Out 3 to power amp: TRS or TS? (Unity Gain)

Quad Cortex
1

Hey folks.

I’m currently using Out 1 (mono) to FOH and Out 3 (mono) to my external power amp for my cab (SD PS170). In the wiki, I found:

The outputs 3&4 are TRS jacks. If you use a TRS cable in output 3&4 you will get unity gain. If you use a TS cable, you will get 6 dB less signal, Quad Cortex doesn’t sense if the signal is balanced or not and compensate. So with a TS cable, you get half the output voltage and the gain must be boosted 6dB to get unity gain into a guitar amp effects loop…

So … even if my external power amp is running a mono (TS) input, I “should” use a TRS cable to get a full unity gain signal? Am I getting this right?

Niklas

1 Like
2

I believe you can use TS but you’d need to boost the signal +6dB for unity gain. At least that’s how it reads. I’ve never used TRS and I’ve never boosted +6dB. Maybe I’ve been doing it wrong this whole time. Haha.

3

I’m not sure the PowerStage even uses TRS for the input, so I feel like it’s not gonna give you a signal boost. Might even add noise possibly?

4

Maybe this is only recommended when using 4CM with a real amp. Sending that +6dB to the return of the head’s FX loop for unity gain. I guess it does say “guitar amp effects loop…” in there, but I completely missed that.

5

I’m just curious if anyone is doing this at all. Every time it comes up it’s mostly shrugs. Ha. Then again, most here probably aren’t using this piece of gear in 4CM with a real amp. I do for certain gigs but currently that’s very rarely.

6

Most amp effects loops want to see line level. For some amps going into the effects loop will disable the master volume, so you have to control it with whatever you’re running into the power amp.