Looking for schematics, update tips, manuals, etc. for Sound Technology 3200B Analyzer and 3100A Generator.

I'm guessing these are pretty old ... late 1980's?
Not much at Sound Technology website: history

Anybody know anything they can share (Richard, Demian)?

thanks,
mlloyd1

Hi:

I did a Power Factor correction circuit using the on-line design utility from IRF.com.
I am using IR1150S chip and now my prototype is working, my goal is to obtain 1kw max. and for now I use a T130-26 toroid core stolen from a damaged PC smps for the boost inductor(too small) wound to obtain the required 270uH inductance.
As I did not find too much information about the type of toroid needed, I would like to know what kind of core material is better for this application, I am looking at 26 or 52 material types and maybe a T157 size would be OK.
Someone can give me advice on that?
I enclose my actual schematic.

Thanks.🙂

I’m working on this amp produces audio but is distorted with some DC offset 6.21 volts at the speaker terminal. I’ve replaced all 540/9540 in the channel still no major improvement. Thoughts on what else to check?

No cash, no paypal, actual swapping of items.

I mean most of have stuff we have and want to get rid of.

Most of us want to play and try different stuff.

I believe only the first person can change what is in a thread.

What if we had an open thread where a poster can change their post all the way out ?

That way we could all look at each others junk and swap for a castle.

We can add more things and remove them also.................

Hi. I need some help with an attenuator pad for a line level signal. I have a 5.2v source that I want to feed to a DSP-408, which has a max input of 3.2v. I was thinking of adding a voltage divider, but I don't know if that is the best way to go, or if it will affect the sound quality. I also don't know what type of resistors are good to use for audio applications and if it is better to use high or low impedance resistors. Any advice would be appreciated.

I have a pioneer 9100 that I would love to resurrect, but one of the issues is a broken volume pot assembly

The original has 2 gangs (two with a ground, six in total) with an additional two prongs coming from the bottom of each gang (what are these?).

I was able to retain the first part of the volume assembly and attach a new double gang pot to the back (keeping the volume limiter (0-30-60db), but I don't know what to do with the extra wiring. There are no pots available which have the same configuration as the original pioneer.

I took many pictures, and looked at the schematic, but I'm not sure what to connect/disconnect so that I can retain (at the very least) the main L/R volume functionality. Can you easily tell what the wires do by their colors?

The link is to a folder with some pictures of the pot. I also have some addiitonal photos if these aren't enough

Pioneer 9100 volume pot - Google Drive

Is this any good?

(stolen trademark removed)

What valves and psu would suit this. May be a bit of an ambitious first step into valves for me.

Hello to all,

I decided to make power supply for my OpAmp:
https://www.diyaudio.com/forums/analog-line-level/352814-hifi-preamp-lme49720-amplification-10x.html

Simple solution is to use L7815 and L7915. I checked data sheet, some schematics and this is the result. The stabilisers are having 100uV noise. Will the coils + caps reduce it well?

Thank you for your tips, tricks and thoughts!

Milan

I'm making my foray into creating a Beaglebone Black based music server. I'm powering the BBB off of a 5v power supply with what I think is enough juice - 800mA. I'm using the 5v power jack which is fed by my supply. When I turn on the unit via the Beaglebone doesn't turn on. I need to pull the barrel plug out and back in again and it powers up. I'm thinking of tacking on a separate power switch on to the BBB itself to see if this resolves the issue. Anyone seen this before and know why it happens?

Looking for a pair of the 30mA single-ended Lundahl LL2765 headphone output transformers. Let me know if you have or know of any for sale.


Thanks,


Jeff

greetings folks

I'm looking for input on how to design a mixer for 80 magnetic coil pickups.

I'm doing a project with a tonewheel generator from a hammond organ where I'd like to control the output from each tone wheel with a digital potentiometer.

I have a novice understanding of electrical signals, impedance etc so the first problem I'm trying to solve is how to sum multiple pickups without significant loss of signal.

My first observation was that I can connect a single pickup to a guitar amp and get a pretty good signal, then connecting a second pickup significantly drops the output of both pickups (due to the increased overall resistance as I understand it)

Can anyone advise on a passive or active mixer design for this use case (suitable for either a guitar amp or a mixer input)?

Thanks!

bought for s 3255 project ended up being the wrong model for the job.

$89.99 shipped esst coast

in open box new condition. only tested.

hello everybody.
I want to build a crossover from elliot sound products
(project 153 'Isolator' Equaliser)


and i need to match a power supply to provide +-15VDC 
i can’t choose if i should go for the p05-mini
(Project 05-Mini 
P05-Mini)

or the project 05 revision d
(Power Supply for Preamps)
the revision d has a optional muting relay circuit and first doesn’t have it.



overall they look similar to me (that’s why i can’t choose) but someone maybe has some experience with them or can give me some hints.



i want to build the crossover using the NE5532, they have max voltage +-22v but since i know, i can power the circuit using even simply -+ 12v isn’t?



thanks a lot for any help

Hi Community !

