Milovana.com

edger477 wrote: Tue Jan 04, 2022 9:08 pm

blondie88 wrote: Tue Jan 04, 2022 8:35 pm
Hey, sorry for sounding dumb but I don't understand what you are saying. If I am currently connecting my black cable from my amp to the black wire on the transformer that says "com" and my red cable thru my resistor to yellow on the transformer which says "8", what should I be connecting my 2 wires to instead?

These are my resistors by the way: https://www.amazon.de/gp/product/B015Z1 ... UTF8&psc=1

Black stays as it is, disconnect yellow one and connect red one (that comes out of transformer at 4 mark) instead.

Thanks edger477, really appreciate you taking the time to help a stranger. Wishing you a good evening!

blondie88 wrote: Tue Jan 04, 2022 10:01 pm
Thanks edger477, really appreciate you taking the time to help a stranger. Wishing you a good evening!

You are welcome, please let us know the effect!

BTW one of my devices is almost identical to yours, I recommend testing it with Estim Tower.

Electronics engineer here : the 4/8/16 ohm winding on the transformer is a little misleading wrt what the amplifier is actually “seeing”, not least because it’s not being used as it’s original intention. Here it’s simply being used as to generate voltage step-up (and isolation) from the amplifier output. The options on each side relates to the number of windings around the core for each connection. The turns ratio of primary:secondary - or effective turns ratio, since there are various options - directly gives a multiplying/dividing factor of the primary:secondary voltage. Similarly there’s a multiplying/dividing ratio for the impedance seen on the primary side for a specific load resistance on the secondary -but it’s (turns ratio)^2.
See link - also shows how these line transformers are normally used :
https://www.electronics-tutorials.ws/tr ... ormer.html

I think I’ve written this already (somewhere) but the 4ohm series resistor just guarantees a minimum if the transformer output is shorted, and a resistor in parallel with the transformer input guarantees a maximum if the transformer output is unconnected. In the case of a class D amplifier they shouldn’t be run without a load - not sure offhand if that applies to the tpa3116 too.

The body resistance on the output side of the transformer can vary a lot according to hydration, skin connection, etc, so it’s not easy to say exactly what the resistance of the transformer seen from the amplifier side is - again, 4/8/16 may not be accurate, or completely irrelevant.

Istr seeing a transformer turns spreadsheet here or on Reddit, not sure what the assumptions were… I’ll see if I can find it..

Edit : the take-home is , if you’re changing winding taps, be aware you need to need to start audio level from zero, since you could be halving or doubling the voltage on the secondary side !)

steelhorse545 wrote: Fri Jan 07, 2022 2:46 pm Electronics engineer here : the 4/8/16 ohm winding on the transformer is a little misleading wrt what the amplifier is actually “seeing”, not least because it’s not being used as it’s original intention. Here it’s simply being used as to generate voltage step-up (and isolation) from the amplifier output. The options on each side relates to the number of windings around the core for each connection. The turns ratio of primary:secondary - or effective turns ratio, since there are various options - directly gives a multiplying/dividing factor of the primary:secondary voltage. Similarly there’s a multiplying/dividing ratio for the impedance seen on the primary side for a specific load resistance on the secondary -but it’s (turns ratio)^2.
See link - also shows how these line transformers are normally used :
https://www.electronics-tutorials.ws/tr ... ormer.html

I think I’ve written this already (somewhere) but the 4ohm series resistor just guarantees a minimum if the transformer output is shorted, and a resistor in parallel with the transformer input guarantees a maximum if the transformer output is unconnected. In the case of a class D amplifier they shouldn’t be run without a load - not sure offhand if that applies to the tpa3116 too.

The body resistance on the output side of the transformer can vary a lot according to hydration, skin connection, etc, so it’s not easy to say exactly what the resistance of the transformer seen from the amplifier side is - again, 4/8/16 may not be accurate, or completely irrelevant.

Istr seeing a transformer turns spreadsheet here or on Reddit, not sure what the assumptions were… I’ll see if I can find it..

Edit : the take-home is , if you’re changing winding taps, be aware you need to need to start audio level from zero, since you could be halving or doubling the voltage on the secondary side !)

On his particular transformer, they do have 4/8 ohm static resistance on corresponding windings, of course it can be less depending on load but measuring static resistance when not in use should provide enough load for amplifier to start.

The resistors used here are winded ones, so if he does not notice difference when using 4 ohm winding, then it might be resistor is acting as a choke due to inductivity of windings.

