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previous: Andy Hi GilYou're probab... -- 3/18/2000 8:10 PM

Re: Mesa/Boogie, hiss versus tone?

3/18/2000 9:48 PM
Steve A.	Re: Mesa/Boogie, hiss versus tone? Andy: On the other hand the tubeboard seems like the safest way for mods... I always figured that with practically any PCB amp it should be possible to replace the cathode resistors and caps with different values because you can always find pin #3 or #8, take the existing components out of the circuit (remove a jumper- not bad/cut a trace- ouch!) and run a new Rk and Ck (possibly with a switch to select different values) to an appropriate ground point. But there certainly are exceptions to that, with everything but the kitchen sink hooked up to the cathode circuit... And if the plate resistors are mounted on the tube board they should be fairly easy to identify, too. Once you get further away from the tube sockets you need to follow the traces very meticulously and hope for the best! (And if you find a double-sided PCB I suggest that you don't even mess with it- other than maybe cutting out a resistor and soldering a new one to the old leads.) Steve Ahola

3/18/2000 9:48 PM

Steve A.

Re: Mesa/Boogie, hiss versus tone?

Andy:

On the other hand the tubeboard seems like the safest way for mods...

I always figured that with practically any PCB amp it should be possible to replace the cathode resistors and caps with different values because you can always find pin #3 or #8, take the existing components out of the circuit (remove a jumper- not bad/cut a trace- ouch!) and run a new Rk and Ck (possibly with a switch to select different values) to an *appropriate* ground point. But there certainly are exceptions to that, with everything but the kitchen sink hooked up to the cathode circuit...

And if the plate resistors are mounted on the tube board they should be fairly easy to identify, too. Once you get further away from the tube sockets you need to follow the traces very meticulously and hope for the best! (And if you find a double-sided PCB I suggest that you don't even mess with it- other than maybe cutting out a resistor and soldering a new one to the old leads.)

Steve Ahola