Hi there, new here and not sure if this is appropriate spot to post this but maybe someone has redirection feedback or a link/reference-- many thanks.

I have an early 1970s Braun integrated stereo with turntable. Its entire casing is sheet metal, and the plug is only two-pin, ungrounded. I'm planning to recap the power supply and do some other servicing, and while I'm at it I'd like to add a safety-ground to the case... for safety 🙂

What's the right way of thinking about this while avoiding ground loops? Currently in the turntable section, the tonearm tube is "grounded" to the chassis, which in turn flows into the "ground" lines of the amp circuitry, but because everything is behind the power transformer, none of it actually goes out to the neutral line of the plug as far as I can tell.

I know enough to be dangerous here but fuzzy enough that I'm not especially conversant in how ground loops happen. Can anyone suggest how the "grounding" path is actually working now without a safety-ground connection (for my enlightenment)? And I know I can simply screw the safety ground into the chassis's metal case but I don't know if I'll need to think about anything else to avoid creating any other issues/loops?

Could someone hell me with a no power Massive Audio E3 nano amplifier.

Because I have a lot of free time these days, I started testing few multi-way speakers I have here, sitting around, unfinished.

One in particular came to my attention: a project of 2-way using some nice pro audio 15'' woofer that happens to climb as high as 4khz while having some very manageable specs to go down to the first octave.

Nothing to win the gold medal of Hi-Fi Olympics, mind you. Just a project for fun, to pass time while I'm isolated at my place. 🙄

So, that particular project reminded me of something very important. Maybe one of the oldest problems in audiophilia, especially for us DIYers.

How, supposedly, the box is the least worst of the solutions

We all know there is basically 3 types of boxes:

• Ported
• Sealed
• Passive radiator

The sealed one is the simplest, obviously. The ported one is the efficient one, while the PR is the ''technological evolution'' of the ported one, so to speak.

So far, nothing too complicated to understand. That's the ''box world'' even though many exotic configurations exists which are essentially variations on the theme.

But here comes the Open Baffle. And, just to be very clear, that's not a thread about how magical are OB's... They're not.


On one side you want to avoid the acoustic short circuit of an open baffle, a ''naked driver'' that most of low-frequencies abilities are stripped off, but on the other hand you ''bury'' the problem in a box... and that generates other problems. Problems ''solved'' mostly by stuffing absorbent materials into said box.

Compromises. Compromises everywhere. Insert a popular meme here.

Problem is, there is a general misconception about an idea in which the box itself -if poorly built- will generate resonances, noises and bottomline what can be called distortion, from the source (music) to our ears.

In fact, the vast majority of boxes, even built by beginners, are probably built in a way that they cannot generate resonances that will be audible, especially not at low/moderate SPL.

What's left then? LEAKS.

Ports, obviously, but also the driver itself. The 15 inches pro audio driver I was talking about earlier. Event though I use it in a sealed box, the internal resonance builds up and it leaks badly through the (big) cone. Of course, I can stuff stuff inside. But it's not enough. Unless I'm looking for other acoustical problems somewhere down the road...

Which do you think, of 25mm thick plywood V.S. 0.5mm paper will block the most sound energy? The plywood, obviously. The big cone here is a massive leak. Only the highest frequencies are blocked.

And, bottomline, it's distortion. Sometimes not too uncomfortable, but distortion nonetheless. The resonance build-up of the box which leaks through the membrane is audible enough to pollute the final sound rendering, sometimes in a very bad way. Like it's the case with my huge 15 PA driver.

The resonances are sound energy that bounces internally, trapped, on the (very) rigid enclosure's walls, and that generates reverberation (echoes) until that energy dies or leak somehow.

Almost impossible to correct on EQ. You can correct amplitude and frequency on a EQ but not reverberation time (RT), unless you try to dim the frequencie(s) where the resonance build-up is at the worst, but then you cheat on the signal, which is not good. Better to solve the problem at the source. Instead of putting out a fire, it is better to avoid having one from the start ...

These resonances are well-known with the ported boxes. That's another leak, ports. The resonances build-up leaks through the port(s) and even though there is many designs to avoid partially the unwanted effects, it's still a leak. At the perceptive level, the ''ported box reputation'' is that the bass is ''slow'', which is mostly explained by the reverberations, of the higher frequencies, that are building up and then leaked through the port, which cause a ''blurr'' in the perception. Less ''clean'', also a common way to describe it. And that is exactly what is it: less clean because polluted by distortion: unwanted sound energy on the original path from the source.

The human ear is unprecise regarding amplitude and frequencies, but very precise in the time domain. We can detect very small RT and that affect our perception a lot.


