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Wiring an autoformer for RCA+XLR in/out?

I have a pair of autoformers for a tube stage or possibly stand-alone passive pre which I haven't wired up yet,
but I'd like to do so. Wiring for RCA inputs and outputs looks straightforward. But how do you wire in the added option of XLR in and out?

I always assumed that you put the variable resistor or I guess autoformer between pins 2 and 3. So I'm at a bit of a loss to see how you combine
phono and xlr inputs and outputs.

Can anybody clarify with a wiring diagram?
 
OK, how would you wire up a TVC for both RCA and XLR?

A TVC input is balanced unless you provide an unbalanced earth reference on your own. For XLR input, pins 2 and 3 go to the input side of the TVC. The RCA jacks connect similarly, and you have the option of providing a DPDT switch to enable or disable the galvanic isolation of the TVC. To maintain the balanced input, you'll want to use a 4 pole switch to let you switch hot/ground on the RCA jacks and +ve and -ve on the XLRs as a function of the input switching.

The output side is a little simpler, as you can have a toggle switch that either earths one of the ends of the secondary winding to allow for unbalanced outputs or floats the winding for balanced output.
 

RLRB

Member
2010-01-16 10:12 am
tx102 as autoformer

Hello
i cant see the schematics.
The question is: do i have to use primary and secondary? in this case ++ goes to 0.
or do i have to use only primary? in this case + goes to 0 i understand
or do i have to use primary and secondary in paralell?
which of three conections has 6db gain?
thanks
 

RLRB

Member
2010-01-16 10:12 am
A TVC input is balanced unless you provide an unbalanced earth reference on your own. For XLR input, pins 2 and 3 go to the input side of the TVC. The RCA jacks connect similarly, and you have the option of providing a DPDT switch to enable or disable the galvanic isolation of the TVC. To maintain the balanced input, you'll want to use a 4 pole switch to let you switch hot/ground on the RCA jacks and +ve and -ve on the XLRs as a function of the input switching.

The output side is a little simpler, as you can have a toggle switch that either earths one of the ends of the secondary winding to allow for unbalanced outputs or floats the winding for balanced output.
you say i can i use the tx102 as autoformer in balanced? with primary and seconday in paralell? if you can make a schema

thanks
 
graph.gif


This image gives you instructions on how to hook up the primary windings in series or parallel. We'll assume you are using these in unity mode.

For SE input, RCA shell goes to - and RCA center pin to ++. You would have a switch to connect - to output cold (which is the circuit audio ground), which you may or may not need.

For XLR input, pin 2 goes to ++, pin 3 goes to -, and pin 1 to chassis.