That what I was thinking in regarding that phasing issue. When a Plexi has both channels jumped, then you have 2 channels going at the same time. So when the Plexi is pushed hard with 2 channels overdriving, it makes sense that you would experience a phasing sound....IMO....but I am by no means an expert.

And I found a quote from a guy (for what it's worth) on another forum discussing using a jumper on a Marshall Plexi, and he posted...
"On my THD Series One Plexi (JMP style amp) the inputs are connected (jumper) internally. The interaction of the two volumes seems to have a fair amount of phase reaction. It is equal or more about setting them for tone than volume in my experience."

And if you read the following thread from vintageamps.com, these guys are discussing using a jumper on different Marshall models, and how on some you can have them sound out of phase when using a jumper on 2 channels. And these guys are using the real amps, so does it give them a bit of credibility in their comments regarding phasing?

http://vintageamps.com/plexiboard/viewtopic.php?f=1&start=0&t=66848]Vintage Amps

So, is the Eleven Rack is just modeling the Plexi TOO PERFECTLY?


Also...For anyone who is interested, here is a wiki definition on the problems of something that gets out of phase...

http://en.wikipedia.org/wiki/Phase_(waves)]Phase

And here is a cool article from Sound on Sound about phase issues and comb filtering...

http://www.soundonsound.com/sos/apr08/articles/phasedemystified.htm]Sound on Sound Phase

FWIW

Edit was adding the links/articles

.

TLTD - i hear you with double-tracking. For the most part, I use the Eleven Rack live, so doubling isn't much of an option.

What's your whole signal chain from the guitar to listening back to the clips? Every little detail...

The fact that it is evident in some clips and not others is interesting. I sometimes think I hear something and sometimes not. I don't know if all the reports of the phasing issue have me trying to hear something that isn't there in my rig...

Ratter - The complete signal chain is: 2005 LP Standard > Monster cable 10' > tru Z input > (shine wah off) > (orange phaser off) > Plexi Variac > G25 cab > 121 mic on axis > Para EQ cut at 125 and 6.7K > reverb > (FX loop off) > main outs.

The clips were recorded with Logic Pro 8, no additional post anything... didn't even level the clips. The first clip is the DC Vintage OD with the same signal chain. The second, and more violent offender, is the Plexi Variac.

Again, I've read lots of different explanations for what could cause the phasing. But the thing that is most troubling is that I don't hear this phasing ON EVERYONE'S CLIPS. (caps only for emphasis, not yelling). If this were an amp that was modeled hyper perfectly, i would expect to hear that phasing decay on all of the EVH Brown Soundish clips made with a plexi variac. But I don't hear it everywhere... just on the clip that inspired a similar thread on the AVID forum, and on mine.

I'm thinking I should just upload the rig and let people play through it. I've posted the audio from it and I can hear the phasing clear as day. And the clip Jimification uploaded; very similar settings and no phasing in the sustained decay.

Thoughts?

Post the rig file and I'll record a clip with it for you...that way you can possibly rule out rig settings as a culprit.

It takes a few seconds so it won't be in some clips especially if you palm mute your guitar just before playing something else. If I had to play live, I'd make some presets with other amps, you can get the sound you want just save them as Plexi names and use M2 Lead or something (sorry not that one but that one but I do like that one a lot). I tried Browntown with green cab and ribbon mic off axis and tames it but you'd have to EQ it and it would probably sound worse than ever lol. I know one that that would fix it for sure is just get a Randall RM 4 and a Plexi module, then you are still traveling light and can put it in your loop and bypass the amp sim and save a preset that you like just for that.

ratter - here are both the DC Vintage OD rig (called Budda SD30) and the Plexi Variac Rig (called Phasy Plexi): http://www.box.net/shared/zbvhl5dqa3

I'd love to hear clips. I just experimented with my other guitars, and the phasing remains. Again, it's in the decay of notes, sometimes in vibrato, and often in the lower registers.

The phasing you hear when you artificially double track by using the same audio signal and just delaying one by a few ms is due the comb filtering that results from the periodic interference of the various harmonics. The way a sophisticated doubler algorithm (like Waves "Doubler") deals with this is to slightly detune one of the signals - not enough so that it sounds out of tune, but enough so that it eliminates the periodic interference between the signals (comb filtering).

That's what I do on the Eventide is shift one of the signals like the waves doubler. Sounds pretty cool actually, can't really tell it's just one take. The phase everyone keeps talking about is actually a sweep like a wah but very little, not cancellation or anything.