Where to find a good (And safe) stereostim tutorial these days?

[MegaErato]

@MegaErato Thanks for your help.
I need to choose an ac-adapter that is safe.
In the Midistim scheme, it is advisable to choose an Agency Listed double insulated AC-adapter 12 V DC (min 4A).
I found this on amazon.es:
https://www.amazon.es/dp/B001W3W12E?tag ... th=1&psc=1
Do you think this ac-adapter is safe, or do you suggest another?
Please if you suggest any ac-adapter, put links from the european amazon because i live in europe.
Thank you for your help

I agree with Hosenguy, this looks like overkill awesome, assuming its barrel is compatible with the amp you choose, go for it! (If it doesn't you could probably just switch out the female barrel on your amp with a compatible one, which are easy to find and purchase on ebay as well. )

[redgreencolor]

Thanks hosenguy and MegaErato for your help.

[memma]

OK, I'm on my way...

I have a power supply (the Leicke one on EU amazon).
I have an amp (a board based on the TDA7297 - I'm happy enough playing with bare electronics, especially if power input is overvolt-/surge-protected 12V)
I'm confident I can find some appropriate resistors.
That just leaves transformers and 'trodes (I like that shortening - it sounds like some sort of cute pokemon-like creature: the lesser-spotted fluffy trode).

For the transformer:

transformers I used (you need 2, one for each channel):
https://www.ebay.com/itm/RT-702510-Line ... 2714853358

Any reccommendations on something available in the UK? Postage for those transformers is more than the transformers themselves.
This looks simultaneously like an exact match but also disturbingly generic.
I'd happily buy something from uk.rs-online.com.

Also, @MegaErato: Your diagram is great. I notice you've got resistors across the left and right channels, after the inline resistors. Would you recommend them?

Now for the trodes:

I'll put up another post on electrodes soon.

Looking forward to that.

I have an all-metal butt plug - I suspect I'll want to go for one with the pole just on part of the insertable surface to target the sensations on the prostate (suggestions anyone?), but I could also do with some cock loops. Any recommendations or warnings before I go and buy a length of conductive rubber tube or strip and get 'stuck in'?

[hosenguy]

I did a quick search and found these. Don't seem to be many sources pop up in UK. Farnell is a really big company and quite professional.

https://uk.farnell.com/mcm/555-7120/10w ... hnicalDOCS

Note that they say back order form the US "OR" you can wait until their stock arrives. That is projected to be this month.

Hope this helps a bit.

[Afapp]

I have an amp (a board based on the TDA7297 - I'm happy enough playing with bare electronics, especially if power input is overvolt-/surge-protected 12V)

Just be careful with this Amp. My DIY based on this amp gets VERY HOT. also the power resistors get VERY HOT. Past recommendations on the "other site" suggest an aluminum heatsink plate for the resistors and a bigger heatsink for the amp chip. I think that this is not just hype. Consider doing this or you may burn the amp out. My go to amp is the TDA3116D2. This board is getting harder to find now though.
Afapp

[MegaErato]

I have an amp (a board based on the TDA7297 - I'm happy enough playing with bare electronics, especially if power input is overvolt-/surge-protected 12V)

Just be careful with this Amp. My DIY based on this amp gets VERY HOT. also the power resistors get VERY HOT. Past recommendations on the "other site" suggest an aluminum heatsink plate for the resistors and a bigger heatsink for the amp chip. I think this is not just hype consider doing this or you may burn the amp out. My go to amp is the TDA3116D2. This board is getting harder to find now though.
Afapp

True! My unit gets warm after a long session, and I have replaced the amp once in the 6 years or so I have been using this build. They are so cheap and readily available, I don't mind risking burning out the amp over time. I did find the amp you prefer though, so maybe its still easy to buy, I might look into trying another build with it! https://www.amazon.ca/TDA3116D2-Digital ... B075M2KWDL

