After you boot into Windows, open the sound mixer and mute all of the inputs. There should be at least a mic, line-in, CD-in, and on some cards PC Speaker.

Thanks but if I hear noise before windows boots I very much doubt it is fixed by a mixer setting.

You said when it's in Windows you need to put it at 5% volume to be at a reasonable level. That means there's some massive amplification going on. Testing the mixer can be done in minutes for free, so I'm not sure why you don't want to at least try it.

You don't list what headphones you are using, just the brand. Do they have their own amp? Try connecting to the line-out rather than speaker output.

SScorpio wrote on 2021-10-31, 14:39:

Try connecting to the line-out rather than speaker output.

^^
This.

wireless mice can cause noise if you use one.
remedy for that is a extension cable to move it away 😀

This card appears to have a speaker amp on it that cannot be bypassed with jumpers like many other cards allow. That's where the excessive levels and noise come from.

Zerthimon wrote on 2021-10-31, 15:07:

SScorpio wrote on 2021-10-31, 14:39:

Try connecting to the line-out rather than speaker output.

^^
This.

Sorry but there is no line out. 🙁

Tiido wrote on 2021-10-31, 15:13:

This card appears to have a speaker amp on it that cannot be bypassed with jumpers like many other cards allow. That's where the excessive levels and noise come from.

I see. Could this be done by rewiring mods?

Yeah, it certainly is possible. The amp chip's inputs and outputs need to be identified, then this sort of thing done :

Ok yeah I might just try something like that. The
amplification chip, KA2206CD, seems well documented.

Thank you

I was wrong when I said the chip is well documented, it is not.

For some reason my multimeter's continuity measurement mode is malfunctioning (no beeps) so I haven't been able to investigate this further.

So uh, why not just connect a 3.5mm jack to pins 7 & 8 on the amp chip for left and right, then a ground from anywhere on the board?

Thermalwrong wrote on 2021-11-02, 21:41:

So uh, why not just connect a 3.5mm jack to pins 7 & 8 on the amp chip for left and right, then a ground from anywhere on the board?

Oh, hmm. This is not obvious to me. Could you explain how you realized that pin 7&8 are the ones? 😀

There's a datasheet for the KA2206 amplifier (e.g. https://pdf1.alldatasheet.com/datasheet-pdf/v … UNG/KA2206.html ) which has pins 7&8 being the inputs for channel 1&2. So those are probably line-out, with pins 2&12 being the speaker out.

Yeah I saw that but mine is called ka2206cd and has 16 legs, not 14, what am I missing here? 😀

Oops, didn't spot that I posted a link to the KA22066, rather than the KA2206. This is probably a better bet: https://pdf1.alldatasheet.com/datasheet-pdf/v … ETC/KA2206.html

Looks like they can come in 2 different packages, one with pins 4&5 and 12&13 joined together as a single pin, and one as a normal 16 pin dip. The 2206 datasheet (or at least one I looked at) doesn't even count them as pin numbers and has inputs on 5&8, which I think is pins 7 & 10 on the dip package. I'd guess the C is for the C version and the D for the DIP package. If your multimeter is still working for measuring resistance then you might be able to try tracing the amp output pins (2&15?) to the output capacitors and then to the 3.5mm socket.

Thank you for the schematics, I could not find them myself for some reason. Sadly my multimeter can't measure a known resistor value so I don't trust it anymore.. I will have to put this fix on hold until I get a new one.