Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "Jim Atwood" <photoshootjapan@...> wrote:
>
> Hello!
> 
> I'm curious if anyone has owned and experienced static output with the Roland S-50.  I'm trying to determine whether I need to replace the Output Jack board or the CPU board.  Static is heard across all outputs including the headphone jack.  Playing the S-50 at low volume levels results in minor static but as you increase playing velocity or volume the static increases.  Here is a file with an example of the S-50 static.
> 
> http://jimatwood.net/synth/Roland-S50-Static-Output.WMA
> 
> Any thoughts would be greatly appreciated.  Thanks!
> 
> Jim
>
The output op amps are going into distortion mode. This is probably due to a less-than-clean +/- supply going to the op amps. Have someone with an oscilloscope check the power supply ripple on the amps. But, if the supplies are ok , I would suggest replacing the op amps.