Re: How to calculate Power supply Resistors?

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In article <muydnfLPUtYaJEfbnZ2dnUVZ_jSdnZ2d@xxxxxxxxxxx>,
Phil S. <psymonds_no_spam@xxxxxxxxxxx> wrote:

defaultuser@xxxxxxxxxxxxxx wrote:

Hi

I'm building an AX84 20W push pull amp, but am using EL84s rather than
6V6 as the
ouput tubes. I took the readings with no tubes installed, with a 47K 3W
resistor on the B+5
as a load. My B+ (other than B+5) Voltages are higher than the
schematic details:
The spec show the AC out of the PT to be 311 AC on each leg and my is
307. The PT is
Hammond 270 EX where they spec a 270Fx, but IIRC the output spece from
Hammond were
the same.

Spec Mine
--- ----

B1: 387 401 DC
B2: 365 400 DC
B3: 344 355 DC
B4: 332 340 DC
B5: 328 325 DC


Besides, it will sink when you put tube in the amp.





Thanks for the advise after inserting the tubes and bringing the amp project
with a variac, I ended up with these Voltages:
B1 366
B2 364
B3 292
B4 282
B5 278

I have only heard it thru a cheapo speaker, and it sounded pretty good. I plan on
hooking it up via a cable to the real speaker in its cabinet today. Gonna keep it
on the bench in case it needs /work/modifications.

I have posted some photos of the build here. Note that the in the schematic that
the presence circuit is not connected, and that I have not changed the
voltage readings on the schematic. Also want to thank the folks at
AX84.com it is their design

Thanks a bunch. This is my first build and can't wait for the next one!

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