Best way rectify a P.T. with only 6.3 heater tap?

[zapped]

I would like to find a use for an old PT removed from a tape deck. It used to power 6 tubes 1ea. 6SL6, 6SC6, 6SN6, 6K6, 6E5, and 6X5 recto. It makes 340-0-340 no load and 430 rectified no load. The heater draw was 2.5a with the tubes listed. I would like to use it with 2x 6v6, and some octal preamp tubes,if possible. Is the 6x5 up to the task? Or. Is there a better 6.3v heated rectifier tube??? Or   If i use diodes would the plate volts be too high for 6v6?? Thanks    Ed

[bluesbear]

There's always the 6CA4. Gibson used it with EL84's so it ought to be okay with 6V6's. How it compares with the 6X5, I have no idea. You could always use a Copper Cap rectifier from Weber VST. You can customize it to any voltage you want and it frees up a bit of current draw from the heater circuit.
Dave

[PRR]

> 6SL6, 6SC6, 6SN6, 6K6, 6E5, and 6X5 recto.
> I would like to use it with 2x 6v6

Small tubes suck 1mA-2mA each.

Power tubes suck 30mA-50mA each.

In general, when counting power demands, you may ignore the little tubes and just count the Big Tubes.

Moreover, 6K6 (really??) is a small big tube: 7 Watts max. 6V6 is 12W. So you are potentially increasing demand from 7+ Watts to 12+ Watts, roughly double the load on the B+.

I'd want much more study before I'd try this.

It might work. Fender found it cheaper to use the same PT for Champ or Deluxe.

Or the tape deck maker may have minimum-sized the PT to keep cost and weight down. (Yes, even though the deck weighed 50 pounds.)

Build a 1-6V6 "Champ". You will have near +400V, must run 6V6 near 30mA-35mA. Use 10K load, 1K cathode resistor.

[zapped]

Thanks for the info. The 6CA4 may work out Bluesbear. Thanks PRR, I measured this PT's size against the posted dimentions for Magnetic Components 70 Ma Champ PT , very close, just 3/16 thinner,(less plates). So i think Champ type is the way to go. I may also try a separate 5v. trans. and run 5y3 if 6CA4 does not pan out. Thanks again.. Ed

[LooseChange]

Simple answer.... Add a Solid State rectifier.

[jjasilli]

Note that those old tube rectifiers need small first stage filter caps in the 4uF - 10uF range.  Check the specs for ea tube.  This tends to produce amps that sound like the bargain basement amps from days of yore.  I like my Silvertone 1482, but don't know anybody who gigs with one.  

An alternative to SS rectification is to use the small filter cap as a pre-filter stage > dropping resistor for isolation > plate filter stage.  Now the plate filter stage can have more modern cap values of 16uF and up.

Rough figure the PT to put out 10 - 15% less voltage loaded:  340 - 10% = about 300 X 1.414 = 424, with SS rectification.  Not ideal but doable & in the Deluxe Reverb range.  A dropping resistor in the B+ rail will get you down below 400; plus simulate a tube rectifier.

[tubenit]

Note that those old tube rectifiers need small first stage filter caps in the 4uF - 10uF range.

And then you can increase the filter capacitance in following stages like  10uf (1st), 22uf, 22uf, 16uf (preamp) etc.....

With respect, Tubenit

[Tiny_Daddy]

Maybe add a 5V, 2 Amps filament transformer for a 5Y3 or 5AR4/GZ34. This would leave more power for the other tubes.