Looking for a non working Decca mk 5/6 cartridge, hopefully good coils.

hi everyone, i was wondering if there is any sound difference in the passive membranes mostly used in portable speakers and passive radiators ( passive speakers with spider etc.), wich 99% of the time are used in the DIY community. the passive radiators seem to have better control because of the surround AND spider but is this really important or is this just a minor thing. passive radiators have a mass (added) limitation and are not that flat while a passive membrame can hold more (moving!) mass because the weight is more distributed over the piston erea instead of a heavy loaded spider wich can become uncontrolable( like a camper behind your car wich goes out of balance on the highway) and is way more flatter( so less space ).

I'm building a 1/4" TRS headphone extension cable, and have a nagging question. Does anyone ever leave the shield floating at the headphone end, the way it's sometimes done in power cables? I assume not, but I just got to wondering.

Thanks,
Bryan

Hi guys,

As I always dreamed about building my own custom mixing desk we decided to start building one. I know it's more oriented to studio etc but here it goes. We started this around a year ago. For the basic preamp we use the neve 1084 design. We like the sound of this preamp and have good experience with building this preamp. We then devised a way to make Inline modules based on the 1084 and also added a balanced insert point. There is ofcourse a lot more to it then this.

The power supply is 3phase Full wave rectification. This way it will have low ripple and the buffer capacitors will have an easy life and will last long. A neve 1084/1073 wants a good power supply. The concept of this console is also to build something that will last and if something happens the session can continue and it can easily be fixed. The raw rectified power supply is then split up in 4 seperate lines. In the console are the smaller power supplies using lm317/lm337. there is one small power supply for each pair of channels. So if something fails the rest will keep on going.

Then the VU meters are set to 8dbu=0VU. Normally this should be 4dbu = 0VU but for some reason today's engineer like to record quite hot.....don't know why you would do that when you have 24bit adc....... but ok. Doing this we avoid that the meters are continuously pegged to the right....

So now some pictures:

first things first and we started out with a small frame prototyping.

After this was tested and checked, the work started on the frame.



And after some more work:

the work also started on the soldering some PCB's....





Elma Switches for the gain switch

P&G faders





after the channelfronts have arrived:

after the Faderpanels have arrived:

The inside of 1 channel module:





the power supply build:



Last update untill now.





I have more photo's but this will do for now. I will add more as progress goes.

Hello,

I have these parts coming from a JVC RC-EZ31 boombox for sale:
- The transport
- The control board
- The remote control
- The puck (which sits on top of the CD)

These parts have been removed (unscrewed) from a JVC RC-EZ31 boombox several years ago, but I never built it.
There has been no soldering or modifications done to the parts whatsoever.

Asking $150 + shipping.

How can one turntable sound better than another? - YouTube

So, is this guy right or not?

Hi !
Tapatalk login not work! I can’t login via TK - Tapatalk from IOS 15.1.

Curious to know who folks vouch for in terms of selection / quality / price / shipping.

For sale is a pair of gold/copper MarkAudio Alpair 10.3M. They were never mounted, used, or broken in. I bought them on a lark several years ago, and they have sat in my hobby cabinet ever since. They are in mint condition. See the photos.

Asking $120 shipped in the continental USA. I will ship worldwide, just ask.

From what I've learned it seems preamp output voltage and output impedance and amp input sensitivity and amp input impedance are key to determining if a preamp and amp are a good match. However it seems very few manufacturers list all those values. Am I missing something or do they need to be calculated for preamps and amps when those values are not listed?
thanks

Hi, I'm back after two cataract surgeries and related post-surgery problems....
I would like to know, in a preamp, if there are any differences between a buffered scheme and one with unity gain.
Thanks!!

Hi,
I wonder if anyone uses Class D technology in active DSP horn systems?
Need 4 ways per channel.

The NC502Mp has slightly better data. The power is not needed.
I like class d technique also because of the efficiency in today's time, if you consider that 8 amplifiers are needed 🙂

Which module would you use?
How does class d sound on high efficiency horn systems?

Best Regards

Barossi

SORRY, THIS HAS NOW BEEN SOLD.

I have a nice Tektronix 465M scope boxed up and ready for a new home. It's in good condition, but hasn't been used in about 10 years so I can't guarantee it. No probes included. This is a gem of an analog scope in a ruggedized hard case. A version of this was used in the military. Info here:
https://w140.com/tekwiki/wiki/465M
https://www.testequipmentdepot.com/usedequipment/tektronix/oscilloscopes/tek465seriesspecs.htm


Cost is free but you must PAY FOR SHIPPING from Michigan. Weight is about 37 lbs ish and box dimensions are 10 x 18 x 22 inches.

Send me a PM if you are interested. Local pickup is always welcome.

I’m planning on buying an IP kit from Zen Mod, but before I do I just thought I’d ask if, by some remote chance, anyone has one for sale?

Anybody knows what exactly is this type of connector and pins (6 pin power supply connector)?

Trying to find it on Farnell, but without success.

Ive been curious a long while now, after working with the 723 on several projects, I must say Im highly impressed with the 723 in terms of price vs. performance, Ive used it several times in HV applications particularly tube based preamps.

There have been a handful of companies that have used the 723, but I'm curious is to why Audio Research in particular didn't implement it in any of their designs, they chose to use the LM329 as a VR in just about every preamp and pre section of Their amplifiers, and its not near as good as the VR in the 723, even with its low grade internal op-amp, if its Vcc is buffered with a BJT it can achieve a 2uV noise level. It doesnt make any sense to Me. Someone help Me out here.

Sorry if this is covered elsewhere, I haven’t been able to find the answer.
I regularly use two different sources and wondered if I were to add a second RCA input to my amp do I have to add a switch or can I just wire a second RCA input parallel with my first one?

Check it out here:

http://www.stormpages.com/elfranche/index.html

https://www.tnt-audio.com/ampli/the_truth_e.html

Looks very simple and seems loved for transparent sound... has this been covered anywhere,

SOLD

Has anyone bought from or have any knowledge of this hi fi dealer based in Batam, Indonesia? I am trying to establish if they are trustworthy.

Hello there.

