[Zoomer88]

I couldn’t have said better. That’s why I’ve created this topic. It’s not about Megaeverdrive (genesis) deficiencies rather about OSSC problems. I’m happy about that it could be solved by firmware, can’t test it right now though.

Great job anyways!

[Zoomer88]

Yay! Great news indeed!

[Zoomer88]

I’ve just checked the topic there and they’re talking about fixing va0-va2 amps, but I’m experiencing the issue on va4 and va5 (only throgh ossc though, not through PC’s line-in or AVR

[Zoomer88]

@gummi True that

@marqs Soldering iron for me is like a gdi ion canon. No way I’m gonna touch that black magic sorcery. But you are correct – lowering Genesis volume slider doesn’t eliminate the distortion unfortunately. What’s intersting is is that only OSSC exhibits this issue. No other appliance has problem with such a signal (several different TVs from sony and lg as well as Yamaha and Denon AVRs – all have no problems with it.

Not to mention that said output is near perfect on my console – no noticeable interferences (well, aside from that VDP noise, but it’s picked up way earlier afaik and no amount of audio circuitry bypass will help to avoid it. Even so, it’s really faint, almost negligible).

[Zoomer88]

@marqs Actually, I don’t believe we have testimonials that the same happens with line out. You see, with model 1 Genesis routing audio from headphone out is considered the only viable option since miniDIN on model 1 is wired only for mono out. Even the official documentation for sega cd model 1 suggests using headphone amp or internal adio lines (audio pins on sega cd connector inside the sega Genesis console) and special cables are supplied with sega cd for that.

All aftermarket scart rgb cables designed for Model 1 would have this additional minijack dangling from the miniDIN connector, while audio pins in miniDIN itself usually not wired at all.

Also this separate headphone circuitry is considered to be superior quality (in addition to being stereophonic of course).

So it’s most likely that those reporting in this topic are extracting audio from Genesis the same way I do it.

Ironically this headphone amp on high-def midel 1 genesis is the only way (well, at least easily accesible way) to have the best audio from genesis, for model 2 and other iterations have other errors and bugs where audio is considered and reqire rather heavy hardware modifications, let alone tracking the proper modifiable model 2 revision (google genesis ccam or megaamp).

So all in all, this is a hardware limitation on OSSC 1.6’s part, I believe? There’s no hope of fixing it in software? Would it be possible to replace 1.6 with 1.5 with audio mod?

[Zoomer88]

@marqs On the other hand it might be related to the fact that we’re using headphone out with a headphone amp meaning audio signal is different from other consoles with non amplified line out. Thus requiring antialiasing. Hence probably the fact that some people with Genesis do not experience this issue – they’re using model 2 Genesis with line out on the miniDIN connector.

Could that be the case?

[Zoomer88]

I only use it for the PAL GC, there’s no csync/luma option available and my switch has trouble with sync-on-composite :/ I’ve heard before that sync strippers can cause issues. Could you explain what kind of issues can be seen?

I don’t see exactly how sync strippers are relevant to this thread especially since the issue seems not even to be related with cables.

[Zoomer88]

Gummi, thanks for trying to help.

Well no, my cables are not from “most recommended cable sellers”. They’re the ones I linked in my first post.

While I certainly can’t exclude the cable quality, I tend to believe this must be something else since a) I don’t get audio quality degradation when I’m not using OSSC, b) audio quality is bad even when I’m using separate high grade minijack-to-minijack cable routing audio through A1 and c) jonlad seems to have the same exact problem using what I believe is most recommended cable.

I might invest in quality cables from said sellers but it would be great if someone else test Genesis audio through scart (preferably from Model 1). I’m not really happy about paying return shipping costs for the cables and possibly for the OSSC itself if there’s no improvement/it’s a hardware bug and not fixable/works as intended etc. Genesis is the only console I bought the OSSC for.

And as I pointed out before – yes, you can plug in any other audio source to A1 and it gets mixed together with audio coming from SCART and sent over HDMI. This behavior is observed on the current (and I believe the only one for v.1.6?) firmware. I’m not sure if this was intended and might be a bug. For what I know this even might be a culprit to the issue.

Edit: now that I’m thinking about it – it might be a great feature – to be able to explicitly disable scart audio and inject audio coming from A1.

[Zoomer88]

I’m getting audio over HDMI from a source plugged into terminal labeled “A1 OUT/A2 IN”. It could be a phone playing music for example. Everything’s getting mixed and send over HDMI.

Back to the issue. When I’m connecting another source to 3.5 jack and playing sound from it – there are no problems. It seems that only audio from the console affected in such a way. Could someone please test Sega Genesis with OSSC 1.6?

[Zoomer88]

Thinking about it – is it possible to disable audio in over SCART? Maybe it’s still active when I’m testing audio signal over separate cable? Perhaps some interference in the SCART cable is still being picked up by OSSC and mixed with clean signal from the minijack in?

Or is the SCART audio disabled when minijack is in use?

Still that does not explain why the issue is present only with OSSC. Maybe it’s sensitive to this specific interference or the interference generated by OSSC’s power supply?

[Zoomer88]

Glad I’m not the only one. Yea, I do confirm that this isn’t the receiver. The distortion could also be heard on tv’s speakers. I’ve also been able to reproduce it on my older TVs with sSCART by connecting and then removing OSSC. The distortion disappears without OSSC.

[Author]

Posts