for Modules B/C/D/E, can be bypassed

Module B – TPS7A8300 low-noise, low-dropout voltage regulator (LDO) capable of sourcing a 5V 2A power for Raspberry Pi

Module C – LT3045 based ultralow noise, ultrahigh power supply ripple rejection (PSRR) low dropout voltage linear regulator can provide 5V 0.5A (1A for dual LT3045 C1+C2 installed) for HAT modules

Module D – LT3045 based ultralow noise, ultrahigh power supply ripple rejection (PSRR) low dropout voltage linear regulator can provide 3.3V 0.5A for HAT modules (or can be configured for any output 0-5V)

Module E – LT3045 based ultralow noise, ultrahigh power supply ripple rejection (PSRR) low dropout voltage linear regulator can provide 1.8V 0.5A (or can be configured for any output for 0 to 5VDC)
5V PI rail and 5V Hat rail can be connected together; in this case module B (or C1+C2) can be used to power both PI and HAT boards, same for 3.3V rail (by default it is connected, but if module D is installed and connected to HAT 3.3V rail, 3.3V PI rail is disconnected from HAT rail)

Below you can find some images for the "Light" version (only Module B installed) and "Full option" Board.

Hi, I own a first generation Quad 405 amp (s/n 49125) which does not have a voltage selector switch on the back panel as was provisioned on later models. To adapt to different world voltages, wires had to be desoldered and reconfigured. Quad published four diagrams that detailed the different configs for 110V, 120V, 230V and 240V. I'v searched online but can't find this diagram. Does anyone have the diagram that they can share?

Alternatively, can someone post a photo of their 405 transformer in this thread if it is configured for 120V?

Pictured is my current wiring config. There is a RED circle around a soldered connection between GREY and BLACK wires. I'm not sure the primary voltage configuration - it might be 230V or 120V.

Hello all!

I have a punch 800a2 which plays music but is slightly distorted.

With higher frequencies it gets more audible , on the scope there is crossover distortion. the same like turning the bias pot completely CCW.

The amp draws only 1 A and the current didnt get higher when turnin clockwise.

Usually if set correct, it will draw around 2-3 amps.

What can cause that no bias setting is possible?

Best regards!

Just yesterday MY QUAD 406 started to have distortion in the left channel of the higher frequencies (treble). Is this an easy fix? Everything else sound good.

I have just completed a new speaker of my own design. It is based on the synergy horn concept, invented by Tom Danley. It is a 3-way design, built into a very large horn, loosely based on the Klipsch K-402 (but about 20% larger). It is somewhat comparable to the Danley SH-96, as it uses a similar driver arrangement. However, my design uses sealed bass drivers instead of ported, and I am using fully-active DSP crossovers instead of passive.

I have decided to call it the Big-*** Synergy Horn and will refer to it from here on as the BASH.

Here are some build photos:

Hi guys,
Yes, I know there's a sticky about this topic, but no-one i've asked so far seems to be able to give a straight answer for a starting point due to the unusually low input impedance.
I'm populating some DIY stepped attentuators for going between my DSP and these boards, precision volume control is not a concern, think of it more as gain control so I can stamp out any noise floor from the DSP and set a safe max volume.

Can anyone suggest what value of pot I should be aiming for. From reading the sticky I'm thinking that 5k would be good, but I wanted to check with you smart fellas first.

No, I won't be adding input buffers or anything else, just passive volume control.

Thanks in advance!

A pair of JBL 2216ND-1 15" woofers, brand new.

These are the woofer used in the JBL 4367 speakers.

Looking for $1,500 for the pair, but am open to offers.

PM me if you are interested.

Brand new in sealed factory box TEAC HA-501 Class A headphone amplifier. USA model in silver color.

Sells and ships to USA residents only.

Item has been SOLD!

Hi, I have a set of PSB bookshelf speakers with subwoofer. The subwoofer is the Alpha Subzero1 (pictured).



The subwoofer is not working at all so I removed the power supply / amplifier board from the unit and discovered several destroyed components where the red oval is (pictured):




The components appear to be 1W resistor, a couple Tantalum capacitors and a couple of power diodes. The damage has extended to the PCB where a copper trace in that area of the board has lifted.

My question is whether or not I should try to repair this board or just abandon the idea and buy a new subwoofer? Thanks for your thoughts.

Questyle CMA800R Golden Class A headphone amplifier in nice condition including original factory box and instruction manual. One of the top sounding HPAs. Well regarded with excellent reviews. The Golden version features a ceramic circuit board for low loss and better performance. Current drive operating mode.

$1195.00 plus shipping. Sells and ships to USA residents only.

Hi Expert !

I am a novice. I have an old NAD 705 which works perfectly, until I cut the speaker wire...sorry...for the first time in 2 years...After that there is no more power, nothing. I check every fuse, everything is good. I notice that there is no current at the Swicth output, so I think it is the RL_301 relay that is blown... I force the relay to turn on by jumping it (see the red line in diagram) and NAD 705 powered on, YES! So I think it was the faulty relay, I change it with a new one and reinstall it...nothing changes...the relay does not close. I check the voltage at the relay, it was only 6 Volts, it needed 13v (see diagram below). So my question, why is it only 6 volts? This is beyond my competence. Anyone have a lead? Thanks in advance everyone.

Designing a Crossover for High End Speaker (Raal 70-20xr + Audiotechnology Flexunit and C-Quenze)

Hi.
For the last couple of years, I have been making my ultimate speaker project. I, in my opinion, have gathered the best parts for that project, where i have been helped by Troels Gravesen and the makers of both Raal and AudioTechnology. I am pretty much done with my project.

However i hit one of the last hurdles on the way. The crossover. I have the measurement for my drivers, in my baffle, and wanted to design the crossover in xSim etc. My only problem is that im not experienced enough, to make the fullest of these wonderful parts. I've uploaded my beginnings of trying to make a crossover, but as you might be able to see, its a mess. I know i can make it better myself, but i wanted guidance first. My question to you guys is how i minimize the baffle refraction on the 18h52 and make the transitions smooth? - The cabinet is set, and is a homage to my uncle, it is already build. What im wondering is how you guys would do it, is there better ways to smooth out etc.

I hope some of you have some ideas or know where i can seek more guidance.