@memma Sorry, not sure where in the UK you would look for the right transformers... I imagine UK based electronic part stores should carry equivalent line matching transformers though.
Regarding the resistors; I didn't get a really smooth or successful experience until I added those resistors exactly as shown in diagram. The 5 watt resistor is the one between channels. Before adding them I had problems with transformers saturating and overheating that resulted in less power to my bits, even though resistors themselves "dampen" the power it actually translates to a more regulated current and although I don't know the ins and outs of why those exact resistors in that arrangement works the way they do, I know from experience its necessary.
For my prostate trode I modified an aneros by running an insulated wire up the shaft with exposed stripped wire under a 1"x1" round cut of aluminum tape right about where the prostate is. Its all held on the aneros with tightly wrapped electrical tape and I smooth out the aluminum contact tape piece till polished so there is no spots it can snag sensitive skin. A more professional way to modify any dildo would be to heat a length of wire till very hot and melt it into the shaft so it forms a perfect wire channel flush with the surface, then glue it in place and insulate with plasti-dip or similar. Then you have a permanent wire lead, and you can just keep experimenting with various shapes of aluminum tape contacts where the wire lead is exposed. Hope that makes sense. Or you could go purchase pre-made anal trodes that target the prostate of course. I think electrodes are the fun part as you can get really creative! Just remember to use non toxic materials especially when experimenting with metals, just avoid plated metals and anything that might contain lead. I make a ton of fun trodes out of lead free silver solder which is really bendy and easy to make all kinds of fun cock jewlery!

[memma]

I've been scouring the interwebs for the bits I need. Ordering various bits from aliexpress, etc.

Now I've got to the resistors and I noticed the suggested resistors are 10W:

Midistim box:

I've put the schematic for the Midistim box here:

Midistim schematic

This is pulled right from the smartstim post and, when followed correctly, works great.

or 10/5W in the hand-drawn schematic (OK, so quoting imgaes doesn't work, but they're marked 5.6Ohm 10W and 15Ohm 5W):

JC stimbox drawing2.jpg

but BoundSquirrel's suggested resistors are 25W:

Resistors:
https://www.amazon.com/gp/product/B00NQ ... UTF8&psc=1

These are listed as unavailable, but there are a bunch of alternatives that should work. Just type, "25 watt 3.9ohm resistor" and you'll find plenty of options.

I'm guessing 25W was used to reduce heat? Or what's the reason? Is there anything I should bear in mind when selecting my resistor values and wattages? How do they affect the feeling (if such a thing is describable), and do different values relate to anything like body build/fat, or anything like that?

Thanks all!

[memma]

I did a quick search and found these. Don't seem to be many sources pop up in UK. Farnell is a really big company and quite professional.

https://uk.farnell.com/mcm/555-7120/10w ... hnicalDOCS

Note that they say back order form the US "OR" you can wait until their stock arrives. That is projected to be this month.

Hope this helps a bit.

Thanks for the link - for some reason the farnell website is being weird with me - I can access it once, but if I refresh the page or try to open it in a different tab/window, I get access denied.

Weird... If it still doesn't work for a bit, maybe I'll try aliexpress or something.

[memma]

I have an amp (a board based on the TDA7297 - I'm happy enough playing with bare electronics, especially if power input is overvolt-/surge-protected 12V)

Just be careful with this Amp. My DIY based on this amp gets VERY HOT. also the power resistors get VERY HOT. Past recommendations on the "other site" suggest an aluminum heatsink plate for the resistors and a bigger heatsink for the amp chip. I think that this is not just hype. Consider doing this or you may burn the amp out. My go to amp is the TDA3116D2. This board is getting harder to find now though.
Afapp

Thanks for the warning - I had already bought the amp, but perhaps I'll buy your suggested alternative as well, and repurpose the hotter-running amp for another, lower current project.

[Afapp]

[/quote]
Memma wrote
Thanks for the warning - I had already bought the amp, but perhaps I'll buy your suggested alternative as well, and repurpose the hotter-running amp for another, lower current project.
[/quote]

the TDA7297 works great but I'll admit I only hooked up to it a couple of times because of the heat and only for 15 min sessions. I still have the box ready to go as a backup. There are a lot of variations of the TDA3116 around. Mine is 2 channel only not 2.1 and has no bluetooth. Also try to find one that has wound copper components on the board I think these smooth out the output. Some of the EE degree guys on the board can explain that better than me. MY TDA3116 has been a nearly daily use workhorse for 2+ years.

Breeze audio design.jpg (195.73 KiB) Viewed 5415 times

[hosenguy]

Golly the specs on this fit into one of my favorite rant topics!

https://www.amazon.ca/TDA3116D2-Digital ... B075M2KWDL
The ad says 160W x 2 Large Power Digital Auto Amplifier Board TPA3116 Dual Channel Amplifier Module Stereo AMP 12V-24V

First, before anyone gets all upset I will state this should work for a stim device. But the ad is all a bunch of foo-foo dust.
If this could be 160 watts x2 and you used a 12 VDC power supply then that would require more than 26 amps! Not happening.

Here is the datasheet of the "original TI chip" they claim is used in this board.
https://www.ti.com/product/TPA3116D2
What is that you say? Only 50 watts capable per channel? Somebody is not working with facts.

But 50 watts per channel (if it does have 2 chips) is still enough to stim. Hell, if this was actually the TI chip then one chip would be enough at 25W per channel.

