AA-151 Transformers

[Vince]

Hi,
This is my first post and I did not want to hijack the other thread so I will post this one.
I have all the transformers from a salvaged Heathkit AA-151.
The AA-151 is an integrated amp which has EL-84 output tubes and I believe it is Ultra-linear.
I had previously acquired a bone stock original AA-151 and was
captivated by its performance but was less than impressed with the
preamp portion of it.
So I got the iron to build my own integrated amp, but I am a newbie. I stumbled onto this this site while looking for a suitable EL-84 schematic for the amp.
I have a couple of questions:
1. Are the AA-151 output transformers in fact ultralinear?
2.I have arrived at the conclusion that the capability of the "D" version of the DIYTUBE board to separately bias the four tubes means matched pairs or quads are not required. Is that correct?
3. As a result of the limited searching I have done,I am puzzled by the apparent fact that as a result of all the tweaking to the factory schematic no one is jacking the capacitance up, ala the various mods to ST-70. Did the factory do it right in this instance?
4. Is the physical distance between this board and the transformers
in anyway critical? I am thinking of reusing the AA-151 chassis.
5. Any suggestions for a preamp I can put on it?
Thank you, Vince

[TerrySmith]

Welcome Vince!

1 Yes, they are ultralinear. The feedback will need a small change.

2 Yes, but matched as close as possible.

3 Yes, the ST35 is probably the best Dyna put out.

4 It may fit in where the 6AU6 and 6AN8 tubes are. Ventilation may be a problem, unless you run it without the cover. Building it on an open chassis is preferred!

5 Use the stock preamp (the 6EU7 section), it will sound fine.

Go way back in this forum, I have two '35s posted and scottfixer has one all with Heathkit iron. I'll find my AA-151 amp and bring it foward to look at.