[RELEASE] E-Stim Fantasy

[Afapp]

I'm casually interested in this, but last night I signed up for the estim website linked earlier in the thread (forum isn't viewable without an account) and I still haven't received a confirmation email. Is the thread mirrored anywhere that doesn't have a login wall?

I haven't been able to log in for over a week now, which is a little frustrating as it means i can no longer get access to the build instructions. Can anyone else confirm that the site is down? Even better, could someone please post the build guide?

I logged in today, so site works. See attached PDF

[Afapp]

I built my box with a few "upgrades".
1) preamp pots to balance the L and R channels. This really is a necessity in my opinion.
2) A "triphase" switch after the transformers. Not a necessity but a really nice add-on.

I used a TPA3116 amp already built in aluminum case with a power switch and Master volume pot. (breeze audio 2.0 @ $28 on ebay). Then built a small box housing the Audio input, preamp pots, postamp transformers, power resistors, triphase switches and 3.5 mm stereo output jacks to the electrodes. plug it into the wall using a GOOD power supply (look for square within a square symbol)
it has been running almost daily for nearly 2 years. Much better audio stim signal than a ET-312 or a estim systems 2b.

[mantrid]

I logged in today, so site works. See attached PDF

Without a hi-pass filter I consider this as unsafe, see my previous post in this thread.

These transformers are optimized for low frequencies (can be dangerous) and damp the interesting frequencies (>500 Hz) to much. Thats why you need so much power.

Output circuit should look like this:

[blondie88]

I logged in today, so site works. See attached PDF

Without a hi-pass filter I consider this as unsafe, see my previous post in this thread.

These transformers are optimized for low frequencies (can be dangerous) and damp the interesting frequencies (>500 Hz) to much. Thats why you need so much power.

Output circuit should look like this:

I appreciate your advice, but not being such a tech savvy person, this diagram goes completely over my head. I can follow the guide from the smartstim page no problem, but without an actual photograph of what this means, and what the actual high pass filter looks like and how it is connected on the board, I myself (and I suspect others) will struggle to actually implement your (appreciated) input.

[mantrid]

Without a hi-pass filter I consider this as unsafe, see my previous post in this thread.

These transformers are optimized for low frequencies (can be dangerous) and damp the interesting frequencies (>500 Hz) to much. Thats why you need so much power.

Output circuit should look like this:

I appreciate your advice, but not being such a tech savvy person, this diagram goes completely over my head. I can follow the guide from the smartstim page no problem, but without an actual photograph of what this means, and what the actual high pass filter looks like and how it is connected on the board, I myself (and I suspect others) will struggle to actually implement your (appreciated) input.

Component are described in my earlier post.

The hi-pass filter is formed by the capacitor and the resistor and impedance of the coil. If you chose the transformer recommended in my earlier post resistor values can be 10 to 20 Ohm and capacitor value is 100µF.

The thing next to "15V" is the bipolar TVS diode which shortcuts voltages above about +/- 15V. It protects against failure of the 12V power supply of the amplifier. Amplifiers are these cheap stereo devices from China which are powered from 12V and usually output +/-12V (+/- 10V is more realistic). Devices with balance knob costs about 20 to 30 EUR. If they can drive 4 Ohm (in our usage scenario they need to drive much less) they are rated with about 15W (equivalent to +/- 11V)

[digitalparkinglot]

Do you use rubber loops or sticky pads DPL? Which do you prefer?
[/quote]

I have tried so many different configurations, and I'll like one for a while and then change and find something else I like. My favorite right now is a commercial bipole trode on the prostate with R+ and R- going to it, a sticky pads on top and one on bottom at the base of the cock with a ponytail holder holding them in place with L- to both of them and a copper wire bent to cover the head of the cock with L+ going to it. I like rubber loops a lot but DO NOT use non-water based lube with them, they will die and loose their conductivity. I need to replace mine.

[Afapp]

Sorry keep stepping in on your thread DPL. All 3 videos are a real tease all edge all the time!
Blondie88: I will try to post pictures of a mock up of a non- solder midistim build tonight so you can see without reading a schematic. Will post in the “all and everything” forum. My go to trodes are a small stainless steel shackle used in boating under the corona, a custom copper triple cock ring at the base of cock and balls, both have banana plug connections (you could use a store bought one and use a tens pad to connect it). For years I used an stim modified Aneros Progasm with a small copper end cap contacting the perineum.
Mantrid: I have never used a bidirectional diode in my builds and never had a problem. If you’re worried about the power supply failing then you can use a 12V SLA battery. If Blondie88 can’t read a schematic then I doubt putting a bidirectional diode in the build is going to happen.

