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

[mantrid]

Regarding the rest of your bill of sale, do you know anyone who has all of that in the exact combination? If not, you could run into problems with matching components.

Guys, there is a spreadsheet where you just need to enter the values and a explanation how to use it: viewtopic.php?p=290244#p290244

An often unconsidered issue is clipping. I noticed this when I attached an oscilloscope to a realistic dummy load. (That is probably the reason why certain files where less harsh for me. But this also influences 3-phase effects.)

[Brickx]

Just refound this website and got TeaseAI up and running and i would like to add a E-stim device, because there is so many info on this site i'm not quite sure if i got it right

TeaseAI has EStim teases? I know Spicy has a E-Stim Systems 2B interface connection, but doesn't have any stim files for audio output. Which TeaseAI teases are you looking to use?

Regarding the 'no balance for the input signal' - I don't think this matters much myself, I've rarely felt the need to adjust it and I only really do if I want to boost volume for a bipolar anal electrode, but even if I don't the feeling is still there. I make the adjustment in software, my operating system's sound settings has a balance function and many audio applications do to.

Regarding the rest of your bill of sale, do you know anyone who has all of that in the exact combination? If not, you could run into problems with matching components. Too weak of an amp and it might fail, too much resistance with a lower powered amp might reduce total output, the wrong turns ratio for the power output and resistance combination might cause an issue with this not feeling like it should. You are talking about adding combinations of additional components that could bleed off power or introduce undesired characteristics to the stim. Looking at two plans for a stim box and picking and choosing one resistor from one, a transformer from another, a random amp, and a few extra random components like a high-pass filter is a great way to end up with an unknowns about what you'll get and if it doesn't all work the way you expect it to, don't expect much support from anyone because nobody has that combination of stuff. It's all a system, change one thing and it can affect the balance of power needs from rest. The solution to when it doesn't work out as expected ends up being to replace those components so they match a good known proven configuration, which means you'll be buying equipment again to get the right combination that should have been bought in the first place. Good luck.

No, but i meant i'm up for isntalling en building ;)

you have a good point, i'll look into it further, it would be nice if i can use the amp i have, makes the build cheaper and makes less trash :)

[phoopha]

Quick query regarding the output side of the design lolol2 posted. In the pictures there are one red, two black, and one yellow sockets.

In standard stereo output, are you connecting and electrode wire to each output socket, two act as two pairs?
Then, with triphase switched on, do you run one from red, one from yellow, and one from either black output?

Also, on the input side, would I be correct in thinking that both sides of the stereo signal have their own volume / on-off controls?

I'm just trying to get everything clear in my head, as I'm planning to order parts soon and just want to understand what the various things do and how it's working.

Thanks.

[Dust]

Just a quick update from me.
Today I put everything together using crocodile clamps as connectors and surprisingly... it works great :).
Finally the pain files no longer get filtered and oh boy, some of them are quite hard^^

There are a lot of teases waiting to be replayed with a proper box, can't wait for the weekend.

[ZeeWW]

Just a quick update from me.
Today I put everything together using crocodile clamps as connectors and surprisingly... it works great :).
Finally the pain files no longer get filtered and oh boy, some of them are quite hard^^

There are a lot of teases waiting to be replayed with a proper box, can't wait for the weekend.

Would you be kind enough to show a few internal pictures of your wiring?

Thanks.

[lolol2]

In standard stereo output, are you connecting and electrode wire to each output socket, two act as two pairs?
Then, with triphase switched on, do you run one from red, one from yellow, and one from either black output?

Yes there are two channels you can use for stereo mode, channel A with red + black1 and channel b with yellow + black2.
For triphase you bridge the both black common ports, you can do this with a cable or just add this little switch like in my build.
Then you only need three cables/electrodes, red + yellow for the both channels and black as common connected to black1 or 2.

For example one of my favorite electrode setup, common on glans, one channel on shaft and one channel under/on balls.

Also, on the input side, would I be correct in thinking that both sides of the stereo signal have their own volume / on-off controls?

The two volume buttons control each channel yes, mostly you want to to set two different volumes depending on your electrode placement.
For example an analtrode needs mostly more volume than an electrode on your glans.
So I would recommend to build a unit with an individual volume control for each channel



@TheElectrician
Sorry can't answer any of your questions.

Would you be kind enough to show a few internal pictures of your wiring?

Would also like to see a picture of your results.

[tudeloo]

On the left side of the diagram, am I right in thinking they are individual channel inputs, rather than something like a 3.5mm stereo have? Likewise, on the right side, are they individual outputs? I think that's the bit that confuses me the most.

