Phase issues with 2 amps


I am trying to run a setup with 2 amps on row 1 and 2 and I have phase issues
Is there a way of reversing polarity in amp 2?
I try to do it by a splitter from in 1 and in M row 2 phase on but sounds terrible so definitely doing something wrong
I wonder if someone can please help?


use a gain block and flip the phase. Unfortunately this will happen quite often if you do things in parallel. Captures aren’t necessarily phase-preserving

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Some amp/cab combos just dont play well together. I struggle with this often and sometimes changing cabs works, sometimes its just the combo of amps and captures and the what not. I consistently forget which amps usually work together and which ones dont. Sometimes i just pan them hard enough until the phase goes away but thats mostly for jamming for me i suppose. Havent had to really tackle this in a recording or live session yet.
+1 to the suggestion above, I’m gonna give that a try as well. Cheers

Had the same thing happen just today. I’ll try the using the gain block idea, but sure would be nice just to be able to adjust the phase as a part of the process of running parallel streams, especially if this is a common occurrence. Thanks for asking this question .

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I haven’t received my cortex yet so I can’t try this. A short delay ( like 10 ms or less) before the second amp should help. I would play with the time.

part of the problem is that phase isn’t preserved with captures. There is no amount of perfect alignment that can solve the problem - which ISN’T the case with most other modelers. I’m not sure if it’s a universal issue or just with some items, but this makes it effectively impossible to combine the QC tone in perfect phase in some cases, IME. Might not be the case onboard the QC though between captures.

Hi man…thanks for that…a bit of a deal breaker for some I’m sure. You know. In the past, I have used 2 amps almost exclusively because I wanted to use a high gain amp along with a more traditional overdriven amp because I hated how the high gain models lose any sense of dynamics, and could be compensated for by using a less overdriven amp. Looks like this can’t be done at least not yet in the quad cortex. My actual purpose, however, in trying this was to get around the limitation of having only 2 parallel rows per signal path. I’m now wondering if I used the same amp model, if the phasing problem would go away. (I was using 2 different amps previous to this) The 2 different amps were unnecessary as all I was trying to do was to have multiple delays running in parallel and not in series (Allan Holdsworth approach.) Thanks for your comments…Brett

Parallel amps in general are much harder to do properly than people give credit for. It works much better in the room via 2 amps and cabs than it does with a mono sum via one cab or monitors - there are phase issues in most cases no matter what

Yes you’re right…it likely occurs regularly but is not diagnosed…not like the old days of listening to everything in both stereo and mono…I have, however, had it be quite successful in, for example, amplitube. I’m not sure why, and perhaps there were issues I wasn’t aware of, but nothing so drastic as the (wah pedal in the 1/2 depressed position sound which occurred when I put 2 amps together in the quad cortex…I’m still going to try using identical amps and see if I can get away with it…thanks for your insight man…Brett