hi =)
my MIDISid is working fine so far, but the midi out isn’t working.
whenever i plu both midi cables (in and out from my computer) there is a strange noise on the audio out. sounds like some kind of midi data because when i start the “get” function in jsynthlib (start a sysex dump) i hear rapid changings in the noise but the dump isns working 
and this high noise appearing when i plug the midi out to my computer is really loud/annoying, too.
best,
julian
Hi,
…hard to give an exact advise then.
Sounds like a kind of ground loop/problem.
Are the connections from the core to midi rather short?
Did you connect ground from the core to your midi-port (disconnect this!) ?
Do you use a shielded cable from Core to Midi-plugs ?
(if you do: Please pay attention, that the shield of the cable is only connected to the core. The other side should not be connected)
Did you connect the audio out of your SID to the PC audio In ? - If so: Just try this connection without the shield of your SID Audio Out. Still noisy ?
greets
Doc
>- Are the connections from the core to midi rather short?
hehe, at the moment a rather long cable
>- Did you connect ground from the core to your midi-port (disconnect >this!) ?
>- Do you use a shielded cable from Core to Midi-plugs ?
nope
>- Do you have multiple Cores interconnected ? -
no, just one so far
>Did you connect the audio out of your SID to the PC audio In ? - If >so: Just try this connection without the shield of your SID Audio Out. >Still noisy ?
the midi signals come from my PC
the audio outs from the SID are connected with a small Mixer and another computers audio in. so there should be no interferences…
I think i’ll just try to remove the ground… I’ll post if it helps
greetings,
jul
hmmm, just deconnected the ground from the midi out…
still the same noise
it even appears when just the midi out is connected…
sounds more like a high frequency oscilator than some normal noise…
very strange…
Are you refering to the SID bug noise? you can’t do much about this…
the audio outs from the SID are connected with a small Mixer and another computers audio in. so there should be no interferences…
Not really right. You still could get interferences via your ground connection (earth of the pc’s).
Can you try it with a short shielded Midi-cable (no ground connected) and perhaps a headphone plugged in the SID Audio Out ? - Just to ensure…
Of course your Audio signal will be very low. But do you still have a noise, when you plug the midi OUT in ?
If you have a little high noise (like arumblack said) - there is nothing you can do against it - thats analog audio !
But if you have a impendance problem or a ground loop it should disapear if you connect a headphone to the Audio out of the sid.
When no midi cable is connected you have no noise, right ? - If so, it couldn’t be the normal sid noise!
If all this doesn’t help twice check the audio part of the sid (transistor in the right direction ? - caps poled right? - all ground pins connected ? Audio IN must be grounded/shorted! and so on)
greets
Doc