I am a user of a 12" EDGE SPL122-e6 sub powered by a Crown XLS 2502 amp on bridge mode. The way I have them set up is this:

-low-pass filter up to 80Hz
-signal coming from a digital equalizer, some frequencies are lowered, some are boosted (very important! ex: 32Hz -5dB bc. of room resonant frequency, 38Hz boosted to 5dB)
-subwoofer box tuned to around 27Hz

The problem is that every time I turn the system loud and some parts of a song have around 38Hz playing through, the subwoofer seems to be bottoming out, even though it never gets hot or never smells. How do I know it never smells or gets hot? Well, when playing 32Hz and lower, it plays just fine and no noises can be heard. I even have sub 30 Hz frequencies boosted up to 3-5dB (21-29Hz) and has no problem playing them, not even at very high volume. The reason, I think, may be because the box is so low tuned, frequencies way higher than the tune frequency (in this case 38Hz) cause the sub to move quite a lot to the point where it actually starts bottoming out. It does that, although I don't think that's the most power the subwoofer can handle. Most people supply up to 5000w to these in a car which is mind-blowing, but I guess they have lower tuned boxes as well.

I have the sub for almost a year I think, there's never been anything wrong with it. I don't think there are coil problems or anything that can redeem it damaged.

Any thoughts on this? I'd really appreciate it.

Don't bother sending rude comments as I won't be taking them into consideration.

Here's how it looks in action: Login to view embedded media
Thanks!

Hi all,

I'm looking to undertake a new speaker project having been out of the game for quite a while. I have a lot of experience with HiFi drivers, I understand their parameters, design and good driver construction principles however I feel there's something a little missing for the hobbyist large companies can afford - testing. I'm looking for information regarding the testing of different drivers for different aspects such as frequency response, distortion etc.

Most hobbyists can't afford to evaluate many drivers to determine which one would be best for their project. I understand zaph audio was controversial but I wonder if there's anything similar that's up to date that can help inform on which drivers would be best for a given application?

Many thanks,
George

Hello. Before putting into bin, for free 2 pairs of CNCd front baffles.
woofer is 182mm and tweeter 130mm. Perfect for for Scan speak 18w woofers and Scan Speak D2905/990000 tweeters.
Dimensions: base 24cm, top 16,5cm height 42cm.
Green ones are 10mm thick and brown ones are 19mm thick.
you will only pay for shipping.

BTW: I have 4 18w8531 that will be for sale very soon.




BTW: I have 4 18w8531 that will be for sale very soon.

I'm new to working with amps that use a switching power supply, and this Lab Gruppen FP3400 has me treading cautiously with regard to hooking up my oscilloscope. Is it safe for my scope and the amp to connect a dummy load to the outputs and monitor a 1kHz sine wave with my scope (analog Tektronix)? Or should I be using an isolation transformer?

I have been measuring this driver and horn combination:
Product - Pro Audio Components
Product - Pro Audio Components
My measurement environment is far from ideal, as the horn exhibits directivity I am assuming no reflection from the rear wall, looking at the impulse response my first major reflection is at 8.5mS which corresponds to 3m (distance from front of horn to wall and back to microphone). Its too late right now to measure loudly and take the light shade off.

I have measured two of driver+horn to see if they are consistent. For all measurements input voltage was 2.83V and the microphone was 1m away on axis.

I'm not sure on a few things:
1. Are the harmonic distortion figures I'm getting normal? I see around 2-3% THD in the operating band. I know that psycoacousticly this is fine but I don't know how this compares to other 1" compression drivers.
2. The horn has an abrupt transition from square profile to round this causes diffraction, is this the likely cause of the boost in the 4-10k band? should I do something about smoothing this? I was thinking wood filler.
3. looking at the distortion curves I think I want to cross using a 24dB/octave filter @ 1.5Khz to my mid range, is this sensible? this is for a PA application as well as for use at home, however I won't ever need to go over 120dB peak/1m.

Howdy folks. Sorry for so many questions lately, but I have one more

I am looking for a midtl cabinet design for the Mark Audio Alpair 7MS 4" driver. Specs attached below, although I'm sure most of you are already familiar.

I'm trying to design a hybrid open baffle WAW speaker, with OB bass and a midtl mid/high end. Aesthetically my speaker will look from the front kind of like a Klipschorn, and I'm going for the same modular design where the mid/hi section can be separated from the bass section.

Does anyone know of any midtl cabinet designs for the 7MS, or of a design that would be suitable?

Dave (planet10) attached this picture in an old thread, and I quite like the look of it, and it seems like exactly what I want from a design perspective. I will attach that also. I am comfortable paying for plans

By the way, I'll be crossing over the Alpair at 550Hz, and I have no preference between an openly vented midtl and an aperiodic. Intuitively, I am guessing probably an aperiodic would be more suitable for my application?

Thanks all

Due to the long lead times of this item I put in multiple orders, but forgot to cancel when the first was delivered. ;-)
These are used in my autoranger.
If by any chance you need these, make me an offer. I paid $ 317 for the 50.

Jan

Hello.
For FREE (you just pay shipping costs) I'm offering a pair of Dali Skyline 1000/2000 ribbon tweeters.
ONE OF THEM HAS NO RIBBON (although is still available at Dali dealers with part number: S300198-00)

Both are in perfect working condition but one ribbon was broken and that's the why I'm giving them for free. I don't wat to put them on the bin not have space for them.

Shipping will be like 10 kg in a 100/20/20 cm box from 29140 Spain
If you only want the ribbon to replace yours I will ship it.

I'm interested in learning more about tube organ design, as I've already ready a lot about tube hi-fi systems and guitar amplifiers.

I think it will be interesting to learn about the earliest active electronic instruments, but I can't find any texts specifically pertaining to these devices.

Any help would be appreciated!

why wouldn’t there be a generic standard just like there is for the speed of light?

And if there was at 345.6 m/s then substantiate the connection to time as 86 400 seconds , 1440 min 24 hours , 1 day

864 hz is 1 meter in 1/4 wave, 345.6 (0.25m) and 4 days. as reciprocating ratio that extends into everything the pivot off of one.

1
2
4
8
16
32
64
128
256
512

1
0.5
0.25
0.125
0.0625
0.03125
0.015625
0.00783125
0.00390625
0.0019503125
0.0009876…

and we can notice an inch to centimeters conversion:

1meter is 39.37007874015748031496..”
2 is 7874
4 is 15748
8 is 31496
16 is 62992
32 is 125984
64 is 251968
128 is 50393(6??) loss of 1
256 is 100787(2?) loss of 2
512 is 201574(4??) loss of 4
1024 is 40314(88??) loss of 8
2048 is 80629(76??) loss of 16
4096 is 161258(52?) loss of 32

0.62012165 vs
0.62011735
0.62 is 1/x ( 1.6129032258064516(then repeats after the 645.16…

now the centimeters is suspicious, but it should be because it’s directly connected to the motor the second and the speed of light at all times, And those are kind of screwy anyhow because if you look at your version to an inch is leaving off all of those decimal points all the time and those decimals are repetitive nature and foreshadowing to the next?

