Stereo Effects - Two Amps

[zpyder]

Hey hey hey hey hey....

As I work steadily toward a perhaps imaginary goal called PREFECT RIG, a few ideas come to mind.  Currently, I'm working on (among other things) getting a gig-ready setup together that utilizes two different amps - thereby taking advantage of their two different flavors, and the added luggability of 2 smaller amps over one huge one.  My current design uses a transformer-isolated splitter to split the signal chain for the two amps.  Some (most) effects go before the splitter and effect both amps, a couple boxes are amp-specific, and come after the splitter.

Now I'm thinking about stereo effects.  I could have my signal ping-pinging between the two amps (stereo tremelo I suppose...), stereo panning, stereo chorus - where I've got certain added harmonics represented in one amp and others in the other (or perhaps there's a more exciting way to do stereo chor.?), etc... However, the stereo chorus pedals I've seen in the past exist within one box that has a mono in and a stereo out - doesn't really fit with my plan here since I would like to keep my two amps isolated to prevent ground potential problems.  That is, of course, unless my stereo fx are before the transformers... Since the splitter ordinarily takes one mono signal, not two, and sends it out to the two amps, I would need a bypass mode for when I'm not using the stereo fx, where the one in signal is split within the splitter into two outs, and a non-bypassed mode where one in signal goes to the stereo fx, which outputs 2 signals, and then send those two through the transformers for isolation...

Sounds like having the stereo fx within the splitter, or in an fx loop off of the splitter.  So in order to create stereo effects going to do different isolated amps, it seems I'd either need to include an effects loop within my isolated splitter before the transformers that utilizes a mono send but a stereo return and the bypass method I mentioned above, or create post-splitter effects that are stereo (A & B, dual mono, whatever you want to call it) in and out, and also transformer isolated to maintain the amps' isolation... This seems to make some of the isolation transformers in my chain erroneous...


hmmmm... a real doozey?  I'm sure people have done this before, but a search didn't turn up much of value.  How have people implimented this or similar designs in the past?

cheers,
zpyder

[puretube]

fourpoledoublethrow...

[Rafa]

Gustavo Cerati from an argentinian band did that, he used a Vox AC30 for the clean guitar and two Roland JC-120 for the effects, wonderful tones.
Rafa

[Rafa]

I found it 

[zpyder]

Gustavo Cerati from an argentinian band did that, he used a Vox AC30 for the clean guitar and two Roland JC-120 for the effects, wonderful tones.

Yea... I'm actually looking at using an AC30 for the clean and my peavey for the distortion...

fourpoledoublethrow...

and plastic 1/4" jacks to isolate the fx loop ground, caus we'd have to switch that too.
a couple CMOS swithces... 4053... that would work instead of a 4PDT as well...

Change S1 into either a 4PDT or a couple CMOS switches:

Switch TR1 between fx loop Return 1 and GND
Switch TR2 between fx loop Return 2 and GND
Switch FX loop send Signal between R13 and NC
Switch FX loop send Ground between GND and NC
Switch LED Ground between GND and NC or use millenium bypass method

zpyder

[zpyder]

******
I just noticed that C9 on that layout is backwards!!

******

[d95err]

Sounds like having the stereo fx within the splitter, or in an fx loop off of the splitter.  So in order to create stereo effects going to do different isolated amps, it seems I'd either need to include an effects loop within my isolated splitter before the transformers that utilizes a mono send but a stereo return and the bypass method I mentioned above, or create post-splitter effects that are stereo (A & B, dual mono, whatever you want to call it) in and out, and also transformer isolated to maintain the amps' isolation... This seems to make some of the isolation transformers in my chain erroneous...

hmmmm... a real doozey?  I'm sure people have done this before, but a search didn't turn up much of value.  How have people implimented this or similar designs in the past?

One very simple way of going stereo is to use one good amp. Mike it, add all the stereo (rack) effects you want, and then send it to the (stereo) PA. You need some kind of mic preamp in the rack though. If you don't want to depend on an external PA, you could use two small powered monitors, one on each side of your amp. A small cheap mixer can be used both as a mic preamp and to handle the stereo effect send/returns.

[Doug_H]

I ran stereo for a while and it was a lot of fun with a fantastic sound. I just got tired of lugging two amps around.

The way I did it was to run into my effects board and put all the mono effects (distortions, etc) first and then my ps-5 which had the mono-in/stereo-out to split. From that point on I had a "stereo buss" and used the stereo inputs/outputs on my roto machine. Out of there I split to the two amps, but on the way to one I inserted my mono delay, with it being on "one side" it essentially gave me a stereo delay. There is a richness to having 2 amps which sound slightly different running at the same time. It makes overdrives and distortions sound "bigger" as well as adding 3-d depth to time delay effects.

In an early version I used a loop selector with my rangemaster in one loop. The output of the loop selector went to the amp that was driven by the rangemaster. The other loop had all the other stuff which included the split out to the stereo amp. When I selected the rangemaster loop, I just got the rangemaster driving the one amp in mono. When I selected the "other" loop I got full stereo. It worked pretty cool too.

Have fun.

[zpyder]

******
I just noticed that C9 on that layout is backwards!!

******

Okay, it's fixed now...

zpyder

[Meanderthal]

 I used to work with a guitar player who used a Hafler 3 channel tube preamp into a programmable digital eq into a common garden variety Art reverb/delay/chorus/ flange multieffects thing designed for vocals I guess into a Hafler solid state stereo power amp into 2 Fender 1 12 cabs. Different patches selected via one of those midi footswitch things. Not only was the Hafler capable of some of the finest tube distortion I've ever heard, but the stereo (generated in the guts of the Art) was absolutely amazing. Some of you guys would no doubt turn up your nose at a rack rig like that, but it was compact, efficient, and I have yet to hear anything like it!
So, yes, stereo is way cool! Especially when it comes time to record...

[Processaurus]

Use a divided pickup and a mixer to pan the strings between the amps...  endless fun