I build a new amplifier (Inspirated of F7 Amplifier /Thank you Mr PASS), but issue with it.
Noise (50Hz) on both channel when I plug the protective earth on the chassis.
Without protective earth ... Dead Silence on outputs.

After few mesurment ... Without protective earth connected, i've ~60VAC on the aluminium enclosure !
i've try to reverse 240V input plug ... same issue.


However, no electic contact between amp boards , capacitor bank , softstart , transformers, outputs or inputs AND the aluminium enclosure ... My questions :

- Why 60VAC present on my enclosure if no electric contact with other parts ?
- Why with protective earth connected i've a noise of 50hz on my speaker outputs (both channel) ?

I've try to disasemble the enclosure , and split the heatsinks with amp board to the power supply section ... and it's ok ... I don't understand.

Wiring diagram and photos

Thank you in advance for your help

L.S.,

I just bought myself a Audio Innovations L1 and a AI 800MkIII. I want to measure all myself and also set the bias for the four EL34/6ac7 tubes. Who can help me to do it. If there is a way to send pictures or a video, that would be most welcome!

Ton from the Netherlands

In both the ARC source (HDTV) and the ARC target (RCVR) ensure CEC and ARC are on.

1. Shut down and unplug both.
2. Remove the 18Gbps HDMI 2.0 cable from both ARC ports.
3. Keep both unplugged for 10-15 minutes.
4. Install the 18Gbps HDMI 2.0 cable in both ARC ports.
5. Plug in the HDTV first, then the RCVR. Don't turn either on yet.
6. Turn the HDTV and pick a source that has 5.1 or above surround sound.
7. Turn on the RCVR. The handshake should be complete and ignore the RCVR input shown.
ARC input overrides manual selection when the RCVR is turned on and ARC is present
at the ARC connector.
8. Choosing a different RCVR input at this time shuts off ARC until power to the RCVR
is secured. It is the RCVR power up software routine that on turns on ARC.
9. Once the handshake history is made it will remain until there is a power outage or
disconnect for several minutes. Repeat steps 1-7 if lost.
10. If either the HDTV or the RCVR gets a firmware update, you must do above steps 1-7.

Calling all high-resolution music collectors: What recording can we use as a test for tweeters with an ultrasonic peak? The Peerless DA25TX00-08 and the SEAS E0047-04 T29MF001 have resonant peaks at around 27KHz. Debate rages as to how audible this is at lower ranges:

https://www.diyaudio.com/forums/multi-way/322746-whoa-cool-tweeter-peerless-16.html

Thanks!
Paul FX

are the OB speakers need a large speaker ?
i have trial on my OB , used woofer 18 inch for get the vibration wave.
i build with small baffle H 57.5" X W 32" X D 18.5"

The Vintage Fostex speakers:
Horn : Fostex H550 and FD600
MId : Fostex F346 Laboratory Series 12''
Woofer : Fostex FW507 18''
Baffle : 2 piece Upper and lower from MDF and solid wood with steel 10mm
upper : MDF 18mm laminated
Lower : MDF 30mm laminated (18mm +12mm)



LINK : Open Baffle Speakers Fostex FW507 /Woofer 18" + 211 SE amp

YouTube

I am looking for a tube line-stage to do both impedance matching and volume adjustment.

I've read very good comments about Abbas Audio products. The problem is that their website is in Russian:

Добро пожаловать на сайт хорошей музыки abbasaudio.com

I translated using google but I didn't understand that much. I tried to contact the company both from website and their ebay writing simple phrases translated using google... but no answer!

Does somebody know their line stages products? I understood they do two lines stages

Abbasaudio, tubo preamplificatore, 6N6P + 6C4P (vicino a 6X5), guadagno 20db | eBay

Предварительный усилитель(Буфер) на 6Н23П(ЕСС88) - Предусилители и буферные каскады - Abbas audio

Although one is only available only on ebay, the other only on their website. Translating those pages from Russian I understood that these circuits are done as buffers/or output stages for DACs

I wanted to ask some questions that I report here just in case somebody has dealt with this:

1. can these circuits work as a usual line stage with a volume pot attached after for doing volume control?

2. I wonder what are the real sonic differences between the two.

I hope somebody has some piece of info on this interesting company.

Hi guys,

Although the amp is half tube, the preamp in question is solid state, so I'm posting here. 🙂

I'm trying to figure out how to safely add a "kill EQ" switch to the clean channel of this amp. In fact, I would like to use the "Normal/Bright" switch for this purpose, which is already there, because I never user use the "Bright" mode anyway.

