Calling all Gurus!!!

[codasound]

Ok, I have struggled mightily with this one. I have ran this rig through probably 10 different setups, and now I need some help! Here's what I have: Mesa Boogie Mark iic+, Mesa Boogie Mark iv, tc electronic g major 2, the ever awesome gcx and gcp, and two Mesa Boogie standard 2x12 cabs. Both of the amps are heads with fx loops. So here's the deal, I want to run them in stereo, NOT PARALLEL, and switch between the pre-amps of the two heads and leave the power amps left and right side. I have already done this with the following signal chain... guitar into loop #1 IN... loop #1 send and out run to the fronts of the mark iv and iic+ respectively... then use the sends from the two amps fx loops into the IN and RETURN of loop #5... from the out of loop #5 to the guitar input on the front of the gcx... split the signal from the guitar out and the feed through into the left and right side of the g major, and from the left and right side outputs on the g major to the fx loop returns on each amp! UGH its convoluted i know!!

Here's the thing. For whatever reason I'm getting tone suck majorly doing this, not to mention its annoyingly noisy. I cant help but feel that the g major has something to do with this, maybe the a/d to d/a conversion...I don't know. So... is there another way to do what I'm trying to do with just the gcx, or is there something else out there that I could benefit from that I don't know about? Ive ran it parallel, and in stereo using just the iic+ and then into the power section of the iv, but I need the iv for cleans and the second "middle" channel. A precursory thank you to anyone who throws some much needed knowledge my way!!

[AllanWilliams]

As a first starting step Codasound, I'd suggest instead of running your guitar in to the loop 1 input that you run it to the GCX Guitar In at the front of the GCX and then bridge the output at the back across to your preamp inputs. This will put the GCX input buffer in there to help drive the signal into the preamps. That could be your tone suck right there.
Your setup is essentially running a merged mono signal into the Gmajor so using the Guitar In for splitting the outputs for L and R inputs to the GMajor at that point isnt doing much for you. Page 8 and 9 of the GCX manuals show the options for switching 2 preamps so have a look at those. See which of those suit your purposes best. Depending on which way you go there, run that output to your Gmajor input. The GMaj stereo outputs then to your two amp effects returns.

[codasound]

Definately appreciate it Allan!!! I know Ive read that manual a dozen times... my brain must have been fried. Thanks again... I'll post back with the results

[nyteowl]

Allan is correct. If you're switching between two heads you aren't running a stereo rig. Depending on which head is active, you'll get either the left or right channel of the GM2, whichever one is feeding the active head. The only way to get a true stereo signal using the gear you described is to run both amps simultaneously.

Also, if memory serves, you do not have to feed a signal to both inputs of the GM2, but rather you can simply feed a mono signal to the Left Input and the GM2 will make a stereo signal available at the Left and Right Outputs.

Something else you might want to consider trying would be running the GM2 Outputs back to the In and Return jacks of a GCX Loop and routing them to the respective Mesa FX Return jacks from there.

With any luck, Joe (aka, a2dconverter) will see this thread and chime in.

[AllanWilliams]

Correct Nyteowl. The GMaj2 does have the option for mono in, stereo out.

So for a simple switching between the two heads Codasound (one on or the other on) the full connection would be:
Guitar into GCX Guitar In on the front of the GCX.
Guitar Out on the back of the GCX to amp1 input
Guitar Thru on the back of the GCX to amp2 input.

From Amp 1 effect send to "Loop 1 In"
From Amp 2 effect send to "Loop 1 Return"
(When the loop is off Amp1 plays, When loop is on Amp2 plays).

From "Loop 1 Out" to GMaj2 (mono) In
From GMaj2 L Out to Amp1 effects return
From GMaj2 R Out to Amp2 effects return

[a2dconverter]

Hello codasound... At your service since nyteowl beckoned me!

Here is my take on your design... it routes the G-MAJOR 2 in parallel with your dry signal so your tone stays intact.



It will require a splitter and stereo mixer external to the amp heads to create the parallel L & R paths.

You are switching the Mesa preamps using a GCX loop and then splitting the Preamp DRY signal to the G-MAJOR and Mixer.

The L/R outputs of the G-MAJOR are mixed with the dry signal, panned L/R and sent to the Head return jacks utilizing the head power amps to feed your speakers for a stereo rig. (On ehe Mixer, Pan the G-MAJOR outputs left and right and pan the DRY signal center)

I assume that the MKIIC+ and MKIV head power amp sections are similar; as when you switch preamp signals, the MKIIC+ preamp will be using the MKIV power amp at times and vice versa.

Make sure that the G-MAJOR 2 is set to KILL DRY.

You may get some HUM and might need an ISOLATION Transformer in one of the amp Return Legs or in one of the amps INPUT legs.

GCX Loop 5 Mutes the input to the G-MAJOR 2 MONO IN so that delay and reverb trails carry-over when you switch patches. To make this work properly, you will also need an Active Splitter before GCX Loop 5. If you try to switch the loop without a buffer, the impedance will change causing a shift in volume of the DRY signal going to the mixer.

After all of that, you will have some left over GCX loops that you can use to switch reverb on/ off, amp channels on the heads.

I hope this helps.

seeya

Joe

[nyteowl]

Hello codasound... At your service since nyteowl beckoned me!

Thanks for checking in, Joe!! Your assistance, and your graphics, are always greatly appreciated.

Regarding Active Splitters, I use an Axess Electronics BS-2. They're out of production now, but occasionally one will pop up on eBay. If I didn't already have a BS-2 I suspect I'd use an RJM Tone Saver.

[a2dconverter]

Hello codasound... At your service since nyteowl beckoned me!

Thanks for checking in, Joe!! Your assistance, and your graphics, are always greatly appreciated.

Regarding Active Splitters, I use an Axess Electronics BS-2. They're out of production now, but occasionally one will pop up on eBay. If I didn't already have a BS-2 I suspect I'd use an RJM Tone Saver.

nice team-work nyteowl!... Just to add to your list, Palmer has a nice splitter as well...

Palmer PGA03 Y-BOX

seeya

Joe

[codasound]

Guys!!!! Man...I dont know what to say!!!!! Thanks a ton for the info!!! I've read through Scott Khans rack book a dozen or so times, and he goes through a few examples of using a mixer. I kept thinking that I might need to look into that, but it always seemed confusing for lack of a better word! Joe your diagram takes all of the guess work out man!!!!

And yes yall are correct about using the mark iv and the iic+ power sections as left and right side. What originally began this build was wanting to switch between the two preamps, use the tc, and run the whole thing in stereo. But no matter what I kept trying, when you unplug everything and stick a cable into the front of the iic+ with the cabinet only, it just sounds better! Gotta go pick up a few things now, cant wait to try it all out!

Let me bug you guys with two more questions before I go... To be clear, when you say active splitter, that does means buffered correct? I'll probably go with one of the ones yall recommended, but for the sake of curiosity...
And also could you recommend a good road worthy, problem free mixer that you've has success with?

Thanks again very much guys! I definately appreciate it!

[a2dconverter]

Hey Codasound...here are some Rack-Mount Stereo Line Mixers...

RANE SM82S MIXER
Rolls RM219 MIXER
Ashley LX308B Analog Mixer
Behringer RX-1602 Mixer

I hope this helps...

seeya

Joe