As I understand it, the higher the Ma you bias the more headroom you'll gain. Higher bias tends to give a cleaner sound. I've been so swamped, NAMM and a Vintage show that I have negelected to get back to discovering the oscillation I'm getting. Something is weird. I may email Ceriatone and ask for suggestions.

I get the same kind of noise when mine is driven. The better output tubes lessen it and I did try some Mullards that removed it alltogether. But I'm now running Siemens and like them best.
I'm going to try input tubes and then try moving wires around, something may be crossing something that shouldn't.
Please post if you find a remedy.

I need to try some CA7's also. A friend just got a Sano amp (60's Ampeg spinoff) with a pair of old CA's in it. I may try thoose and see what  happens. I do get a swishing noise  (almost like a flanger is running) when I'm running things hot, have you had any thing like that? I don't think it's output tube related, but the better tubes lessen it. I am going to try moving wires around and changing input tubes.

I got a pair of NOS Siemens EL34's for xmas, yes I am that big of a geek (tubes for xmas, shameful I know...). So, I got some time to test them out. Not as elborate as the 1st test but I think the Siemens are the ticket. I ran the Telsa's and got used to them, then I switched themout for the Siemens.
The Siemens are very compressed and give me that tubey violin sustain that this amp gives so well but are smoother in character than the Telsa's and the other standard EL34's (sovtek & EH). I think the Siemens are going to be the goto tube for this amp. I got the compressed huge sustain when driven and enough ring when clean but the overdriven sound was smooth and detailed. The cleans are a bit mid rangey, not as much ring and shimmer but still nice and can breakup and bite when I picked hard. So far the Siemens are the best of the bunch for this amp.

I have not tried any 6ca7's. I think the best of the bunch were the Sovtek's to my ears. But I am going to look for some Siemens and I'll look for those also.

I think they are older ones. I don't know the exact age. They are ARS Tesla Van Nuys, CA EL34's. They sound great. The pair I have just happens to match when biased. They compress and really drive when overdriven, a bit fuzzy but in a good way.
I use a Trainwreck ZAirBrake to atenuate and I should have tried the Mullards with that, they may have been more playable atenuated.

Yes, sorry 30ma biasing for all. Recommended by Nik.
As for pre's, 12ax7's. An RCA in 1, Sovteks in 2 & 3. I used the same pres for all the tests. I just pulled them out of the bag randomly as I did for the ARS EL34's when the amp first arrived and hey sound great. And the ARS's happen to match when biased.
I also played the same thing for each of the tests. Cleans I used an open chord thing I came up with and for the distored I used the melody to Jing Chi's 'That Road'.

Today I did a taste test with sets of tubes in my new expression.
Here was the setup:
Expression everything set to 2:00 with the brite switch up (on).
Speaker cabinet, Kerry Wright custom 2x12 with vintaqe 30 celestions
Guitar LP standard: neck PU vol=10 tone-rolled off , Bridge PU vol=3, tone-10
All tubes biased to 3Ma
Tubes: ARS Telsa , Mullards (vintage expensive ones,$100/each), EH & Sovtek. The Mullards, EH & Sovteks I borrowed for the test.

Results (IMHO)
Mullards very mid rangey, less high end shimmer, less ringy on the cleans.when cranked they are not compressed much, very open and glassy. Kind of a overdrive sound more than the compressed fuzzy sound. Much louder and harder to control, feedback alot. A very unique sound compared to the others. I would have to get used to them.
The ARS, Sovtek and the EH are almost identical. Very ringey in the cleans, with a more full range. When distorted they compress and are fuzzy and very driven. Easy to play and sustain notes. I actually liked the ARS & Sovteks the best for what I'm wanting from this amp.
Interesting test, I wanted to see if I could hear the difference and are the Mullards actually different from the rest of the pack, enough to warrant the money. I can say they are different, not sure in a way that I would like. Though I think I will hunt for a pair to have if I want to try that sound.

I would think a clone of either an Ampeg Jet or a Gibson GA-20 would sell great and be an easy build. I have an Ampeg Jet and am looking for a GA-20.
There is always Maggies (Magnatones) that are great amps. I have a Da Vinci like a 280, great amp.

Got this expression last week and I'm loving it. Great work and the tone I was hoping for. Cabinet to come, I have someone local for that.


IMG]http://i28.photobucket.com/albums/c201/DaGlenster/Trainwreck002.jpg[/IMG]



Here are a couple clips, sorry for the sloppy playing they were done in a hurry. I'm using a Trainwreck Z Air Brake attenuater - bedroom level.
1st movie
Guitar settings Bridge PU, Vol 3, tone wide open

2nd Movie
Neck PU, Vol 10, tone rolled off