Is 4/8 ohm actually measured ? If so, that’s surprisingly high, I wonder how it’s been measured - in isolation, or in-circuit ?. (Btw - the impedance in use will be higher than the resistance measured at dc.) To look at it another way, the point of the 4/8/16 ohm winding in its intended use is to connect to a loudspeaker of that impedance to a long line running at a higher voltage - if that winding is a similar resistance, than you’re losing half the power in the transformer. I’ve just measured a tr1005 - a similar 10w transformer- and the loudspeaker connections are less than 0.5 ohm, which is more what I’d expect. By comparison, the ‘power’ windings are 200- 1k ohms.

Higher power resistors are often (more usually ?) wire wound - tho can be constructed to minimise inductance. Yeah, there’ll be some inductance, but at audio frequencies/low resistance values I’d doubt that it’d have a significant effect at audio frequencies at the output side of an amplifier. (Within an amplifier design it could be more significant.) . But something worth wondering about..

Oh, one thing to puzzle over is whether it’s worth adding the parallel 16ohm resistor across the transformer - class D amps shouldn’t be run load less, what the effective load of the transformer looks like to the amp could possibly be quite high - or higher than the tpa3116 (in the OP’s case) is happy with. Clutching at straws, maybe ?

steelhorse545 wrote: Sun Jan 09, 2022 2:10 pm Is 4/8 ohm actually measured ? If so, that’s surprisingly high, I wonder how it’s been measured - in isolation, or in-circuit ?

Measured with digital ohmmeter just black to yellow/red outputs, disconnected from everything else.

Thanks for weighing in with more info guys, much appreciated.

The thing is, from what I've read, tons of people built this DIY rig and loved the results, with some recommending it to be even superior to some professional devices, and as I (to the best of my knowledge) followed the schematic directly, I can't help but wonder why it doesn't feel so good to me.

I did change from red to yellow Edger477, and I would say it did feel 20% better, but not massively better (and even that could've been placebo) but as I used the recommended transformers and resistors, I can't really see where else I can go from here that will make sure a big difference.

But alas, I might get chance to try again tomorrow and I will play around with some different electrode placements and stuff. Thanks again all

blondie88 wrote: Sun Jan 09, 2022 8:50 pm The thing is, from what I've read, tons of people built this DIY rig and loved the results, with some recommending it to be even superior to some professional devices, and as I (to the best of my knowledge) followed the schematic directly, I can't help but wonder why it doesn't feel so good to me.

Keep in mind that stimming involves a learning curve. It's not something you can connect to once and get the results you want. I think I've been doing this for 3 or 4 or more years now and two nights ago, I found a new setup that is even better than I'd done before. It's a labor of love that just keeps paying off more and more. It's also a hobby that can get expensive if you start buying a bunch of electrodes to try out.

Half of the battle of getting a stim signal to feel good is to be in the right mindset. If you're watching porn that isn't appealing, the signals can be the best in the world, and it's not going to do it for you. A lot of posts out there even suggest that you just lay back and let your mind go blank or use your imagination with no visual stimulation. Not for me, but hey, different strokes, right?

The next thing is to not turn the signal up too high to start. You don't want to be zapping your junk to the point that you're jumping out of your chair with every beat. I keep my volume so low at the start that I can't even feel it, or, at most, can barely feel something from the right channel. After a minute or two, with no volume increase, it starts out as just a warm sensation instead of an acute zap, tingle, etc. If you're expecting the DIY box to feel like you're getting a blowjob as soon as you click 'play', you're looking at it wrong.

Third is to not be afraid to help yourself along. HFO's don't happen the first time for most people from what I've read, and certainly not for me. For some people, they never happen. You have to train your body and brain that what you're feeling is good and that it's ok to react like it's a good thing. So, the more you give yourself a hand, the more your brain associates the tingle feeling with good feelings and the closer you'll get the next time. Don't go into it expecting the signals to make you nut. Go into it expecting them to make you feel good. If you get pleasantly surprised by an HFO, great.

Fourth is that it's a marathon, not a sprint. Some people talk about 3 hour sessions. I don't know how you all have the willpower to do that. I don't. But it's also not a 5-minute game of whack-a-mole either. Set aside an hour or so to let your body get into it.