So, which section of the signal path I should cut and connect to the switch?
Do I need the switch to be DPDT or i can use the current SPDT (which is the Bright switch)?

Any help will be greatly appreciated!

Here is the full schematic:
https://drtube.com/schematics/musicman/rd50a.gif

Side question: can I safely bypass the whole preamp by plugging directly into the return of the reverb tank and use the Reverb pot as a "master volume"?
Or, can I safely use the reverb connectors as Send/Return and the Reverb pot as Mix?

Just discovered this site via a drummers forum, figured there will be a lot of good information here! I've played drums and guitar for a while and I've recently become interested in building speaker cabinets. No doubt there is some good knowledge to pull from here. Looking forward to learning!

Ces741 amplifier is very successful.
Its assembly is very important. I cool the drive transistors separately. Need to connect the bias transistor to the main cooler? Or should it stay idle?
Video test :
YouTube

This Walky Talky powers on but that's about it? Does anyone know how to fix these things? 😀

I use ffmpeg but not efficient enough and the cpu usage only use 1 core
Is that any other software or command line exe that can extract audio from mp4 as quick as possible and use more than 1 core?

While fixing an old Luxman tube pre-amp (CL-32) I noticed that the turn-on delay relay was not working (the relay was going immediately on/off with the power supply), so I checked the semiconductors on the little board and found 2 bjts and this zener faulty.

The zener was marked W054 but, finding no info about it, I guessed it could be a 5.4V zener (I discarded the 54V idea because the bjts are rated 35V).
Putting a 5.6V zener at its place made things work again, but I wonder if I used the right component.

Can anyone help me?

Cheers

Andrea

I have read many specification sheets for speaker drivers from various manufacturers and they all list some measurement of the driver's power handling capability. The most common way of defining this parameter seems to be the listing of two wattage measurements: RMS and Maximum (or Peak). RMS, as I understand it, is the measurement that defines the watts that the driver will tolerate in an extended period, while Maximum defines the watts tolerated in an instantaneous peak. Some companies deviate from this specific terminology but still present the same measurements---Seas, for example, lists "Short Term Power Handling" and "Long Term Power Handling" which clearly refer to Peak and RMS respectively.

But what is to be made of the Peerless/Tymphany "Rated Noise Power"? All the spec sheets from this company that I have read list this parameter, and the web site shows it referenced to the IEC 268-5 18.1 standard. What does this number represent? Is it RMS wattage? Is it peak? Is it something else? I am hoping that a more knowledgeable member who knows for certain what this number is can clue me in. Thank you.

I recently purchased a pair of Model Ones, seem to work beautifully but am wondering if upgrades are in order.

Below are some pics of one interface. Looks original to me. Is it?

Also below is a pic of the pc board, albeit a newer version I believe. Is this readily swappable into my setup?

I do have a schematic of the MK-141 but does anyone know of a parts list for modern parts?


Of course, any suggestions appreciated.

Thanks.

hello guys here we go again. I'm trying to calibrate the bias currents of a marantz pm 80 bought today at a old market with some outward sign but at a good price.
The service manual show to calibrate Class A to set trimmer to 198mV but coming barely 70 mV in Class A. Mistake some step? should be shorted inputs? I use all 4 points tp? No signal 1khz to test? Thank you

Hi,

Assembling my 500ASP amp, I am a little confused on where and how wire the ground/earth. According to the amp's manual, the 3 pin input connector on the amp (earth, line and neutral) goes to the mains IEC connector.

But, what about the earth pin in the IEC connector? It goes to the chassis (unpainted part) and also to the amp's earth connector?

Also, I am using balanced input... and according to the manual the pin 1 of the XLR input connector is also connected to the chassis. Is this correct? Or I can omit the use of the "fourth" pin on the XLR input.

Any help would be greatly appreciated.

PASS B1 board plus 4 closely matched 2SK170 BL JFETS. Condition is new. Purchased for B1 build but no time.£20 plus postage.

Hi.Finally i cut birch ply sheets and ready to make the sealed enclosures of SB34 woofers.I will make side firing woofer because of WAF.When i simulate on hornresp there is almost no difference when put SB34NRX75-6 on top and near middle of the box(when stuffed with polyfill).
But i do not know how to measure the needed distance between the drivers.Should i measure between the fullranges middle point to subwoofers middle point?Because of SB34 are big it can not be very close to fullrange boxes.Which crossover point you suggest?340Hz too high?I already have aucharm 4inch fullranges which i like the sound but i also want to try fountek fr89ex and 3 inch fostex too in future.So i want to make crossover point as high as possible.It may also reduce distortion of fullranges i think.

