Playing through a two-amp setup

Discussion in 'Amp Central Station' started by heshan, Jan 17, 2018.

  1. heshan

    heshan Tele-Meister

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    Hi guys.
    Lately I've been very interested in playing through a multiple amp setup, especially after watching That pedal show's episode on it. I just have a few questions about it though

    First of all, I have an AC15 and an Orange micro terror, and I want to play through both of them together (not switch between them). The last pedal on my signal chain is a Flashback delay with stereo outs, so I thought I could go out into both amps directly through this

    I do know about the noise issues that I would encounter, but I read some people talk about safety issues with using two amps, but that's only if I remove the ground from one of the amps, right?

    Basically, my first question is: if I want to just experiment playing through two amps, and both these amps are grounded (they both have the ground pin on the socket), and I connect to both amps from the Flashback stereo outs, it'll be perfectly safe?

    Second question is, what do any of you guys personally use to hook up your rig to two amps? I read about isolated ABY boxes etc. but any recommendations (especially on a budget) would be great! The GigRig Humdinger looks pretty good - the only thing is that it doesn't allow you to switch between amps, which would be a nice option to have in case I wanted to do that

    Oh one more question actually: The solution of using a device to isolate the second amp, using an isolating transformer...this has nothing to do with the way I plug my amp into the wall socket, right? It's simply using a transformer to isolate the signal?

    Thanks guys! :)
     
    Last edited: Jan 17, 2018
  2. nojazzhere

    nojazzhere Doctor of Teleocity

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    I rarely go to the trouble, but last pedal in my chain is a stereo chorus. As far as grounding, I know both my amps are "wired" correctly and they both have 3-prong plugs. I plug them into the same a/c outlet, so I know the ground, hot, and neutral are the same. If you're worried about electrical shock, use an extension cord with an integrated GFI.
     
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  3. FenderLover

    FenderLover Poster Extraordinaire

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    Start off simple by plugging both amps into the same outlet or power strip. Chances are you'll be fine and won't have to go any farther. As safe as safe can be. As long as one amp (Main) has the 3-prong power cord the player will also be safe if the Amp 2 ground is lifted with a cheater plug (if necessary, and only if necessary). This is because the shield connections on you cables are still directly connected to the Main amp with the 3-prong cord, and Amp 2 has its own fuse. It may not protect Amp 2 in a catastrophic failure, but the player is still safe and a catastrophic failure is pretty unlikely. I've been doing this for decades. If you don't like to gamble or are fearful, get out your checkbook and visit the Radial website.
     
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  4. JustABluesGuy

    JustABluesGuy Friend of Leo's

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    If both of your amps are grounded it will be safe, but you might get a ground loop (60 Hz hum) or speaker phase issues.

    A stereo pedal “might” work if you’re lucky (try it if you already have one), but the previously mentioned issues are very likely, and it will be stereo, but without the switching capabilities.

    A good AB/Y pedal is much better, and required if you want to use one amp, the other or both. I found a Radial ABY that handles all of that used on ebay for a very reasonable price.

    Hope this helps. Good luck!
     
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  5. heshan

    heshan Tele-Meister

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    @FenderLover Yes I'm pretty fearful when it comes to electrical stuff haha. But thanks for the info. One question on that, which amp would be my main amp? Or is the main amp simply the one on which I keep the three-prong cord?

    @JustABluesGuy Yes I am expecting noise and phase issues but just thought I'd experiment with my Flashback stereo outs, before spending on a Radial ABY or similar. But I think I probably will have to get something like that in the end. I just checked, the Radial ABY sells for $99? That's cheaper than the Humdinger!
     
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  6. ebb soul

    ebb soul Poster Extraordinaire

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    You want the amps in phase. This wont happen thru a stomp pedals sterio
    I run two amps myself, dirt on one clean on the other.
    Often simultaniously. But I far preffer to be able to switch between them.
    I use a fulltone ABY, no reason to scrimp here.
    Has ground lift and phase. Both important.
     