[hosenguy]

Without a hi-pass filter I consider this as unsafe, see my previous post in this thread.

These transformers are optimized for low frequencies (can be dangerous) and damp the interesting frequencies (>500 Hz) to much. Thats why you need so much power.

Output circuit should look like this:

I appreciate your advice, but not being such a tech savvy person, this diagram goes completely over my head. I can follow the guide from the smartstim page no problem, but without an actual photograph of what this means, and what the actual high pass filter looks like and how it is connected on the board, I myself (and I suspect others) will struggle to actually implement your (appreciated) input.

Component are described in my earlier post.

The hi-pass filter is formed by the capacitor and the resistor and impedance of the coil. If you chose the transformer recommended in my earlier post resistor values can be 10 to 20 Ohm and capacitor value is 100µF.

The thing next to "15V" is the bipolar TVS diode which shortcuts voltages above about +/- 15V. It protects against failure of the 12V power supply of the amplifier. Amplifiers are these cheap stereo devices from China which are powered from 12V and usually output +/-12V (+/- 10V is more realistic). Devices with balance knob costs about 20 to 30 EUR. If they can drive 4 Ohm (in our usage scenario they need to drive much less) they are rated with about 15W (equivalent to +/- 11V)

The folks at Smartstim that are involved with the design of the midstim device are engineers in the electronics field. I think that the midstim is the best design for beginner to advanced users.
I would like to comment on some of your statements.

Your hi-pass filter is a circuit that is good for you if it makes you feel good. It really does nothing unless you stim to music which is full range. That is usually not good with an audio device. The issue I have is overall loss of some signal and that this condition should not happen. (But you can never have enough safety circuits.)
The biggest issue I have with adding stuff is that the marginally competent builder will have more problems due to added complexity. I believe you should build a basic proven design first and see that it works correctly and then add additional components when you are certain they do what you expect.

The signals used for stim are usually made with simple wave generators, usually a single frequency on each channel. These are swept over a frequency range (FM) and/or amplitude modulated (AM), along with phase shifting. There are exceptions but most folks make stim tracks to use with stereo stim amps, or they state that a 312b or a 2B should be used to modify the signal to a useful pattern. 600 hz to 1,200 hz. center frequency is typical, but there are exceptions. Commercial units like the 312b goes down below 100 hz and the 3rdh device is believed to go much higher.

I cannot comment definitively regarding the transformers you have linked. I could not find specs that convinced me that they would handle 10 watts of power continuously nor could I verify the needed impedance was correct.
This is on me and I need to read more and study the data sheets a bit more. The link I posted earlier in this thread has impedance tables to help with transformer selection.

Next is the 15V TVS diode. This will not degrade or load the signal. I have not seen this before. This component will stop over voltage events to some degree. Safety is good but again I would add this after I had my amp working.

The statement about the amps output ratings and the equivalent voltages you are making are a large assumption. Many data sheets do not take into account heat buildup, just plain over-rating, or using peak values for their specs. I was involved in load testing several types of amps before the group made the recommendations for the midstim and I can assure you that the ones they recommend will stop a lot of problems. The Davey box was very popular but it created a thread of "Help" comments that never ended. Many loved them and many hated them and some were burned too. The quality and testing that was done can solve many of these problems but the build has to be per their design or you are on you own.

The power needed to stim is a varying load not designed for any audio amp that comes from China or anywhere else for that matter. You could spend hundreds for a constant current (edit) amp, like medical devices do, but not likely. This is what the series resister in the transformer's input tries to simulate.

I put an individual volume control per channel, in each stim amp I have ever built. This works better than a balance control in my usage. Also I believe you need a kill switch, specifically to disconnect the trodes on the output side of the transformer. Many amps send a nasty pulse during power on and off that the disconnect/kill switch allows you to miss out on. This assumes you are like me and hook up prior to remembering to turn power on.

I am going to add a short, incomplete description of a condition to be avoided. The signal at the trode connection to the body needs to be without DC offset. The signal is centered over ground with half of the signal going + and half going -. If this is not true you will create an electrolysis causing some sort of damage to you. That is one reason for the transformers. If you use LED in the output circuit (after the transformer output) to indicate signal level, you must make sure they are balanced both ways. Better yet don't include this type indicator and use a VU meter at the input to your amplifier.

