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previous: Mike Thanks - just finished talking with... -- 2/10/1999 5:14 PM View Thread

Re: '68 Super Reverb

2/11/1999 3:54 PM
MJ Harnish
Re: '68 Super Reverb
I would agree about the *voodoo* associated with amps. My thinking is that some it has to do with lead dress. I have a friend who does a LOT of tinkering with amps and he swears that moving certain wires a 1/2" can have a big effect on tone.  
As for you super, it can be made to sound good IMO. You might have to invest some time into it though; you might consider making it an ongoing project. It's possible that the tech who BF's the amp (chances are that if it was a '68 it had the BF circuit so who knows what they did) screwed something up. It's worth a close inspection.  
My first suggestion would be to photocopy a schematic and then work through the amp highlighting on the schematic (component values and layout/placement) what's different about yours compared to the AB763 schematic. Look for items that are missing or shouldn't be there. Make sure somebody didn't replace a few choice resistors with carbon film (they're usually light,glossy brown in color vs. the chocolate color of carbon comp resistors), etc.  
Some things to test (easy to do once you know how to work SAFELY on the amp) with a multimeter:  
1) Test your bias and see what the tubes are running at  
2) Test the plate voltage and B+ voltages and see how they compare to the schematic's voltages

Mike Thanks for the comments. I'm new to... -- 2/11/1999 9:55 PM