[Tutorial] Building your own DIY E-Stim Stereo Device

[diglet]

To test the transformer, attach them to your amp and play a sine wave. Use multimeter to measure the voltage over the low side of the transformer, and then the high side (don't connect anything to the high side). The ratio between them is the approximate winding ratio.

I tested 6 transformers from conrad, but one of them had a manufacturing defect that was difficult to spot. You can try repeating the test above with a 1kohm resistor attached to the high side (Be quick or the transistor will burn..), both transformers should read the same values.

[Nobody81]

(Sigh)...okay, I've tried to see what might be wrong with the transformers, and they're working fine. As a matter of fact, I've tested everything else twice over and saw that the amp was bungled and I had ordered the wrong sized parallel resistors. So I ordered a new amp plus the proper resistors, along with a new set of pot knobs, some pre-wired switches since the other one didn't hold up very well to the solder heat I was subjecting it to, and finally, some of those WAGO terminal crimps I've seen all over this thread. Had everything hooked up and ready to go...and I still got no fuckin' CURRENT!.

I'm almost at my wits end. I think it might be the On-Off switch, but I'm not sure. What should I do?

[Nobody81]

Here is the switch in question.

[Míchael]

Cant tell you much about the switch but what i see is that you go into the transformer with one ressistor in series not parallel. I also see only one ressistor per channel. What schematics are you using ?

In general on a different note i would skip the complicated switch which aim it is to shut off everything at once. For my build I went with a simple on / off switch for power and each channel.

[Nobody81]

Im building this based on lolo2's second iteration with this board, but I was trying different configurations to see if that did anything. This switch is 3PDT which I have wired so "on" let's the current through the wires for power and "off" let's the current only through the cha... shit, I think that's it.

[Nobody81]

NOPE, That wasn't it either. Despite having dropped another $50 on replacement parts, it still doesn't put out any amps. You know what? Screw it, imma go back to pre-built amps and figure out a way to have dual volume knobs and a tri-phase switch unless anyone else can give me a suggestion on what else might be wrong.

[Míchael]

NOPE, That wasn't it either. Despite having dropped another $50 on replacement parts, it still doesn't put out any amps. You know what? Screw it, imma go back to pre-built amps and figure out a way to have dual volume knobs and a tri-phase switch unless anyone else can give me a suggestion on what else might be wrong.

I would not focus on measuring amps tbh. Test all continuity / shorts and test for voltage and ohms. Make sure your connections and parts are working.

1. put in some audio input cables and test for continuity.
2. test if the pots are working correctly. Also make sure you use the right pot for the right channel (i made that mistake and it drove me crazy)
3. check if you have any shorts
4. put power to the amp, It has blue leds that should be on once it has power
5. check input voltage which should be 12v dc
6. put in some audio signal and check the speaker voltage should be around 10v ac. If there isnt any voltage:
check the pots resistance. If the resistance is 0 check the pots on the amp itself
7. check the output voltage (ac) at the transformer.

[Nobody81]

I had it working...I finally had it outputting current when I realized my electrode wires were bad and replaced them. Then, in my excitement, I wired the resistors to the transformer in the wrong polarity and now I think I've not only fried the amp since it started clicking on me when I turned it up, but also my transformer and my power supply too.

(Sigh)

Thank you anyway.

[Míchael]

I had it working...I finally had it outputting current when I realized my electrode wires were bad and replaced them. Then, in my excitement, I wired the resistors to the transformer in the wrong polarity and now I think I've not only fried the amp since it started clicking on me when I turned it up, but also my transformer and my power supply too.

(Sigh)

Thank you anyway.

Ok first of all resistor's dont have a polarity. Remember that transformers generates a buzz sound when you put power in them. In germany we call that "spullenfiepen". You should test the box in parts now to be sure. First only hook up the amp check for the leds and the voltage. Then hook up the transformer.

[Nobody81]

I FINALLY FUCKIN GOT CURRENT AFTER A MONTH OF WAITING TO BY A NEW AMP! Bonus, the transformers and the power supply are fine though I've bought extras along with the amp just in case but still...wheewww. Now I can finally end NNN with a bang!

[Art2034]

Hi guys
My first post but just had to thank Iolol2 for his clear explanation of how to build a DIY box.
Started estim last year and quickly progressed to a 2B which is great albeit with the limitations all of you know about. Finally decided that I needed the full experience and therefore had to build my own box. Followed Iolol2 revised build (page 12) and collected up all the bits needed.
Assembled it yesterday and tried it last night - wow!! What a blast, the difference between dial up and fibre! if it wasn’t addictive before it certainly is now.
Thanks for all the advice - mine to anyone considering this is just do it, read the whole of this post but don’t get bogged down in the technical stuff, you don’t need to know all that. Enjoy and thanks

[Nobody81]

I..I don't know what happened.

I got current through one channel but not another, so I figured after testing the other components of that non-functional one, that it had to have been the wiring of the audio inputs and volume knobs.

After that, something strange happened. I tried testing that one channel again, but still nothing. Then, as I went to turn down the volume on my laptop where i was feeding the machine a signal, i got shocked everytime my fingers got close enough to the copper contacts under the key. Literally everything i touched that was metal shocked me but i felt no current where it was supposed to. Even weirder, i tried the channel i know that worked, and the same thing happened.

Now im thinking i got another board fried for something stupid I did, and im probably just gonna go back to what works for me which is the Breeze Audio amp Tronic's got listed in his schematics.

But just in case anyone knows, what happened to me exactly?

[fishyfish]

Hey,

I'm looking to build one of these too. All other parts were easy to source but the transformers seem more tricky.

Model: Compact transformer unencased, vertical model
Primary: 230VAC 47-63Hz
Secondary: 24VAC
Power: 25VA
Dimensions: 52 x 55 x 89 mm

voltage: 2 x 24V
current: 2 x 0.250A
transformer can be screwed onto a PCB
operating temperature: -20°C to + 70°C
dielectric strength: > 5000V
meets the following norms: BS 3535, VDE 0551, IEC 742
a thermal fuse can be fitted
primary AC line: 230V - 50/60Hz (parallel and series connection)
other VA's and sizes available on request: up to 250VA

Would either of these happen to be suitable for the project?


Edit: Found a better alternative

[Electro]

You want an audio line transformer of a reasonable physical size that has the right turns ratios, the one described doesn't sound like it is one. People are able to find the correct ones depending on their location. If you are looking for the right one, knowing your country would help with providing a suggestion as others in probably every major country/continent have built a Stereostim.

[fishyfish]

You want an audio line transformer of a reasonable physical size that has the right turns ratios, the one described doesn't sound like it is one. People are able to find the correct ones depending on their location. If you are looking for the right one, knowing your country would help with providing a suggestion as others in probably every major country/continent have built a Stereostim.

I'm from Finland.

They have some audio related transformers here: https://en.uraltone.com/electronic-comp ... hokes.html

I'd appreciate help very much! I'll also study the turn ratios. I suppose it's not always listed?