Question about running 3 amps. Wiring help.

Discussion in 'Amps and Cabs' started by stonem, Aug 13, 2019 at 10:00 AM.

  1. stonem

    stonem Member

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    Hello, I appreciate any insight here.

    I've been running 2 amps in stereo for years (vht d60 and Mesa single rec) with an aby box. I recently got a mark iic+ and decided to throw it in the mix.

    Anyway, I kept my two amps in the aby and then plugged the c+ into my stereo chorus that is in the effects loop of my recto, I noticed when I change channels on the recto it changes the channel on my c+. Why is it doing this? Is the c+ bypassing its preamp and using the recto preamp as a slave or something? I intend to eventually get a voodoo amp switcher but in the meantime any suggestions or advice would be appreciated.
     
  2. Blix

    Blix Supporting Member

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    Yes you are sending your C+ the preamp signal from your Recto so what you hear through your C+ follows that.
     
  3. stonem

    stonem Member

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    Thank you. I suspected because of the tone. So this would be the case no matter what as long as the c+ is feeding into a pedal in the loop of the recto? Theres no way around it without a dedicated amp switcher/abcd box?

    Also if I reverse the two amps I would hear the c+ through the recto right? Thanks again sir.
     
  4. Blix

    Blix Supporting Member

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    Yeah, no way around it.

    Yeah correct. :)
     
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  5. stonem

    stonem Member

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    Ok, thanks I really appreciate it man.
     
  6. eigentone

    eigentone Supporting Member

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    A second ABY (ie using two ABY boxes) or an ABC could get you by in the meantime. If you are sending the input to two amps at the same time or if you have long leads, then I recommend an active box.
     
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  7. stonem

    stonem Member

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    Wouldnt this cause ground issues? I can build an aby no problem but from what I read they say you get ground lift. I dont really know, I'm asking. I looked at the Morley tripler but from what I read the voodoo switcher seems better. This is my first foray into 3 amps. FWIW it sounds amazing running all 3 at the same time, issues aside lol.
     
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  8. Steviecaster

    Steviecaster Member

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    You most likely will get ground loop issues. You can get isolators, or if you have a ground lift on one of your amps(don't really recommend this).

    I run a Plexi and a Bassman at the same time. I have a 3 prong to 2 prong adapter, if I get ground loops, but this isn't safe, and Im getting an isolation transformer to plug one into, or whatever they are called.
     
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  9. eigentone

    eigentone Supporting Member

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    Most good ABYs solve this issue for you, though a lot of cheap ones do not. The Radial Bigshot ABY has an isolation transformer, a ground lift switch, and a polarity inversion switch. That's really what is needed for the second signal.

    Since you are playing through multiple amps at once and sending your signal to two or three amps at the same time, you should use an active switch. Basically, this adds a buffer to the signal which avoids the varying levels of "tone suck." The Radial Twin City is an active ABY with isolation transformers, a ground lift, and polarity inversion.

    For controlling three amps from one unit, it looks like a Radial Switchbone V2 would do the job.

    The Morley Tripler doesn't have isolation transformers, ground lift options, or polarity switching. I would personally avoid that. It's a cheap solution.

    Voodoo Lab's Amp Selector has been discontinued but they say a new version is coming soon. Maybe you can find one on Reverb?

    I do have a Voodoo GCX. It's not a great solution for amp switching when playing through multiple amps simultaneously. It has an optional buffer and several relays. That's nice for pedals and effects as well as routing to one amp at a time and controlling amp functions. Overall, I am happy with it. MIDI communication using program changes on a specific channel would have been easier for me than CCs. But no biggie.

    Lastly, I'll add that a polarity switch is not a cure-all. The truth is, a guitar's signal is inverted many times when going through a pedalboard or amp in many rigs. Enable an effect or switch to another channel on the amp, and that may change the number of times your signal is inverted. If the number of times the signal is inverted changes from even to odd (or odd to even), then the signal will be out of phase. @DeBatz created a thread on this recently: https://www.thegearpage.net/board/i...oughts-on-simple-vs-complicated-amps.2067174/

    As you can see, playing through multiple amps at once and getting great sound can get a bit complex. I use multi-amp setups but I almost always use one amp at a time. I am going after a more "direct" sound, as opposed to layered. For me, layers generally come from other tracks.
     
