Prince O Wails modded Princeton questions

[tubedood]

Just a quick post to see if anyone has experience or tips in this build. It was featured in the 90's in Guitar Player magazine featuring a modded Princeton circuit designed by John Mcintyre that has a lot of tonal control and much higher gain. My first build attempt was mediocre at best due to my lack of skills but I'm starting a revisit that is more methodical. Any one else ever tried it? Here's the schematic. Any input is very welcome!

EDIT: I inserted full page display of schematic into initial post here to make it much easier to read.
Steve Ahola, super moderator (07/17/2016)

[Enzo]

Hi, welcome.

Well, I don;t like the drafting style, but that is just my personal taste in drawings. Has nothing to do with how well the circuit works or anything.

Some novel looking ideas there, like the bias adjustment scheme. And I am not familiar with the phase inverter, at least as I see it on the page. I wonder if those bias adjustments, which seem DC coupled to the PI grids have any effect on that tube.

[tubedood]

Hi Enzo, true that the schematic is a lil crowded looking! Last time I attempted this build I had to ask an old Navy electronics guy to help keep me on track to figure out what the thought process was through-out it. Now that I'm older I know that circuit is cramped and less can = more in keeping things simple. I can vouche that the tone controls do work as expected, with the push/pull boosts and the mid cut does have an impact. The soft clip switch did have a noticeable difference that my ears could tell but I had no O'scope to look at what I was hearing. I'm a novice totally that wants to try this build again... Hopefully others have tried it that can offer some input!

[Enzo]

Doesn't matter what it looks like, if you hear the difference and the change is useful to you, then switch it is. Switching cathode bypass caps in and out is an old approach to changing gain and response.

[bob p]

schmitt