Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
I was at an estate sale and picked up a collection of UTC transformers:
6 x A-11
1 x A-19
1 x A-20
1 x A-22
I have a friend who can use the A-20 as part of his recording studio. It looks like the A-19 is for something like a 12AU7 driving a pair of output tubes. The A-22 is listed as a transistor interstage. I see that people have used the A-11s in moving coil preamps.
I'm just trying to understand exactly what I have and what to do with them.
Here's a link to a PDF of the 1963 catalogue. Should answer most of your questions. Good Luck, Paulie
A-11 is Lo-Z to Hi-Z. Secondary is 50K Ohms, primary can be configured for 50, 200 or 500 Ohms. They are useful to connect LO-Z mics into a tube preamp.
I don't know what A-19 is.
A-20 and A-21 are line transformers, useful for converting unbalanced sources to balanced, and vice-versa. You can use them to break ground loops by floating the ground on the secondary. Also, because both the primaries and secondaries have multiple impedance taps, they can be configured for some voltage step-up or step-down for level matching.
I think the A-19 is intended to be used rather like the phase inverter transformer in an amp like the Gibson Skylark where you have half a 12AU7 driving a xformer primary while the secondary is connected to the grids of two EL84s.
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: