Re: [Harp-L] Low plate voltage on the preamp tubes?

["steve" <mudharp@xxxxxxxxxx>]

 Michael,I've done them to an old Blues Jr I had and to a friends Pro Jr.  He really liked the results from what it was (feedback ridden).  Now, if I remember the Pro and BLues Jr. have somewhere around 275 volts on the preamp plates.   To get them down to the 85 volts you'd need about 200K ohm resistor on the power supply dropping resistor.  I personally think that's way way too much for an amp with this design. It really took away from the bark.  I even added the Weber Rectifier Module to introduce some sag.  You don't want a real big voltage drop, so you should stay in the WZ34 range.  The WY3GT is too much.  When I bought a cheap ole Harmony 305A for 162 bucks it sound better than the modded Blues Jr I had.   Much warmer, quiet, way less feedback and the plate voltages were already at 150.  I experimented with many different preamp voltages and the 80-85 turned the amp into mud.  I ended up about 105 and it still had some bite and had plenty of warmth. Unless you're ready 
to experiment with different values and then quickly change them then I'm not sure if you should pay someone to try all this UNLESS the tech would allow you to be there and try them before he puts the amp back together. Could be a crap shoot.  Been there. hope this helps.stevethunderharpmics  

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