But they’re also directly related to the same number they are in’pi’ numbers???

8÷2.54 is 3.1 496(Plus the missing 0.00000062992…) as pi is 3.1416( 0.0080 difference).


if we look at a squared plus B squared equals C squared we notice using three as the speed of light or similar the combination

3 - 0.75 is 2.25
(1728)^2 - (864)^2 is (1496.492)^2

86400 x2 - 86400 is 86400sqrt 3.

The Pythagorean theorem is originally a description of time over distance at 30°?

0.5236 or 12 on 6.9375 Can be doubled and see it again in a 300 cm offset driver qw pipe fix the notch at 86.4 Hz and transferred all the way to the one at 144 Hz???

why are those numbers

300 x 0.3490658
as 104.72 and 195.28 cm

which is the reciprocal if divided together of 1.8648 and the reciprocal of 03490658 and 300 is 2.8648. if you run out the decimal points on both of those they are infinite it seems?

and if you use pi divided by nine and pi divided by three to maintain high level of accuracy you’ll see I need a more accurate version.

If you take us 360 cm pipe and you put drivers at 30 cm exactly I need side pipes running parallel 180 cm each, It will tune to 28.8 it will remove the 86.4 notch and it will go up to 144 and depending on the drivers TS parameters it may not be too shabby looking i.e. flat.

what does G is completely annihilate 864 Hz and every inch of all of it at 288 hz over and over and over again in Peak or ultimate cancel over and over.

and those numbers end up being units of time as well but they’re also the radius and diameter of the moon and sun almost precisely into miles in kilometers already?

And technically that 144 Hz seems to end up at about 149.6 If you look through the details of a simulation tool at a impedance or phase or SPL landmark everything has a unique connection to one word under further investigation because they very well define description of specific things in our existing solar system at the very least also showing why some are quite peculiar where they are currently an orbital mean radius , you notice the same exact numbers as the distance to the moon or the distance it is traveling away logarithmically scale down(3.84cm 384,000km).

If all of these things are coincidenceRight now then what were they 66 million years ago

2 pieces Accuton C173-6-090 high end midrange. Only briefly tested, very good condition (10/10), in original box. Datasheet: https://accuton.com/home/produkte/lautsprecher/hall-fame/Keramik-C173-6-090 High sensitivity, smooth frequency response, large voice coil, very strong motor.

Price: 500 Euro each.

Shipping is paid by the buyer, location: Germany.

This amp uses HIP4082 and IRFZ44N on the audio side, and then regular IRFZ44 on the PS. All need to be replaced.

I have IRFZ44Z in stock (Lots of them). RDS on is different between the ~3. Would the Z be suitable in the audio section? Or I can go with something like IRF3710 (Non-Z) in the output section.

Hope I can fix this one. Any service manuals/schematics available?

All,

I have designed a stereo RCA (single-ended) to XLR (balanced) converter.

I will have both fully assembled and bare boards available.
Fully Assembled boards: 150 to 180 USD + shipping depending on interest
Bare boards: 12 to 18 USD + shipping depending on interest, see BOM in attachments.

Parts used are OPA1622 as initial buffer to OPA1632 for SE to balanced conversion.

Input impedance: is 47k
Output impedance: is 100 ohm.
Gain: 2.5V/V or 8dB (can easily be adjusted if you get the bare boards with resistor values)
Input Voltage: 9V
Onboard very low noise LDOs: LT3090 and LT3042

Can be ordered at link below, with 20% off, coupon code is "rcaxlr". Delivey in June/July.
https://orchardaudio.com/product/rca-to-xlr-converter-module/

Thanks;
Leo

need transistor numbers
fet 191
fet 192
fet 401

Inspired by Patrick Turner(RIP).
The tube line-up is 12at7, 6sn7 LTP, and kt-88.
The OP transformers are from HK Citation II, an ebay purchase from long ago,
I wasn't the one to part-out the Citation.
I don't expect anyone to verify component values.
Should any filaments have raised voltages on them?
All comments welcome.

Dear DIYers,

I am trying to hookup a Hypex UcD250lp-m and not getting any throughput. Here is the pinout I am using.

1,3 => -30v dc
2,4 => +30v dc
5 => amplifier ready output reads -0.7v
6 is tied to 7 with a 4.7k ohm resistor
8 =>
9 => RCA core
10 => RCA shield (not tied to ground)
11, 13 => speaker hot
12, 14 => ground (speaker return)
15, 16 =>

I have attached the manual.

Happy listening,

John

I got hold of a beat up MC420M that was missing it’s meters but it worked otherwise, so I decided to emulate new meters using microcontrollers and LED screens. Sharing, in case anyone else would like to do the same.

Mac Meters

Hi everyone,

I am looking to build tops to go over some Cubo15/Tham15s and I need them to play pretty low... 80-100hz. I initially thought single 12" were the way to go, but a dual 12" will give me some more height.

I have been looking at Rog's x12 plans , which recommends a P.Audio SN-12MB. Being in Canada that is totally out of the question to get. I do have readily available access to B&C and Eminence though, and I was thinking the B&C 12NDL76 would be a pretty good driver.

So I am assuming after handles, etc the interior volume is going to be around 75l, so I put it into WinISD, but I really don't know what I am doing. I'm not sure what my tuning frequency should be. Assuming it is 50hz which is what the 12NDL76 calls for on specs, the graph seems to fall off pretty bad. Can someone double check what I am trying to do? Will they speaker be suitable for a dual 12 that drop down to 80-100?

Excuse my noobness! Trying to learn.

Thanks!

Good day/evening wherever in The world you may be reading this from.

