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

[Míchael]

Hi, I'm currently collecting the parts to make the tronic Midistim for the first time and was wondering what is a good electrode socket to purchase for 3.5mm size so I can solder it to the transformer wires. I have a 2B and want to use the 3.5mm to 2mm output cables that they gave.


Parts I plan to use were:

Transformer: Parts Express 70V 10W Speaker Line Matching Transformer

Amp: Nobsound HiFi 2.1 Channel Bluetooth 5.0 Power Amplifier Board Case Stereo Subwoofer Amp

Power: [UL Listed] Chanzon 12V 5A 60W AC DC Power Supply Adapter (Input 110V-220V, Output 12 Volt 5 Amp 60 Watt) DC Converter LED Driver Lighting Transformer for 12 V 5 A Flexible LED Tape Strip Light

Resistor: Uxcell a12040600ux0286 Chassis Mounted Aluminum Housed 25W 3.9 Ohm 5% Wirewound Resistors

For my first box I used this one as audio input:
https://www.conrad.de/de/p/tru-componen ... 64526.html

Should also work fine as elektrode input.

[pess1]

Hello!
I am looking to build my own stereo stimbox.
Tho firstly i'd like an amp that is ready out-of-the-box.
I'm basically illiterate when it comes to audio tech and electricity is like magic to me
Anyhow, on reddit and some posts here i've seen there's a mix between amp with 50*2 and 100*2.
and my question is whether a 50*2 would be enough for a stim out-of-the-box, before i eventually do a build?
i have 3 different psu's
1: 12V 3A (The Handy power source, type II. Works with my 2B)
2: 19.5V 6.92A (Laptop charger)
3: 19V 6.32A (Laptop charger)

Option 2 and 3 does not have the "type II; square within a square" mark, but a "-" going to a "half circle encompassing a circle" going to a "+".
Are any of these viable, safe options?
this is the amp i'm considering
https://cdon.no/hobby-fest/zk-502c-hifi ... p149952962

[limitsky]

For my first box I used this one as audio input:
https://www.conrad.de/de/p/tru-componen ... 64526.html

Should also work fine as elektrode input.

Thanks for the link! Following the midistim schematic, it says one jack would be L+ and one jack would be L-, same for right channel. If I'm using those sockets for electrode input, do I solder the L+ onto left channel and L- to ground? Or would both L+ and L- go to the LEFT channel on the socket?

I'm imagining it like the 2B electrode jacks where I just plug in one 3.5mm jack for one channel and connect the electrodes, so I would only need 2 of these sockets (one for channel A and B) instead of 4?

[Míchael]

For my first box I used this one as audio input:
https://www.conrad.de/de/p/tru-componen ... 64526.html

Should also work fine as elektrode input.

Thanks for the link! Following the midistim schematic, it says one jack would be L+ and one jack would be L-, same for right channel. If I'm using those sockets for electrode input, do I solder the L+ onto left channel and L- to ground? Or would both L+ and L- go to the LEFT channel on the socket?

That is up to you I would say. The socket has as you noticed 3 connections (left, right, ground) and you need only two (left+ and left-). You can ignore the ground or just connect it with the lower connector.

I'm imagining it like the 2B electrode jacks where I just plug in one 3.5mm jack for one channel and connect the electrodes, so I would only need 2 of these sockets (one for channel A and B) instead of 4?

That is correct if you do it like this you only need 2 ports instead of 4.

Hello!
I am looking to build my own stereo stimbox.
Tho firstly i'd like an amp that is ready out-of-the-box.
I'm basically illiterate when it comes to audio tech and electricity is like magic to me
Anyhow, on reddit and some posts here i've seen there's a mix between amp with 50*2 and 100*2.
and my question is whether a 50*2 would be enough for a stim out-of-the-box, before i eventually do a build?
i have 3 different psu's
1: 12V 3A (The Handy power source, type II. Works with my 2B)
2: 19.5V 6.92A (Laptop charger)
3: 19V 6.32A (Laptop charger)

Option 2 and 3 does not have the "type II; square within a square" mark, but a "-" going to a "half circle encompassing a circle" going to a "+".
Are any of these viable, safe options?
this is the amp i'm considering
https://cdon.no/hobby-fest/zk-502c-hifi ... p149952962

In regards to the amp. Most amps have two run options. 12V and 24V and all builds i have seen are usually running with 12V and 50W per channel from the ampside. 50W per channel are plenty enough to do stimming with. We want a very low current and and a high voltage.

For the PSU. You can use the first option. Dont use #2 and #3 if they dont have the typeII symbol!. However #1 could be too weak. The usual suggestion is to go for 5 or 6 Amp PSU. Im using a 5A 60W psu. You have to remember that you power 2 channels with the psu so you have roughly 1.5 Amps per channel. You can try it for sure but maybe you need more power.

[pess1]

Thank you for your response and insight. I will give it a shot then reiterate and upgrade as needed!

[Xiphid]

I've just finished my first device based on lolol2 v2 (messy but works!)

Estim.jpg (152.37 KiB) Viewed 9974 times

I'm having issues with my right channel being about 1/4 of the power of my left channel. I've checked with the meter and at the board with a file playing I'm getting 1.5 on the right and 5.6 on the left. I've checked the resistances, the pots, my connections and everything seems okay, but I have to admit my electrical knowledge is limited.

Can anyone provide suggestions what I should check to find out what's wrong or what could be causing this?

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?

Thanks

[tommarr]

Finally updated my wire mess which was quite similar to viewtopic.php?t=23322. Biggest issue was it was just a mess to get and start using and store away

Ordered bahar case because it looked nice and built everything into it

Spoiler: show

Much better now And I kinda like the case

Still need to test try that how does it run and I'm a bit mad that I accidentally ordered momentary ON-OFF-ON switch for swapping channel. Figured it would be nice to have option to switch channels but no can do. Maybe I'll get correct switch later

[lolol2]

I'm having issues with my right channel being about 1/4 of the power of my left channel.

It looks like the pods on the amp are in different positions?
The small white round things next to the 3 pin connector input.
Those should be in a straight line matching the pin connector like shown in the picture of the connection plan.

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.

2) I have routed the output over the power switch for both channels, this prevent to have any not wanted AMP noices which can appear when you turn of the power. This is more a safty feature I wanted to have, when you switch off the device, you also cut you off from the electrodes. I have experienced this with the listed AMP, so I would recommend to add this switch.

Otherwise your box looks really nice, totally fine with the cabeling, this should do the job!

[tommarr]

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

[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.