So, even though the 6.3 2A winding is isolated from the 330v 300ma winding, my b+ will have more current behind it if relieve the PT of most of the filament duties? Why does this happen?
I had another univox that I removed the reverb, tremolo and recto tube from, as I thought I would lessen the strain on the PT. the power tubes started red plating. I guess now I know why!
Univox U-152
Moderators: pompeiisneaks, Colossal
Do you have a schematic
I had an Univox 1221 I think it was. Check the schematic and see if they use a voltage doubling circuit in the power supply.
I tried to use the power transformer in a different amp project and it wasn't able to produce sufficient B+. I suspect the problem was related to the current capacity of the power transformer since the output section was used the same tubes, 6L6 but in a different power supply configuration. The B+ in the 1221 was about 600 VDC.
Silverfox.
I tried to use the power transformer in a different amp project and it wasn't able to produce sufficient B+. I suspect the problem was related to the current capacity of the power transformer since the output section was used the same tubes, 6L6 but in a different power supply configuration. The B+ in the 1221 was about 600 VDC.
Silverfox.
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joshdfrazier
- Posts: 109
- Joined: Sun Sep 29, 2013 12:23 am
Re: Univox U-152
Started working on this again.. Installed octal sockets for 6L6/EL34, etc and replaced the OT with a hammond 1650N (50w, 4.3k primary). The amp is MUCH louder than it was, but still not as much clean volume as I want! (I may never be satisfied)
The current PT inside of the amp is 330vdc CT at 100ma. I have on hand a Hammond 272JX which is 300vdc CT at 275ma, with 12 amps of heater current available(!!)
Right now I have 396vdc on the plates, -32vdc on the screens and each 6L6gc is drawing about 17ma of current. If I increase (or decrease?!) the screen voltage to -16vdc, my current draw increases, but my plate voltage goes down to about 350vdc. I would like to get each tube at about 52ma with 396 on each plate. Will that get me the clean volume I want? Will the hammond PT work for this purpose?
The current PT inside of the amp is 330vdc CT at 100ma. I have on hand a Hammond 272JX which is 300vdc CT at 275ma, with 12 amps of heater current available(!!)
Right now I have 396vdc on the plates, -32vdc on the screens and each 6L6gc is drawing about 17ma of current. If I increase (or decrease?!) the screen voltage to -16vdc, my current draw increases, but my plate voltage goes down to about 350vdc. I would like to get each tube at about 52ma with 396 on each plate. Will that get me the clean volume I want? Will the hammond PT work for this purpose?