The speaker consist of the following parts:
Raal 70-20XR-NC
Audiotechnology C-Quenze 18H52 06 13 SDKAM-LR
Audiotechnology Flexunits 12 B 77 25 10 KAP

Best regards, Mads

I think it is wise to post articles on how we hear (i.e., humans) vs. issues with multiway loudspeakers. Tom Danley of Danley Sound Labs (the maker of Synergy multiple entry horns) recently talks about the issues with having vertical or horizontal separation of drivers in a loudspeaker and how that interferes with the perception of stereo imaging:

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I recommend watching the entire 10 minute video to understand before commenting or asking questions.

Chris

Does anyone have experience with having the bass go directly into the floor so that the sound only comes out of a small crack. Tune audio uses that principle a lot. On their Anima, however, they have the bass at the top, with the sound only coming out just above the floor via the cabinet, which is a horn. I am considering trying something similar, however not with the bass at the top but with the bass just above the floor and then the cabinet upwards. It is only for the deep bass maybe max 200 Hz or less. It naturally provides some amplification, but it is also a nuanced and fast bass, it should not just be fullness and hum.

Just wanted to get some opinions on the merit and implementation of this idea. I bought the 8" Yamaha ceiling speakers, but I don't like the idea of just slapping them in and covering with insulation. I was going to build a box within the joists for them, but having been playing around with the BiB calculator, I got to thinking, why not just build a BiB out of it since the speaker is intended as full range and I have an entire 10" joist making space above the ceiling for the box.

Plugged 80hz into the calc, it comes out PERFECT with a tapered box about 12"x16"x 8' long which puts my speakers in exactly the right position for the Dolby recommended placement, and the depth of the speaker is just shallow enough to allow the backpanel to just miss it. So it looks like this should be pretty simple:

1. Cut a 4x8 sheet into about 16"x8' strips to fit between the joists.
2. Install speakers in middle of chosen space between joists about 6' from either the front or rear beam (which places the speakers smack in the middle of my room).
3. Place 16"x8' strips with tips glued to the back of the ceiling panel 20" from the speaker and glued to the top of the beam at the other end. I might need to add some height to the beams and joists at the wide end to make it 12" instead of 10".
4. Cut a 12x16" opening for the port at either the front or rear edge of the ceiling with some sort of finishing for appearance sake. My wife, "So you're going to put huge holes in our ceiling that are open to the attic?" "No, just into the speaker box, duh." "So we'll still have huge holes in our ceiling?" "Well, yeah!" Lol, I'll probably cover them with something white and acoustically transparent.

So questions...

• Is this a dumb idea, and should I simply slap them into the ceiling with a back box or just lay the insulation over the backs?
• With speakers in the middle of my ceiling (a 5.1.2 atmos setup), would it be better to have the ports at the back or front? I was thinking back so that, although I don't have rear ceiling speakers, the opening would sorta simulate some bass coming from back there since the placement of extra speakers would be in that exact position in my room.
• Should I tune lower than 80hz? I'm sure the 8" drivers could handle lower, especially with a BiB that enhances the low end, but my sub covers that well. Some sub bass from the ceiling might be nice, but it's not very directional and would probably require something longer than a panel cut from an 8' sheet, further complicating things.
• Should I glue some sort of dampening to the back of the ceiling panels? Some ceiling acoustic treatment in the room would probably be good for my bare ceiling too, eh? I've never played with wall/ceiling speakers, but I've read that it's not ideal placement for them. Kinda hard to avoid that on the ceiling tho. Any tips there?

Edit: Looking at the specs, it says they have a "sealed back cover," but that's not exactly accurate...

Finished first speaker of my 3-way active speakers project. Full desctiption here.

hello
so i replaced the main caps in my linn lk280, all seemed fine until next day i switch on speaker cones push right out ,loud noise. then when i turn off and unplug input cables it comes on fine all fine i can tap the input pins and all sounds correct, put inputs back in power up again and all is fine for long term use. Until next day exactly the same, please help 🙁( please note i leave the speakers connected all the time its as if some kind of dc charge has to dicipate first if i leave for an hour or so and switch back on its still fine ,if i leave over night WWWHHHOOOOMP!! speakers pushed right out and has to be on for a few mins with no input connected then its fine with the same inputs connected.

shane

Can anyone find a 24mm 500k balance/blend potentiometer?

I need to buy one to replace my Mcintosh C20 balance potentiometer.
Part of black resistor tape on the PCB in the pot was peeled off.

I found some 500k balance pots but they are all 17mm.
I have to use old shaft from C20, so I need 24mm pots

I'm searchin a pair of Triad HS-50 (HS-54 might also do) and also a pair of Triad HS-29

Powering Tinysine TSA6179 miniature Bluetooth module.

Interested in wiring a Monarchy DIP to a Magnavox CDP-460 CD player. The thought is to use the digital out of the CD player to the Monarchy. From the Monarchy back into the onboard DAC of the CD player. Has anyone ever done this? Is it a possibility?

The thought is to add a reclocker/dejittery thing in line without spending big bucks. Essentially like adding a tentlabs like item just outboard. I have a schematic for a Philips CD-160 which appears to be the same exact unit. Any thoughts would be welcome on how to accomplish this goal? Thanks in advance.

The Hammond catalogue here http://www.hammondmfg.com/pdf/5c0050.pdf gives a figure for "Maximum DC Bias". Does anyone know what this means?

Looking at the suggested tube applications, it would make some sense if this was a near-to-saturation peak current and the transformer was gapped for an optimum idle current of around half this value. When it comes to the 1638SEA, though, 45mA would not be optimum for an 845 or a 211 with a 10k load.

(I have tried asking Hammond about this, but technical questions are diverted to local sales staff who have no technical knowledge about the products they sell, and who are unable to find anyone in the Company who does.)

Hello.
On page 68 of the book "A u d i o P o w e r A m p l i f i e r B a s i c s" by Bob Cordell there is a diagram
"Figure 3.13 Amplifier with double output stage". I tried to model it in lt-spice. That's how I described it (picked it up) and that's what I got. I got an order of magnitude more distortion. Did I do something wrong?
That was the first question. The second one will be next. So I made such improvements and got such a result. What do you think, colleagues, will this work in hardware in reality? I even made a psb for research in a hurry. Is there something that I didn't take into account, which is why my version of the amplifier may not work (I'm talking about both options, but of course I'm more interested in the second option).

