[sdiy] roland sh-2000

[jakob stoller]

hello finlay

thanks a lot!

i did look at the VCA section. on the schematics, there are various 
trimpots. but the one, which is acccessible without disassembly the 
whole synth is the "VCA OFFSET". i'm a bit chary to trim at this. what 
do you think, is there an interrelationship between the bleep and the 
offset of this op-amp?

you'll find the schematics here:
http://www.iaqob.net/ftp/sdiy/

best, jakob


Finlay Shakespeare schrieb:
> Hey Jakob,
> That sounds to me like something's wrong with the VCA section along the 
> line - it isn't closing properly and is letting a little signal bleed 
> through. That could be sorted by tweaking a trimpot - can you see any 
> little preset pots on the VCA board?
> It seems a little odd to me that Roland would keep the pitch high as a 
> standard... but I guess it's easier to have a high pitch all the time 
> then add resistance to it to drop it.
> Cheers,
> Finlay Shakespeare
> http://www.futuresoundsystems.tk
> 
> --------------------------------------------------
> From: "jakob stoller" <office at iaqob.net>
> Sent: Monday, June 02, 2008 7:32 PM
> To: <synth-diy at dropmix.xs4all.nl>
> Subject: [sdiy] roland sh-2000
 >
>> i got a roland sh-2000 preset synth some days ago and it is working 
>> quite proper and i guess will have a lot of fun with it...;)
>>
>> there's just one problem, probably a bug an i thought, there's someone 
>> out there, who knows more about that. in the way "this electrolytic 
>> capacitor is buggy or look at this component..."
>>
>> description:
>> independent of the selected sound- it doesn't matter if there's a 
>> sound selected or not- a quiet high frequency tone is coming out all 
>> the time. it's a really high frequency tone, which is corresponding to 
>> the last key i did push on the keyboard. furthermore it's reacting to 
>> modulation, portamento, random note, transpose, tuning etc. so, i 
>> guess the tone occurs already in the vco.
>>
>> do you have any idea, what could be wrong?