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right PT for Fender Deluxe

PostPosted: Sun May 25, 2008 9:30 am
by susomora
Hi guys , there goes one more question Yellow_Light_Colorz_PDT_14 .
After reading many forums and checking several suppliers , I've got a Hammond 373X PT ( 700 V CT , 110 mA ) . The amplifier will be a Fender Deluxe 5E3 .
Many guys ( Triode electronics for instance ) sell a 700VCT as the PT for their Deluxe Kits, but I'm afraid that if I use it (along with a new production 5Y3, closer to a 5U4 than to a real 5Y3) My B+ is gonna go around 420 VDC , even with a NOS 5Y3 could go around 400 VDC .
I guess I could use this PT anyway , reviewing the resistor values on my Power Supply and on the cathode of my power tubes ,but of course the overall "spirit" of the Deluxe would change and/or my tubes would run hot and have a short life .
I know there are some ways to lower the B+ ( using Zener diodes from the CT to ground ) . Are these methods safe ?
Would my power tubes be still running at safe values if I leave it as it is now ?
Thanks in advance .
SUSO

PostPosted: Sun May 25, 2008 9:52 pm
by Gingertube
I think you will end up with around 400V as you suggested.
NOS 5Y3 are still cheap.
I'm not sure what the original Deluxe 5E3 ran into its 6V6 output tubes. I believe that they ran up around those voltages.

If you have to go to modern production 6V6 then the JJ Electronics 6V6 will handle voltages upto about 500V. I'm running some old AWV 6V6G (Coke Bottle Shaped) at 380V (25mA idle current) and they have been quite happy.

Cheers,
Ian

PostPosted: Sun May 25, 2008 11:09 pm
by wyatt
The plate voltages of a 5E3 running as intended (not correcting for higher modern wall current, etc.) is around 375VDC. 400 will be high and definitely have an affect on the tone.

A good 6V6 should be able to handle 400VDC or higher (don't buy Sovtek), Deluxe Reverb runs around 425VDC on the plates (I guessing that the transformer in question is actually a better match for the Deluxe Reverb than the 5E3).

You could order a custom Copper Cap from WeberVST. They make SS rectifier replacements that give a similar voltage drop and sag of a tube without needing any filament current. The standard models are built after known tube rectifier, but they'll build one with any requested voltage drop or amount of sag.

PostPosted: Mon May 26, 2008 2:09 am
by susomora
Thanks guys ,
5E3 voltages are in between 350 and 370 V , although some versions (like Mission Amps Tweedy Deluxe ) work around 400V .
I think my best bet is lowering my B+ using a 20W 50Volts Zener .
Cheers
SUSO