Price lowered/Set of 9 excellent UTC transformers, A-15, A-18, A-22, NE

269,-eur
Price lowered

Up for sale set of 9 excellent UTC transformers :

SOLD 1. A-15 - 10/2.5K CT> 2K/0.5K - 2pcs, same series DP25
SOLD 2. A-18 - 15K CT > 80K CT

Sold! A-22 - 0.5K CT > 0.5K/0.125K - 2pcs, same series 7312
Sold! A-22 - 0.5K CT > 0.5K/0.125K - 2pcs
Sold! Northern Electric R20536A, Ind 0.323H/ 5:1

Nice condition.

Questions, info, pics on request, any time.

Transformers will be packed carefully with international tracking across all distance.
Sending from Ukraine. Payment by direct wire transfer.

FREE shipping to EU/UK.

----
See also other our items, we can mix all them together with our another items :

Grayhill 2, 3, 4 decks, single shaft rotary switches, up to 2x6, 1x12 poles

Grayhill 2 & 3 decks, dual shaft rotary switches, up to 12 poles

Canare L4-E6S pro audio cable 6mm, 4 wires 9 colors ~97m

Mogami W2944 pro audio cable, 2.5mm, 8 colors, ~236m

FS: Few different itmes - NEC relays, Meters, Caps, Cam, Cable

This is a group buy for circuit boards and MOSFETs to make a DIY Classic Aleph clone amplifier. This board set is designed to work with the diyAudio store UMS mounting pattern. The boards are flexible for making different Aleph variants, and power supply boards are also available.

You can see the main thread here: Classic Aleph Amplifier for Modern UMS Chassis

Group Buy #2 is now CLOSED.
Group Buy #2 closed 13 March 2022.
GB#2 Sign up sheet is here:
https://docs.google.com/spreadsheets/d/1w05jKUUwXxJUVIjuJXX3zeGQBRJD7ez2fiJqjWsOkS4/edit?usp=sharingLike Round #1 I'll reach out at the end to confirm order details, ask for email / name / shipping particulars.

GB#2 update 28 Feb 2022: I have purchased a bag of ZTX450's. There is a column to add those to your order in the GB#2 sheet to make life a little easier for folks. Stock is limited to 80 total. 2 needed per channel, 4 for a stereo pair. I'm not selling in bulk.

GB#2 Update 05 Mar 2022: I have matched a batch of FQP3P20. These are an alternative to IRF9610 for Q1-3. I'm adding these an option the sheet.

Post GB#2 Update - May 2022:
I have extra PCBs and MOSFETs available, please send a private message to me if interested. ZTX450's are gone.

Builder's thread is here:
https://www.diyaudio.com/community/...or-modern-ums-chassis-builders-thread.382316/

Hello.
Anywhere in net I have info that output is full discrete but on picture is 4 op amplifiers.
Maybe it is stabilizer for supply or output stage part.
Maybe someone make some upgrade this dac?
Thank you for your answers.
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Greetings all.
I have a nice Lambda LPT-7202-FM power supply with some trouble. I have the service manual with the Part List, but all of the parts has a Lambda internal number. So I cannot replace the solid state parts like the integrate circuit that the number is FBT-031... I am looking for some chart able to give me the commercial part number.
Does anybody has this information that want share with me ?
Any help will be appreciate.
Best regards
Victor

Hello everyone,

I just got a Quad 405 that I want to refresh parts.

It is with the board ISS9 so I was wondering what are you guys replacing obsolete parts with ?

This is what I got so far.

1) All electrolytic capacitors were replaced by Nichicon 105C electrolytic.

2) Both 10000µF were replaced by Nichicon LKG1K103MKZ 80V instead of 63V to fit original size mounting ring (50WX80H) with soldering lugs like the originals.

3) Output transistors have already been replaced on one side, they are toshiba on both side but different year, I'd like to replace them with all the same version and year.

Original output transistor are 2SD424 and can be directly replaced by MJ15001 if I am not mistaken. If you have other suggestions, I'd be happy to see what you guys did.

4) Op map are missed match and one have been replaced (on the side where the output transistors have been replaced).

On the side that has already been repaired, the op amp is UA301ATC from 1977.

On the side that looks original, op amp is LM301AN from 1975.

I'd like to have both of these replaced but I have a hard time finding the right component. If you guys could tell me what you use on your 405s that are using the stock boards, I'd appreicated it !

Here are all the cross-reference I've found so far but not sure which one to pick at this point.

LM318, OP07, OPA134 and OPA277 all seem to match pinout but I am not sure about the rest of the specs.

5) The 40872 pre drive are originals from 1978. I think they can be direct replaced by TIP42C if I am not mistaken.

6) R30 and specially R31 have got a lot of heat, the circuit board has change color, I have redone soldering but the leads of R31 look oxidated. The value reading is spot on at 570ohms, they are 5% tolerance as the orignal schematic state for 10%. Not sure it is worth replacing them because of the heat stress they got...

Other than that, it's pretty much it. If you guys have any thoughts, I'd like to hear about it ! I tried to find information on the threads in here about the 405 but it seems many of you guys are having newer revisions and parts were not matching what I had here.

Again, I just want to refresh the components and that they be identical on both side and put the cover back on.

Thanks for all the input !

Let's ignore the ER4 which has been discussed here and there. How're those Eton dome tweeters? The totl 29 HD2 and 28 HD1 is so-called Mg-ceramic hybrid, I don't know what exactly that means, but their prices are lower than the high priced Scan Be tweeters...

Does anyone have any experience with the 5879 phono preamp in the "RCA High-Fidelity Amplifier Circuits" booklet? The schematic is as follows.



I have looked pretty extensively and only found a mention or 2 on the web, but nothing significant. I'm looking to build one as I have a bunch of the 5879 tubes and have used them in guitar and audio amps with good success. I have an entry level (at best) turntable with the Audio Technical AT-3600L cartridge, and I'm totally happy with the sound. That either makes me a noob or a philistine, or maybe both. Anyway, I proposed some changes as follows.



1) Grid stoppers on all sections
2) 5879 screen bypass capacitor to cathode instead of ground
3) Instead of a 7025/12AX7, a 6AV6 and a 6C4 cathode follower (it'll be driving a 100k load). If the gain is too high, a 6AT6 can be swapped in.
4) Larger cathode bypass capacitors, because it's much cheaper in 2022

Also, how much of a difference would there be if I used a 22nF and 4.7nf caps for C5 and C6?

