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

[Míchael]

I also get a small electrical signal when I turn on the machine (even if the file isn't playing when the switch gets turned on I get a pulse and it's not always the same strength), would this be some sort of grounding issues?

For that add a 3 channel switch like mentioned in my design.
Some AMPs are "noisy" when they loose power, that is normal.

I'm also having this spike with the freshly built unit which already implements this 3-channel switch to connect/disconnect right/left channel with power. This is happening when turning on, not when turning off. I was also checking the amps and they do spike when powered on quite high compared to normal usage. Not sure where that is coming from. My build is also based on lolol2

I'm just having crappy 5 dollar multimeter at home which is really slow and not a scope so can't really see clearly what happens at outputs just after turning the power and connecting channels

Thats because amp it sends power to both channels (left / right) for a second after it turned on. I mitigate this by simply starting the amp with both channel switches to off. I moved away from the 3 way switch design and have one switch per channel.

[Storm123]

so im working on building a box, tough i was wondering what are the actual differences on the taps from the transformer i mean 0.25w vs 10w tap for example, what specifically is the change from one to another and, as i have seen a few going up or down one tap, what is the difference in feeling if any?

my transformers are the speco T7010 (70v) ones, sadly the tap markings are a mess on these (i know what taps should be on it but not what wire is which), would it be possible to measure out the taps by measuring the resistance between C and each tap? if so would a higher ohm mean a tap with more watt?

any input that helps me figure out what tap to use would be amazing ^.^

[edger477]

if so would a higher ohm mean a tap with more watt?

It is opposite actually, higher ohm (More resistance) is less watt.

On input side (towards amp) most people use 4 Ohm taps, and on my highest are around 400 Ohm (on 0.625W) and I use these but on some transformers the 2nd highest (around 1w) feel better.

[Electro]

so im working on building a box, tough i was wondering what are the actual differences on the taps from the transformer i mean 0.25w vs 10w tap for example, what specifically is the change from one to another and, as i have seen a few going up or down one tap, what is the difference in feeling if any?

my transformers are the speco T7010 (70v) ones, sadly the tap markings are a mess on these (i know what taps should be on it but not what wire is which), would it be possible to measure out the taps by measuring the resistance between C and each tap? if so would a higher ohm mean a tap with more watt?

any input that helps me figure out what tap to use would be amazing ^.^

If it's the newer Speco T7010 transformer with a blue wrapper and on one side(this is the amp side) you have labels for 0 and 8ohm and the other side for the electrodes you have taps labeled 0.25,.5,1,2.5w,5w,10w,C The black is C, blue is 0.25w, purple is 0.5w, yellow is 1w, orange is 2.5w, magenta is 5w, brown is 10w.

The recommended tap to get started for this transformer is the .5 watt tap which is the purple one. If you end up in a situation where you are stimming for a long time and you find that turning the volume up no longer increases the intensity, especially for stuff intended to be a higher intensity(painful) that gets muted out or you are stimming for hours and eventually find that turning it up is 'hitting a wall' which is more likely to happen with larger electrodes that need more power, you can swap to the yellow 1w tap to give more intensity headroom. I wouldn't recommend starting at that point because you are raising the maximum power cap of the stim rig which means if you play a stim file that has a large volume increase, your computer blasts out a loud system sound, or you accidentally knock the volume control on the amp or your computer to a much higher than intended level, you will get hit that much harder with an unwanted intensity of stim.

For what it's worth, I'm currently using the yellow tap because I play with a lot of the pain stim stuff and also run stim sessions for hours on end and have run into the max I could get from the purple tap, but it took awhile before I developed a tolerance and compatible electrodes and configurations that allowed that level of stim to be comfortable to me.

This all applies to the newer style Speco T7010 blue wrapped transformer, we are really aiming for a certain ratio of turns within the transformer and the different model transformers aren't all the same for the different wattage and ohm selections(for the transformers that have more than one option on the 'ohm side'), so for those other transformers these numbers aren't necessarily a match to this one.

[Kjetiljoh]

Hi,

I am sketching up my own e-stim stereo and have a question related to the Stereo input.
is it a reason why some choose to have left and right stereo input, wont you gain the same results by having one Aux input?

[Míchael]

Hi,

I am sketching up my own e-stim stereo and have a question related to the Stereo input.
is it a reason why some choose to have left and right stereo input, wont you gain the same results by having one Aux input?

Thats a personal and maybe skill based decision. Its easier to solder one 4mm port per channel than to solder an 3.5mm port for both.

The result is the same my box uses 3.5mm jack as input.

[Mistypanda22]

is there an american version of the shopping list? having trouble finding 1 for 1 copies

[DefinitelyHere]

Been enjoying my stim box for a few months now thanks to everyone's help on this thread, but running into an issue lately and been troubleshooting for weeks now, wondering if anyone else has encountered this.

Both my left and right channels seem to be working fine, but when I run into a triphase signal, usually in the 900hz range, nothing happens. I can turn my volume all the way up during these sections in files and nothing happens. I do have the 2 extra resistors that people have been saying are not necessary and wondering if that is the culprit.

I've already tried a few things, resoldered connections to stereo jacks, replaced banana plugs, replaced transformers, replaced triphase switch, replaced tpa amp board, resoldered connections to potentiometers, and checked connections on the wago connectors I'm using.
Just kinda lost at this point and hoping someone experienced something similar. Any advice would be greatly appreciated. I'm using the updated design, with Bob's parts list around pg15-18.

