Amp is a bit buzzy, could use some advice

[pdf64]

… Using the 7H in the power section and then plugging the 5H in between the power tube and the preamp gets it pretty close. It behaves well until the volume knob starts closing in on max, at which point it gets a bit buzzy …

A full schematic may be helpful in working out what’s going on there.

[Lynxtrap]

Agree to the above.
IMHO a circuit like that shouldn't need a massive choke to produce decent sounding overdrive, so perhaps put up the schematic and get some more insight from the experts here (I'm not one of them).

[alnight]

Yes, I have been thinking that it might be about time for me to sit down and draw this thing out. I am fairly settled on the values (or at least the value range) of most of the components, to the point of "season to taste".

Interestingly enough, my addled mind has lately been recalling a phone conversation I had with Mr. Emery (who's circuit this amp is based on) about seven years ago. When I asked if he had considered a high gain version of his circuit, he admitted that he had played around with Ken Fisher's universal gain stage (same as I am now) and found it to be "kind of buzzy" and it just wasn't something he was really interested in pursuing. He also opined that one could probably get it to behave with 10 to 15 pounds of choke, but he wasn't going to put a big chunk of iron like that on his amps and if someone else wanted to spend the time to figure it out they were welcome to, as he was satisfied with his creation.

I can find no fault with that.

At the time, I never imagined that it would be me trying to figure this out just for my own personal gratification. I had just built my first amp then, which was the kit that I eventually ended up gutting and building this amp on. I would seem to have come full circle, or maybe I'm just doing doughnuts... Wheeee!

[alnight]

Ok, so I have won enough of a victory over my seasonal allergies to try and draw a schematic of this thing, only to realize that I am blissfully ignorant of how to properly draw the tone stack or the voicing switch. What I shall present instead is a layout I drew when I initially built this thing which I found in my folder of amp stuff. It does not contain the additional gain stage or the choke that I am currently trying to work with, but does provide an accurate representation of where I am starting from.

Changes include ---
The universal gain stage gets inserted after the second gain stage here.
The power cap for the preamp section gets changed from a 10uf to a 22uf.
The .1uf coupling cap gets move from the tone stack to the output of the universal gain stage, other coupling caps get shuffled around and seasoned to taste.
250pf cap between the first two plates to mitigate oscillation.
All plate load resistors 100k.
5w 200ohm resistor in power section replaced with 10h 200ma choke.

Those are the broad strokes at least. I'm sneezing so hard my brain is rattled again, because ragweed sucks. But that is beside the point.
I wonder if perhaps changing from a cathode to a fixed bias might allow me to dial this thing in a bit better.