Princeton Reverb w/ 4 x 6V6

[DummyLoad]

a friend asked me to look into a 30W princeton reverb - al-la AA1164 type.

since he loves the sound of 6V6s so much he requested that i not consider 6L6Gx for the output stage.

i have attached a schematic to plan that i think will work. has anyone here built anything similar? thoughts?

any input welcomed.

much thanks,

--ISO




 

[tubeswell]

Hi ISO, why not just save the weight and use 1 OT?

[Geezer]

I have the same question about the dual OT's, but that the (probably) the surest way to preserve the original tone, only louder. A single OT with PP pairs would (maybe) be something "different", even if only slightly.

Is this going to have a single speaker, or 2x?

If 2x (10? 12?), then possibly assign each OT a separate speaker jack(?)
Again, that would be the surest way to get a louder true PR tone....paralleling the OT outputs may again produce something "different".....

$0.02

G

[phsyconoodler]

I would also say just use one OT.The amp will sound great.Do it buddy!

[DummyLoad]

Is this going to have a single speaker, or 2x?

customer wants just a head. speaker option up to the customer.

i will test with both single and dual jacks - i'm leaning for dual jacks and a 20W dummy load circuit for the second if the jack is left open.

why not just save the weight and use 1 OT?

grid leak with 2 6V6 tubes on 220K circuit /phase is trouble - have been down that road.

that would be the surest way to get a louder true PR tone

that's the idea. any problems i think will be related to loading the tremelo driver and concertina circuits  - do you guys think tremelo drive circuit can handle the 110K /phase load? perhaps with some tweaks?

paralleled 6V6 w/ 120K grid ckt. /phase into a single xformer is the most realistic and certainly the least complex plan, however, i is my belief that duplication of the output stages will best preserve tone. in retrospect, perhaps even the entire output stage including the PI. maybe add another concertina (6AV6?) and split after the last gain stage. along the same lines of thought, another option would be to turn the concertina in the fender plan into a switch selectable gain stage and add another bottle for 2 x concertina.

i'll be building it on the breadboard over the next coupe of days.

glo-champ and BK amps going on back on the back burner - this build will bring in more fun $$...

thanks guys, as always, your time and thoughts are greatly appreciated.

-ISO

[jjasilli]

Some comments:

1.  I think a 33K grid stopper GIVES less attenuation than a 33K input resistance (2x 68k resistors in parallel Before the 1M grid leak).  FWIW my SF Princeton and Vibrochamp prefer low power input #2 when used with humbuckers.

2.  Preamp looks cut & paste, except 10uF bypass caps.  I like 1uF, especially 1st stage, but this is subjective.

3.  40uF filter caps -- another subjective matter, though I put 40uF in the 1st filter stage.

4.  OT's -- you know more about trannies than I do, so I assume you have the correct impedances worked out.  I agree that it seems excessive to use 2 pieces of iron where one will do.  Another alternative for power cut with one OT:  use the KOC "SE Mod":  a vol pot, or ganged pot, to turn down signal to one set of power tubes (or, here, to one tube in ea set).  Then you can turn down to half power; and impedances are not altered.