Help pls: DLCP+NC122MP+DLCP SMPS: Standby and eliminating powering down pop

Hi everyone, I would like support from this forum regarding this. This is my very first DIY build and I have very basic electronics / electrical engineering knowledge which includes limited exposure to associated terminology.

The setup is as follows:
1. DLCP
2. DLCP SMPS
3. 3 units of NC122MP

Objective:
1. To eliminate popping sound from speakers when switching off power mains. NC122MP and DLCP SMPS currently connected to a single power bus.

2. Putting DLCP on standby and thereby placing all NC122MP on standby.

What's missing for an easy solution:
1. I do not have and do not intend to get the DLCP controller board and the remote.

What's been done and thoughts so far:
1. emailed Hypex - Quote

"The standby state of the supply (and thus the DLCP) can only be controlled via the button on the control board. If you don’t have one, the only way is to disconnect the Supply standby pin from the DCLP (and possibly the standby voltage, too) and control it externally.

Also note that the NCxxxMP range is not compatible with the DLCP. The PS_enable pin works exactly opposite of the Supply standby pin. So you’ll be needing some external circuitry to make this work anyway."

2. Making sense of datasheets. I understand that the logic states for amp enable / amp mute between the DLCP and NC122MP is not compatible.

Thoughts:
- Do I need to create a logic inverter to make standby work?
- Should i just use a mechanical switch between pins NC122MP J6.3 - J6.9 to deactivate PS enable. How would this same switch tie in to the DLCP to place DLCP in standby?
- Can the DLCP be the main point of standby control for all the amps?

3. Eliminating pop
- Would activating standby modes automatically eliminate the pop on power down?
- Does the amp need to be muted first before power down?
- Can the amp enable pin on the DLCP J10-15 pin 3 be made to work with the NC122MP?

I may be thinking about this totally the wrong way with the wrong lens.

Any advise appreciated and thanks to all in advance.

Best regards
Fai

Trying to build a lamp bulb tester but been around every store possible in Helsinki area (and north of Helsinki) and don’t find anything else than LED lamps

Is it possible to buy a flood light (that usually see in construction) with either 80, 250 or 500w tubes? Those are incadecent bulbs i think right ?

Is it possible to get higher wattage bulb by serie connect say 2x80w to 160w?

What does the Pro’s say here?!

I'm trying to identify this Schottky Diode.

I haven't found a data sheet for it.

But did find a diode chart on line
that displayed the color code for Schottky diodes
or maybe it was diodes in general.



Doing the diode check with my HP34401A meter
one way was open
the other way gave me a 605 ohm reading.


Here is a close up pic along with the colors.


Cheers,

I think of swapping old sencore lcr bench for new portable meter.

Criterias :
- 4 points testing
-usb transfer included
- sigrok support
-correct price

any advice ?

Picked Up a New Zealand Made Holden 100 reverb, anyone got a schematic.


also out put tubes say 6C50 on top made by raytheon look like kt88's any info on these? can't find on google.


cheers

Noobie looking for advice on first speaker build.

After significant research, I have decided to build small 3 way speakers for my 14x14 bedroom. I have narrowed my search down to the following 2 speakers:

Phiharmonic Audio BMR speaker Kit - Meniscus Audio
The Travelers Loudspeaker Kit - Meniscus Audio

Is there anyone who has heard both of these speakers? If not, does anyone have any advice on how to determine which will be the better speaker?


My current (but possibly incorrect) assumptions on each:


BMR: Perhaps better sounding RAAL tweeter on axis, but much narrower sweet spot. Premium 7" Scanspeak woofer is great, but will probably not match the 8" woofer in the Travelers. No idea what to expect from the BMR mid in comparison.

Travelers: Wider tweeter dispersion with the 3/4", but maybe not a nice sounding on axis? Better bass with the larger woofer and cabinet. Again, no idea how the mids compare with the BMR

The key is how the mids and highs play together, but I just know how to wrap my mind around the differences in each's sound. Thanks in advance for any and all help!

hello,

due to difficulties to find a decent curve tracer, I focus on a quick way to match power transistors.

I found this circuit
Matching Power and Driver Transistors

Any links or advices ?

Hi folks, just wondering how to properly use a scope to setup the turntable parameters. Anyone here do this? I have the Analog test disc with the 1khz some wave, anti-skating tests, resonance frequency test, channel separation...
Cheers

What horn would fit the BMS 4595ND-mid compression driver?

Also, any recommendations for a tweeter to pair with this driver? First one I've looked at is the Beyma CP12n.

hello someone will take a photo to help me rebuild this part

Nazar's Dual Mono Headphone Amp

///

Anyone know what power supply fets this amp takes or that I can use ?

