Two Rock Jet head into Mesa cab phase problem.

blueswallace

Hey,

I'm look for a little help regarding the the phase of my Head/amp combo. I have a Two Rock Jet 35 head and a Mesa (C90 Celes speakers) cab 2x12. I got the cab for free so it's all good. I was recording recently and the audio engineer checked the phase of my head/speakers and advised the speaker is pulling first. I believe this can cause problems with headroom and tone. It still sounds good, but I'm wondering if there's an easy fix or would I have to get a new cab?

There a little burb on the Two Rock FAQ that will explain it better than I can. All I know it my set up is out of phase.

"Care needs to be taken when installing new speakers or adding other manufactures cabinets to our amps. All of our amps that have reverb have a reverse phased output section. What this means is that the signal is in the negative swing as it leaves the amplifier. Traditional wiring of speakers takes the “+” positive terminal and connects it to the tip of the speaker jack, and the “-“ negative terminal and connects it to the sleeve of the speaker jack. When the speaker gets the signal in this configuration the speaker will push first and the pull. If the wiring of the cabinet is “Out of Phase” with the amp then the speaker will pull first and then push."

The Jet does have Reverb.

Thanks in advance for any help

ICBM

If you're just talking about one amp and one cab it won't make any difference to the headroom at all, and only barely to the tone - more of a "this is subtly different if you quickly A/B it" effect than "obviously different".

The only time it's really an issue is if two cabs are out of phase with each other when connected to the same amp - that can reduce the volume and low-end. Even two amps being out of phase doesn't usually matter, unless they're set for very similar sounds - and even then, the engineer can just flip the phase on one mic.

If you want to see what difference it makes, you can simply get a cross-wired speaker cable - that reverses the phase of the cab relative to the amp.

The "speaker pushing first" idea is nonsense - it totally depends on the direction of the initial transient in the signal, for which there is no standard. If you reverse the phase of the guitar pickup, or use a pedal which reverses phase - quite a few do, and that doesn't mean phasers - then you'll get the different initial direction of movement from the speaker too.

StuartMac290

Precisely. Find a new engineer!