Looking at the job SG John has done, one could easily believe that he has done this before, no doubt about it. IMHO, he chose wisely because
(1) He is familiar with this circuit from it being used in the book he has to describe how each stage of an amp works.
(2) It IS a simple design, about as simple as it gets. These type amps, the Champs & Princetons, were Leo's "student" models. About 5 watt output power, low parts count so cheap to produce. A 1 watt tube amp would be no simpler.
(3) They sound fantastic. These type amps have been used on countless recordings through the decades & continue to be used. Guitarists of the calibre of Eric Clapton & Keith Richards have, at times toured using them on stage. Guys like these can use most any amp they want, so that they have used Fender Champs & Princetons speaks volumes about these type amps.
To really get the best out of this amp SG John, try some old glass in it. NOS/NIB USA made 6V6's are still readily available & reasonably priced, same with the British made types.
For a 7025/12AX7, if you don't want to spring for an RCA, a (50's era) Sylvania will sound great, usually last almost forever & they can had at good prices.
Cheers
You're right. I did build it so I could comprehend what I was doing, and get the most from it. Some day, I feel like i'm trying to cram 5 gallons of knowledge into a pint sized brain. Today, I was chasing PLC problems in a safety circuit on a Heidenhain CNC control. My brain hurts right now.
Since it's so simple, it also gives me the ability to change around cap and resistor values, and see how it affects things.
Thanks for reminding me. I'm pretty sure that I have a single Raytheon 6V6GT leftover from when it's mate melted in my Deluxe Reverb. I'll have to hunt for it. I don't think I have any more RCA 12ax7s laying around. Several years ago I bought several, and I think they are now in amps. I may have a Philips or something else nice. I've been meaning to stock up again, but money has been tight.
I'll admit that I sniff quite a bit of cork at times, but there's a lot to be said about NOS tubes for amp designs that where built in 50's and 60's.
I know those corks well. Almost all my amps have either the correct NOS tubes for when the amp was built, or earlier. My '64 Bandmaster has nothing but early sixties RCA tubes in it, and the '71 Deluxe Reverb has a nice selection of Raytheon, RCA, and Philips in it. My Marshalls all have old Mullard, Siemens, or Telefunken tubes in them, and my DST-30 is full of Telefunken EL84s and the rest are Amperex, Mullard, and Brimar. I have a nice stash of NOS Mullard EL34s from the Blackburn factory for my Hiwatt. I need to undo a couple of mods first, then I'll go with all old glass in that one.
As a result, the amps rarely need maintenance. Just an occasional shot of De-Oxit. With the right tubes, you do get what you pay for.
Did you get zapped at all?
No, not at all. I'm very cautious with electricity. The bus bars on the servo amplifiers and drives I work on are usually 200 and 400 volts AC and 650 volts DC. I had a coworker hit me with 400VAC once because he is a wreckless imbecile. It's not fun.
Used a dummy load on the speaker jack, and a variac to bring up the power slowly with no tubes plugged in. Once we were sure that no fuses would blow at start-up, we powered down and put the tubes in, and let her rip.
