SLuckey Vox Double Shot Question

[wakingmatthew]

Hi all and thanks for any info or help!  I'm about to start a new build of Sluckey's Vox Double Shot from his website. https://sluckeyamps.com/misc/Vox_Double_Shot.pdf.  I was going to use a Hammond 290cz PT (AC15c1)for the build as I happen to have one.  Since it has no 5v tap I was just going to use 1N4007 diodes in place of the rectifier tube.  Anyone see a problem with this and leaving the above schematic as is?  Will the 10-20% higher voltage of the ss rectifier need to be reduced with power resistors? Should I up the uF of the reservoir cap?  Thanks for your thoughts.

[SEL49]

I would use an EZ81 rectifier tube. Filaments can safely be connected to the 6.3VAC filament string.

[wakingmatthew]

I could do that. Thanks.  Kinda just wanted to see what, if any issues I'd run into if I do decide to SS rectify.

[Willabe]

Kinda just wanted to see what, if any issues I'd run into if I do decide to SS rectify.

Yes, too high B+ dcv.

[SEL49]

Kinda just wanted to see what, if any issues I'd run into if I do decide to SS rectify.

If you just gotta then copy part of the AC15C1 power supply. It uses 180Ω/5W resistors between the PT and the diodes.

[HotBluePlates]

... Kinda just wanted to see what, if any issues I'd run into if I do decide to SS rectify.

310v x √2 = 438v DC at the first filter cap, instead of 325v DC.

Adding the resistors SEL49 mentioned will reduce the rectified AC, which will reduce the DC Output.
Using less µFs (than 47µF or 32µF) will also reduce the DC Volts at the filter cap.

[tubeswell]

I was going to use a Hammond 290cz PT (AC15c1)for the build as I happen to have one. 

As others have said - B+ will be too high for EL84s. However, if you 'happen to' also have a suitable bucking transformer, you could theoretically use that to lower the B+ without losing High Tension supply current. Google bucking transformer arrangements.


Otherwise consider getting a PT with a 190-0-190 or 200-0-200 HT winding (if you want 2-phase SS rectification)

[wakingmatthew]

Well, decided to go with a ez81 for the double shot.  B+ is still high with the 290cz PT.  I see on the AC15c1 schematic that they have 180ohm 5w resistors on the secondary before the diodes of the ss rectifier. Is it correct to assume they lower the voltage to the diodes and would this be an acceptable way to lower the voltage to the ez81?