Any comments or insights will be greatly appreciated.

Hi! Trying to build a bedroom system with dual (2pcs) sealed, passive, down-firing subwoofers. Main Speakers would be KEF LS50 so would need dual subwoofers to complement them and would need suggestions on drivers and any tips on the build.

GOALS: I don't listen loud in that room so 75 to 85 db max volume is okay, I just need the lower octaves fleshed out. As far as f3 is concerned I can be very happy to get stereo audible 40hz.

Crossover: Planning to crossover the Kefs at around 80hz since it's down firing so localisation shouldn't be that much of an issue. Ill be using a minidsp for this one.

Here's the challenge:
I can only build out these dimensions per sub woofer : Height 4" (4.5" with rubber feet) x Length: 20" x Depth 15"

Do guys have any recommendations on:
1. Low Profile Subwoofer for this use with a mounting depth of around 3+" ? Ideal budget would be 175$ for both drivers but the upper limit is 400$ for both drivers.

2. A cheap AVR that can drive the kefs and the subwoofer to around 85db.

This is a sealed subwoofer or so I'd like to imagine, any other suggestions on the cabinet build would be welcome.

Thanks in advance!

Hello,

I am attempting to sell a QA401 Audio Analyzer by Quantasylum in nice and ultra-mint condition!
Since arrival, due to busy schedule, the QA401 here is used just for several times.
The QA401 I am selling is super new that I bout it directly from Matt in QA, every function is normal.

We are now in a severe semiconductor Crisis, and it seems it not going to relieve in a short time.
Many parts have incredibly long lead-time or prices.
So, I will just sell this out to invest other lab Test and Measure tools.

Send me a PM and We can discuss the price and shipment cost.

Regards,
Jen

Hi folks, I figured I would pick your brains to see if someone has some ideas.
I've been thinking about adding a subwoofer to help the main speakers and add a little more bass (music mainly), but I'm unsure what route would be best.
My current amplifier has 2 (balanced) outputs from the DSP, but they are on two different DSP boards and can therefor not be summed there, so I need to sum Left and Right before the amplifier (if I would add two subwoofers later to eliminate room modes I would still want them to play the same).
I don't believe I need much power by the different subwoofers I've simulated, 200W seem to do it, if it's more then of course it's not a problem.
I might end up with a driver that has 4Ohm load, and accounting for a slight dipp bellow that is probably wise, so 3Ohm stable (?), but I guess I could find a driver that's more forgiving.
Is there any good options/solutions out there for DIY? Something that will make it as 'user friendly' as a plate amp that has two low level inputs.

Thank you in advance.

Hello any advice would be greatly appriciated, i hVe just bought 2 elx118p subs and 2 ZLX15P tops. Can anyone tell me about the mic/line faderon the speaker do we put that quite high and the alter the master on the speaker? With regards to the subs do we setthem to around 120hz and on Boost for live show. We also use the allen and hearh wz3 16.2 s desk, so subs chained to mono and tops to left&right or from desk to top then link down ro sub each side. Any advice would be great thank you

I recently built a Class D amplifier from the ICE modules offered on Parts Express. Very nice amplifier but now I want to move up a step or two. Who sells a complete Class D amplifier using the lasted Class D technology. Want to keep it under $1000. Thanks

Ok I searched this question has not been asked.
Im keen to get my REW system fired up and am on the look out for the bare min / cheapest calibrated mic.
I've given up on trying to build my own setup.
The two options Im looking are the Sony ECM-AC2 for 29$ on amazon.
The other option is the Dayton Audio iMM-6 for about 24$
I got all the parts to build my own. Like a 2 pin mic and some opamps. But calibrating sounds daunting.
But then on another post I was told to get a mic with phantom power, then to avoid USB.
My application is very simple freq res tests to see if the graphs supplied with drivers is accurate or not. And to get the data when they are not provided.

This enclosure has a unique construction and does not use sound absorbing materials.
Compared to enclosures of other structures, it produces a unique sound.

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A friend of mine gave me a pair of very nice output transformers he has had for years, and I am trying to figure out the windings and impedance ratio and such, he says they were for an SE 300B or similar, and I could use some guidance to figure out the output windings.

I spent a few hours today driving the xfmr with a sig gen and measuring the output on my scope. It's not a normal secondary winding with the usual 4, 8, 16 ohm taps, it's 3 separate identical windings. I connected my sig gen to the primary winding, put in 40 VAC @ 1KHz and measured the following.

Each of the 3 output windings gave the same result, .75VAC out each. I tried connecting them all in series and made an LT Spice diagram so it's easier to see what's going on. The 300B SE could be anywhere from 2K to 5K plate load depending on plate volts and anode current. The measurements seem plausible but I could use some help to determine what I really have here. My ultimate goal is to scratch build an SE 300B with minimal driver stage, maybe xfmr coupled, not sure at this point, I'm working my way in from the back end. 😱 My speakers are Big Reds, 16 ohm. The turns ratios I came up with gave me what seem to be correct results for the 16 and 8 ohm windings, the 4 ohm seems way off. I won't say any more as I don't want to influence your thoughts....

Attached is the diagram I made of the transformer and AC measurements @ 1KHz. Ignore the Lx desinations, I couldn't figure out how to delete them in LTSpice.

Any help, much appreciated.

Cheers

This amp came in with IRFZ44 PS fets and 47ohm gate resistors blown in the PS.

On the output side; Q506/Q507 IRF540 completely shorted and the 100ohm resistor very close to the MIC 4427 crispy but still reading well.

I replaced that 100ohm resistor, all 4x IRF540 with IRF540N, and put a single IRF3205 into each PS bank.

Amp powers and plays out of the sync briefly under 4-ohm load to about 10 amps draw.
Seems like it might be OK but I dont really know these amps well enough to verify full operation just yet.

On the 540 vs 540N, seems parts for 540 and 540A may be scarce which is why I installed 540N for right now. The only 540 I am reluctant to try are the expensive Vishay brand.

Any pointers on what else I might need to check next? If the IRF540N are not suitable are there any suggestions? I read the entire JL 500/1 page but there seems to be a LOT going on with these which I am now trying to get familiar with. I usually pass on servicing JL but alas here one is.

