Build suggestions for Hammond 279X

[ncusack]

I just picked up a few Hammond 279X power transformers from a government auction. They are 115V Primary 850V center taped @ 172mA, 5V@3A and 6.3@5A. I'm curious what you guys would suggest building with one of these.

[Phil_S]

Wow! You've got plenty of current on tap with that and plenty of heater supply. The problem is taming the B+ voltage. 850V will give you near 600VDC with a FW rectifier.

There's a thread I started a while back about a choke input power supply. https://tubeamparchive.com/viewtopic.php?t=28802 I was working with similar voltage, but only had 100mA winding, so i made the power amp single ended. You've got enough there to make a 50W amp of your choice -- a nice 50-watter with 2 preamp channels. Not to start a class war here, but that sort of voltage might be low enough to get into a PP Class A 6L6 amp. (Who really cares about class of operation?)

With a choke, you'll end up in the 350V range. This is a little lower than many amps, but you can work with that very nicely. If you don't want to use 2x EL34 or 6L6, look at 4x 6V6. I'm thinking final B+ might be too high for 4x EL84.

[strelok]

My 2 cents. Tube rectified cap input supply with a pair of KT66's or KT88's for the output. Probably could get away with EL34s as well as the tube recto (depending on what you choose) will get you well under 500v most likely.

[rp]

Those are quite common values for several classic hifi mono blocks - you say you have a few? There's pretty much all you need on DIYA forum <http://www.diyaudio.com/forums/tubes-valves/>

Here's a start, Radio Craftsmen C-500 (there are a few variants, so check up):

How can you possibly resist!

[M Fowler]

Here is a KT88 Rocket schematic Rob posted years ago as you can see the mA rating is way higher then your 172mA which may not support a pair of KT88's?

Mark

[didit]

KT77?

Or better yet, put a choke before the first tap for plates..

Best .. Ian