The original ones are burnt and the only numbers I can see appear to be BN7112

Also does anyone know what outputs belong in this amp ?

Hello everybody fellow enthusiast,
I need some help for my recent purchase, a long time dreamed Threshold S500 series II (not a optical bias version).
Actually it works, or better, can properly switch on but the maximum volume is very low driving a pair of Tuscanini Idillia speakers that are almost a full resistive load of around 6 ohm and 85 db of sensitivity. The difference using my other amplifier, a McCormack DNA-2, is huge (same source, same pre amp).
This issue is present since my first use, I have had this amplifier for just one month.
Now, I'm aware that the DNA-2 has 300w/ch at 8 ohm, gain 30db, input sensistivity 1,5Vrms against 250 w/ch for the S500, gain 26,6db, I don't know the sensitivity, but all above considered for sure something in the S500 is wrong.
I checked all fuses and are ok.
Any suggestion to fix this issue will be very appreciated.
Maybe Nelson Pass could intervene here?

Thank you in advance to everyone that can help me

Scrapped guitar amplifier project and this one I have no use for. Asking $20. Brand new.

I rarely run across instances where the clamps are not installed with the hole centered between devices. The only time I can remember ever coming across this, I needed to replace the device under it anyway. Anyone have a tip they could share for this scenario? I have other clamps that I could just wreck the clamp, but I'd rather learn a new technique.

I have designed most of my per-amplifier, including the inputs.
All I need now it a way to use buttons to select input.
I have taken a look at the push button in hope that it could be used

But I have not been able to find a way to make 4 alternating latching buttons or a way for the interface to "remember" wish was pushed last time.


The way I have build my pre-amp, do that I can ignore how the circuit will effect the sound.



I have a 5V-10V DC input and want to go trough to output 1,2,3 or 4, It would be fantastic if an LED could be lit over each button that are selected.


To me do it look like a big project to use push buttons.


How did you solve it, besides using a turn-selector?

I have this 10 inch subwoofer driver which comes from EDGE STREET ED510A active subwoofer (I don't have the original box or amp, only the driver).

I recently measured TS parameters of this driver using ARTA LIMP:
(used method described here: LINK)

I have a coupe of questions!

1) Could the measured parameters be realistic? Just wondering, maybe they are completely impossible.

2) What enclosure type would you suggest? I've read that with Qt value this high (0.92) it would sound bad in a ported enclosure, yet it originally comes in small ported box and currently is in a little bigger ported box tuned somewhere between 30-40hz, which generally sounds pretty good, except when down low at 25hz.
(I want to achieve not too far from flat response between 25 - 125hz if possible)

3) What box designing software would you suggest? Right now I'm using WinISD

4) Any way to take car interior resonant frequency into account to get flatter curve? I haven't measured this yet, but I guess that shouldn't be too hard to find out.

EDIT:
Checked my front speakers, I can safely filter them and subwoofer at 80hz, which gives me narrower band requirement which could be 25-80hz

Can somebody please help me identify the type of plug shown in the attached pictures. The plug is used to connect various probes to the PicoTech data logger.

The blades are roughly 7.7mm apart and 0.83mm thick. Wide approximatly 2.4mm and 3.1mm.

Thanks!

N.

Joy and Peter Bond
Gina Goulet
Elizabeth Joanne Thomas and John Joseph Zahl
Corrie Ellison
Dawn Madsen and Frank Gulenchyn
Aaron Tuck, Jolene Oliver and Emily Tuck
Sean McLeod
Alanna Jenkins
Tom Bagley
Lisa McCully
Const. Heidi Stevenson
Heather O'Brien (RCMP)
Kristen Beaton
Greg and Jamie Blair
Joey Webber
Lillian Hyslop

All killed by a madman April 18/19 2020.
22 victims of N.S. rampage include retirees, pregnant health care worker, veteran | CBC News

Hi all!

For sale is a pair of Morel CAT 378 which need no introduction.

Bought 9 months ago and have been regularly but lightly used in my front room. These can't have received many watts at all owing to their high sensitivity and my listening proximity.

These are boxed which I am led to understand is unusual and it's a mighty lovely one (normally they come loose from polystyrene crates - not good).

In the UK they retail for £110 + postage.

I would like £75 ONO. Hit me up!

Graham²

PS - the light in the pictures makes them appear dusty which they are not.

PPS - would swap for good condition Seas DXT or other good waveguide tweeters.

I've got a Phonic Max 860 plus with two eh... molten caps. I'd like to replace them and get it working again. Does anyone have the schematic for it? My thanks would be great!

After just restoring my "Electrocompaniet The 2 channel preamplifier" it's now time to restore the amplifier.

