In the quest of tone and my final attempt this is a bit long so bear with me.

[catnine]

 When I built my 6G2 from end and connected it to a 5E3 power section what I had was a vol and tone control just like the older fenders had . There is no NFB of the 5E3 yet there is a cathode bypass cap on the second gain stage this would be V-2 on a 5E3 and the amp sounded perfect . Then I had this insane idea of changing the vol and tone stack into a BF vol/treb /bass and what this did was suck out all the open tones and harmonics , made the amp sound dry and sterile so I put it back.

 Now here comes the Champ AA764 with the same bf tone control and I do realize that a champ is a single ended amp and not the same power section of the 5E3 push/pull .

 On this note I built a princeton 5F2-A same tone stack as the 6G2 yet it had the NFB and no cathode bias cap on the second gain stage and was lower voltage PT. I hated that amp.

 Now if I were to take my AA764 champ as it is now yet change the tone stack to a 5F2-A add no NFB , keep the cathode bypass cap on the second gain stage is it possible that I will end up with a higher gain more open version of the old 5F2-A. Has anyone here done this?

 I don't expect it to sound like a smaller version of my 6G2/5E3 build yet hoping it may be similar .

 Or is this hoping for something that may well be a complete waste of time?

[LooseChange]

Yes. You will get more gain. The BF tone stack sucks a lot of gain.

[firemedic]

  Now if I were to take my AA764 champ as it is now yet change the tone stack to a 5F2-A add no NFB , keep the cathode bypass cap on the second gain stage is it possible that I will end up with a higher gain more open version of the old 5F2-A. Has anyone here done this?

 I don't expect it to sound like a smaller version of my 6G2/5E3 build yet hoping it may be similar .

Yes. No NFB + cathode bypass cap on 2nd gain stage + low loss tone stack. Plus a single-ended power section, as opposed to push-pull.
You are going to have plenty of gain. If it's muddy I would try a smaller cathode bypass cap, maybe 4.7 or 2.2uF.
 

[catnine]

I was trying to use the duncan tone stack calculater to find a vol/treb /bass that would come close to a 5F2-A yet they do not provide the old princeton stack to figure it out and I admit I have a difficult time using their calculater . perhaps what I need to do is remove the mid to o ohms and change the pot values to both 1 meg audio pots . I am not sure .

[firemedic]

You may as well try. A quick & easy experiment is to replace the 15k mid resistor w/ a higher value so less mids get sucked out of the circuit.

[Fresh_Start]

There are lots of 5F2-A type circuits out there that have a cathode bypass cap on the 2nd triode, often switchable. 

OTOH you could add a MOSFET cathode follower right before the TMB tone stack.  That would reduce insertion loss and let you use different values in the tone stack.  .022 Mid & Bass caps, plus 33k-68k slope resistor, plus 15k-33k mid resistor.  It won't sound like a Blackface Champ, but you don't like that sound.

HTH

Chip

[catnine]

 Perhaps I'm looking at this the wrong way or not doing a good job of explaining what I'm after. Probably both.

 I am not looking for more gain which is what a tweed champ or princeton will bring . When fender came out with the 6G2 princeton they kept the same tone stack as the 5F2-A and it was a push/pull 6V6 fixed bias with a NFB loop. More output and cleaner sound . Around the same time they were cleaning up the sound of the SE champ and seemed to reach this using the BF vol/treb/bass tone stack .

 My 6G2 /5E3 is by no means high gain even without the NFB . I also changed the bias on the 5E3 power section to a adj/fixed bias  instead of the cathode bias , like the 6G2. One other thing , this build was gainy when I had a 12ax7 preamp , when I changed it to a 12ay7 preamp like the 5E3. It's very loud and tons of bottom and clean until you really crank it up like past 7 .

 What I was trying to do was get that sort of sound out of my AA764 champ build , now wondering if I should try a 12ay7 in the champ , see what this does and then if needed to open it up more change the tone stack like that of the 5F2-A or 6G2 , same thing . Yet if the Champ being a SE amp perhaps it is not that adaptable. Looking at the BF tone stack compared to the 5F2-A the 5F2-A has a .02uf coupling cap off the plate before the simple tone stack to the grid of the second gain stage. On the BF stack this cap is not needed , seems the preamp plate has to flow through caps whcih are varied in value dependant of the position/resistance of the tone pots so in some sense what the BF stack seems to me to do is vary the coupling cap value before the signal reaches the grid of the second gain stage. The mid is fixed , then there is the 100k slope resister that seems to set the freq of the bass pot so due to the path the plate signal travels it is a loss of gain. Does that sound close to true?

 You can change gain by tubes and/or componants.