I have a Marshall Kilburn Bluetooth speaker and live in a country where our power grid is failing, to be optimistic... sometimes daily loadshedding for up to 4hrs and rarely 6hrs a day. It must have been plugged into the mains to charge the batteries (which I find contradicting info on) The original pack is attached in pic and 2 positive and 2 negative wires plug directly into a joined single positive and a single negative input. I assume this means that the 4 batteries are in pairs that are in series per pair at 7.4V. And then linked in parallel to double the mAh. Despite stating 14.8V on the pack which is stone dead. I made up a battery pack 7.4V two series 18650 cells that provide a parallel output of 7.4V and used Samsung 2600mAh to total up 5.2Ah at 7.4V. And she sung like a multicoloured Canary for all of 4 to 5hrs then output signal declined notably. If anyone has info on the power battery pack that will be appreciated.

Now for the doozy...
It derives it's power to charge the batteries from a 220V source. And I couldn't figure why it was not charging the batteries. Opened her up and what looked like a blown trace was component "LL10" which comes from the source of Mosfet 10A60D, through a "Thermistor" I think and fed into the transformer via "LL10".
2 impossible questions scratching the inside of my uneducated skull...
1) is this a normal smd inductor? and...
2) how can I find out the component, it's value, (uH, mH...) and replace it without an inductance meter?

I have asked Marshall and they won't help. If I know the exact component of happily order and replace. As I did with the blown FET.

Consider myself uneducated, but self taught in electronics. So I'm a novice and anyone that is able to assist, please forgive any errors made with terms and descriptions I may have used. If I can get the primary side healthy and working so it charges the batteries ill be very happy. As of now I am sitting with the task of having to remove the battery pack I made and charging on a separate source each time.

Thank you for any feedback and criticism offered. How will we ever better ourselves if we aren't critiqued. Be blessed and I hope you're warm and safe where ever in the world you may be. And I hope you have some tunes to soothe even the savage beast.
☮️

CH3/4 of this amp has an issue. I believe something wrong with the IRS2093M driver which is running CH1-4. CH5 is running from a pair of IRS2092.

Amp normally idles at 1.7A.

Ch3/4 under load works for the first few amps of pull up to about 7A, well before clipping, but then after that switches to massive oscilation and the amp will continue to draw 4A at idle. CH3/4 came to me stating not working. The amp is not going into protect, no shorted transistors from what I've tested. Amp will continue to work just fine on CH1-2 and CH5, and then CH3/4 will work again until over-drawn when power cycled.

IRS2093M... seems to be unavailable, and also not sure if my re-work station can handle replacing this component at this time.

Any advice?

Hello, I've paired this amp WONDOM JAB with two 8ohm speakers (ND90) powered by a 5s battery pack for a Bluetooth speaker project. I have added a volume knob on the amp (comes as kit for this specific amp). Every time I modulate the volume using the knob I can see the speakers moving in and out (while music is not playing of course), moreover i get a fairly substantial noise coming from them when the knob is turned higher than 9-10 o'clock (noise stops after a while when there is no music/signal, i suppose the integrated Bluetooth module /amp goes into a power saver mode when it sensing that there is no signal). Power supply is common for source and amp since the Bluetooth is integrated on the amp and besides it doesn't sound like a ground loop. I suspect it might be the volume knobs cables that pick up noise (I attached a photo of the wiring you can see the map on the right hand side and the cables that run to the volume knob which are folded not looped).
Do you have any recommendations on how I should try to fix this these two issues?

What is everyone using for an Android music app for local (on device) files?

I'm looking to try something else other than VLC, and I will only use something from the official Google playstore..

EDIT: I certainly don't mind paying for quality... Actually prefer to pay for something that isn't scrapping my cell phone and selling the data.

Please and thank you in advance!

I’m starting a new thread on this amp so there is no confusion as to the problem .

The amp shorted the outputs and the power supply fets after rebuilding it .

The outputs shorted gate to drain .

I’m going to rebuild this amp again .

My question is I’ve heard a few different things about repairing this amp .
I don’t wanna say 1 person is right one person is wrong . Everyone that has helped me with this amp so far has given great advice .

Ok so here’s my question .

The output transistors shorted gate to drain I removed them and checked the gate resistors . Some read 32.9 ohms and others 32.8 ,32.6 ect .

Wondering when repairing these large amps like this should the gate resistors be all matching as far as value like getting all of them to read 32.9 for example or does it matter if 1 reads 32.9 the other reads 32.6 ?

I’m wondering if this causes issues in these large amps since first rebuild was unsuccessful.

Hi All,

I have just bought a used Wadia X32 Digimaster digital computer in immaculate condition from the USA and hence it is a 110V product. I am based out of Asia and require this to be plugged into a 220V ac mains line.

The IEC receptacle at the back highlights 110/120/220/240V but pulling the fuse out, I see a card which mentioned 110V. I opened the top cover and saw that the inside of the IEC receptacle (made by Delta Electronics) also mentions 120/240V and 50/60hz on it. There are a couple of metal lugs which are not connected there. Please see attached photos.

I can't locate either an operation manual or a service manual for this DAC.

Can anyone, who has worked with this Wadia before, please help me with the exact steps on how to convert the voltage on this DAC from 110V to 220V. I read in another Wadia manual for another dac that they used to ask folks to send their dacs to Wadia's factory to get the voltage conversion done. I don't obviously have this option to avail. Even if you have the operation/service manual with you, appreciate if you could mail it to me on my email id (can share with you over a PM).

Highly appreciate your help on this matter. I can obviously resort to using a step down transformer but if there is a way to straightaway use the dac with 220V, I'd rather do that.

I am building an ESS AMT-1 type "clone" using a new Heil AMT and a new ESS 10" woofer. I want to duplicate the original AMT-1 crossover (see schematic attached), but I want to increase the crossover point from the original 800 Hz to 1100 Hz.

I could use available design software to make a Linkwitz-Riley 2nd order at 1100 Hz, but I want to use the original ESS design.

I have a LOT to learn about crossover design and function.

- I understand the 3 position switch/tweeter attenuation circuit, but what purpose does R1 and L3 serve in the original design?

-How would an L-pad be inserted into the original design to replace the three position switch attenuation circuit?

-Will the typical crossover design software values work for replacing C1, L1 and C2,L2 to raise the X-over freq to my desired 1100 Hz....and would the values of R1 and L3 also have to be changed at the same time.

Thanks to the group!!
Wayne

Hi,
I have a TCC TC-750LC phono preamp. I want to increase it's gain by about 6db -10db. It seems that I should be able to tweak the values of a couple of components to do that. But I would be mostly guessing what to change since I only partially understand the circuit. Anybody have some good thoughts on how to accomplish this without hurting it's other performance levels?