What I'm looking for is some photos and assembly instructions of the internal, of the original "Electrocompaniet
The 2 channel amplifier" from about 1978.

I would like to rebuild my one that's I decided to dismantle about 20 years ago which was a fatal mistake.

I now need to make a new case and some new PCB's as these parts have gone missing all that I can find
from the original amp is the transistors, transformers, heat sinks and front panel.

msdin

I need to get a programmed PIC controller to the US but international mail from Belgium to US is shut down for now, due to lack of flights.

I have the .hex file, so am looking for someone in the US I could mail that file to and who could load it into a PIC16F1788 and mail that to Arizona.
I'll pay for the chip and mailing of course.

Jan

Here is a note from AndrewT's sister Nadia. I hope that some of you local to Andrew can attend.
_______________________________________________________

Our late brother Andrew Tymkewycz was a member of DIY Audio. We are holding an open weekend at his home, near Heriot in the Scottish Borders ( 30 minutes south of Edinburgh) on
Friday 26th April from 3pm to 7pm and
Saturday 27th April from 10am to 4pm.
Other dates can be arranged by appointment.
We have many pieces of audio making equipment and electronic components to sell and give away for a donation.
Please note your interest by email and to receive directions to Andrew’s house.
Contact nadiarutherford@btinternet.com

Thank you
Nadia

Hi all 🙂,

I'm building another tube amp after the 10-year hiatus (lockdown does horrible things to people, revivng the hobbies long dead), and this time I'd like to make it more user friendly than my previous builds.

It's a classic stereo point-to-point wired PP amp with fixed bias (with 4 separate pots and 4 typical current measurement resistors between cathodes and ground). So I need to make 4 test points (plus 1 or 2 for the ground) somehow, and I'd like them to hold multimeter probes reliably for having my hands free. And probably another 4 test points for measuring bias voltages to be able to match the output tubes using just the amp itself.

So, obvious options are:
1. External tip jacks and exposed pot shafts in the style of many guitar amps. Obviously the most convenient option, but not the most practical in terms of build (lots of chassis area covered in holes, sub-optimal pot placing, etc.)
2. Some kind of dedicated inner test terminals (isolated panel with tip jacks? dedicated turret/lug strip?). I don't mind flipping the amp once in a while, but the space inside the amp is tight, so I need the most compact solution possible.
3. Some "test extensions" (pieces of thick solid wire?) added to the test points (tube socket pins and ground), sticking above the rest of components. Simple, cheap, sounds stupid and unsafe.
4. Using hooked probes directly on the measuring points and just don't bother.

What do you think? What do you use? Any ideas are welcome.
Thanks!

Hi,

For some reason the search function doesn't appear to work so I am posting here on the off chance!!

I have designed an hf horn eq circuit with rcl impedance correction. I have tested it as a hard wired circuit but would really like a pcb designed for it. I don't have "Gerber" files but do have a circuit diagram and component list with component types, dimensions, lead our wire specs and where appropriate, weight.

I have only been able to get quotes from commercial outfits which are inappropriate in my circumstances! I am happy to pay of course but the quantities would be initially prototype...

Anybody out there, particularly in lock down, who would be happy to help me with this??

Cheers...

I have tried using two Hammond 156C in series as plate chokes for a 26 tube. They sounded better to me than IXYS active loads, but were rather prone to hum and hard to get quiet.

What would be the ideal plate choke for a 26 with its Rp of around 8.5K?

Looking at Lundahl

LL1667-05mA 810H
LL1667-07mA 580H
LL1667-10mA 405H

Which of those?

Any experiences with these, or something else again?

Andy

I got a lovely MiniVol board with the PGA2320 chip driven by a AVR microcontroller from diyaudio member, theAnonymous1. The minivol provides vol up/down and mute, controlled by push switches or a rotary encoder.
The MiniVol is described here -

http://audio.gotroot.ca/minivol/

I also wanted a channel selector. So I rigged up a small
circuit around a CD4017 to step through the channels.
The DPDT relays are driven via 2N2222s.

To control everything, I got a cheap 4 Channel RF controlled switch on ebay. The receiver has a couple of
jumpers to choose the mode - toggle, latch or momentary.
I used the momentary mode. The 4 channels are used
for Vol Up, Vol Down, Mute and Channel select.
The open RF receiver/relay board, and the remote alongside are visible in one of the pics.

The PGA2320 is a really nice volume control chip, sweet
and transparent.
I wanted an appropriate box, so I put
the whole thing in a Ferrero Rocher chocolate box!

I am also attaching the Eagle files for the channel select circuit.

Hey all,

I’m starting a new thread on this as I can’t seem to find a definitive answer on it anywhere so apologies if this is common knowledge!

