kdawg
Well-known member
Hi all... I have a Roland JC-120 Jazz Chorus amp that I love, but is quite hissy. I have the schematic (Apparently there are about 8 different Revs) and was trying to decide what to replace/upgrade to get the noise floor down.
The schematic is temporarily up at http://www.jnd.com/kdawg/my_jc120.pdf
Noise floor is about the same on both channels, so I thought maybe its power supply related. I put a scope on it a while back though and it didn't seem too bad. I'd love to get better noise floor transistors but I'm not very good at cross-referencing these japanese transistors.
Any help is greatly appreciated - I actually made a list of all the caps and there are 100+. I don't want to spend a fortune on parts but would like to replace key elements to get this thing going again. Thanks
-kdawg
The schematic is temporarily up at http://www.jnd.com/kdawg/my_jc120.pdf
Noise floor is about the same on both channels, so I thought maybe its power supply related. I put a scope on it a while back though and it didn't seem too bad. I'd love to get better noise floor transistors but I'm not very good at cross-referencing these japanese transistors.
Any help is greatly appreciated - I actually made a list of all the caps and there are 100+. I don't want to spend a fortune on parts but would like to replace key elements to get this thing going again. Thanks
-kdawg