MXR M80 DI / Ampeg SVP pro

[Lfalex v1.1]

My MXR M80 works fine. And it sounds pretty good.
I like the full and clean fundamental it gives, with plenty of attack. Just what good a solid state pre should deliver.
I don't like OD as much as the nice valve crunch the Ampeg can give.
Yesterday I had both plugged into a small mixer and headphones for practice.

I had it wired thus;




[>>>> Mixer ch1 (via DI)

Bass>>>> MXR M80[

[>>>> Ampeg (via "wet" 1/4" output)>>>> Mixer ch2 (via DI)

Figuring I could blend the depth and power of the MXR with the warmth and edginess of the Ampeg.
However, with both pres running at approx the same level into the desk, they virtually cancel each other out!

Does anyone know if the MXR's wet output is in negative phase to its DI out? Or is it the Ampeg that's phase inverting?
If you cut the level on Ch1 or 2, the other channel regains its former level from the mixer.

Hope this makes sense!

Alex.

Edited August 21, 2008 by Lfalex v1.1

[escholl]

is there not a phase switch on the input of the mixer? most mic pre's will have something to that effect to ensure that several mics running into a mixer from different positions will not phase cancel.

i don't know if the devices themselves are phase inverting, but that's been a big no-no in the industry since about the 70's, so assuming anyone with half a brain designed it that shouldn't be the issue.


have you tried a different xlr cable? it's possible that's the problem, if it's wired up backwards at one end; that would also give you the same phase problem.

[Lfalex v1.1]

[quote name='escholl' post='267673' date='Aug 22 2008, 10:15 AM']is there not a phase switch on the input of the mixer? most mic pre's will have something to that effect to ensure that several mics running into a mixer from different positions will not phase cancel.

i don't know if the devices themselves are phase inverting, but that's been a big no-no in the industry since about the 70's, so assuming anyone with half a brain designed it that shouldn't be the issue.


have you tried a different xlr cable? it's possible that's the problem, if it's wired up backwards at one end; that would also give you the same phase problem.[/quote]

No phase selector/s on the mixer. It's more of a diddy 8track mixer than a dedicated mic pre...
The leads were all bought at the same time, so I doubt they're differently wired.

I think it's that the MXR's DI and "dry out" are deliberately out of phase with each other, possibly to prevent feedback if you cable it up like a numpty...!