Yes, they are, but they could easy be replaced with the connectors of your choice. I personally simplified by own design of my most recent build and bought a Nobsound amplifier that uses the TPA3116 amp chip. https://www.amazon.com/Nobsound-Channel ... 00WTOAC1M/
This saved on buying and wiring a few of the extra pieces and I just bought a 3.5mm to RCA cable. The amp is currently $33 and has a 5% "coupon" thing too. Be sure you use a 12 volt *double insulated* power supply (should have a depiction of a square inside a square). At least 3.8 amps should cover it.

I advice people who are interested in safety not to buy these chinese firecrackers. Bad components (cheap caps go boom), sub optimal design, bad layout design (might not care about thd) and sometimes even very dangerous (mains not secured internally, wires can touch output rails etc.), because they almost always neglect all safety-norms. Buy a named amp, you can use it for more than just your balls, but know this: take some hints from madrid and lolol2 design and isolate it and if not stated that you can connect the negative of channels A and B with each other, dont attach it to yourself and thus close the loop!

Why is there no fuse in this design anyways? I mean, it is such a simple measure to ensure low current-only and in case of failure of any component to limit high current tissue burns.

The reason for the high price of a stim device is simple: they give you a safety standard that is out of reach of most electronic amateurs. Tho, I do think some are overpriced without havnig a med-cert.

[phoopha]

On the left side of the diagram, am I right in thinking they are individual channel inputs, rather than something like a 3.5mm stereo have? Likewise, on the right side, are they individual outputs? I think that's the bit that confuses me the most.

Yes, they are, but they could easy be replaced with the connectors of your choice. I personally simplified by own design of my most recent build and bought a Nobsound amplifier that uses the TPA3116 amp chip. https://www.amazon.com/Nobsound-Channel ... 00WTOAC1M/
This saved on buying and wiring a few of the extra pieces and I just bought a 3.5mm to RCA cable. The amp is currently $33 and has a 5% "coupon" thing too. Be sure you use a 12 volt *double insulated* power supply (should have a depiction of a square inside a square). At least 3.8 amps should cover it.

I advice people who are interested in safety not to buy these chinese firecrackers. Bad components (cheap caps go boom), sub optimal design, bad layout design (might not care about thd) and sometimes even very dangerous (mains not secured internally, wires can touch output rails etc.), because they almost always neglect all safety-norms. Buy a named amp, you can use it for more than just your balls, but know this: take some hints from madrid and lolol2 design and isolate it and if not stated that you can connect the negative of channels A and B with each other, dont attach it to yourself and thus close the loop!

Why is there no fuse in this design anyways? I mean, it is such a simple measure to ensure low current-only and in case of failure of any component to limit high current tissue burns.

The reason for the high price of a stim device is simple: they give you a safety standard that is out of reach of most electronic amateurs. Tho, I do think some are overpriced without havnig a med-cert.

Do you have an example of an amp that you'd consider both safe and suitable? (Preferably with a UK link for purchase? )

[Dust]

Just a quick update from me.
Today I put everything together using crocodile clamps as connectors and surprisingly... it works great :).
Finally the pain files no longer get filtered and oh boy, some of them are quite hard^^

There are a lot of teases waiting to be replayed with a proper box, can't wait for the weekend.

Would you be kind enough to show a few internal pictures of your wiring?

Thanks.

Uff, I forgot to add that my wiring is a total mess but I guess I can share it (but don't expect anything helpful^^). I really expected it to not work, so I did not put any effort in to make something clean. And now I don't want to touch it: Don't fix something that is not broken or something like that...

Let's start with the nice and pretty pictures from the outside.

The front:

Spoiler: show

The back:

Spoiler: show

The inside o.O:

Spoiler: show

Btw is it normal that with tri-phase on, the combined signal can feel completly different from the two separate ones? For example (and my most radical experience) two smooth signals resultet in a pointy one. This was while 3 electrodes where attached in a line (on some part of my body ) and the common one was NOT in between. Or is something fishy going on?

[lolol2]

That doens't looks soooo bad!
My first battery build was more messed up and also worked fine.

Spoiler: show

1.jpg (480.48 KiB) Viewed 4317 times

Thanks for sharing.

And yes triphase can feel completely different, when both channels have different frequencies you will get that amazing stroke feeling you can't experience with a stereo electrode setup.
With stereo you have the advantage that you have two channels you can control completely independent in volume.
With triphase the volume is always a mix of both channels, so when you turn down one channel to zero, the volume of the other channel will also drop a lot.

Both fun to play with, some files work better with stereo and some with triphase.