Thanks,

Specs. for the TC-750LC:
12 volt DC,
Output level control with >85dB range,
RIAA freq response 20hz-20,000hz +/- 0.5dB,
S/N ratio >85dB,
THD <0.05%, input sensitivity 3.0mV,
Gain 40dB,
Nominal / max output 300mV / 1.8V,
Output impedance 1k ohm,
Input 47k ohm /220 pF

Here is a link to a schematic. and a couple of pictures of the PCB I took:
http://beavishifi.com/articles/phono-preamps/TCC-TC750-Phono-Preamp-Schematic-1200.png

Newb to DIY audio, but I have experience soldering and think I do a reasonable job.

Long story short, everything was I storage after divorce and move, storage unit burglarized and everything is gone. All tools, car, bicycle, electronic, etc.

Finally getting to a point to start working on audio projects, so I need a new soldering station, desoldering, etc. I'm just a part time hobbyist, so price is an issue. <$100 for soldering station is preferred ($75 or under would be ideal), will need desoldering and pretty much everything to start.

I've been looking at this soldering station...

T12-959 Soldering Station Iron Kit, LCD Screen with T12 Soldering Iron Tips, Automatic Standby-Automatically Wake up, for Electronic Repairing With ILS JL02 KU BL BC1 tip (SET5) https://a.co/d/7opEkWq

But what other equipment would be considered bare essentials? Links appreciated.

Cheers!

-Alex

A few years back, I was doing a search for various all tube power supplies and came across a General Radio supply that had a very interesting layout
the specs are fairly good, and it has some interesting features which include feedback, and the use of a 6AN8 triode as a cathode follower to control
the pass tube, although it uses some feedback to improve the gain of a cathode coupled pair of triodes, which I think is its primary weakness,
and since I had been using a 723 regulator in some projects, why not use the 723 for the reference/error amp instead of the 12AT7, and I came up
with this creation, it works well in spice, and breadboards nicely, I will need to fine tune some of the resistor values, but all in all not bad.
and it improves regulation greatly, both the reference voltage(7.25VDC) and error voltage are virtually spot on, about 0.01%.

i tried this board in two amps and the same ting happend ,2 output transistors blew and all the power supply mosfet.amp played clean and all of a sudden it blew.what on the drive card could cause this to happen?

I want to build a 2-range speaker system (treb and sub). I came across 2 circuit diagrams. One uses a preamp to filter out the frequency and then connects to the amplifier.The other one does this using a crossover.



What is the difference between a preamp and a crossover when it comes to filtering out the frequency?Which one would work best in a small speaker setup?

My setup:
Amplifier: Tpa3116d2
Woofer: 4ohm - 20w
Treb: 4ohm - 15w

Moving from two homes to one necessitates that I sell the smaller of my two speaker systems. For sale is my Hornshoppe “The Horn” complete speaker system. These speakers are so efficient that they sound more than loud enough to me in an 11ft X 15ft room powered by a 1.5 watt/channel DIY tube amplifier. The speakers consist of:

The Horn speakers $450obo ($925 current new price)
The Cube base enhancer with Dayton Audio APA150 crossover/amp $300obo ($575 new)
ESS Great Heil $450obo ($700 in 2012)
The Horn –> Heil crossover – included free with The Horns ($75 in Erse & Auricap parts)

More about the Horns: The laminar finish has striped lines (referred to as “beauty marks” by Ed Schilling) that also appear in the cube. The speakers were upgraded to the Fostex FE126en, but one of the center domes was dented in by a grandchild. I couldn’t hear any sound difference, but I wanted to point out the defect. Matched replacement pairs are available from Ed Schilling for $100/pr.

the horn shoppe

SOLD

Asking $275 $250 $175 plus shipping

For sale is a pair of Electro-Harmonix 300b power triode tubes. Russian tubes are no longer being imported. These were manufactured just a few years ago.

These were used for about 150 hours in a SET amplifier without issues. Great 300b sound!

The tubes were retested after use on my eTracer computerized tube tester. Tested at 350 plate volts, -71.5v bias. New plate current (Ip) is 60mA, transconductance (gm) is 5000

Tube R Ip = 47.73 mA (80%) gm = 4888 (97.8%)

Tube L Ip = 51.01 mA (85%) gm = 5016 (100.3%)

Tubes come in original boxes with full testing data on box and original factory testing numbers.

Shipping via USPS Priority Mail only.

I have the model in title and looking for schematics. I know that it could be called by other names bc they use amps in different models. Has 4 6L6GC in output stage.

I have this model of my midbass enclosure in Sketchup but it won't give me volume. As a matter of fact it won't even close up the sides, maybe something about the odd shape but none of these surfaces are curved just different angles. There is one side it closed by as you can see I made an X in the other side and it didn't close it up.

Solid Inspector has errors but they dont' make any sense to me. I even erased half of the walls and redrew them, then deleted the others ones and redrew them with no difference made. I don't want to go down the math rabbit hole on this one!


I dow

Hi,
I've just finished a protection schematic for my audio system. Some circuits are my idea, others are found on the internet. The schematics are tested only in LTSpice so far. I want to know your opinion before I start building it.

It has the following features:
- 2.2s start delay
- disconnect speaker in 120ms after power down
- disconnect speaker in 50ms after 50V DC on amplifier output
- disconnect speaker in 100ms after 1MHz @ 3Vp on amplifier output
- disconnect speaker in 1...10ms after exceeding maximum current
- thermal shutdown with programmable temperature
- variable fan speed controlled by temperature
- clipping indicator

If you know other usefull fetures, please let me know.

SOLD



For sale is a pair of unused Genelex Gold Lion Reissue PX300B tubes manufactured in Russia and not presently being imported.

The tubes were taken out of their boxes for inspection and photos, I added an R and L to the bottom for identification.

They have not been in an amplifier.

Date codes match at 20 02

Factory testing matches at 57mA @ a gm of 5,600 umhos

Come in original boxes.

I will ship only via USPS Priority insured mail.

For sale in Germany a complete kit for a Salas DCG-3 preamplifier as it came from Tea-Bags group buy: https://www.diyaudio.com/archive/blogs/tea-bag/865-group-buy-salas-boards.html

Price: €70,00 plus Shipping

Hi people,

Long time lurker here, finally decided to make an account to ask a burning question.