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  7. FenderLover

    FenderLover Poster Extraordinaire

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    You got it.
    Ebb soul is also right about phase, although I've had good luck with stereo pedals. Just something to be mindful of if things sound dull, or a little 'off' somehow. The main thing about power and grounding though is hum and noise, so that's a different thing that is easier to recognize.
     
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  8. heshan

    heshan Tele-Meister

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    Thanks guys. Yeah I guess it doesn't make sense even trying going through the Flashback stereo outs, but I thought about experimenting and just wanted to make sure it's safe with both amps grounded via each 3-prong cord! Haha. I might still give it a shot though!

    Regarding ABY boxes I think the Fulltone is out of my budget! Any other options, along with the Radial (which is more in my price range I think)? Thanks!
     
  9. ZenGuitarist

    ZenGuitarist Tele-Holic

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  10. TokyoPortrait

    TokyoPortrait Tele-Afflicted

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    Hiya.

    No help with the safty issues, sorry. However, I can point you to That Pedal Show for wet dry and stereo use.

    A search of their YouTube channel will bring up quite a bit of stuff on running wet dry rigs with two amps. You could start here. There is a fair bit oth other related stuff here too.



    Hopefully of some help.

    Pax/
    Dean
     
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  11. jvin248

    jvin248 Poster Extraordinaire

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    I keep meaning to try out two amps and build one of these pedals to do it.


    This should be the video Phil X talks about running two amps


    .
     
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  12. sergiomajluf

    sergiomajluf Tele-Meister

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    I’ve run a stereo rig for a long time. Never thought about any of the problems, but 99% of the time both amps where on the same AC outlet. I’ve mixed valve and transistor amps, and many other hacks.

    My “splitter” was a Boss chorus. One out was always clean, the other toggling between wet/dry.

    I had a delay after the chorus, on the clean line, because when used in stereo, my Ibanez delay would only output signal when active, and the other output was always clean.

    Just plug your stereo pedal and experiment.

    Another idea would be go into amp1, then use the FX loop for the pedals, and then return one channel into amp A, and second channel into amp B, either front jack or even loop return.

    Many many different possibilities!!!
     
  13. heshan

    heshan Tele-Meister

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    Thanks guys. Comparing the Radial Bigshot ABY and the Twin City, the Twin City is buffered, does that make a big difference?

    @TokyoPortrait That's one of my favorite shows, I've probably watched the episode but I'll check it out again, cheers

    Thanks again
     
  14. Ex-riverman

    Ex-riverman Tele-Holic

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    First of all, I’ve never had a problem running into two amps - for better or worse, I never thought about it.... I’m wanting to put together a better stereo setup. I have stereo pedals that I run into a vox ac15 and a monoprice 5w tube amp (or a mixer into my computer). It works well enough for messing around with but I either want two of the same amp or a Roland jazz chorus 22 with two cabinets.
     
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  15. ozcal

    ozcal Tele-Holic

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    i use a startouch ABY... vox ac15 into a 2 x 12 cel blue & g12h30 and a hh ic 100c (70s english 2 x 12 solid state combo)... love it...
     
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  16. knockeduptele

    knockeduptele Tele-Meister

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    I run a similar setup - stereo TC Flashback x4 right on the output of my board with its output split into a Deluxe and Supersonic. The only time that version of the pedal becomes real stereo is when its running in ping pong mode, I do however run an AB box in front of the Flashback and since that version is also a stereo looper using both paths through the pedal allows you to do all sorts of amp and sound switching - eg you can put the rhythm track through the Deluxe for cleans and lay the lead part through the supersonic on the vintage burn - loads of fun to be had and i also modded the AB so it grounds the unused output go keep the noise down.