For the two opamps on the output stage on a CDP (specifically a Marantz CD63), would a FET or bipolar input be more suitable? I can see both types being readily recommended in the CD63 mods thread specifically but with seemingly no preference either way.

Both the original NJM2114D’s and the LME49720NAs I’m using now are bipolar so if there’s no good reason a FET might be an “upgrade” I’ll probably stick to the original.

Trying to put together a amp using boards, I noticed amplifiers like the 12 channel Dayton class D uses two Toroidal Power Transformers. Im looking to use SIX two channel amp boards, most likely TDA7498E DC 24V 2x160W Dual Channel. Looking for a way to power 6 of them without having to have 6 power supply's and 6 mains plugs 🙂

3 friends build speakers.

#1 builds a sealed 2-way, 250mmWx300mmDx500mm tall. The instructions say line the back with 3" of fiberglass, so he does.
#2 says, "Your box has back waves bouncing around inside." So #2 builds a box 250mmW and 500mm tall, but he increases the depth to 600mm, and inserts 600mm of fiberglass. He says, "This will kill the back wave".
#3 builds the same box as #2 (250W x 600D x 500 tall) and inserts the 600mm of fiberglass, but he inserts wire mesh to hold the batting and leaves the wooden back off the cabinet.
That's right ..... no back. Just fiberglass batting, 600mm thick.

Question: is there merit to the design of #3?

Thanks. Jim

Hello!
Since the Tango MCT 999 is no longer make, I want use Jensen JT 34K DX for substitution. Would it be possible? Any drawbacks?

Thanks!

Edited! Buzzing and no volume problem

I have ShockWave HI-FI Model: SW390. It had burned IC TDA2030, i replace it power it up and after few seconds of buzzing capacitor blew up and resistor burned. I don't know what caused to burn but i want to change them to repair it. I was trying to find datasheet about this HI-FI so i can see the circuit components and what i need to replace but unsuccessful, the capacitor i was able to replace it, it was 10uF 50V i replaced it with 10uF 63V but i have problem replacing the resistor, i don't know what resistance it had. Can anyone tell me how can i find what resistance i need so i can replace it? What can caused blowing the capacitor and burning the resistor? (there was no shortage, even if it was a shortage the fuses will break before these components)

P.s: i was not sure if this topic is for here.
https://imgur.com/a/Pz92UVa

Update: i replaced the resistor with 100 Ohm and it turned on but now i have some buzzing/hum noises ( i don't know how to explain them so i recorded a video)
Video: https://imgur.com/a/kGXN806

Hello,
i'm trying to understand if my moded chicken vibe works.
It's a univibe guitar pedal
here's the schematics.


What i don't understand is the intesnsity of the effect fades out as i reduce speed.
So i looked at the schematics and traced the oscillator with my scope.


When speed is at full setting i get a nice sweep, about 4v peak to peak oscillation just before the depth pot (at C103).
When i reduce speed, the frequency slows down so it kinda works but the amplitude of the sweep reduces too... to almost nothing at minimal speed


So here's my question, given the schematics, is it normal for amplitude to reduce with speed control ?
We're not talking about the rest of the schematics, just the oscillator part.


thanks!

in reflex loading equivalent circuit, the vent is high-pass or bass-pass ?
since with vent i increase the slope for example in respect the closed box i think it is an acoustical high-pass, but electrical bass-pass
does it true ?
I hope I have asked the question well😱

Hi,

I first posted this in the solid state forum, but realized that it probably belongs here.

I'm in the process of building an integrated amp with an Aleph J and BA-3 front end. I am planning to power both off of the 24V Universal Power supply, using a 18v/18v 500VA transformer.

I want to add the following remote control ladder attenuator, which appears to require 5V/1A.
High Quality Audio & Industrial Attenuators


What would be the easiest way to power it? Am I going to need to try to fit another small transformer in the case? If so, is this a good option:

10VA 5V + 5V 10VCT Small Toroidal Power Transformer Antek AN-0105 | eBay


Much Appreciated!

Would a classic 47 headphone amp make an effective buffer for the input of an IcePower 50ASX25E? (Schematic for the 47 attached) My input sources are literally Schiit: Mani or Modi into a Sys for switching and volume control.

Hi guys,


Need some help plz



As I am a DIY lover and this quarantine gives me plenty of time, I came up with a project to recycle old sound systems that are good but that are no longer used and leaning against a box in the storage room waiting to go to trash (thing that I avoid as much)

There I have a Trust 7.1 audio system for a 110W rms pc + a pair of 20WRMS JBL PRO 2.0 speakers (old ladies but pretty cool)

I will remove the core and the plastic goes to the ecopoint ;-) So I'm going to put everything together in a single transportable speaker (yes it's not so portable) like Marshall speakers that have a vintage look, 10.2 to be used as a soundbar in the room.


