Amps in Stereo...ABY Switch or more too it?

  • Thread starter Thread starter Anxiety Serum
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thegame said:
Be careful with phase relationships. Every gain stage in an amp flips the phase 180 degrees. For example, running one amp with 3 gain stages will be out of phase with another that is using 4 gain stages. Or, say you have two amps with each one running 3 gain stages as your main tone. Fine, until you switch channels on one of them and then this other channel adds or removes a gain stage. Then it'll be out phase. The only way to counter this is a device with a programmable phase reversal function, or run a programmable loop switcher (ones typically used for FX switching before the amp where every pedal is in its own loop) and have a specific pedal or something that will reverse the phase when kicked in. That way it can be programmed to be in the signal path when mismatched gain stages between various amps in are play, and out when its not needed.

Glad I'm into mono setups.
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Thanks for posting that. That is pretty intense actually.

How would I know if I was out of phase?

I don't think I have that issue but my Recto has a ground lift plug on the power. So that completely eliminates all noise I was having before (outside of normal amp hiss) and this is fairly high volumes and boosted. I believe I read someone where that when you do this pick your 'best' amp to be grounded (ie. best built, best chance of not having soldering issues, etc).

Edit: What I mean by that is pick the best amp to be the ground for all. And the lift on the Recto was not because it is noisy on its own, it was having 2 amps on an ABY pedal that doesn't have any of these special features.

I guess everyone needs to take their own environment into consideration. I'm set up in the basement, with a carpet floor and a heavy duty surge protected power strip in a well grounded house. Conversely, if I was a sketchy single floor older home and running just on the Recto I suppose I would run the risk of getting a shock or the amp frying if my house got struck by lightening.
 
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311splawndude said:
Thanks for posting that. That is pretty intense actually.

How would I know if I was out of phase?
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Generally, two amps in phase will reinforce each other and be more present with additional layered frequencies (each amp adding frequencies the other one doesn't). Two amps out of phase will cancel some frequencies out and sound/feel more distant, hollow and have less punch. The out of phase blend may still add some frequencies to the mix but more will be cancelled than added.

To get really deep in the subject, many, if not all, components in the signal path introduce some degree of phase shift but good amp designers in general aim to achieve a coherent phase relationship from input jack to output speaker jack.
 
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Best way to listen to phase relationship is in the low to low mid frequencies. Together in phase, it will sound full and thick. Out of phase, it will sound weak and thin. If you get the ABY with a phase switch, you'll know pretty quick.

Funny side note: A buddy of mine was running a guitar through a guitar rig, and through an octave pedal to a bass rig for a rock band a while back. He used a Boss tuner to split the signal up front. Rocked it for years.

I let him borrow my ABY for a bit, and he discovered that the two rigs were out of phase all these years. He never noticed, because the octave pedal shifted things enough to make it work. It blew his mind when he flipped the polarity and heard his old rig in phase for the first time. I kinda wish they were still jamming, but drama and whatnot.
 
I hope Anxiety Serum doesn't mind but here is an in-room clip of my new ABY pedal (prior to the Mimiq).

It was generally fairly quiet (relatively) but this is AFTER I got my ground loop sorted. It was a hot mess before this clip. BTW - not trying to show off or anything, I know my limitations as a guitarist :D.

The MXR ABY has no phase or ground switches etc, and I cannot find anything on line about it being built in. It is also only $60. :LOL:

 
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Cut a guitar cord in half.
Splice both ends together on another 1/4 inch jack and plug that end into your guitar and the other two ends into the amps.
Stand in a puddle of water.
Get your mouth close to the ungrounded cheap PA microphone.
Bang that first power chord while screaming into the mic....total redneck style.
Make sure you video it for posterity. Post video on YouTube.
Become RigTalk Legend.
 
Out of phase, Im pretty sure you can flip the positive and negative on one end of the speaker cable to cure that.
 
I did run an Randall RM100 together with an Vox AC30 and I needed the phase switch on my Lehle Switcher to be engaged as the sound was quiet and thin if not. I as well needed the ground lift as I had loud hum.
Still, the Mimiq looks intriguing for a two amp setup.
 
