Galaxie BR20

[TIMBO]

Thanks guys, All good stuff.
Sluckey, The original circuit did not have dedicated screen resistor as you pointed out, I have add a 470r/5w resistor to the each of the screens.
The original circuit also had what I think was two 10k/1w resistor in parallel between nodes A and B and these were rather toasted but still on spec.
I have replaced this resistor with a 4.7k/5w and with all power tubes tried these resistors hardly get warm.
So now that I increased the dropping resistor to 5w are the two screen resistors required, although I would not think that 470r would drop the voltage much.
I had thoughts of redoing the B+ chain similar to most circuits and have a small value (270r) between nodes A and B (470r screen resistors off B) 10k between B and C and so on.
All this is easily done But the original designed was done this way for whatever reason???
Thanks PRR, At some stage someone has taken the time to graft these odd parts together to produce this masterpiece, the best we can do is make it work with what we got.

[sluckey]

I had thoughts of redoing the B+ chain similar to most circuits and have a small value (270r) between nodes A and B (470r screen resistors off B) 10k between B and C and so on.
All this is easily done But the original designed was done this way for whatever reason???

You can certainly increase the screen voltage to squeeze out a little more power, but do you really need it? That's about the only benefit to the power tubes. Increasing the B+ going to the preamp may give you a little more clean headroom. Do you need that?

I think the original design was smart and conservative by using a lower screen voltage. It could be improved at the cost of adding two dedicated screen resistors. That's about all I would do to it. But you're safe to experiment with it. Let us know if you can really hear a difference by increasing the screen voltage.

[TIMBO]

Thanks Sluckey, I think this one is DONE. I have a mountain of amps to get through, just bough TWO more 

[sluckey]

The first step to recovery is to admit it to yourself. Go ahead. Just say it. "MY NAME IS TIMMY AND I'M AN AMPOHOLIC!"

[kagliostro]

 

---

All together we may found the association Anonymous AMPOHOLICS

Franco

[TIMBO]

  ARGGGGGGH DON'T CALL ME TIMMY. 

[darryl]

I have a mountain of amps to get through, just bough TWO more 

You obviously disregarded the advice I offered earlier in this thread . . .

Hey Tim, if you stopped buying old amplifiers, you could afford a pair of shoes . . . 

[sluckey]

ARGGGGGGH DON'T CALL ME TIMMY.

Sorry 'bout that. I never liked to be called Stevie either.

[kagliostro]

Anyway Stevie is a nice name for a Wonder 


Franco

[TIMBO]

 

[TIMBO]

Hi guys, Things have move along and I think its turned out great.
I tried to copy the Vadis 408r as it was the only photo of what I think would be a close match for a head cab, although this should be a combo.http://www.ozvalveamps.org/vadis.htm

[TIMBO]

I forgot to mention that one of the PT winding strands can just be seen as the paper has broken off.
What can I do to repair this. Thanks

[kagliostro]

If you have enough space you can try to push a thin strip of paper between the lamination and the sprocket and glue it as a ring

or you ou can simply glue a piece of paper to cover the broken part

That is on the external part of the winding and you can use common paper

Ciao

Franco

[TIMBO]

Grazie amico

[TIMBO]

Hi guys, one of the local boys gave it a bash https://www.youtube.com/watch?v=v6bt-Cmr3GA&feature=youtu.be
He says that he aint given it back. ARE but I've got his sound city 120r 

[DummyLoad]

impressive restoration work!    


--pete