[tudeloo]

Sorry, I cannot recommend any normal audio amp for estim. There is inherent danger in shorting out - you being in the middle, touching another case of a device etc. - and thus creating a short with mains.
(see: https://www.youtube.com/watch?v=xaELqAo4kkQ )

I will only ever recommend an estim device or a certified medical device. Those are made with exactly these problems in mind, also current flow between channels in "triphase" mode that can damage amps.

[mantrid]

touching another case of a device etc. - and thus creating a short with mains.
(see: https://www.youtube.com/watch?v=xaELqAo4kkQ )

It shorts you with Earth which has the same potential as N(eutral). This itself may only be dangerous for Martians.

Did you watch the video? Because the DIY recommendations in this thread contain transformers which isolates you galvanically from the amplifier. I.e. There can't be any current from amplifier through the body to Earth. The guy in the video talks about that (isolation).

But even without that, the maximum potential difference between the amplifier and Earth is the voltage of the power supply (usually 12V), provided that you use either an unisolated supply (normal switching supply) or that the amplifier input is DC coupled to an unisolated PC.

Nevertheless, your statement is not completely wrong: If there is a power supply failure either of PC or of amplifier power supply or if there is a lightening stroke and if you are DC coupled to the amplifier output and if you touch Earth it will become dangerous. This is why transformers are used. (In order to protect against spikes I also recommend TVS diodes.)

[Electro]

On the left side of the diagram, am I right in thinking they are individual channel inputs, rather than something like a 3.5mm stereo have? Likewise, on the right side, are they individual outputs? I think that's the bit that confuses me the most.

Yes, they are, but they could easy be replaced with the connectors of your choice. I personally simplified by own design of my most recent build and bought a Nobsound amplifier that uses the TPA3116 amp chip. https://www.amazon.com/Nobsound-Channel ... 00WTOAC1M/
This saved on buying and wiring a few of the extra pieces and I just bought a 3.5mm to RCA cable. The amp is currently $33 and has a 5% "coupon" thing too. Be sure you use a 12 volt *double insulated* power supply (should have a depiction of a square inside a square). At least 3.8 amps should cover it.

I advice people who are interested in safety not to buy these chinese firecrackers. Bad components (cheap caps go boom), sub optimal design, bad layout design (might not care about thd) and sometimes even very dangerous (mains not secured internally, wires can touch output rails etc.), because they almost always neglect all safety-norms. Buy a named amp, you can use it for more than just your balls, but know this: take some hints from madrid and lolol2 design and isolate it and if not stated that you can connect the negative of channels A and B with each other, dont attach it to yourself and thus close the loop!

Why is there no fuse in this design anyways? I mean, it is such a simple measure to ensure low current-only and in case of failure of any component to limit high current tissue burns.

The reason for the high price of a stim device is simple: they give you a safety standard that is out of reach of most electronic amateurs. Tho, I do think some are overpriced without havnig a med-cert.

I've seen the inside of this amplifier and don't feel it has any of the issues you are trying to suggest an amplifier might have. Some of your other statements like cheap caps go boom is somewhat misleading because a popped capacitor can happen in any device with capacitors and the result is they basically stop performing their function, one down isn't going to be a major concern apart from the noise made when it happens.

Regarding fuses a carefully chosen double insulated power supply that isn't overpowered for the rest of the design is the safety factor. The resistors and transformers also work together in adding extra layers of safety by effectively wasting power in a calculated way.

At this point, the way you are trying to come in and say a bunch of safety issues suggesting to buy an expensive device with a med cert without knowing what was behind this type of design with a track record of over a decade of people building this type of device successfully while people who use estim also find numerous undesirable qualities of many estim devices on the market as well makes me think you are affiliated with an estim manufacturer and working to defend them.

"sometimes even very dangerous (mains not secured internally, wires can touch output rails etc.), because they almost always neglect all safety-norms."

mains isn't inside this box, this isn't a giant surround sound amplifier with a built-in power supply. It's a small bookshelf speaker type of amplifier design with a double insulated 2-prong 12 volt power supply(you clearly glossed over this part about a double insulated power supply) external to the box, because of the double insulated power supply, there is 12 volts going into the box by design, not mains.

[phoopha]

I seem to be struggling to find all the parts in the UK.☹

Any other UK members had any success in sourcing the components for a build?

[ZeeWW]

I seem to be struggling to find all the parts in the UK.☹

Any other UK members had any success in sourcing the components for a build?

Also in the UK. I got all the parts from Conrad Electronics who ship to the UK. I've just not made the unit yet as I need to fully understand the wiring