First amp build

[AlNewman]

The B+ is high because the transformer was designed for an organ.  Organs have a massive preamp section which creates significant draw on the B+.
I tried to explain this 2 pages ago.

[Mongrel714]

The layout indicates 9V caps in the Bias supply. Should be a minimum of 63V based on a calculated Bias range of -11VDC to -49VDC with a 25K Bias pot. Typo or problem?

Is the B+ high because there are no power tubes in or they are not conducting?

Hello, The Caps in the bias supply are 63v, typo, The tubes test good, 95 on a scale of 0 to 120, emmission test is good, heaters are good, no shorts, (I have a tube tester) and it is a 50k bias pot.

[Mongrel714]

The B+ is high because the transformer was designed for an organ.  Organs have a massive preamp section which creates significant draw on the B+.
I tried to explain this 2 pages ago.

Im sorry, I am new at this and taking in a lot of information, I am reading everything I can on this subject, and I am going to check out all the information all you gentleman have provided here! I really appreciate all the answers and comments, I am just learning this but I do feel im getting close here, thanks again everyone!

[Mongrel714]

B+ is too high. What does it measure when you install a rectifier tube?
It appears that the AO39 power amp used a 5U4GB and two 6BQ5. It worked for Hammond. It should work for you. Hammond used 10 watt dropping resistors and two 30uf capacitors in the B+ feed.
Sluckey has been down this road. See his conversion!!!
https://www.sluckeyamps.com/hammond/hammond_ao39.pdf
The cap can next to the power transformer looks very old. Does it test good?
more conversion problems solved at:
https://sluckeyamps.com/index.htm

My rectifier tube gave up the ghost, Have to order a new one, I will read through Sluckeys post and check out his site, the can cap does test good, probably would not hurt to replace it as it is old, on a slight budget here, but trying to pick up pieces weekly, It is the first of the week so I am not sun stroked out from my job, will cram all this info.

[astronomicum]

The B+ is high because the transformer was designed for an organ.  Organs have a massive preamp section which creates significant draw on the B+.
I tried to explain this 2 pages ago.

The OP keeps posting pin 3 is 0V. There is a 1R monitoring resistor. Is this a measuring error or is it really 0.000V? It should read 0.somethingV if the tubes are in. Is the meter on the right scale?

[Mongrel714]

The B+ is high because the transformer was designed for an organ.  Organs have a massive preamp section which creates significant draw on the B+.
I tried to explain this 2 pages ago.

The OP keeps posting pin 3 is 0V. There is a 1R monitoring resistor. Is this a measuring error or is it really 0.000V? It should read 0.somethingV if the tubes are in. Is the meter on the right scale?

The meter may not have been on the right scale now that you mention that, it was on the 600vdc scale.

[Mongrel714]

New Rec tube is on the way.

[Mongrel714]

Ive got S Luckeys schematics printed out along with the original Hammond schematics from my old organ, I will study all this and try to figure this out, I really appreciate the help guys!
Oh and re tested the EL84s, they passed all the tests and on the "Quality meter" registered 100, My tube tester is a B&K Model 600Dyna Quick, prior owner said resistors were replaced (which I checked and they are new) and calibrated.

[Mongrel714]

And I did ask Sluckey if he minded that I study his schematics!

[ac427v]

Check your original Hammond Organ schematic to see if it had a second Power Transformer used for the preamp.

If it had two power transformers, the 140ma specification listed for the power amp power transformer may allow you to get B+ similar to the organ and similar to Sluckey's conversion.

If the organ had only a single power transformer it will not work with your plan.

[Mongrel714]

Check your original Hammond Organ schematic to see if it had a second Power Transformer used for the preamp.

If it had two power transformers, the 140ma specification listed for the power amp power transformer may allow you to get B+ similar to the organ and similar to Sluckey's conversion.

If the organ had only a single power transformer it will not work with your plan.

They have an extra input Tranny and output tranny for organ voicing but no extra PT, the PT and Rec tube itself was in a separate enclosure from the main amp.
  I am re vising my plan at the moment, working towards using a 3 tube pre amp and a power section based on the organ power supply, this approach has been in the back of my head for awhile now, after looking at Sluckeys schematics it seems like the way to go, Ill have to replace some parts as I go, the 5U4GB rec tube should be here this weekend, and a new load of resistors, Ill keep going till I get it figured out with everyones help! Thank you!

[AlNewman]

Have you figured out yet what your tubes are dissipating, or the current draw of your amp?

[Mongrel714]

Have you figured out yet what your tubes are dissipating, or the current draw of your amp?

Haven't got that far yet, not had a safe voltage for the tubes to run for any amount of time, Myself, being a noob at this, I don't know if you can or should run the plates and screens at +425vdc, was afraid of frying the screen, no body's really said if they will stand up to this voltage for any amount of time.