Thank you

Since the Raspberry Pi folks are still having production issues I'm entertaining ordering a competing product to tinker with. Has anyone done a shootout or at least compared the boards first hand. This will be used as a streamer and whatever I get will likely be overkill from a power standpoint, and that's fine. My pi4 is several years old and will one day be repurposed for something else, so I don't mind having more horsepower than I need for a given application. Things I'm curious about...

Does one company have an edge on board power management (less noise)?
Does one company have an edge on USB implementation?
Does one company have an edge by using a better clock or a better implementation?
Not necessarily looking to get into a discussion on why these things do or don't matter. The questions are what they are. Some of the manufacturers I'm looking at include:

Pine64
Odroid
Khadas

If you have any specific experience with something you liked, I'd love to hear about it. My current plan is probably DietPi or LibreElec. Also open to personal experiences there. The end goal is to install Roon bridge. Thanks in advance.

After the great success the first version Quanghao opens a new group buy to produce a new series of DAC ES9038PRO:
[URL="http://quanghao.com/product-es9038-pd94325.html"]10th birthday anniversary[/URL]

Es9038 PRO DAC - Design by Andrea Ciuffoli-Quang Hao

• Based on the ESS Sabre32 Reference (ES9038PRO) DAC chip
• Support 44,88,96,192,352,384KHz PCM and DSD to play SACD ISO.
• Full ground isolation from USB module
• On board reference 100MHz Crystek oscillator with a jitter of 0.5psecUltra fast oscillator buffer

Output: Stereo balanced output impedance: 202 / 4 = 50 ohm
DC-ouput: +1.65VDC.
Output impedance: 100 Ohm.
Output: 2-Channel (stereo) outputs can be used in current-output or voltage-output mode
(depends on output stage used)

Input: 4 inputs:
1. USB -match with Amanero USB (not included). Have pin I2C for other USB
2. Spdif
3. AES/EBU.
4. Optical

Digiltal supply:
1.2V core: LT3042
3.3V oscillator: LT3042
3.3V digital: LT3042
3.3V Top-botton chip
3.3V USB: LT3042 (If you not like us 3.3v from Computer for USB)

Analog supply:
1.2V analog (left and right separated): LT3042
3.3V analog (left and right separated): LT3042
5V for LCD: LT1117
5V Analog supply: LT1117
5V Digiltal supply Digiltal supply: LT1117

Controls and features:
1. Standby mode.
2. High volume display.
3. 20 x 4 LCD display.
4. Select the 4-way input and display the frequency on the LCD screen
5. Fuse protection - 220 VAC power supply / 5W
6.Turn on, off with remote control or buttons.
7. Simple and appropriate use for DAC chips: ES9038PRO, ES9028PRO.
8. Set up customizable protocols such as: volume, input as you like.
9. Select modes such as filter, frequency, left channel right.
10. Special and unique - Store settings according to your preferences:
A, Keep the big picture to the desired: lowest -100dB, largest 0dB.
B, Select and store left or right channel output - No need to reverse the output.
C, Selectable filter modes: (Pass band): 47kHz, 50kHz, 60kHz, 70kHz.
D, Option: PCM Filter Characteristics
E, Selectable filter modes: (Pass band): 47kHz, 50kHz, 60kHz, 70kHz.
F, Option: PCM Filter Characteristics: Fast, Slow Roll-Off, Apodizing, Hybrid, Brickwall.

On-board DAC ESD9038PRO includes:
1. ES9038PRO chip.
2. Clock 100MHz CCHD-575, Ultra-Low Phase Noise Crystal Oscillator.
3. All Input connecters, Amanero USB (not included)
4. All low noise Lt3042
5. LM1117

Use: it is simple and need:
1. Transformer 15VA to 25VA: 2 x 6 - 8VAC: Talema 70050 or Talema 70060 Or equivalent
2. Use LCD Control board off Andrea-quanghao for ES9038PRO, ES9028PRO

This options are available and here the new cost:

1) DAC module assembled and tested with all components:
- ES9038PRO chip,
- CCHD-575 Ultra-Low Phase Noise Crystal Oscillator: Ultra-low phase noise CMOS oscillator provides 168-dBc/Hz noise floor | Electronics EETimes
- 7 x LT3042 linear power supply regulator 1uV noise
- 5 x LT1117 linear power supply regulator.
- All input connectors
- BUT NO OUTPUT STAGE
price 400$

2) DAC controller- Encorder + 4 x 20 LCD:
see video for LCD: https://www.youtube.com/watch?v=4owu...ature=youtu.be

• 20x4 LCD
• Infrared remote command
• Remote silver
• All connectors

price: 150$

3) Amanero module
Please purchase from: : Amanero Technologies

4) Transformers, for the DAC: 6.5V x 2 / 15VA
price 30$ each

5) Chassie: include: weighs: 10 kg
- 1 x chassis, iron powder coated black, size: 420 x 380 x 86 mm,
- 1 x front surface silver anodized scratch: 430mm x 92mm x 10mm.
- 4 x rubber feet: 20mm high, 50mm wide
- 2 x aluminum knob 26mm x 38mm
- 1 x Plug + switch
- 20 x copper base 10 x 3 mm
- fasteners: catch the front, the back, motherboards, storage tank foam.
price 150$


Shipping by TNT:
A. The options : 1 to 3 : 60$ ( the same price)
B. The options : 1 to 4 : 75$ ( the same price)
C. The options : 5 : very heavy, calculated separately for each country.

This project is a great DAC, I want to share with you,
However, I need your help, let me do it!
The minimum required number 15 set: DAC+ Controle DAC
I started producing.
Payment: half the amount for the selection, the remaining amount of money + shipping payment before shipping.
Payment by paypal: quanghao168@yahoo.com.vn
Paypal free: 2%.
Note: Because this is a shared project, and need money to produce,
Therefore, you have paid half of the money for the project will not be allowed to get back the money - this is a mandatory provision of this buying group!

One-year warranty.
You send me back defective products and carrier billing yourself.
I return it to you and I pay for shipping to you, after you're done!

And what chip ?

Today is the anniversary of the first public demonstration of the Edison cylinder phonograph!