I recently came into possession of a NAD 705 that sounds very nice but runs way too hot. Within minutes of being turned on the central heat sink would literally get hot enough to burn fingers. Top case off made no difference. 😵

At first I thought this might be a DC offset issue, but I measured the speaker terminals and got 15mv, which was within spec. The I did a visual inspection, looking for bulging caps and burnt looking resistors, couldn't find any either. I'm at a bit of a loss what to check next.

What does the collective wisdom here think? Any tips for me?

Service manual attached, for anyone interested.

Cheers

I've just finished a full recap and service on my recently acquired Philips CD100 vintage CD player.

After overcoming a few unexpected issues the player now reads and plays well part from the fact that towards the end of a disc, say track 10 or 11 on a typical album, the player starts to make a strange high pitched ringing noise.

It sounds just like running a wet finger around the rim of a wine glass! Up to around track 10 it is silent and then beyond that point the ringing noise starts.

Has anyone here ever experienced a problem like this and what did you do about it?

Hello everyone!

I was wondering if it is possible to run TPA3255 in a composite amp configuration? LM4562 is something that everyone seems to be using as error correction opamp, so I figured will be nice combo.

Where can I find resources on that kind of information?

Thanks in advance,
Pavlo

OK-

So I need a sanity check- I have all the parts- needed. FRD/ZMA for SDS woofers for simulation provided and measured on 37.5H 8.5W 10.5D box with DATS by someone in another DIY forum.
FRD/ZMA for D220TI were also provided and measured I was told- not sure baffle size...anyway I am just trying to get close and use some these drivers I have. WG will most likely be HM17-25 seeing as I already have 2. I have 3 dayton audio H6512 but not sure how id like such a large wave guide going vertical. If you think im being an idiot please let me know lol- if you see a issue please explain it to me like im an idiot-

This will be a good way to use up a lot of stock sitting around and if it turns out they way I hope, I plan to do the rest of my speakers like this for our theater.

SDS 160F25PR01-08 is the woofer. again I have everything I need minus the 30uf cap if thats better- I have 1.5Mh but no labels haha so will be pain figuring out which ones they are..


With this XO i have 5DB NULL at XO when inverting tweeter..




WITH THIS VERSION i have 10DB NULL AT XO- I just changed CAP on Woofer to 30DB

Hey everyone,

New to this forum.

I'd like to get better (and nice looking!) sound in my small office room, which is about 10 square-meters big, even less when I come to think of it. I'd like to get a pair of regular sized bookshelf speakers together with a vintage Marantz receiver.

I love the look of the 22XX-series, but I can't really decide (or know) how much power I actually need. I've heard that "marantz watts" can't be compared to a modern receiver denon/onkyo watts, and that's my only reference as I've never owned vintage.

I know the 2270 is the one to go for as you can never get too much power, and things tend to sound better even on low volume with more power. However the price for the 2270 is a bit steep so I'm thinking if the 2245 will be enough. Again, I want to emphasize that I won't connect floor standing big speakers, but a set of smaller bookshelf speakers. To give you any reference, I am currently running a Marshall Woburn in this room, and I found that loud/good enough for the size of the room.

Do you think I'm set with the 2245 or would you go 2270? Or is even the 2245 too much for what I'm pairing it with? Will even a 2215 do?

Thanks for any input, completely new to vintage receiver.

Vol

I have a unique situation and as I'm more mechanically inclined that electrically, I could use some help from the resident experts. I have the Corsair HS60 Haptic headset. For bass frequencies, they use a Taction Technology tactile transducer instead of an audio driver. Thus, it seems they have an analog or digital crossover to divide the audio frequencies between the tactile transducer and the traditional audio driver.

For my application, these are the only headset/headphones that are desired and currently commericially available. Taction Techonology used to sell the Kannon headsets which have a 3.5mm/1/8" TRS plug. While I also own a pair of the Kannons, as they have been discontinued for a while, they are expensive, somewhat fragile, and hard to find used.

What I would like to do is convert several Corsair HS60 headsets, which only accept digital audio via USB, to analog headsets (stereo audio + microphone). I recall in car audio enthusiasts would tap into audio components PCBs before or after the DAC (I don't recall which). Thus, I am wondering if it is possible to bypass the DAC on the HS60 headset so it can be converted to analog?

One complicating factor is the dual drivers (tactile + audio transducers) and whether the crossover is digital or analog.

It seems the current HS60 audio path is one of the following options (Left/right audio only, excluding the headset microphone):

1) USB>Digital Crossover>DAC>Analog amplifiers
2) USB>DAC>Analog Crossovers>Analog amplifiers

I suppose there is remote possibility that the amplifiers could also be digital, but I doubt it as digital audio amplifiers are very rare, especially in headphones.

Is it relatively easy to identify the DAC/analog crossover on a PCB? If it is, then it seems that it should be possible with good soldering skills to convert this headset from USB audio to analog. Another complicating factor is the amplifiers likely drawer power from the USB port, so a 5VDC power source would likely be needed.

Attached are some photos of the PCBs (there is one in each ear cup) for the experts who understand the components. These are old photos, so if I need take the HS60 apart for better photos, let me know.

I'm curious if just from looking at the PCBs whether it is obvious if the crossovers are digital or analog and if the analog signal after the DAC can be tapped into to convert the headset microphone audio and Left/Right channels to analog.

I am looking for plans for a simple, easy to build, light weight top that is useable with the Tham15, which can't play very high.

Can anyone link or suggest some recommendations? Everything I am finding doesn't go low enough or is way too heavy/complicated with too many drivers.

I am very green and my building skills are new.

Eminence, B&C and Goldwood drivers all available here, but I struggle to find most other brands.


Thanks!

Hello Jason! 🙂
I'm not sure wether I updated my membership (and to what level), so there are 2 questions:
Can I see my membership-status?
Can I up my membership (from aficionado to fanatic or even conoisseur)?
thanks, for everything!
david

Hi, i building this kit from Aliexpress.
im repurposing the heatsinks from an Onkio amp I salvaged for parts.
made some modification with:
1. added foil capacitors parallel to the original electrolytic once.
2. bypassed the power supply diode with a short.

i wanted to cramp it all in a reasonable small enclosure. but common sense indicates EMI RFI potential interference.
what do you think? i guess i can try it before i cut the rear panel with CNC. if the SMPS will stay out i will make the enclosure smaller.

link to photos

A few months ago, @gpapag posted up some linearity plots of a couple of experimental 'Abbado' DACs I'd sent him. Below around -66dB (equivalent to the 11th bit), the results begin to look not too great, certainly not in comparison with DACs based on much more modern S-D chips which tend to have near-perfect performance on this particular metric. I played around with making some low-level measurements myself and confirmed the basic premise that low-level linearity is an issue and from varying the input levels t looked to be due to inaccurate bit-weightings in the DAC's internal architecture. What I didn't know though was how big of a bit-weight error is needed to give rise to such deviations from linearity - I wanted to get a handle on the order of magnitude involved. I figured maybe I could coax LTSpice into doing some simulations of this.

