Introducing PROCYON, My First 300B Amp
Posted: Tue Jan 27, 2015 12:26 am
And it's only the third 300B I like the sound of
The AIST (Active Inter Stage Transformer) works quite well buffering the otherwise-unable-to-drive 6SL7 mu-follower.
I couldn't Google worthwhile info, but 300B grids aren't as delicate as people's opinions lead us to think. I've had her pretty hard into A2 and the distortion on bass isn't that objectionable and not near as nasty as the transformer saturating. Couldn't even see a stress on the grid even through my camera on macro, which is pretty IR sensitive.
I'm still playing with the cathode resistor. Got a pair of el-cheapo Valve Art tubes in there now, but when dropping in Sophia mesh plate, they are so hot that a typical 880R cathode resistor will make the mesh plates redplate with 400Va-k.
The pic shows a 5U4 in place of the GZ34... that's because we only had one in the store and the boss snitched it to demo the Golden Tube 300B up front
A big complaint people have is a 300B with ZNFB has no bottom end... well, the CFB makes this a "fat bottomed girl"
Cheers!
The AIST (Active Inter Stage Transformer) works quite well buffering the otherwise-unable-to-drive 6SL7 mu-follower.
I couldn't Google worthwhile info, but 300B grids aren't as delicate as people's opinions lead us to think. I've had her pretty hard into A2 and the distortion on bass isn't that objectionable and not near as nasty as the transformer saturating. Couldn't even see a stress on the grid even through my camera on macro, which is pretty IR sensitive.
I'm still playing with the cathode resistor. Got a pair of el-cheapo Valve Art tubes in there now, but when dropping in Sophia mesh plate, they are so hot that a typical 880R cathode resistor will make the mesh plates redplate with 400Va-k.
The pic shows a 5U4 in place of the GZ34... that's because we only had one in the store and the boss snitched it to demo the Golden Tube 300B up front
A big complaint people have is a 300B with ZNFB has no bottom end... well, the CFB makes this a "fat bottomed girl"
Cheers!