You could triode connect your 6v6 and disconnect the NFB.
Believe it or not, the triode mode has less distortion than pentode mode. And the pentode distortion has odd harmonics where triode mode is generally even harmonics. This is the reason triode mode typically sounds darker than pentode mode; the brighter sound of pentode is really the odd harmonic distortion and greater overall distortion (even before the sound is obviously "distorted").
Agreed that no-NFB and adding bypass caps will boost the drive through the amp.
... I have room for another 12AX7 ... I'm thinking of paralleling V1 ... I'm also thinking of adding some sort of tone control. Any ideas as to what to do with the other 1/2 12AX7?
Parallel the 2nd triode, too?
Cascade 2nd triode into new 3rd triode. You could add a gain (volume) control between them, even if it's an internal preset. You could fiddle the gain control for your fave setting, then replace with a fixed voltage divider of two resistors. You could use a split plate resistor output of the 2nd triode instead of the gain control or 2-resistor voltage divider.
For tone control, a "tweed style" single knob control as found in the tweed Princeton or Deluxe will prevent there from being a lot of signal loss. A typical tone stack has a very large cut in the midrange and variable "un-cut" (which you hear as boost) of the treble & bass.
Instead of 3 gain stages & a cathode follower, you could put the cathode follower after the first stage, then have your full-featured tone stack with less loss. Then either use the last 2 stages in parallel or cascade.
I haven't tried any of the above, I'm just throwing out possibilities to use up what you have.
... I don't want to go the Hi-Octane route as the chassis I have has limited space so I'll need a small board. ...
You
don't have to use a board. Look at the "Preamp Overview" picture in
this thread. I used turrets on either side of a row of tube sockets, laid in the wiring from socket-to-turret first, then installed parts spanning the turrets over top of the sockets. That entire chassis is only 4" wide from top to bottom, and there was room to fit big RV4-style pots on both the top and bottom panels. There is a can-cap and a preamp power supply with as many filter caps as most Champs. With some planning, I bet a small PT and OT could fit if I shuffled the position of a few things.
I show this only to say there may be alternate ways to accomplish you goal. The potential downside of the approach above is it's on you to plan it in detail (cause no one else is building that way), and a tight chassis like that sometimes requires you build sub-assemblies outside the chassis to be installed as a unit. For example, pots can be mounted to a plexiglass panel with holes spaced the same as your chassis, so you can do all the pot wiring without obstructions (stole that idea from Doug's board-building directions in the Library at the bottom of this page).
Topic: Suggestions for a meaner champ? (Read 4792 times)