Bogen Lo-Z Transformer Options

(and a brief intro to inputs)

The J330 has three XLR connectors and one phono connector. The XLRs are for mics, primarily, which means they are for low-impedance (lo-Z), balanced lines. Most intruments, OTOH, use hign-impedance (hi-Z), unbalanced lines.
A lo-Z, balanced line uses two conductors to carry the signal, and a shield (hence, it requires a connector with at least two pins and a shield, or three pins, eith the 3 pin XLR connector being the most common). The hi-Z, unblanaced line uses one conductor *and* the shield to carry the signal. It kinda cheats. 8^) Hi-Z lines require only two pins, or one pin and a shield; typical hi-Z connectors are the 1/4'' phone plug (guitars, basses, keyboards, most instrument/amp stuff), and the RCA phono plug (home audio and some studio equipment).
Anyway, the best balanced inputs use transformers, usually refered to as mic transformers, balanced line transformers, or just input transformers. With most equipment you don't get a choice - it either has transformers or it doesn't, and if it doesn't have them and you want them, you add an external transformer (check any musicians or Radio Shack catalog (including many online) to see what those look like). If it has them, you're set. (With the exception of cheap, cheesy transformers, you'll almost never find someone who has transformers and wishes they didn't!)

But the Bogen gave you options. If you look inside the cage, just over the inputs, you'll see three sockets right by the edge of the chassis. Any, all, or none of these sockets may have a short, squat, R2D2 sort of steel can in it, shorter than any of the tubes. These are plug-in transformers. Any inputs without these should have a wire shorting the two pins (holes) on the side farthest from the XLR connectors.

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Last updated: 15 May 1999

Copyright 1999 Miles O'Neal, Austin, TX. All rights reserved.

Miles O'Neal <> [remove the "XYZZY." to make things work!] c/o RNN / 1705 Oak Forest Dr / Round Rock, TX / 78681-1514