Hey all,
I could really use some help with parallel resistors, I'm really bad at them. I don't really understand how it works. I am trying to wire up a device using this schematic :
DIY_estim_build.jpg (206.98 KiB) Viewed 3476 times
I am unsure about the part with the 15W resistor between the amp and the transformer, which should be wired in parallel if I am not mistaken.
I have it wired like this for now:
Inked paralell WAGO.jpg (829.8 KiB) Viewed 3476 times
I'm wondering if that's the correct way to do it, or if you can even do it with WAGO connectors. If I am incorrect could someone who knows about wiring please enlighten me?
This resistor is "parallel" because it is connected as "load" (same as transformer). Depending on transformer and amplifier it can have effect, or not. For example, my transformer has 4 Ohms resistance statically (so when not connected to anything) so amplifier will see the load and be fine. Some transformers have much less resistance until they are in dynamic mode (when signal is being played), and some amps do not produce output if they do not see enough resistance (that depends on particular amp).
It might be that your amp works perfectly fine with your transformer, but this resistor makes it so that you are on safe side. Just check during first few sessions if it gets very hot while in use, you do not want this resistor burning out mid-session :)
If it does get hot, first thing to try is to play without it and see the difference.
Right its a TPA3116 based amp which I used a different variant of successfully already on another box, without these resistors. The transformers in both cases are the Speco T-7010. The whole build is rather similar to this but without these parallel resistors, and some other features. I'm not so much worried about safety as I am the feeling of it, and just wanting to follow the schematic as its written.
Thanks for the help, and the information!
The feeling will be most affected with high-pass resistors. But if you are playing mp3 files, you can do high-pass filter in Audacity, and also normalize (to move to 0 DC) for very similar effect.
edger477 wrote: ↑Tue Dec 13, 2022 12:30 pm
The feeling will be most affected with high-pass resistors. But if you are playing mp3 files, you can do high-pass filter in Audacity, and also normalize (to move to 0 DC) for very similar effect.
I'm confused now, you said in another thread that software processing doesn't work well or as intended, at least that's how I understood it. I probably misunderstood it then. Can the hardware (330uF capacitor) high pass filter be equally well replaced by software processing, using Audacity or some some software to do real time output filtering?
fl0w wrote: ↑Tue Dec 06, 2022 9:23 am
Can this processing be done for a DIY on the software side? Some kind of pre-processing of a script/audio file to filter out the unwanted sharpness before sending it in through the wire? Maybe using a regular software EQ? Or even a hardware EQ that sits somewhere between the laptop and the amp/stimbox?
The problem with processing with DSP is that it changes the signal, it often uses its own carrier frequencies that then modulates (whether by frequency or amplitude) to introduce some diversity of signal that is controlled by input. You get much more uniform output but many of the intricacies of signal get lost (mostly from the triphase-intended signals as those need to have certain phase shift between channels that does not get through processing).
One easy and cheap way to add some pain-proofing to DIY box is high-pass filter with capacitor. Check the dedicated thread for exact value, but important is that it is bipolar capacitor, the capacitance value was between 100 and 330uF.
fl0w wrote: ↑Tue Dec 13, 2022 2:51 pm
The problem with processing with DSP is that it changes the signal
This was referring to processing in boxes like 2B, Coyotte, 3rdh etc. They are not using high-pass filter, they are generating new signal just using input to create variations in it.
The high-pass filter is just removing low frequencies (so signals that have them will feel quieter/weaker) but not changing the signal in general as long as it has components above the frequency filter.
fl0w wrote: ↑Tue Dec 13, 2022 2:51 pm
Can the hardware (330uF capacitor) high pass filter be equally well replaced by software processing, using Audacity or some some software to do real time output filtering?
You could use i.e. Voicemeter to pass the audio through to your output device and in it activate EQ on that particular output.
InkedPXL_20221214_010710340.jpg (513.87 KiB) Viewed 2996 times
what did I do wrong here? This is taken from the bottom of the Pot, and my understanding of the diagram is that it was the top of the pot. So I thought this was how it was meant to be. Or do I need to do something different with the capacitor and resistor? seems like the signal is just passing through the POT with no effect. The only pots that work are the little ones attached to the PCB
In that photo, it looks to me like the resistor may be shorted to the case of the potentiometer (hard to tell for sure).
If that were the case, then you would be sending the signal on one side of the pot, and through the resistor to ground on the other side; therefore you would see little change in the volume of the signal by turning the pot.
Simply bend the capacitor and resistor away from the case of the pot a little and see if that helps.
Stop the violins! Give pizza chants!! Shave the whales!!!