So here it is: I wonder if a fellow DIY enthusiast or any lab or company ever did a study, a test about the following:

To enclose a small full range speaker IN a larger box.

First, a completely closed box, sealed like a can. Then measure what comes out using sweeps or pink noise.
The result will be the resonance of the box itself, its walls and possible sound energy leaks, within limits of what the small fullrange can generate, in both frequencies and SPL.

Then, the same process but with a box, still of the sealed type, loaded with an inactive (bigger) driver. Ideally with a burnt/locked voice coil so it won't generate sound waves by itself...
The idea of course would be to measure what comes out via the membrane. So we can have a good idea of ​​the leak compared with that the benchmark (the walls of the box, from the first test).

Any idea? Any comments?

🙂

if you need a reason to celebrate.

Hi I bought a Pearl 1. My problem is I'm just learning and trying to read schematics and build basic electronics. Can anyone help me and tell me or point out which caps would benefit from being run in parallel or changed out to a better quality cap. I have some nice caps laying around from a crossover upgrades. I have some .01 Jupiter bypass caps. Clarity cap CMR, sonicaps gen 1, Auricaps and Rel caps in different large values that if run together they would add up to needed value in power supply caps, it has Mundorf M-caps in there now for the 10uf and 1uf. Would this be beneficial or would it be best to leave all alone. Is the C-11 a signal cap?Would it benefit from being bypassed? Sorry for all the questions just wondering how far this amp can go with better parts, thank you Paul

Hi!

I'm currently selling my brand new still original boxed Edcors.

This is a good deal if you're located in Europe (no high overseas heavy shipping cost, no local customs taxes and no waiting time)!

Only $189 for the pair!

Please check here:

Edcor CXPP10-MS-10K Audio Tube Output Transformer PP HiFi (pair) | eBay


Thank you!

Miguel

on Craigslist for $30. I figured I could use the chassis for a preamp or a chip amp. The amp is an Ultrack KAC1240ME.

I was a bit surprised to see the two torroidal transformers and the nice heat sink. I have no idea what value the transformers are. Also, they look to be epoxied to the chassis.

What do you think- A home for Bob C’s new chip amps? Maybe a chassis for my Bosoz preamp? Anyone know anything about the trafos?

I am planning a 3 way Studio monitor stereo setup using SEAS components and figured it would be wise to make a stop over here in case anyone can point out potential pitfalls.

Details

Components:
Tweeter: Seas Prestige 19TFF1 (H0737)
Mid-Range: SEAS Prestige MCA15RCY (H1262) 5.5" Coated Paper Midrange
Woofer: SEAS Prestige CA26RFX (H1305) 10" coated paper woofer

Port:
I am not sure what I want for a port setup, as I value time-domain response far more than frequency response so I suppose I would stick with a sealed cabinet. I did try to pick speakers that were matched in sensitivity and their respective bandwidths, though.

Goals:
However, in the lack of any actual available waterfall graphs on these speakers, I've just been planning around frequency response while taking stabs at preserving a reasonably dampened time domain characteristic.

For the woofer's frequency response, I am hoping to get 50-200 Hz +- 3db out of it.

For the midrange, 200-5000hz? Does that seem reasonable? It's just before the breakup on the graph. Maybe I should cross that over lower...

For tweeters, 5k-20khz. The tweeter's manufacture graph suggests it can go down to 2k easily which seems in line with Adam A7s I have on hand from what I can tell. Maybe I should really consider crossing over the tweeters lower.

Method:
To design the crossovers I was just going to use the XSim software after I get the FRD files generated with the cabinet built. The cabinet will most likely be a 3-way classic design...but it would be nice if there was another piece of software that could simulate the enclosure's transfer function combined with the speaker parameters as well? I can see how XSIM measures that but by then I've already built the cabinet haha.

The lynch pin of the build though is if the 10" woofer offers a slower transient response with no added frequency response compared with smaller drivers, then why use it? Should I just copy the 3-Way Classic entirely IOW just buy it lol?

I have about 10 outstanding orders placed within the last two months, many approaching the expiration period with no delivery. I was reliably getting my Chinese trinkets earlier this year, even in January and February, in about 3 weeks. But now, seems delivery has gone to crap. All of my items say they have arrived in the US 4 to 6 weeks ago. But going on to 60 days from order period and nothing. Various types of items from different vendors and shippers. I'm wondering if this is also others' experience. Heads up, seems like something has happened to this pipeline.

I was digging through my stash of transformers for something to power a DAC regulator and I found this old Antek. Apparently, when I bought it years ago, I never really looked at it, but it is definitely oval in shape. I would love to hear if anyone else has ever had something odd like this and if you would even use it?

