High end vanishes when using two amps

Quad Cortex
1

Hi all,

So I’m using a capture of a Sovtek amp in parallel with the Quad’s built in JCM800 (2203).

And for some reason no matter what I do to the EQ, the Sovtek’s high end is just gone. It’s really boomy and bassy.

I’ve tried using a gain block to flip the phase but no joy.

When I open up a blank preset and have nothing but the Sovtek it sounds great.

So I’m not sure what it is about using two amps together that’s making this happen!

Any thoughts?

Signal chain is a

bunch of effects---- Sovtek with a cab and slapback delay

Splitter before the amp to the 2203 and some other effects.

Thanks!

2

I’m guessing it’s a phase issue, I’m just not 100% sure just how much latency each block is actually adding, which would be very useful info for NDSP to provide. My best suggestion is recording both to separate tracks and zoom in to see how much the phase is off and adjust until it’s close. Ideally, I wish the QC had some kind of compensation option, either some kind of algorithm for automatic phase compensation or at least a sample accurate delay, but for now, your best bet is manually moving the tracks after recording. If you’re just blending both signals on one track, then there’s not really much of an option at this point other than adding more blocks, but again, we don’t know just how much latency is added for specific blocks, so it can’t ever truly get to the point where it’s almost perfectly in phase.

3

Yeah, the problem is it’s for a rig I’m using live for a covers band.

It’ll sound less full I guess but I suppose one solution is just to go to a single amp signal chain!

4

can you upload/share it so we can take a look in detail?

5

When using dual amps of any sort, you have to address phase. If the amps have a different number of tube gain stages, or a different approach to the power amp phase inverter, they could be out of phase. For example a Fender Twin Reverb and Fender Showman both using the Vibarto channel will be out of phase. You have to introduce a phase inverter in the signal chain somewhere and try flipping the phase to see which sound better.

2 Likes
6

Which blocks have you been using commonly for phase inversion?

1 Like
7

I use the cab block.

2 Likes
8

So you invert the phase of the cab? Is that the circle symbol with the line through it? If so I tried that and it didn’t seem to make much difference.

Re; Previous poster I’ll upload the preset in question to the cloud if that helps? My username is StevieQ and it’s Wolfstorm Les Paul.

9

Solved! Used the splitter to invert phase!

3 Likes
10

That’s a great option too. You could it with the cab block if you had different cab blocks for the different amps.

1 Like