Whither my transformers?

[Enzo]

I have a couple NOS Stancor A-3881 transformers on my shelf, and they are just itching to go into something. I have no idea what so far though.

It is a single ended output transformer, 15k primary to 4 ohm secondary, 5 watts, 10ma max primary current. At 5 watts, it is roughly golf ball size, plus mounting holes of course.

It's not like they will go into a repair very likely, so I need to make something with them.

[Don Moose]

How 'bout a nice little tube stereo?

[Enzo]

Hadn't thought of that. Was thinking guitar amp mainly. Maybe.

[Five_E35]

A 2x8 5 watt/channel version of a Magnatone 280??

[octal]

Use a pair. Wire the primaries and the secondaries in series to make a P-P transformer, which would be 30K:8Ohm, then drive two four ohm speakers in paralell to refect 7.5K back to a pair of 6v6s or EL84s!

[6267]

That sounds pretty right for 6sn7gtb stereo, or 6cg7 if you want the 9-pin. Put a cathode follower in front of the grid, even, and get a nice A2 output stage...6DN7 would work too, although it might be over-damped by the high load resistance. Get more power with that tube than even a 6sn7 though, about 10w PD, probably right in the ball park for 5w out max in hard overdrive.

[6267]

They'd also work good for transformer driven outputs in a BIG amp...you could drive the hell out of the grid of a KT88 or whatever, 1k or smaller grid resistor. Tubes would keep from running away real good and you'd get tons more power out, without grid clipping.

[Enzo]

KT88 drivers... oh dear lord.

[octal]

I have two other ideas:

1.) Put 'em on e-bay and use the $ to buy something better suited to your needs

2.) Overkill reverb driver transformers? Reflecting 30K back with an 8 ohm tank would probably work with the right selection of driver tube.

[Chuck H]

+1 on what Octal said. How about a stand alone reverb with all nine pin tubes?

Unless you could use a couple of single ended EL84 amps with a 2 ohm secondary?!? What ere they originally designed for?

Chuck

[Enzo]

True, I probably would get a lot more for them than I spent if I sold them.