Cello Amplifier Schematics

[moray james]

I have a buddy who has a cello amplifier which is doing some strange things. The amp seems to suffer a degridation of bass then midrange after it has run for several months. He first thought the problem was cable related but that does not seem to be the case. He is looking for assistance in trouble shooting the amp and wonders if there are any available schematics? He has tried several obvious sources including Mr. Levinson with no or little success. Any suggestions or directions any of you can suggest? Thanks for any help. Best regards Moray James.

 

[tomtt]

cello

this might work
http://matthew-james.net/interview_6.cfm

 

[jam]

Moray,

Look for defective capacitors in the feedback loop, assuming the amp uses a capacitor in the feedback loop. They can dry out and change value and cause the problem you mention. This can be easily checked with a scope and squarewave generator or plotting frequency response with a good VOM.

Jam

 

[moray james]

Thank you for your assistance> I have passed along these letters to my buddy. Should anybody know where to find schematics that would be a real bonus. Regards Moray James.

 

[ezmeralda11]

I thought viola labs (www.violalabs.com) had taken over for Cello. Maybe they can help. If not there should be someone out there who (can't recall who) can test/repair an amplifier of that caliber--its not like its an Adcom or anything cheap. Assuming you are wanting someone else to work on it.

 

[analog_sa]

Delegating these sort of repairs to a third party seems like an exceptionally bad idea. Are repairs really needed? Can the degradation be measured? If a problem really exists and it is common to both channels that only leaves common components. PS?

My guess is that's it's a severe case of audiophilia nervosa. The only good medicine is selling/incinerating the troubled device.