    Last edited: Aug 13, 2019 at 1:14 PM
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  10. Pete@Morley

    Pete@Morley Member

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    A switching device with an isolation transformer like our ABC Pro would remove the ground loop hum:

    https://www.morleyproducts.com/abc-pro-selector/

    You could also use a HUM-X on the culprit amp, but for your application a good switcher is the way to go.
     
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  11. Mickey Shane

    Mickey Shane apolitical Silver Supporting Member

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    Move the stereo chorus to out in front of the Recto.
     
  12. De Batz

    De Batz Member

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    My experience with the BigShot ABY (I still have it, but it's off the board) is that the iso transformer needs a buffer driving it or it can rob a lot of high end. You can have decent sounds out of two amps with that thing, and even with two at the same time, but if they hum, the iso is too much of a change to the basic sound if everything in the chain is true bypass. I had an MXR boost thing set to unity at the front of my pedalboard (which made a lot of other things with germanium transistors in them sound rubbish, I learned some time later) and never noticed an issue, but then tried to use the BigShot on a fully true bypass board and it was dreadful.

    Having said that, I don't know if that's inherent in the design or if, in some way or other, mine is knackered.

    I've moved on to a Fulltone ABY, which is better as you can switch the buffers in and out. The buffer can make a bright amp too bright, an example being the Cornford (when played through V30s, at least).
     
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  13. eigentone

    eigentone Supporting Member

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    That's the problem tackled by the Drag control on the Radial boxes. Drag is a variable (knob) that loads your guitar's pickups down, which can compensate for the loading eliminated by the buffer. It restores your degrading high frequency rolloff. :p

    Other devices, including wireless packs, have similar functions. Not sure about other switches, but I figure they are out there.
     
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  14. De Batz

    De Batz Member

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    Not on the passive one though! That setup was great, but I mostly used the aby as a silencer rather than for two amps...
    The Twin City was on my list but the fulltone came up cheaper...
     
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  15. eigentone

    eigentone Supporting Member

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    Right, Drag's not a feature on every Radial box. It's more of a deluxe feature. Seems like Radial has 2+ solutions for every use case. Personally, Drag isn't a feature I have ever needed. I just twiddle the guitar's volume and tone controls, adjust my playing based on what I am hearing, and I'm off.
     
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  16. stonem

    stonem Member

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    I think I experienced this last night. I was changing some stuff around per suggestions in this thread and got crazy amounts of buzz. This would be a ground loop correct?
     
  17. stonem

    stonem Member

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    I've been doing some reading on the switchbone v2. I think this is what I'm gonna go with ultimately. Thanks for the info.
     
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  18. stonem

    stonem Member

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    I dont know why I haven't tried this yet lol, never thought of it. I'm gonna give it a shot tonight. I just need a solution until I can get a dedicated switch. Thanks.
     
  19. De Batz

    De Batz Member

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    Actually, I had a thought. When you drive the BigShot with a buffer, all three outputs can be on at once - it has an always-on tuner output, you see. But what you'd lose would be the ability to switch all three on and off at will.

    Just to be clear, the drag control that @eigentone described does the same job as the buffer - it makes the signal going to all the outputs a decent signal - but it seems to be more tailorable so that you don't necessarily get battered by high end (or lose the whole lot, as the iso tranny in the BigShot seems to do to me). So buffer + BigShot (which will be a lot cheaper than the Switchbone!) might be all that you need.

    Does your ABY have a tuner out?
     
  20. stonem

    stonem Member

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    No tuner out on mine. It's a startouch aby, so pretty basic switch. So you mean I could get a bigshot and use a buffered pedal like a boss in the loop to get the same result as a switchbone?
     

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