Finally, don't try some weird tri-phase with the negative common split between here and there and hanging upside down while you smoke a blunt and do a no-hands-tequila shot. Stick with the basics; 2 discrete sets of electrodes, each with a positive and negative. Maybe right to the taint and balls and the left to the base and head. Figure out what feels good from there. Once you get yourself feeling good a few times like that, then start experimenting with different electrodes, positions, and whatever else comes to mind (as long as it's safe!) If everything you've tried so far has been with 1 signal or signals from one author, switch it up. I've got a few files out there for some older CockHero videos, but the newer ones put out by Puste, LondonGent, and DigitalParkingLot are all outstanding. I know there are others too, but those three come to mind, and are all very effective.

blondie88 wrote: Sun Jan 09, 2022 8:50 pm
I did change from red to yellow Edger477, and I would say it did feel 20% better, but not massively better (and even that could've been placebo) but as I used the recommended transformers and resistors, I can't really see where else I can go from here that will make sure a big difference.

But alas, I might get chance to try again tomorrow and I will play around with some different electrode placements and stuff. Thanks again all

Mine is almost same components but I have wrong resistor and should have worse issues than you, but it works fine (on yellow). Do you play sound (source for amplifier) on maximum level? If yes try to reduce to maybe 70%, experiment a bit, and adjust on amplifier to compensate.
Also try with brand new sticky pads, and if is better buy tens spray to use before sticking them.

Hello, I have tried commercial estim cables from estim systems in the UK and speaker cables from
Amazon. I can’t tell the difference between the two except the estim specific ones are more comfortable to use, lighter gauge, connectors fit my attachments better although both work.

I also enjoy Hi-Fi audio and in that circle there is a lot of debate about speaker cables. Many say they can’t hear the difference between cables at different price points, I know I can but for estim, it all feels great so why get fussy!

All the best!

I enjoyed reading the thread on DIY stereostim box builds and this thread on electrode cables. So I thought I would share a cable problem I just experienced. About 3 years ago, I built a basic stereostim box based on TroniC's MidiStim design. Worked fine! Lately, I noticed that one of the channels would intermittently go dead. Yesterday I decided to do some troubleshooting and try and determine and locate the problem. The steps I used might be useful (especially for non technical types), so here they are:
Signal Troubleshooting steps:
1. Generatd three MP3 audio test files using Audacity: Stereo, Channel 1 only, Channel 2 only.
2. Multimeter continuity tests: 3.5 mm male Audio patch cable to box (OK). 3.5 mm female splitter cable to two phono jacks in the back of SMLC amplifier (NOT OK). No continuity to Channel 2 signal lead. Channel 1 and ground were OK.
Voila! Problem located. As luck would have it, I had a spare 3.5 mm splitter cable that tested fine
To complete the troubleshooting:
1. Confirmed audio source (iPad) was outputting sound by listening to it.
2. Conformed that MidiStim box was outputting voltage on Channel 1 and Channel 2 using the MP3 audio test files. This was helpful in verifying which MidiStim output jacks were Channel 1 and Channel 2.
3. Since I use some conductive rubber tube loops as electrodes, I checked the continuity and resistance of the wire cables and 4 & 6 mm diameter loops. The wire cables tested ok. The 8 " long conductive rubber loops had about 500 ohms resistance. The 12" long loop tested at about 3000 ohms. On a hunch, I snipped a bit (1/4" to 1/2") off the ends of the loops, since this is where the 2 mm electrode jack pins plug into the loops and might have worn out the end sections. The shorter loops resistance dropped somewhat. The longer loop resistance dropped to about 800 ohms. I was interested in the resistivity of conductive silicone loops, so I contacted Gary at HappyStim-USA. He quickly replied, and when asked, was happy with me sharing his reply on the forum.

Spoiler: show

(From Gary) T"hanks for your follow-up related to the conductive silicone tubing.
First of all, glad that you were able to find the short in the audio
cable. Most of the time, wiring is the problem, as they are used over
and over.

You are correct with the tests and the resistance of the tubing too.
Because conductive silicone is made by adding carbon powder to a block
of a specific grade of silicone that is melted and mixed with a recipe
of a specific amount of carbon powder. Once it is run through dies and
cured, as you can imagine the molecules holding the silicone and carbon
powder together are not bound tight like metal is. Thus, the Ohms or
resistance on a longer length of tubing gets higher and higher as you
test it down the length of tubing.

You found this out by testing the longer loop. :)

The attached is a list of properties of the conductive silicone that you
can look over. Note the resistance per centimeter of the tubing. As
you move down the length it does loose some of its conductivity.

Hope all of this helps,"
attachme

I couldn't wait to do a test run, so I wired up and played some of my favorite stim videos, and the results were gripping (great)!!
FYI - The replacement cable in this case was fairly robust, 4' long with a 3.5 mm male jack on the long end and a short Y split to the two phono jacks on the amp. The box Now has a longish cable sticking out the back. It's not as compact as before, but I've replaced one connection with a quality cable. So it's a good trade off.