The windings are all tight and visually uniform. The thickest part is 36 mm and the thinnest is 30 mm, so a difference in thickness of about 6 mm. My guess is that the core is the cause, but I don't know.

Any thoughts?

Jac

Hello,
Like new, great but very heavy unit.

The shipement cost :
28,55 € for the France
61€ for the EU
XX€ for the world


https://nsa40.casimages.com/img/2020/04/17/200417054825998182.jpg


https://nsa40.casimages.com/img/2020/04/17/200417054826391923.jpg


3.25” Voice Coil
2000 Watts Peak Power Handling
Ferrite Magnetics
Precision Circular Inside/Outside Wire Geometry
Die Cast Aluminum Chassis

Small Signal Parameters :
Nominal diameter : 381 mm/15 in
Power rating : 500 W(AES)
Nominal impedance : 8ohm
Sensitivity : 97 dB
Frequency range : 45-3500 Hz
Chassis type : Cast aluminum
Magnet type : Ferrite
Magnet weight : 29 kg/1039 oz
Voice coil diameter : 825 mm/325 in
Coil material : CCA-W
Former material : Glass fiber
Cone material : Paper
Surround material : Cloth
Suspension : Single
X-max : 4,8 mm/019 in
Gap depth : 100 mm/039 in
Voice coil winding width : 196 mm/077 in
Net Weight : 10,2 kg/225 lb
Packing Dimension WxDxH : 430 x 430 x 220 mm
Shipping Weight : 11,3 kg/249 lb

Re : 5,5
Fs : 41 Hz
Mms : 90,0 g/317 oz
Mmd : 74,95 g/264 oz
Qms : 4,21
Qes : 0,41
Qts : 0,37
Vas : 183,44 lt/648 ft
BI : 17,76 Tm
Cms : 17e-04 m/N
Rms : 5,51 Ns/m
Le (at 1kHz) : 0,43 mH
Sd : 881 cm2

Hello,
Like new and free in its original crate.


https://nsa40.casimages.com/img/2020/04/17/200417124146447803.jpg


https://nsa40.casimages.com/img/2020/04/17/20041712414826666.jpg

* 1400 watt continuous program power capacity
* 100 mm (4 in) copper voice coil
* 30 1000 hz response
* 95.5 db sensitivity
* double silicone spider w/optimized compliance
* nominal diameter 460 (18) mm (in)
* nominal impedance (1) 8 ohm
* minimum impedence 6.3 ohm
* nominal power handling (2) 700 w
* continuous power handling (3) 1400 w
* sensitivity (1w/1m) (4) 95.5 db
* frequency range 30 - 1000 hz
* voice coil diameter 100 (4) mm (in)
* winding material copper
* former material glass fibre
* winding depth 21 (0.83) mm (in)
* magnetic gap depth 10.5 (0.4) mm (in)
* flux density 1.05 t
* thiele & small parameters
* fs 30 hz
* re 5.3 ohm
* qes 0.41
* qms 4.6
* qts 0.39
* vas 245 (8.6) dm3 (ft3)
* sd 1210 (187.6) cm2 (in2)
* eta zero 1.6 %
* xmax +/- 8 mm
* xvar +/- 8 mm
* mms 202 g
* bl 22.5 txm
* le 2.1 mh
* mounting & shipping info
* overall diameter 460 mm (18 in)
* bolt circle diameter 440 mm (17.3 in)
* baffle cutout diameter 422 mm (16.6 in)
* depth 197 mm (7.75 in)
* flange & gasket thickness 16 mm (5/8 in)
* net weight 10.5 kg (23.1 lb)
* shipping weight 11.9 kg (26.2 lb)
* shipping box 500x500x250 mm
* (19.7x19.7x9.8 in)

I am about to start building my first DHT amp - a 45 parafeed headphone amp, with the output being cascode CCS loaded (IXYS depletion-mode MOSFETs) and auto-biased.

I am using Rod Coleman's filament regulators. Re-reading the manual, I realized I had overlooked a design consideration - I do not have a delay / soft start mechanism for the B+.

How concerned should I be about applying bias when the filaments are partially warmed, along with cathode stripping? Given this is a headphone amp, the 45 bias is not aggressive, around 200V at 32mA. My understanding this is more of a concern with transmitting tubes with kV-level anode voltages.

Space, power supply, and layout considerations would make adding a soft-start PCB quite the pain. I am inclined to move forward without it, but would love to hear some opinions, seems cathode stripping is something of a controversial topic 🙂 thank you.

Are ground loop protection circuits legal in Illinois?

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