6550 amp

J J Harmon · From: Reynolds, GA 31076

I have an amp that I got a long time ago. It was part of a PA and the mixer part has long since gone. I played thru it some but that was 12 years ago. It is super heavy and 100 watt. The outputs from the transformer are labeled G,25,70,CT,70,25 with no 2,4,8 Ohm connects.

It doesn't have much power now.

I need to recap but I think it needs a new output trany.

Any suggestions on an inexpensive trany?

Jim Pitman · From: Waterbury Ctr. VT 05677 USA

Yeh, that's designed for that old PA standard. It think it's called distributed array (?), whereby many speakers, in different rooms are driven like in a school, and each speaker has its' own transformer for converting to lower 8 ohm impedance. The speaker wiring is drop node and can be relatively light gauge since transformation is increasing the current remotely at the load.
You might take it to an amp tech and have the output transformer replaced with one intended for say a Fender Twin or something comparably powered. Unfortunately, unless you can find a deal on a used transformer on Ebay, a new one will be over $100.00. Check out Weber.
My guess is that the output power section has the standard long tail pair driving two pairs of 6550. This is the same concept as most high powered guitar amps.
You'd do well to find a schematic on the web and compare to a 100W tube guitar amp schematic to make sure it is feasible before laying out the money.
Is it a "Bogan" by any chance? - very popular in the sixties.
I had two British made types. Fortunately, their output transformer had a very flexible secondary that could accommodate 8 ohms and 70V line. I regret selling them.

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