exxos's Atari, Amiga & retro forum

I just realised I didn't post the pics of the MIDI fix part on this thread. I'll do that later once I get to the machine.

exxos wrote: 21 Oct 2022 09:34

Bikerbob wrote: 21 Oct 2022 02:39
Got it.. SO if I have no plans to use the MIDI board then the MIDI fixes we just discussed above are not really required then? Good to know. Maybe I do them later if and when I decide to do the midi board.

No.. That's not what I said. I said you need to do all the new fixes. Its irrelevant if you use midi or not as the noise is on the all circuit power rails for both YM and MIDI.

ah ok.

Icky I think I spoke to you at the meet-up event about there not being an audio-fix guide for my version of the H5 (the first run) I have the winamp board installed - but the main motherboard circuitry is totally different since on later revisions the winamp board was merged onto the motherboard, if you get my drift.

If you or exxos still have an original board with winamp-pcb installed hanging around, I'd really appreciate a guide, if only for the small handful of us who have the first revision.

Thank you,

The winamp board has way to many faults for it to be any use anymore. I would suggest just not using it. It only corrects volume issues on the midi synth IIRC. They are not that off to start with. It was more of a prototype for moving to a new amp circuit which has had many mods since the winamp board. To the point you will add more faults than it fixes in fact. The original transistor based amp doesn't suffer from faults which were introduced with the IC based amp circuit. So your better sticking to how it was.

EDIT:
I've taken the module out of the store and updated the page saying not to fit it anymore. It was only intended to beta test the new audio circuit. Such testing is long since gone.

Okay, so after that is removed I may still need a guide for removing the noise on the audio line right?

Steve wrote: 25 Oct 2022 21:02 Okay, so after that is removed I may still need a guide for removing the noise on the audio line right?

Which board do you have exactly ? If its the transistor based amp then it doesn't suffer from that problem anyway.

I think there is some confusion in the timeline of all this..

The H5 Ax and Bx series had the transistor based amp circuit. This was basically identical to the original ST audio circuit. Of the top of my head the only fixes for that was the volume fading out. I think there was a missing cap on the YM circuit somewhere, but its all documented anyway. There are no known faults outstanding on that audio circuit that I am aware of. If there was it would be a fault in the original ST's as well , as it is basically the same circuit.

The "Winamp" board was just a prototype to adjust the volume level of the midi synth board. When @Icky did the original testing I think he did not even notice the audio difference. But me being me, set off my OCD and I had to design the Winamp board to correct the audio levels. In hindsight I really wish I had not have bothered if I knew how much hassle it was going to be :roll:

So then the H5 C1 was born with the new amp circuit. Which introduced its own faults which @Bikerbob found. But note this is with the IC based op-amp on the H5C1. Previous H5 A&B series did not have these problems because it was a totally different audio circuit anyway.

EDIT:

There was a guide on how to fit the Winamp board already anyway viewtopic.php?p=55170#p55170

@exxos mine is the first H5 board, the A3. With Winamp installed. I get the floppy noise interference through the speakers, same as bikerbob has.

So you think I should just remove the Winamp board. Alright I'll try that sometime. (I never tested the audio BEFORE installing the Winamp board, so perhaps the problem may have been introduced by the Winamp board)

Steve wrote: 26 Oct 2022 11:55 @exxos mine is the first H5 board, the A3. With Winamp installed. I get the floppy noise interference through the speakers, same as bikerbob has.

So you think I should just remove the Winamp board. Alright I'll try that sometime. (I never tested the audio BEFORE installing the Winamp board, so perhaps the problem may have been introduced by the Winamp board)

Yep the winamp board was built before all the problems were found,