Scored some nice vintage iron: What to do?

[Blair]

Hey guys,

Just scored a few matching trannys and some randoms from a nice guy here in town. The ones I'm most interested in are the:

820vct @ 100ma
6.3v @ 1.25A
6.3vct @ 2.5A
5v @ 2A

They are potted Carol Electronics corporation trannys with

CA-1024 TF1RX03YY Grade 1 Class A

Anyway, I was pretty exited about it because they were free! :o

Any suggestions for monoblocks?

Thanks for any input,

Blair

[erichayes]

If you wanted to build a "classic" benchmark to compare all your newer amps to, you could go with a pair of 6L6s driven by a 6SN7 being fed by another 6SN7 operating as a cathodyne phase inverter. Use a 5AR4 working into a choke input filter, which would give you around 330 volts on the output plates, or use solid state rectifiers and pick up another 30 volts. That would give you somewhere in the neighborhood of 20 to 25 watts operating AB1. Give me a call if you want me to whomp up a schematic.

[Blair]

Well Eric,

That sounds really nice. I'd prefer to try the 9 pin tube compliment you talk about frequently or something with the 6H30. I've heard good things about that tube. My phone is at work unfortunately. I can call you this weekend though.

There is also the possibility of a SE kt88 or el34 amp such as:

http://diyaudioprojects.com/Tubes/KT88/index.htm

I'm game for anything. I should have buil't monoblocks in the first place with my last amp. It was inevitable! I also scored a pair of 10H 200ma stancor chokes I think, I'll have to go through the goodies. Oh, and I prefer SS rectification because of the simplicity and one less tube to change.

Thanks,

Blair

[erichayes]

That was just a suggestion, to throw you back into the headwaters of high fidelity. We can certainly adapt that concept to miniature drivers, although I think--given the heater winding current ratings of the transformer--6L6s would be the output tube with the most bang for the buck. There's no reason, however, not to use 6BQ5s for the outputs.

Give me a holler over the weekend.

[Blair]

I'm okay with the 6L6 power tubes, and I have no problem using 6SN7s, but I wanted to do a different combo for the driver/inverter stages. I'll give you a call.

Thanks,

Blair

[EWBrown]

...Or you could try 6SL7 VA -> 6SN7 PI -> PP 6L6s using a similar circuit topology of the ST35.

Or borrow from the Eiclone design which could use 12AX7 / 6SL7 VA -> 6SN7 LTPI -> PP 6L6s (in place of EL34s).

/ed B in NH

[Blair]

Hi Ed,

Why could I not just use the Posie design and sub the driver tubes. I'm actually satisfied with the 12AU7, but I'd like to change the VA tube. I was looking at these:

http://www.tubedepot.com/nos-c3m.html

They look kinda cool. I haven't looked at the pinout, but they may mount straight to the board.

Blair

[EWBrown]

These look like a loctal base (8 pins and the metal prong in the middle acts as the locating key and also locks it onto the socket rather firmly.

C3m Tube data here (Telefunken):

http://frank.pocnet.net/sheets/128/c/C3m.pdf

It should work in triode mode, but won't fit to the posie board directly, but could be wired from lthe octal socket to the board. As always, there's a "catch" in that it has a 20V filament.

If you "yahoo" or "google" C3m 300B you'll get a lot of interesting applications for this pentode.

/HTH

/ed B in NH

[Blair]

This one looks nice, and the current rating on the tranny is on par with mine.

http://webpages.charter.net/dawill/tmor ... 6L6_PP.gif

Blair