Allison Research RM-160 Gain Brain Kepex Rack Wiring

[BrianJSiegel]

I understand that these units are unbalanced?  What I’m confused on is why there is hot, cold, and ground for the key input, the audio input, and the output (on the 9-pin Molex connection). Also curious as to the key input being called ‘stereo interleave’ on the back of the rack unit.

Just trying to understand, I’m sort of at the beginner level which I’m sure was pretty obvious from my questions. Thanks for any help you can pass on to me, much appreciated for the assistance so far

 

[JohnRoberts]

hot is audio signal, cold is clean audio 0V reference, and ground is dirty shield-chassis ground....

JR

 

[BrianJSiegel]

hot is audio signal, cold is clean audio 0V reference, and ground is dirty shield-chassis ground....

JR

Yes, I know that much. But I thought thats for balanced signal? These are unbalanced inputs and outputs from what I have read. That’s what I’m trying to understand

 

[JohnRoberts]

Yes, I know that much. But I thought thats for balanced signal? These are unbalanced inputs and outputs from what I have read. That’s what I’m trying to understand

This is (should be) well discussed in the literature. "Balanced" refers to similar impedance in both legs, with other imagined constraints. 

Effective signal transfer can maintain signal integrity even with unbalanced interfaces as long as signal is extracted differentially between audio hot and (clean) cold feeds.  Treating the cold separately from shield ground avoids corrupting that audio 0V with ground noise.

JR

 

[PRR]

>>  ...  hot is audio signal, cold is clean audio 0V reference, and ground is dirty shield-chassis ground....
> .... I thought thats for balanced signal?

If JR meant "true Balanced" then why did he write "0V"? True balanced interface, both wires have voltage.

I wish the old Rane Notes were easier to find.