I believe that this uses a knock off Chinese made chip (speculation, prove me wrong, please). They can be reasonably good.?? Probably all that you can buy come from China anyway.

My point is that they start with impossible specifications for their product. If this was as powerful as stated it would not heat being used as a stim amp unless your willy was melted at the same time. Can you imagine a 160W signal spike across the trodes?

As always, buyer beware.
I would use this amp after some testing on my bench, but it would not be my first choice.
But my choices can be questioned too, because I used a powerful car stereo for my first box.

Most of us built something and then either got lucky or rebuilt it later after we knew better. And all of us I know of still have working willys!

[Afapp]

Golly the specs on this fit into one of my favorite rant topics!

https://www.amazon.ca/TDA3116D2-Digital ... B075M2KWDL
The ad says 160W x 2 Large Power Digital Auto Amplifier Board TPA3116 Dual Channel Amplifier Module Stereo AMP 12V-24V

First, before anyone gets all upset I will state this should work for a stim device. But the ad is all a bunch of foo-foo dust.
If this could be 160 watts x2 and you used a 12 VDC power supply then that would require more than 26 amps! Not happening.

Here is the datasheet of the "original TI chip" they claim is used in this board.
https://www.ti.com/product/TPA3116D2
What is that you say? Only 50 watts capable per channel? Somebody is not working with facts.

But 50 watts per channel (if it does have 2 chips) is still enough to stim. Hell, if this was actually the TI chip then one chip would be enough at 25W per channel.

I believe that this uses a knock off Chinese made chip (speculation, prove me wrong, please). They can be reasonably good.?? Probably all that you can buy come from China anyway.

My point is that they start with impossible specifications for their product. If this was as powerful as stated it would not heat being used as a stim amp unless your willy was melted at the same time. Can you imagine a 160W signal spike across the trodes?

As always, buyer beware.
I would use this amp after some testing on my bench, but it would not be my first choice.
But my choices can be questioned too, because I used a powerful car stereo for my first box.

Most of us built something and then either got lucky or rebuilt it later after we knew better. And all of us I know of still have working willys!

Ok lets assume it's a piece of crap, and I "got lucky". I run mine with only a 12V power supply BTW. I am also not taking off the heatsink to prove whether its a TI chip or a knock off. My board is made by breeze audio/Nobsound and has differnet capacitors and inductors than other TDA3116 boards. My experience about both chips is anedotal and I said that. I'm trying to help other builders with my observations. I have NO background in this field, but I have built about a dozen boxes of all kinds. The 3116D2 has by far been the most stable of all my builds with heavy use. Please make a chip recommendation and help us all out.

[hosenguy]

I did say several times that this should work as a stim amplifier. It should be overkill actually. It should not overheat with those ratings. But those are some unbelievable specs!

Good Stimming!

[BoundSquirrel]

I've been scouring the interwebs for the bits I need. Ordering various bits from aliexpress, etc.

Now I've got to the resistors and I noticed the suggested resistors are 10W:

Midistim box:

I've put the schematic for the Midistim box here:

Midistim schematic

This is pulled right from the smartstim post and, when followed correctly, works great.

or 10/5W in the hand-drawn schematic (OK, so quoting imgaes doesn't work, but they're marked 5.6Ohm 10W and 15Ohm 5W):

JC stimbox drawing2.jpg

but BoundSquirrel's suggested resistors are 25W:

Resistors:
https://www.amazon.com/gp/product/B00NQ ... UTF8&psc=1

These are listed as unavailable, but there are a bunch of alternatives that should work. Just type, "25 watt 3.9ohm resistor" and you'll find plenty of options.

I'm guessing 25W was used to reduce heat? Or what's the reason? Is there anything I should bear in mind when selecting my resistor values and wattages? How do they affect the feeling (if such a thing is describable), and do different values relate to anything like body build/fat, or anything like that?

Thanks all!

I can't really say there was a reason that I went with those resistors. I'm not an electrician and only learned how to solder so I could zap my junk.

What I do know about electronics is that resistors are more about the ohm rating, and that the wattage is more the max they can handle. I don't remember if I got these because someone recommended going to 25w or if a schematic called them out, or what the reason was. I also know that I've had my Midistim box for about 2 years now and nothing has fried, it works great, and has those resistors. SO, I can say with certainty that they work.

[MegaErato]

@memma I have had good results doubling up my resistors in mono, so going with larger resistors is totally fine as well, the ones @boundsquirrel suggests may even be a better bet for system stability if you want to play it safe and make sure nothing is going to overheat.