LTSpice allows input of .wav files to the sim, the data is converted to analog automatically before being applied to the circuit. What I really needed in order to test out DAC linearity was the ability to input digital data, not analog. As far as I'm aware that's not an available feature so I wondered if I could develop an ADC which would convert the .wav file back to digital in the simulation and then I could apply that digital stream to my simulated DAC. By tweaking the bit weights in the simulated DAC I might be able to see how linearity is affected and get a feel for the degree of effect. But how to design an ADC?

There are two kinds of ADC which might be suited to this task - a 'flash' and an 'SAR' type. The flash type has the disadvantage of complexity - it needs of the order of 2^N comparators for an N-bit ADC. I figured I'd want to begin with a 5 or 6 bit ADC and to save on a lot of copy pasting to create a flash ADC I wondered if the SAR type might be better suited. An SAR ADC only needs a single comparator but has a significant disadvantage of needing a clock and a register to remember the results of earlier comparisons. I've never built any clocked logic circuit before in LTS and, being very lazy I decided to at least try to combine the clock-free nature of the flash converter with the low component count of the SAR. Perhaps I'll call my approach the 'FA' for 'flash approximation' - it falls between the two in complexity, only using one comparator for each bit. It needed a little bit of tweaking to create what appeared to be a working 6 bit ADC out of 12 voltage controlled switches and 6 reference voltages - being as the switch type in LTSpice is a single pole and I wanted a changeover function I wired two single pole switches in anti-phase. Of course such a design would never work in the real world but that doesn't matter in this instance, its only going to live inside the sim. Being as it produced a nice stepped waveform for an input sinewave with very little effort I began to be suspicious if there wasn't some hidden gotcha going to bite me further on down the road. So I needed to characterize my 6 bit FA ADC to ensure such a simple design really delivered the goods.

To characterize it it needs to drive a DAC back to back and then I can do tests on the DAC's output waveform. The DAC is almost the same as the ADC and uses 12 voltage controlled switches and again 6 voltage references (but different instances) for the bit weights. I hooked up a sinewave voltage source at full-scale into the input and ran an FFT on the DAC's output. Looked respectable indeed and the SFDR was in the region of -60dB, too good to be true! I took the input amplitude down to 2LSBs (about 30mV) and wondered what would show up. Quantization distortion, that's what. Ah, dither would come to the rescue I thought. I had to delve into the workings of LTSpice for this as I'd never created an explicit noise source before - the 'White' function serves a good purpose. TPDF dither (needing two uncorrelated sources summed) would have to wait as just creating two instances of 'White' can't uncorrelate them. How to set the dither amplitude? I figured do it by eye when the FFT completely lost the spurs of the harmonics of the test tone. The 'White' function also has a parameter which seems to relate to the bandwidth of the noise generated, I got decent enough results setting this to 44,100. But I couldn't resist high-passing the output before applying it in series with the test tone.

So now I had what appeared to be a kosher ADC feeding a perfect DAC and at least based on FFTs, the results were as close to textbook as I could have hoped. Time came to try making some linearity measurements - I figured to get the best measurements of amplitude I'd want a low-pass filter do get as clean signal as possible, so I plugged a 1kHz 5th order Chebyshev lowpass on the output of the DAC, the stimulus being 1kHz. Using the 'step' feature I ran a sequence of different levels into the ADC and made '.meas' of the output. Still being a bit suspicious of my ADC though I also put the amplitude quantized analog version of its own digital output through another instance of the same filter and compared. The ADC line wasn't straight at lower levels, it had a bulge. Hmm, what could cause this?

<attached George's linearity plot of the prototype Abbado DACs which use TDA1387>

I'm still fairly new to DIY audio and had a quick question (that may fall into "there are no stupid questions, but this one is stupid").

I have a TOA P-300D I am using as a sub amp, I do realize it is not the best amp but it was part of audio lot being sold by my local school. I do not think it has been serviced in quite some time but it is in operable condition. My question is will servicing the amp have a chance to improve the headroom of the amplifier. Within its limits it sounds fine but once it crosses over into clipping (even for brief transients, like a kick drum) the distortion really picks up.

Or is it simply just the wrong tool for the job? My guess is this is an amplifier more for a paging/intercom (very compressed signals or speech) in its design where it can provide its maximum RMS power forever, just don't ask for more. The user manual does show the power curves vs distortion and past its rated power there is a huge almost vertical spike in distortion. So maybe it is only operable for 1/4 of its RMS rating for musical applications.

I know some of the other more dramatic symptoms of an amp needing service but I'm not sure if this is one or not.

Any input will be greatly appreciated, thanks in advance!

Also incase it would help with the question, the amp is running a jbl 2242 in a 9 CF box tuned to 25hz, with B6 alignment (almost like a 4645C), but it is 1 CF larger so it would have the same footprint of the Altec 518 cabs (speakers that came with the amp). I know the 2242 are not the ultimate in VLF reproduction, but once again the price was right ($200 for an unopened box NOS pair)

I believe PLLXO is the quintessence of crossovers. Super clean, no ill effect, just pure loveliness. But they have a huge problem. Matching with the actual amplifer and its input impedance. And especially your next amplier. Until now! Our hero enters - Adason!
Here is his contribution to humanity - a buffered PLLXO.
His own thread: https://www.diyaudio.com/community/threads/simple-active-crossover.368702/


I have a strong desire to try this out. This thing is sleak!

However, I lack any skill, or even talent, in the electrical field. I have to do this in the short brakes I have from cutting human tissue samples looking for cancer, and other unimportant tasks.

I have come up with this completing schematic which might help anyone who tries to mimic this circuit.




