heater connection problem

[alexg]

I had a power transformer custom wound for my 12sn7 SRPP preamp and I gave my winder the wrong specs.

I forgot to include a 0-6.3VAC for my 6X5 rectifier.

I have a 1.5A 6.3-0-6.3 heater supply.

This is what I am planning to do:

Elevate the center tap of the 6.3-0-6.3 by about 75VDC (my B+ is 250VDC), and use both ends of the winding for my 12.6 heater connection for the 12sn7 (total of 0.6A). I would then connect the heaters of the 6X5 (needs 6.3V) on the center tap of the winding and on one of the 6.3 taps.

Would this work?

If not, I would just have a small 0-6.3V transfomer wound for my 6x5 heater.

Thanks.

 

[kmaier]

Yes, that could work as the 6X5 has an isolated cathode specifically for use in a power supply where all filaments are run from a single supply. You could also use a 12X4 rectifier... smaller envelope and 7-pin socket but is very close electrically.

Regards, KM