[Harp-L] Re: Re-tube Baseman 100 top

[Jim Rossen <jimjimdr@xxxxxxxxx>]

Would try-
Use bass channel with deep switch on and the master a little down (you
probably do this already).
12AY7 in V1
12AU7 or 12DW7 as phase inverter
Your amp currently has a ton of NFB-  reducing it may increase
feedback in addition to thickening the tone.
Bias it very cold to get some crossover distortion.   This will
probably require revision of the bias circuit.   You amp has a bias
balance instead of bias adjust circuit.  Change to bias adjust is
fairly easy.
Pull two power tubes, one from the left pair and one from the right
pair.  Check the bias if you do this.
Reducing plate voltage of preamp and power tubes would probably help
alot, but would require circuit changes.

Jim R