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

[InfamousPlantain]

Easy answer... I have seen people using the 22ohm in combination with the 3.9ohm and decided to use them too.
There was no big math behind that decision.

So I can't tell what exactly the diference to smaller ones would be.
I only can say that this combination is working for me.

thanks!

[ssw]

Hi Guys,
I live in Australia and sourcing the exact parts for this build have been an issue,
the transformer I am using is
https://www.jaycar.com.au/5w-line-speak ... r/p/MM1900
and the amp i am using is
https://www.aliexpress.com/item/1005003447250822.html

Luckily me for me i test the voltages before getting anywhere near my junk, at first i started using a pure tone audio as a baseline to get the multimeter readings, all seems fine. in other scenarios when i test using the back of my hand it can go from a slight buzz to a jolt worthy of an electric fence.

Is it possible that voltage is accumulating in the amp or transformers ?
if i put the transformers close to each other can the voltage jump from one to another. ?

Thanks for any feedback, im keen to try it again but not with such random spikes

[19Hellothere83]

I finished buiding the latest version with the new amp.
However I noticed that the two channels influence each other much more than on the version before.
What I mean is that when I switch on triphase one channel influences the other extemely.

E.g. on triphase the feeling on the left channel may vanishes or gets too stron when dialing up the right one.

I did not notice this in the previous unit?

EDIT: 2022/07/07 - I was testing the unit with different files ... after testing the two units with the same files I must say that this issue is not really present, I am sorry for writing stuff before properly testing the unit

[edger477]

I finished buiding the latest version with the new amp.
However I noticed that the two channels influence each other much more than on the version before.
What I mean is that when I switch on triphase one channel influences the other extemely.

E.g. on triphase the feeling on the left channel may vanishes or gets too stron when dialing up the right one.

I did not notice this in the previous unit?

Connect headphones to amp output and check if is amp doing cross-talk from one to other channel... that way you can isolate whether is amp or midstim stage. Some amps have sensitive inputs, it could also be inducing to other channel if you have long cable from sound card to amp, if you see amp is doing cross-talk, try connecting only one channel from sound card to see if it is in amp or in cable.

[19Hellothere83]

I am using a 2 pole shielded liycy cable from the cinch input to the potentiomenter, from the potentiometer I use the original amps imput cable which looks to be a 2 pole shielded cabe also.

2 poles for left and right and schield = common ground

[19Hellothere83]

I finished buiding the latest version with the new amp.
However I noticed that the two channels influence each other much more than on the version before.
What I mean is that when I switch on triphase one channel influences the other extemely.

E.g. on triphase the feeling on the left channel may vanishes or gets too stron when dialing up the right one.

I did not notice this in the previous unit?

Connect headphones to amp output and check if is amp doing cross-talk from one to other channel... that way you can isolate whether is amp or midstim stage. Some amps have sensitive inputs, it could also be inducing to other channel if you have long cable from sound card to amp, if you see amp is doing cross-talk, try connecting only one channel from sound card to see if it is in amp or in cable.

connection between sound card and amp is a good quality jack to cinch.
How do I recognize cross talk with headphones?
Should I play to different things on each channel and see if i can hear it on the other channel?

[edger477]

Should I play to different things on each channel and see if i can hear it on the other channel?

If you can connect headphones to amp output, yes, but first try them with normal input to make sure it works (with low volume) and you don't burn out headphones. Or if you have a good speaker for that amp.

[InfamousPlantain]

Hi Guys,
I live in Australia and sourcing the exact parts for this build have been an issue,
the transformer I am using is
https://www.jaycar.com.au/5w-line-speak ... r/p/MM1900
and the amp i am using is
https://www.aliexpress.com/item/1005003447250822.html

Luckily me for me i test the voltages before getting anywhere near my junk, at first i started using a pure tone audio as a baseline to get the multimeter readings, all seems fine. in other scenarios when i test using the back of my hand it can go from a slight buzz to a jolt worthy of an electric fence.

Is it possible that voltage is accumulating in the amp or transformers ?
if i put the transformers close to each other can the voltage jump from one to another. ?

Thanks for any feedback, im keen to try it again but not with such random spikes

What kind of case and input/output jacks are you using? In my case (heh), which sounds kind of similar to yours, I had a metallic case and it was causing all sorts of issues with the input/output jacks not being properly insulated. see my post here on the other thread: viewtopic.php?p=315216#p315216

[19Hellothere83]

Here some pictures of my new unit.

Spoiler: show

Front with stereo sound level display

50319A39-7369-43F6-B0F8-494A4A047AFE.JPG (563.93 KiB) Viewed 4889 times

Mounting plate below with fan and temperature sensor

0D3591BD-8C1A-4877-9D5D-27F863B1932B.JPG (737.08 KiB) Viewed 4889 times

inside

3FC45C5D-4A31-49E0-98EA-A65594082AD0.JPG (842.89 KiB) Viewed 4889 times

[LegendaryDrive]

This is fantastic! Which schematic did you use? I’m wanting to build this and have started accumulating the parts.

[19Hellothere83]

This is fantastic! Which schematic did you use? I’m wanting to build this and have started accumulating the parts.

I build two units with the first schematics and the last one with the latest schematics.
Having some issues with the two channels interfering with each other in the last one, hope I can understand the root problem soon...

[lolol2]

I don't noticed a big difference between both designs in channel interfering.
Triphase has always a kind of interfering in volume between the channels when you use one common electrode.

[19Hellothere83]

I don't noticed a big difference between both designs in channel interfering.
Triphase has always a kind of interfering in volume between the channels when you use one common electrode.

next week ill use same setup for both boxes and see... maybe its just me ... ill report later next week

[arig4711]

I don't want to discuss the obvious anymore, but please be aware of the risks (also the recommended 12V Power supply is not Class II).

Can't hop into that discussion because I'm not that deep into electronic stuff but let me add that the Leicke power supply's should be all class 2, also the linked 12V one (Model NT03015).
The shown picture on Amazon is just a general one, not representing the actual device.


p.jpg

I bought the power supply because of this information. The power supply is definitely not Class II and the picture on Amazon is the right one. Perhaps Leicke changed this. Has your power supply two or three pins? If it has three pins, it has a GND-pin and afaik can not be class II (although it has the symbol). The only class II-power supply with more than 7.5A / 12V I know is one from Meanwell (GSM160B12-R7B, quite expensive), which is used in medical environment. Anyhow I have to return the power supply.

[lolol2]

Thanks for this information, did you buy it over the german amazon.de link?
Maybe a change in production could happend... I have two of them -> both 12V 10A with class 2 and only 2 pins from the socket.

I have added this as a note to my guide, can't confirm this, only can say that I bought exactly this model over this amazon link and got a class 2 two times.