Stimming seems to be safe when done correctly.
It is certainly like nothing else.
It can be addictive too.
enjoy

edited due to many typos. I was rushed to dinner during the first post.

[mantrid]

I just wanted to share my safety concerns. I don't want to tread on someones toes and I don't want to explain myself more than once (as I do below).

• In my first post in this thread I stated that TVS diode (and series resistor) are optional. These components costs less than 20 cents. If you think they are not worth it or if you limit voltage and/or current in another way you can omit them.
• I consider the hi-pass filter (capacitor) as most important part in my output circuit. If you are sure that your device does not amplify low frequency components more than high frequency components and if you trust in estim file generators or analyze the files before usage you can omit it.
• Not just DC currents are dangerous. As lower the frequency as more dangerous it is and as lower the admissible currents. Maybe the hi-pass filter is not necessary (i.e. the bandwidth limitation if the transformer is sufficient), but I don't want to try it out and I want to avoid protein denaturation as much as possible. Thats why I invest about 1 EUR per channel in order to block frequencies I don't need.
• I recommended the transformer because I use them (in combination with 10 Ohm and 20 Ohm series resistors and 100µF capacitors) The transformer does not even become warm (unlike amplifier).
• Power rating of the amplifier is a rating. The values I stated can be used to select an amplifiers which uses (almost) the full range. Effective power of a sinusoidal signal can be calculated from peak voltage (or current), the impedance and power factor (which is assumed to be one for power rating). This is what I did. I never commented whether these ratings are realistic.

Your hi-pass filter is a circuit that is good for you if it makes you feel good.

I think It's more than a placebo, see above.

I believe you should build a basic proven design first and see that it works correctly and then add additional components when you are certain they do what you expect.

You can believe that I already did that, see above.

The signals used for stim are usually made with simple wave generators, usually a single frequency on each channel. These are swept over a frequency range (FM) and/or amplitude modulated (AM), along with phase shifting.

These signals only have frequency components of the carrier waveform, not of the modulation waveform (analyze them spectrum if you don't believe it) That's why you can block lower frequencies without losing something.

Also I believe you need a kill switch, specifically to disconnect the trodes on the output side of the transformer. Many amps send a nasty pulse during power on and off that the disconnect/kill switch allows you to miss out on. This assumes you are like me and hook up prior to remembering to turn power on.

At least amplifiers based on frequently used TDA7377 have a pop prevention (capacitor on pin 6). On my amplifiers these capacitors had a to small value.

The power needed to stim is a varying load not designed for any audio amp that comes from China or anywhere else for that matter. You could spend hundreds for a constant current (edit) amp, like medical devices do, but not likely. This is what the series resister in the transformer's input tries to simulate.

A current controlled device is indeed what we want. This is achieved by the transformer with a (much) higher output impedance than load resistance (high transformation ratio). In order to achieve the same on the primary side the series resistor would have to be (much) higher then the impedance of the primary coil.

[Afapp]

Mantrid, that high pass filter was designed by “Bonnie” on the other site specifically for blocking EM interferences she was getting because she lived right next to electric transmission wires.

[hosenguy]

I am very happy to see that we are passing good knowledge on to diy builders! If this much knowledge is used then there will be very happy stimmers.

The lost part in this thread, my fault included, is the time, trial, and knowledge used by authors to create the tracks we play through the devices we build.

Thank you, Lovecraft, for this fine E-Stim Fantasy. Please continue your efforts.

[BoundSquirrel]

For balance knobs/separate volume knobs, can these be added post-amp? The reason I ask is that I have a stock SA-36A amp that goes into the midistim transformer/resister configuration. I really don't want to build another box to go in front of the amp and have plenty of room in the box with the transformers. If I were to put a volume knob on each channel on the input side from the amp to the transformers, would there be any downside to this?

[hosenguy]

They can be added post amp but must be a large enough wattage to not burn out. 15 Watt might do.

[Afapp]

Newer DAP (digital audio players) have balance control built in. Or a laptop can control balance.

[BoundSquirrel]

Thanks, hosenguy. Afapp, I currently use the balance on my PC. When I've got a video playing, it's a lot more of a pain in the ass to fine tune a digital slider than an analog potentiometer.