It was invented a bit earlier but as mentioned the first public showing was down in an interesting manner.

https://en.m.wikipedia.org/wiki/Phonograph

I'm looking for Boards for pure IV ess dac (quanghao)

Thanks

Ages ago I bought on eBay a Kenwood LM-07 Mk11
It died an inglorious death but I have been hanging on to it.
I just started to disassemble it and found NEC capacitors A1007A & C2337A and not the high speed originals so it had been rebuilt at some point before I bought it.
I am assuming that all the T0-3 on sale from China are clones [ to put it politely] but I am wondering if there is anything I can do to reuse the chassis as it really is a work or art in some respects

SB12NRX25-08 4" woofer and SEAS Prestige 27TFFNC/G 1" tweeter. You can see it was a little windy today reflected in the low frequency response. Volume for woofer is a tad under 2 liters. Tweeter is just setting between strips of open cell foam, but I have determined where it will sit in relation to the front edge now.

No wires will exit the rear in the final speaker, they will be active and wireless stereo. Building a base to house the amps and power supply is next. I turned all the pieces by hand on the lathe. The wood is Spalted Maple with all kinds of worm holes and bug tracks, I could stare at it for hours lol. It has all been molded with extremely hard epoxy before turning, and is generally 3/4 to and inch thick. I wanted the effect of blowing through the wood and seeing into the speaker in some spots, very happy with the result. More layers of epoxy will be dumped over it before it's finished, definitely not going to leak anywhere lol
Crossover is 18db/oct Butterworth at 1800hz on the tweeter and 24db/oct LR at 1600hz on the woofer. The resulting acoustic crossover point is 24db/oct at 1500hz. These measurements are at 50 inches. Only the measurements at 150 and 180 degrees have a significant dip, and up to 60 degrees off axis it is practically omnidirectional up to 5000hz. The VituixCAD data is for 0-180 degrees.

I'm sitting between them in the nearfield on my shop bench as I write this and thoroughly enjoying it.

My ribbon drivers for headphones

Hi all,

Greg Ball has decided to release the schematic and BOM to the public.

http://www.ska-audio.com/Forum/YaBB.pl?num=1370063142

I have one and still really like it. Small tweaks have evolved over time over at the SKA forum.

Stu

I put a pair of Alpair 10.2 in a repurposed pair of cabs from an old pair of B&W DM100 speakers.
They do make pretty decent bass, but the mids ended up 'shouty' sounding. There was too much midrange; they sounded far too 'forward' and 'aggressive'. Not horrible, but noticeably off.

I have a collection of 30-some odd years' worth of speaker chokes of various values, and a decent selection of 5W wirewound resistors. I read up on baffle step compensation networks, calculated a ballpark set of values, and wired them in.

After experimenting for a few days, I wound up with a 3.3mH choke and 10R resistor in parallel, placed in series with the + lead from the amplifier to speaker + binding post.
The - lead from the amplifier is connecting directly to the speaker's - binding post.

I used two pairs of speakers I have as references, and tried to get the Alpairs to sound as close to those speakers as possible. (The other two speakers are JBL Studio 530 and Snell E/III.) I got close enough to where I'm now happy using the Alpair 10,2 speakers as my nearfield PC speakers.

My question is, do my BSC values sound in the ballpark, or am I making a mess of things?

Hello Guys hope you are doing well.

I got a pioneer gm-201 and I'm trying to make a cable to connect it from the din 8 pin connector to a newer eclipse cd8443 head unit. I've seen the schematic on the manual and signal are pin 2-5 and 3 is ground they go to the RCA from the head unit
7 is illumination goes to +12?
4 is mute. Maybe to mute cable from head unit or unconnected?
But I'm confused with the swd and unswd cables pins 1-6 . Where should they go?

Please any help would be appreciated

I have for sale a Firstwatt F3 board, completed and in perfect working condition. Worked for some 30 hours in total. I will include a pair of the llu and the power IRFS as spares.

The price is 100EUR + shipping and paypal fee. The boards are located in the EU.

First I must note that I'm new... So please excuse some possibly obvious mistakes🙂

My problem is as follows: I'm in the UK and hoping to build a sub for my secondary system, I'm having trouble finding components at prices that don't end up as near as "might as well not risk it" to a sub I'm already running on my main system which I'm more than happy with.

Having bought a nice new system (speakers/amp/dac) for the bedroom, it needs a subwoofer. It's nothing high end, but in many ways betters my downstairs "main" system - So I don't want to do it a disservice by partnering it with junk. This is a music system. If it can handle music as I'd like it too, occasional movies will be no trouble. I'd love to build my own subwoofer if I can make it financially not-silly to do so... I enjoy building things, but parts seem rather expensive.

The crux of the matter is this: I've got a BK XXLS400 and some DSP in the front room doing a wonderful job, and I'm having trouble figuring out a driver/amp/box pairing that would out-do the equivalent B-grade BK. Now, I'd be happy with a XLS200 for this new system (£315). But when a XXLS400 is £410 and shakes my window frames when needed while being quick enough to blend in well enough for my ears, it's a tough sell. I've heard subs that do some incredible things, but this is a home system, my expectations are realistic.

As an exercise, finding a driver that models how my 400 performs on my main system, then looking at the price of plate amplifiers to power it, I'm left wondering how to get anywhere close.

My hopes are thus:
-I'd like bass down somewhere into the 20-somethings. Basically I'd like to be able to play The Mountain Will Fall by Dj Shadow without having to imagine the low notes.
-It doesn't have to be loud, but it has to be quick and deep (enough).
-I don't mind if I have to make the box a reasonably daft size/shape, but this isn't a dedicated hifi room.
-As mentioned, I can tame the room with DSP.
-I would quite like a plate amplifier on the back powering the thing. That's not a deal-breaker, but it'd sure be nice having all the right controls in what I consider the right place.

Is that possible for a novice builder, when I suspect the XLS200 at £315 (or worst case the 400 at £410) will do me well enough?

I can't seem to model anything that gets close - but then I am a beginner at this driver/box modelling stuff.

Thanks for reading,
J James.

I made a PCB for Bourns EM14 optical encoders.
This board is compatible with the MUSES 72323 volume control made by Meldano on this forum.

One board is fully populated and is working perfectly, I have one spare optical encoder.
Encoder type is: EM14R0D-M20-L064S
I moved from the ALPS to these Bourns Encoders as I had bad luck with the ALPS going bad pretty fast, the feeling when rotating the Bourns is from a much better level as well.
Reason for sale is that I moved from 64 to 32 PPR. 64PPR was about 1 full rotation to get from 0 to full output in my system.