    Regarding grounds - it's a real safety issue - i'm in the UK so we have much higher AC voltages flying around (240v) and things can become lethal very quickly - the effects pedals are not really grounded - most wall wart PSUs over here have a plastic pin for the ground prong (take a meter and buzz yours through you may be surprised at what you find) so you cannot rely on it being your main system ground as it is effectively floating.

    So two amps both with mains grounds on will give you hum, but the level of it much depends on how your local electricity company bonds neutral to earth - the UK is unbonded, Europe is mainly bonded and in the US last time I was touring there it (which is now more years ago than I care to think) it varied dramatically across the continent and you would sometimes find balanced 55 volts around the ground (still 110v Live Neutral) So this is why the same power strip trick works for some but not for others.

    I lift the AC ground on the Supersonic to get rid of the earth loop to make it all quiet, but do so by inserting a 6" extension lead that has the AC ground lifted, so it becomes a conscious effort to lift the ground, I also apply the rule of no amp patching while they are turned on - two guitar cables into amps one ac ground lifted - one in each hand is full AC straight across the heart and death - many many musicians have died that way usually between grounded mic and un-grounded amp - hand on the guitar strings hand on the mic - bang shock straight across the heart and you cant let go - its not just the amp environment that you have to consider

    If you are gigging you also have to consider the venue and the integrity of the venue ground - did a club gig on beach in texas and half way though the show all the gear went live as the tide went out and the ground stake ended up in dry sand as the water table dropped.(did the first stadium tour of India back in the early 80's and my core job was to stop the band and crew being electrocuted but that's another story)

    No jazzhere's comment of using a GFIs (we call them earth leakage circuit breakers over here) is essential if you are the slightest bit unsure about what you are doing if you lift AC grounds

    The Gig rig box is a good solution just to put in one of amp lines to isolate it rather than use as a splitter meaning all ac grounds stay on and my next act after hitting the post button will be to order one as the post has raised my awareness and i want to live.

    Sorry to go off on one (wont talk about phase on multiple amps setups cos i'll write another three pages) but lifting AC Grounds is a huge huge safety issue and it would be nice to make sure all members (and others) don't get killed doing the stuff that we love.
     
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  17. heshan

    heshan Tele-Meister

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    Thanks for all the replies! And thanks for the interesting post, @knockeduptele :) I know I'm just going to stay safe and not mess with anything related to the power of my amps haha. It's 220V over here too!

    If at all, I might just hook up both amps via my stereo pedal, just to experiment and see what the noise/phase issues are all about. But I'll definitely be getting one of these A/BY boxes as soon as possible!

    Would someone be able to explain what the ground lift on one of these A/BY boxes does, though? I know both amps remain grounded, right? That's why it's safe. But what does it mean when the A/BY box says its lifting the ground on one of the outputs?
     
  18. FenderLover

    FenderLover Poster Extraordinaire

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    The idea is that each amp has their own ground plugged into the wall, but the chassis are tied together by the cables in your rig forming a physical loop in the ground connection that can sometimes cause hum. The ground lift on one of those splitter boxes breaks the ground loop in your cables by connecting the signal with a transformer, and you are left with one ground path to the other amp.

    The connection is made with a transformer either way, but the ground lift disconnects the transformer from the chassis to provide isolation from ground on the second (third, fourth...) output. By calling one amplifier 'Main' again, the 'chassis' in this case is the Main amp still wired to your rig, and you are lifting the grounds to isolate ground paths to other outputs/amps.

    I have built several splitter boxes with isolation transformers, and I don't even wire in a ground lift switch. I just leave the outputs isolated (permanently ground-lifted) because the the Main output is always connected (no transformer), as would normally be the case when plugging straight into an amp.
     
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  19. SacDAve

    SacDAve Poster Extraordinaire Silver Supporter

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  20. nosuch

    nosuch Friend of Leo's

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    Did you even try it? Gives you a lot of sexy stereo delay options and that‘s what the stereo delay output was designed for. I wouldn‘t hesitate to use it.
     
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