Christian Serig wrote:

I have some Valley People gear I would like to attach pigtails to. But
the symbols on the terminal strips are throwing me off. On the input
there is a 3 connections +, - and ground. On the output there is only
two + with a minus below it, and a ground.

The inputs are balanced, so you have two signal leads of opposing
polarity, and a shield wire that is grounded. The outputs are
unbalanced, so you have a single signal lead, and a ground return.

If you're feeding this unit with a balanced source, it should be
self-explanatory. If you're feeding it with an unbalanced source, then
you can just tie - to ground at the terminal strip, or leave it
floating, whichever seems to work better.

If this unit is feeding an unbalanced destination, it should be
self-explanatory. If you're feeding a balanced destination, you should
use twisted shielded pair wire ("balanced" cable) and connect the "hot
wire from the "+/-" terminal on the VP to the "+" input on your
destination. Connect the "cold" wire from ground on the VP to "-" on
the destination. Connect the cable shield to ground on the VP _or_ to
ground on the destination, but probably not both. There's all kinds of
dogma surrounding the best approach but usually it depends on the
equipment so it's best to go with whatever gives you the least amount
of noise.

ulysses

Justin Ulysses Morse wrote:

Christian Serig wrote:

I have some Valley People gear I would like to attach pigtails to. But
the symbols on the terminal strips are throwing me off. On the input
there is a 3 connections +, - and ground. On the output there is only
two + with a minus below it, and a ground.

wanna sell any of itG???

The inputs are balanced, so you have two signal leads of opposing
polarity, and a shield wire that is grounded. The outputs are
unbalanced, so you have a single signal lead, and a ground return.

yup... ulysses beat me to the punch!

If you're feeding this unit with a balanced source, it should be
self-explanatory. If you're feeding it with an unbalanced source, then
you can just tie - to ground at the terminal strip, or leave it
floating, whichever seems to work better.

In the case of the VP cards I have it appears that grounding the unused
input pin works best. Most of the time leaving an input pin unterminated
is a bad idea. But it never hurts to either check the schematic or just
experiment to find out for sure!

If this unit is feeding an unbalanced destination, it should be
self-explanatory. If you're feeding a balanced destination, you should
use twisted shielded pair wire ("balanced" cable) and connect the "hot
wire from the "+/-" terminal on the VP to the "+" input on your
destination. Connect the "cold" wire from ground on the VP to "-" on
the destination. Connect the cable shield to ground on the VP _or_ to
ground on the destination, but probably not both. There's all kinds of
dogma surrounding the best approach but usually it depends on the
equipment so it's best to go with whatever gives you the least amount
of noise.

There is an approach referred to here and elsewhere as impedance
balanced. I'm too lazy to type in all the details, so try a google
search of this news group for the two words in quotes.

The benefit is that you don't have to mess around with the hookups based
on whether or not you are driving a single-ended or differential input,
and all your wiring can remain balanced.

Bill