As you will notice on the pictures, a 78L05 is installed to take care of the 5V for the encoder. I'm supplying this board with 12VDC, offcourse 15V is no problem either.
The 3V3 is not needed for this board to function.
The circuit is based on: https://www.diyaudio.com/community/threads/muses-72320-electronic-volume.220792/page-27#post-6419562

Populated board + spare encoder = €50 excl shipping. (this is lower than the price of the 2 encoder together!)



Any body interested? I will only sell both items together.

Had a bit of spare cash (rare these days) so looked into buying a better 12th gen processor.
I bought a 12400F but found it doesnt have graphics onboard.
So decided to go for 12000 series but with graphics and something a little faster.
The 12600k works at 4.9GHz and takes about 125 watts max.
I also looked at 12900k 5.2GHz but that takes up to 250 watts max !
So for 300MHz more it needs twice the power !
So went for the 12600k.
Seems to do the job well for what I need it for, mostly PCBCAD work and software development.
The 12900K is also about twice the price of a 12600k for not a big difference in performance.

Hello

I Had this non-working Sony TC-K850ES cassette deck in my shop for some time. A customer who was interested in this model messaged me to buy this. I restored the deck with original genuine Sony Pinch Rollers, Belts and an assortment of gears for the mode encoder mechanics. Replaced the SMD capacitors on the direct drive board and replaced the Standard capacitors on the motor controller board with Nichicon Fine Gold. After restoration the deck records and plays back as intended. The head was in good condition despite it being permalloy material. The deck has Nichicon muse in the recording and playback chains. A solid built machine

I noticed the deck was using some outdated op amps and a low grade 4066 chipset which downgraded the sound quality potential. I went ahead and replaced all op amps in the circuit with Texas Instruments NE5532P and the 4066 upgraded to the ANT4066B. A significant improvement now in recording and playback. Much better than the original state

I added the original advertising stickers specific to this deck as a finishing touch

The deck is now complete and with the new owner.

Hello,

I have for sale my modded Aleph J pcbs. These were just pulled out from the enclosures and replaced with an output stage similar to the F4.
The pcbs were come from Peter Daniel.

The pcbs have the aleph ccs resistors and the mosfet degeneration resistors replaced with a lower value, 0.33r, which gives higher bias current, 1.6a/fet.
The ccs that biases the front end is replaced with an tl431+bjt ccs.

I used the pcbs as monoblocks with 30x16x4cm heatsinks, having 2 mosfets on one heatsink(4 heatsinks in total).
The heatsinks were sitting ~30c above room temperature.
The power supply voltage was close to 22.5v.

All caps onboard are elna bypassed with ero.

The mosfets and the teflon isolators were cleaned.

I am attaching a few thd measurements.
My speakers are a bit inefficient at only 87db and also low impedance, 3.4r. This was the reason of needing higher bias.

Price SOLD

I have a pair of magi 3.7i and would like to convert the crossover from serial to parallel.
So I can bi-amp them and play around with better parts.

From the schematic it looks like, and I am guessing 😊

12 db on the tweeter
6 db band pass on the midrange
6 db on the woofer

Am I right?



Found the schematic here http://www.integracoustics.com/MUG/MUG/tweaks/neolith/
I don't know where I can find neolith so I hope it's okay to use his material

I have far too many projects either on the go or waiting to be picked up so I'm going to cull some.

A set of PCBs and matched LD1014D FETS, courtesy of Nelson Pass, for a clone of the First Watt F3 amplifier. Purched via a GB here on DIY Audio, details here;

https://www.diyaudio.com/community/threads/f3-clone-board-set-group-buy.373750/

I have:

2 x amplifier boards
2 x output boards
2 x PS boards
2 x LED boards
2 x XRK mpunting boards for LD1014D devices

The LD1014D devices were a gift from NP to the DIY audio community and I'm not looking to make money on them so the cost is just to recover my investment in the PCBs - looking for £25 plus shipping at cost.

Hi to everyone,

i wanted to share a project i was working on for a while. These speakers are a clone of the concept utilised by the german company "ME Geithain", which famously supplies the german state broadcast. The company is located in the former East Germany and the boss Joachim Kiesler was building speakers behind the iron curtain using technologies such as waveguides (RFT BR25/BR50) and line arrays (Geithain ITS50). The first quasi-coaxial speakers (Geithain RL900) also originated back in that time and were first supplied to East german Broadcast and opera houses. These were utilising classic bass-reflex enclosures with the addition of the cardiod version in the early 2000's.

The goal of this project was, to understand the influence of different damping materials as well as port size on the directivity of the woofer.
In the future, i want to compare the quasicoaxial arrangements to more traditional 3-way setups with a large dome and cd-horns.
But first, more about the current setup.

The tweeter is a Dayton ND25-TA which works fine for the job. Seas 27TFFNC/G would probably be better, but i was a cheapskate.
The midrange is a Faital 3fe22 without enclosure but damped with a basotect ring around the rear.
The woofer is a Transfer Audio AR 25. Again Seas L26ROY would be better but i got these for 30€ a piece and they have an xmax of 9,5mm one way.
The crossover is done using EqualizerAPO so there is only one D/A conversion.

Crossover is at 800hz and 3,5khz resulting in the characteristic dip in the directivity index between 3 and 5khz. This will also investigated further. ME Geithain has an in depth understanding of speaker directivity but decides purposfully to put this dip in the directivity index.
the enclosure meassures 33x36x25cm and the rear port equals 135cm² (1/2 Sd) At the moment the damping is archieved by stuffing the eclosure with rockwool but in the future i want to switch to dense polyester damping material. I will post meassurements of the enclosure with and without damping material next week. For the general size, there is a great excel file on Linkwitzlab which calculates the bass roll-off as well as the resonances which occur at the back of the speaker an need to be damped.

​

As title says I did buy this eBay DAC board and associated enclosure from along1986090. Used my transformers.
CS4398 with CS8416+CM102s, provides coaxial SPDIF and USB inputs.
First impressions:
Enclosure definitelly well done, with (almost) all necessary hardware, holes in exact locations to match the board. Kind of long (10", plus 1/4" front aluminium plate), I guess it can be used to add a dedicated headphones amp.
I did buy the pre-solderd board. Inspected with the magnifier glass showed an OK grade of soldering. PCB is in filled ground technique and parts are like shown in the picture.