P.s. Anyone know if there is any commercial triphase box coming anytime soon? Would rather just buy something already setup than troubleshooting every few months

[darthjj]

Been enjoying my stim box for a few months now thanks to everyone's help on this thread, but running into an issue lately and been troubleshooting for weeks now, wondering if anyone else has encountered this.

Both my left and right channels seem to be working fine, but when I run into a triphase signal, usually in the 900hz range, nothing happens. I can turn my volume all the way up during these sections in files and nothing happens. I do have the 2 extra resistors that people have been saying are not necessary and wondering if that is the culprit.

I've already tried a few things, resoldered connections to stereo jacks, replaced banana plugs, replaced transformers, replaced triphase switch, replaced tpa amp board, resoldered connections to potentiometers, and checked connections on the wago connectors I'm using.
Just kinda lost at this point and hoping someone experienced something similar. Any advice would be greatly appreciated. I'm using the updated design, with Bob's parts list around pg15-18.

P.s. Anyone know if there is any commercial triphase box coming anytime soon? Would rather just buy something already setup than troubleshooting every few months

Just a wild guess, but perhaps a shortcircuit or incorrect grounding somewhere? Make sure the speaker out signals from your amp (going to the transformers) and the secondary circuits (coming out from the transformers) have no connection with each other, or ground.

I assume you've verified that a signal on the left channel is only felt on your channel 1 electrodes, and vice versa.

[Cdsmith12]

I am building my first E-Stim based on lolol2 v2 and have never used these types of resistors. Is it ok to bridge the 2 resistors that are connected to the 4 ohm (8 ohm in my case) connection since they are both connected to the same wire on the transformer? I have attached my sketchup design and the part of the schematic I'm talking about.

Thanks

[edger477]

Is it ok to bridge the 2 resistors that are connected to the 4 ohm (8 ohm in my case) connection since they are both connected to the same wire on the transformer

Yes but the 22 ohm resistors aren't used anymore, last 4 amplifiers I bought worked perfect without it (but consumed less power since you don't waste the output into resistor).

[darthjj]

Yes but the 22 ohm resistors aren't used anymore, last 4 amplifiers I bought worked perfect without it (but consumed less power since you don't waste the output into resistor).

I first build a power box without parallel resistors (they're 15 Ohm 2W on the reference design I used btw) since it did indeed look a bit wasteful to have them there. However, I added a pair later, since they appear to "smooth out" the perceived intensity change when altering the carrier frequency. I.e. without those resistors, it felt like the signal got much stronger when the carrier frequency was lowered, and I had to reduce the amplitude to compensate.

[edger477]

I first build a power box without parallel resistors (they're 15 Ohm 2W on the reference design I used btw) since it did indeed look a bit wasteful to have them there. However, I added a pair later, since they appear to "smooth out" the perceived intensity change when altering the carrier frequency. I.e. without those resistors, it felt like the signal got much stronger when the carrier frequency was lowered, and I had to reduce the amplitude to compensate.

oh I guess in my box that is achieved by audio condensers that the signal goes through

[wmounted]

I'm new to estim and planning on building a diy powerbox using lolol2's design. I've already ordered parts and waiting for delivery.

But I'm very concerned about using mains power to power the device,
I understand that many of you guys use class ii power supplies, if you have a real class ii power supply then it's probably safe enough. but i'm having a hard time trusting the labels on powers supplies found on amazon & aliexpress. Especially after seeing this video.

Spoiler: show

So thinking about using batteries instead, and i have a few questions.

At first, I was thinking about using a 12v lithium polymer battery (LiPo), but its nominal voltage is 11.1V, and it might cause issues with the amplifier used in lolol2's design (XH-M543) since it's designed for 12-26 volts. So now I'm thinking about using a UPS battery (sealed lead-acid), their voltage ranges from ~12.9 to ~12.2V (100% charge to 50% charge). I will add a volt meter to the design so i can shut it off if it goes under 12.2 volts.

Assuming efficiency of class D amplifier is 90% and it consistently output 50W(it won't) power when estiming
Input Power required = 50W / 0.90 ≈ 55.56W
In amps = 55.56w/12v = 4.63 amps

So, a 12v 9AH lead acid battery should last about ~58 minutes. (Discharge Time to 50% = (9 AH / 4.63 A) * 0.5)

Is this battery setup safer than using a power supply ?

Do you guys know any other types of batteries that can work better for this purpose ?

My main concern is that if something goes wrong with the amplifier, the batteries could potentially provide a large amount of power instantly, whereas a power supply might not be able to do so. Is this a valid concern?

Sorry for my bad English.

[diglet]

Sure aliexpress and amazon sell crap power supplies. But are you sure you can't source one from a reputable brand?


If you want to use batteries, you can try looking for an USB-C powerbank that supports one of the power delivery standards. I did a search for local options and found "Xiaomi Powerbank 20.000 mAh V3" which supports 5, 9 and 12v output with the appropriate cable. You will need an USB-C to 12v cable such as this one from aliexpress (https://www.aliexpress.com/item/1005006 ... pt=glo2nld), these will only work if your powerbank supports 12v. Support for 12v is optional in the USB-PD standard, not all power banks support this.


This does sound a lot easier than messing around with bare batteries. The circuitry in the power bank will keep the voltage stable at 12v until the battery is dead.


As for power usage, with efficient waveforms my stimbox draws max 2w from the wall (including conversion losses). With inefficient waveforms it can go up to around 10w. You should be able to get quite some run time out of a normal powerbank.