First impressions.

The Radial Twin City Works great - I can't notice any tone loss vs plugged straight in. Running Guitar>Polytune>Ditto Plus>Jerry Cantrell Wah>Twin City>Mimiq>splitt to 2 amps ( VH2 and Mark V25).

Can't really tell a major difference with Phase switch, so I can see how people didn't even know they needed it until they tried it. Maybe at louder volumes its more noticeable (I'm pushing 80-90bs max at home)

Mimiq definitely fills out sound, but sometimes it sounds better off than on. Still need to play with it and see where I like it on or off better.

Tight switch about 9 o'clock (tighter) for distorted tones sounds best and 3 o'clock (loser) for clean single notes. For strumming clean chords, tighter is better (maybe there is a sweet spot for both as I wouldn't want to change the knob mid song).

Can't decided if I like 1,2, or 3 dubs best.

I've just maxed out the two other knobs (Dry and Effects). In 1 Dub its like a left and right volume control (cutting off one of the amps if turned off). This makes sense given its just your Dry guitar in 1 amp and 1 effects dub in the other (as I understand it).

In 2 dubs its meant to be a center dry and left and right wet effect (not sure how given only 2 speakers but that's what TC says). In 3 dubs its meant to be wet and dry each in both amps (4 sounds). Wish their manual said all of the above, had to watch their video on Sweetwater to get all that.

Pedalboard.jpg
 
Wow, you didn't waste time :lol:

The mimiq definitely takes some tweaking. Raceu4her told me to put everything at noon. Not sure how I like it best yet. I really need to see if can find room to get more separation on the cabs.
 
311splawndude said:
Wow, you didn't waste time :LOL:

The mimiq definitely takes some tweaking. Raceu4her told me to put everything at noon. Not sure how I like it best yet. I really need to see if can find room to get more separation on the cabs.
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Yeah that's an issue for me. Not a lot of space for separation.
 
For me it really spreads the sound out left and right even thought the cabs are next to each other. It must me dat algorithm playing tricks on my brain me thinks :yes:
 
Stupid question but is it possible to play two amps through one 4×12 cab at the same time, with an aby switch?
 
I recently tried using an Axess BS2 Buffer/Splitter to run a SS100 with a Tremoverb and I thought the two amps complimented each other great. It has an Iso'd Out and phase switch. I was surprised how huge it sounded.

El Cap is in SS100 loop, everything else in front of splitter. Each amp had the normal noise floor. The MXR Flanger requires a dedicated supply or its clock fucks with the Belle Epoch.
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Metalhex said:
Stupid question but is it possible to play two amps through one 4×12 cab at the same time, with an aby switch?
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Not unless you wire the 4x12 as two 2x12s and have each head use 2 speakers. Each amp needs its own load. However there are amp switchers that do switch cabinets but they are more expensive.
 
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SpiderWars said:
I recently tried using an Axess BS2 Buffer/Splitter to run a SS100 with a Tremoverb and I thought the two amps complimented each other great. It has an Iso'd Out and phase switch. I was surprised how huge it sounded.

El Cap is in SS100 loop, everything else in front of splitter. Each amp had the normal noise floor. The MXR Flanger requires a dedicated supply or its clock fucks with the Belle Epoch.
IMG-20220305-055249.jpg



Not unless you wire the 4x12 as two 2x12s and have each head use 2 speakers. Each amp needs its own load. However there are amp switchers that do switch cabinets but they are more expensive.
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I also used an Axcess BS2 when I ran two heads and it worked great. I recently stumbled across what appears to be the Suhr equivalent which seems like it would do the same;

https://www.suhr.com/electronics/tone-tools/suhr-buffer/
 
ABY are cool if you want to run two amps. Also nice for a clean/dirty switching. Buffered is a bonus.
I run one amp with a mild chorus the other with a slight delay. It’s a eargasm

If you want to only run two amps just get a buffered signal splitter.
 
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