Initial tests had a sligtly distorted signal and analized with my E-MU1820m showed a really bad signal. I did replace the 5532 that was on board with LM4562 that I hade around and everything started to look better. I suspect that the 5532 was either a fake or a damaged exemplar. There is no capacitor or resitors on OpAmp outputs, so it is easy to be damaged.
At -2dB looks decent. The output stage overloads my ADC input at higher than -2dB (all the other DAC's that I tested didn't manage to do that).
The output stage is not done per recomended schematics in the datasheet.

USB input:
CM102 locks only onto 16bit/48kHz signals. 16bit/44.1kHz is not supported in Windows7 mixer (WASAPI).
If looses the connection with the PC, static noise is outputted till the next power off/on cycle. The automatic switching could be done better I guess...
Altough in Win 7 there is no need for drivers, here is a package that provides a little more that basic USB. This driver looks like it does the resampling to 48kHz automatically.


Coax SPDIF:
Locks on 44.1-96kHz, 16 or 24 bit. I don't have a SPDIF source capable of 192kHz to fully test the CS8416.


Using Foobar with resampling to 48kHz would allow USB connection to work at any rate, but I do prefer the coax.

All in all, sounds decent, especially for the price. THD+N with LM4562 is at -94dB. OpAmp upgrade is strongly recomended and looks like some of the AC grid noise could be reduced by better filtering.
Direct coupling of the outputs leaves some higher levels of 10Hz noise creep into the output chain as seen in the coax graph (at USB I forgot to extend the range below 20Hz).

The seller give the schematics (at my request).

I came across 6 of these planar drivers. From the very small amount of info I have found, they look like they would make for a great OB speaker. Does anyone have any data on these? I have found very little. Thanks for any help...

https://headwizememorial.wordpress....e-ended-otl-amplifier-for-dynamic-headphones/ I'm interested in building this amplifier, but I'm unsure of the power supply circuit. The transformers are quite expensive and aren't readily available in europe. Is there an alternative power supply I could use? Is any 150vdc power supply suitable?

I brought this around 25 years ago (sn#12)when I had a second home in the country as the power was horrible and all over the place (105 to 127) and noisy
It died around a year ago and sadly ps does not fix it and offers a discount on other stuff
Around 10 years ago after hurricane ida the damage up here was really bad and I fought the power company and got my own pole and transformer ,it's been fantastic
So instead of salvaging for parts or dumpster contenders,I thought a simple 60 hz signal generation to an amp to get 120 v out
Am I dreaming or is it possible as it's just a ac generator
Thanks

Hello everyone, I was watching Erins Audio Corner a few days ago with Dr Geddes as a guest and he briefly mentioned group delay and used BMR drivers as an example, then said no more on the subject. I became very interested in the tectonic 2” BMR after reading Erins shining review. It seems like the ideal driver for my tastes as I can’t really hear sparkle (I’m 41 as of today) and the frequency and polar response are stand up, which is much more important to me.

But, I worry now about group delay distortion smearing in the time realm. I imagine that the sections resonating semi independently might take enough time in relation to the higher frequency cycles to matter where we’re very sensitive. Would anyone care to share their understanding of this?

Some might be tempted to point out that if I have to ask then I obviously don’t notice it even if it exists and it doesn’t matter then. The thing is years ago I didn’t know about the stereo illusion but now I do, and it matters. There was a time when I didn’t know that my car door speakers were beaming and there was a major problem in the upper midrange response at the listening position, and that most certainly mattered. I wonder if the tradeoff for the wide dispersion is group delay as Mother Nature gives with one hand while taking with the other. Is this concern valid?

I very recently began designing and assembling a small stereo system from the basic components. Kabd amplifier boards, open frame power supply, raw drivers, ect. I chose a two way system with the BMR 2” not because I couldn’t implement a decent three way, but because I felt I didn’t have to with the BMR. If there’s a real problem with the BMR’s I’ll be looking at the RS100 or RS75 and one of the reference tweeters. There’s a chance I’d go for one of the other Dayton 28mm tweeters because of availability. I have some beliefs regarding crossover points that might be too careful but this can wait to be discussed under after the group delay thing has been sorted.

My bookshelves currently have the Tectonic 2”, Anarchy 704, and RSS210 passive radiator on ~60w and 15w respectively. I’m really happy with the result but I want to make sure I’m not missing something that once I perceive it it’ll bug me ferociously. Btw is Erin @bikinpunk here? He’s Erinh on diyma where I’ve basically learned everything I know.

I'm temporarily going back to my Thorens TD160 turntable, in order to capture all my LPs in high resolution, cleaning the records from surface noise, clicks and pops at the same time. I have already done that with a friend's Luxman high resolution system, with V15 cartridge, and the results were fantastic.

The I proceeded, using Audacity, to clean the LP from all surface noise and eliminated all the clicks and pops I could find. Capturing at higher resolution, like 96KHz, would allow higher accuracy in the noise elimination. In any case, the files sound excellent. We still have to make a comparison between the original LP and the CD with the processed files and see how they sound.

Now I'm the process of building the RIAA preamp. This has been commented elsewhere, which generated a very constructive discussion, where I learned a lot, using LTSpice simulations to compare results from several highly regarded commercial designs.

The choice for the first preamp will be one using two FET ICs with a passive RIAA network between them. My idea is to use an existing RIAA kit sold by AliExpress, which will provide the pcb and some of the parts, then buying the ICs and some specific passive parts to substitute key ones in the RIAA filter.

My question is what to do with the very low frequency vibration, probably around 3Hz, that seems to occur apparently on all belt turntables. That's what I have been told it happens. My friend's turntable, where I made my first capture, also had them. Of course they didn't show on the captured digital tracks.

In my past turntable arrangement, I used a discrete two stage passive preamp, and the vibration was there alright. This preamp used a 470n polystyrene input series capacitor as high pass. To visually cure the vibration I had to lower the capacitance to 100n, which didn't seem to affect the audio quality.

Now I ask: should I worry about that? Can that low frequency intermodulate with higher octaves response?

The circuit I'm using now does not use an input series capacitor.

Does anybody have a 6P7S 6P7C tube spice Modell for pentode /tetrode