Some things I am trying to figure out:
¤ Bi-polar caps on input and output. Should probably be used.
¤ Dual Rail - important to understand how this works. See V+ and V- and ground in schematics.
Adasons preference is something similar to this PSU that can reduce the need for the 100uF/V35.
https://www.ebay.com/itm/164845881741?hash=item266194898d:g:ObUAAOSwxmdgj2z3&amdata=enc:AQAHAAAAwNGeP5fYh2oIx+yK4Io3k2fHDvEu5iQEkIL08ckzHZTCZERincMe2HroKGMBjI9NoePqlCIF04GR+QU43jNO/3SE6NKRPArKb8eDvh8Lhgtr3PSM1NmE3c7C2cJ99GSr5GFyHrxVm6oxJTKYz/Yuj6Xlceo0NN9gfvm1zdjGnQFIirgfSnixy3ZW1k/WGBwITaSy4U3TtIW7bX6Sjd8JnXKltnMAp0I7bkxrjvW2TcZIuZsMh6rbXCG9i4b9EM1rkA==|tkp:Bk9SR_jc5unWYA

¤ How to modify the circuit for other frequencies:
The schematic says first, choose C. Well, choose C based on what?
In Dave's pages, which Adason refers to, is says choose R.
Somewhat contradictory,
take
Let a known example of the 150Hz that Adason was working with:

If C= 0.1uF
Then,
R = 1/ (2 x Pi x "crossover frequency" x C
= 1 / (2 x Pi x "crossover frequency" x 0,1 uF
= 1 / (2 x Pi x 150Hz x 0.1uF
= 1 / (2 x 3.14 x 150 x 0.1uF) = 10k Ohm

Adason is using these values a lot in his schematic. I am not sure if every value is based on this formula.

And reversed:
C = 1/(2 x Pi x "crossover frequency" x 10 000 ohm
C = 1/(2 x Pi x 150Hz x 10 000 ohm)
= 1/(2 x 3.14 x 150 x 10 000 ohm)
= 1.06157113e-7 F
= 0.106 uF
= 0.1uF

0.1uF - same can be found everwhere in Adaons schematic.
According to Adason, if using a really clean PSU, you might not need to use the unmarked "rails ripple shaving caps", as ZM so kindly pointed out that they were called.

Anyone are welcome to help me and others to understands this circuit and solder ourselves a working example. Please correct it!

Hi,

here's something that may sound like a beginner's question, but believe me, I really don't know how to: I've got some old transformers from Hammond organs. Their leads are isolated by some white plastic material covered with coloured cotton (?) fabric. How do I remove the isolation successfully? I tried my insulation stripping pliers that works well with modern PVC and silicone isolations, but fails here. Using a knife always leads into cutting some of the braid wires. How do you guys proceed with that?

Best regards!

Same old story, the freaking neighbour's dog keeps barking, yapping and howling almost every day all day long when left in the garden. Not sure what breed this dog is but it barks even without any reason, even if neighbours are at home (but not in the garden).

We have a wooden fence. I've tried 4 different ultrasonic deterrents but none of them were effective. I've done some Googling but nothing seems to be working.
It is not possible to do direct line of sight. Cutting a hole in the fence and putting the device there is also out of the question.

I'm in the UK so 👎th amendment or whatever you call it in the US doesn't exist here. Complaint, court, local council or any other ******** doesn't work. I've already tried. Can't shoot that fu**ing dog because we don't own guns. My neighbour is an *******. Want to try something which works without resorting to the "Ultimate Solution".

Does anyone know any device, custom build or how to build it or whatever works in shutting up this neighbour's dog behind the wooden fence?

When making an enclosure, ideally one would make the walls non-parallel. But how is non-parallel is non-parallel? What about 5 degree on the front, is that non-parallel enough with a vertical back? I would assume at only 5 degrees enough wave would get back to the front. So what is the lowest limit? My thought would be one where the other side would not hit the other wall with a perpindicular line so maybe this would vary with the distance between the 2 walls? What has your experience been?

hello everyone, I am writing because I would like to have some opinions on a midwoofer that is rarely talked about on the forums and that is the seas w12cy003.
in particular, it could be used with a 9500/9700 or the illuminato 660000 scanspeak tweeter?
my idea is to build two mini monitor of 4 or 5 liters.
thank you

Hi all,
I'm building a pair of wmtw towers. Drivers are Beyma 15lex1600nd, 12p80nd and JBL 2451 in a JBL 90x50 waveguide. Om my testboxes i have the slots for the 15 inchers located horizontally below and above the drivers in each end of the baffle. On my final boxes however, I'm thinking of placing them vertical on each side of the 12" and waveguide like on the Genelec 1032.
My concern is how it will affect the sound? The bass wont get additional support from floor but what else?
Thanks for any advice!

I just completed a hot air repair to the output stage of a VX1000/1i, replaced all the outputs and the HIP2101 drivers. But I noticed the silpad making the thermal link between the output devices and the sink is some sort of putty type stuff, and normal silpad isn't thick enough to fill the gap. Anyone happen to know what this stuff is or where I can obtain some?

For sale some 10 years old transformers taken out of Sound Carrier 807PP amplifier. I contact the company in Croatia and they confirm that this transformers were hand made in this company. The company makes some verry good transformers and hiend tube amps. This pair was in amp that costs 3k euro. So they give me some data. Primary 5Kohm,secondary 4&8 ohm,40% UL taps and good up to about 60watts.Each transformer is 12x12x10cm big and 5 kg havy. Price is 50eu for bouth plus caa. 30eu shipping inside EU.

Hi...

One of my friends will give me some parts of old SA3 amplifier. Parts will include amp PCB's and PSU, unfortunately missing part is amp enclosure and heatsink with output transistors. Some modifications are existent on PCB's (he told me that) . Please help me with some guidance. I found on internet not so clear schematics of S300 (basis of SA3) and to put PCB to original state my idea is to put all new transistors and acquire all transistors for output stage.
My question is: is this transistor lineup in SA3
MPSA42 14 pcs,
MPS6571 8 pcs,
2N4250 2 pcs,
MPSA92 6pcs,
MJ15022 14 pcs,
Mj15023 14 pcs
2n3440 2 pcs
and 2N5413 2 pcs.

Thank you all for help on this technical topic...

Hi Guys,

Hope you can help with a quickie:

I'm building some big active three-way monitors and have a question regarding passive radiators: is it possible to mount the PR on the front baffle together with the bass driver? So they're basically pointing the same way?

Hope you can help a complete noob🙂