Fillmore 50 and the Effect loop

I was finally getting around to test configuring my WDW rack with the first two amps of the three that I will most likely use, a Fillmore 50 and a MarkV:35. I will be adding a TC50 later once I have these two setup and working.

I am running a Volcano from Soundsculpture in the effect loops of each amp.

So as not to complicate the description, I will cut to the chase and not get into the detail of all the connections, since I am using 2 GCX's and 2 SM10's for switching and mixing.

When i run Chnl 2 of each amp in tandem with distortion, it sounds great no issues, nice and loud, lol!

But when I go to Chnl 1 of each amp in tandem, clean, I get a very weak signal, that at times can distort a bit if i strum some chords. It does not sound like the typical "out of phase" signal that I have heard before when I would run my LSS and MarkV:35 in tandem with distortion on Chn 2. I solved that issue using a buffer in the loop of the LSS, that was inserted in a loop on the GCX, that would reverse the phase when switching to Chn 2 on the LSS. The manual also states this may happen when running another amp together with the LSS, because of the tube phase inverter.

I tried doing the same thing on the Fillmore 50 with the buffer, but reversing the phase did not help. I found that if used the Isolated out of the buffer, the clean chnl 1 running in tandem on both amps would now sound "normal", full and loud.

To summarize, I can run Chnl 2 in tandem on both amps, with distortion, without the buffer in the loop of the Fillmore 50 and not have any issues, but need to have the buffer, using the isolated out, in the loop, when running chnl 1 on both amps in tandem, clean, so that I get a normal signal.

If you made it to the end of the post, thanks for reading! lol

Any ideas? Thanks in advance!

peace

If you get any suggestions I'd be surprised. You might try reversing phase on one of the amps (speakers) while on clean to rule out that that is or isn't the problem.

plan-x said:

If you get any suggestions I'd be surprised. You might try reversing phase on one of the amps (speakers) while on clean to rule out that that is or isn't the problem.

Click to expand...

Thanks for the suggestion, but I'm actually using cabclones, with the speakers on mute, on both amps then into a mixer and then headphones, since i live in a housing situation that does not allow me to run out loud. I'm doing the preliminary setup and adjustments this way, then will rent a reheasal room for a day or so to setup and mix at "show" volume. i seem to have solved the issue using the iso out on the buffer for the fillmore 50 loop, but i may try your suggestion when i go do the live sound testing. i'm just curious as to why this is happening and if maybe it has something to do with the way the loop is wired on the fillmore verses the other flavors of mesa amps. it almost feels like it has to do with the ground being reversed when going from clean to distortion on the fillmore, thus when i isolate the loop with the buffer, it disappears. :?:

i'm hoping "official mesa boogie" chimes in, cause i agree with you that this is something that may not be very common out in the "wild" because of my particular circumstances. thanks again!

peace