High voltage on a pair of 7027A

[TIMBO]

Hi guys, I have a local built 100w amp that would have a quad of EL34's.
Plate voltage is around 700v from a voltage doubler.
OT is 4K into 4 ohms or 8K into 4 ohms.
I really don't need a 100w so removing two power tubes is my first thoughts.
But don't have much options on speaker loading on the OT
And I don't have any EL34's
I do have a nice pair of GE 7027a.....
So thoughts on having a pair of 7027a with a plate voltage around 700v and a 4k primary
Thanks

[Latole]

From RCA Receiving tube manual

7027A. push pull class AB 600 volts max
Class A 250 volt max

[tubeswell]

7027A were supposedly ‘designed’ as ‘high voltage’ rated 6L6s (but the word on the street is that they didn’t live up to expectations at high voltages, so weren’t produced in big numbers). So maybe use a bucking PT to lower the HT voltage, or get another PT better for 6L6s or EL34s.

[Latole]

To drop some B+ voltage I often use Zener diodes stack ; work fine and they are cheap

[shooter]

take the doubler out, use 6V6 at 8k:40ohm that way you don't need rubber gloves 

[PRR]

Yes. What shooter says.  Un-double to 350V, install 6V6es. Book says 280V and 8K per pair is 14 Watts. Fender went 350V for ~~22W/pair. 44W is less than 100W but still a major player. And 6V6 are available everywhere on a weekend.

[TIMBO]

Sounds like a good plan.
 

[DummyLoad]

pair of KT88 & run it with 4k reflected load.


--pete

[TIMBO]

Thanks DL, works a treat.