Components:

The box is 90cm x 19 Height + 16 prof in 1cm thick MDF.

Speakers:
2 x 10W tweeter (which I will still buy)
8 x 10W Middles
2 x 40W subwoofers (I will buy 1 more, love powerfull bass - BUoUoUoMmMmM 😀)
2 x Passive radiators for subwoofers

Electronics
2 amplifiers (what I already have 7.1 modified + 1 that I will buy for subs)
Tone Board (bass + middle + treble) + volume
2 x 3-way crossovers
bluetooth module
Decorative and operating LEDs


This will be all ultra low cost as the objective is to reuse what I already have with the least possible expense.

Now my doubt is in the subwoofers, what is the best position?
Facing? beside? down? They are 2 ...
The box will be ported, what is the best position for them?
Being a rectangular box with + - 17 liters useful because each sub needs 8lt + - and an port of 3cm in diameter each, do I need to make a maze to improve the resonance in the bass?

I intend to build a box that allows me to optimize the sound quality as much as possible, as I'm afraid I will get some color in the middle, which I don't like at all,



What is the best option?
A or B


I ask your opinions plz


ps: I'm Portuguese, I apologize for any mistake in English


thanks ppl

Hi guys hope all is well. I need some help with this amp it birnt all the drivers on the one bank aswell as resistors but i cant identify them

I select some pairs of 2N3773 for quad 405 new boards.

Initialy, I thought of using Moto for a set of two boards, and ON for another set of two board. (comparaison purpose)

Old 2N3773's from motorola
Hfe 10uA, 1mA, 10mA
0, 38, 75

New ON's ones
Hfe 10uA, 1mA, 10mA
53, 199, 115

Amplification differences between 1980 and 2018 transistors can be understood. Old curve is linear, ON have gain fall. Any opinion ?

I know, there must be hundreds of such discussions everywhere, but they all seem to be regarding guitar amps where the interest is in distortion characteristics. I need to know the subjective and the objective differences between the two, especially in SET application.

Any subjective listening opinion on the qualitative differences?

What should I know about the technical differences to build a SET amp around them?

Thanks

Hi all, and sorry for the rookie vibe I´m going to pass out here now.

Not sure if I hit the most correct category here but here we go.


I have today a couple of HiFi speakers that I don´t have any use for. But would like to try do do something fun with.


I have a small Stereo amplifier with BT.
I want to connect this to one of the two speakers today and will have to mix this into mono. Fair enough so far.

BUT, it would be fun to repurpose the existing speaker connectors on the speaker, making a switch that turns the audio back to its originally stereo and then being able to use both speakers.

Anyone have a schematics or DIY description to how to achive this switch in a good way?

$115 shipped US for 08 -- new or like new
$105 shipped US for 07 -- green dome, new or like new

07 is my favorite dome tweeter, if it matters.
Not bright (I find every dome tweeter too bright), similar too XT25 on the high end, but way way more low end.
08 is pretty good too.

Hello,
I'm looking for the 32 bit driver, is someone among you, who uses exaU2I, would have kept them, because I sent a message to exadevices, they only have the 64 bit version,thank you.
Best regards,
Stefano

Hello everyone, hope all is healthy and well.


So I've been doing some browsing, and came across this: https://www.headfonia.com/2013-spring-tokyo-headphone-festival-impressions/9/


I see that they are typical Cmoy tradition, sticking a headphone amp in a mint tin. But I've never seen something like this before. They appear to be hybrid amplification because there is 1-2 valves/tubes and then an op amp. From a general knowledge point of view, these tubes aren't powered like they usually would at around 200-300 volts, and instead by a couple of rechargeable double A's. Most of the amplification is probably done by the IC. I know that a few years ago a designer that goes by the name of FredsAmps built similar designs to this as a kit on his website, but is now shut down.



I was thinking of building one of these myself, as I would like to know what all the tube hype is about. What do you all think?

Folks,


I was interested in building one of these, but I am a bit overwhelmed when trying to find a good chassis that's a good fit. Can someone help me with a specific model that works well as a chassis for the Whammy?

I am designing a drone to play sound. I can 3D print the horn. Would like suggestions for some light weight PA horn drivers. Any search I do for horn drivers only shows high frequency tweeter drivers. I need mid range for voice signal.

Would something like this work? It is a neodymium speaker designed for portable devices.AIYIMA 2Pcs Full Range Portable Speaker 2 INCH 4 Ohm 16W Sound Music Neodymium Audio Speaker Driver For Computer Loudspeaker DIY - Aliexpress

Or this? TEAX32C30-4/B | Tectonic Round Audio Exciter, 30W nom, 30W max, 4Ω | RS Components