#1
Hey guys,

Just wondering if it's possible to A/B any amp? Or is there a specific feature that an amp needs to be able to A/B'd?

Reason I'm asking is because I love my Orange Jim Root Terror to absolute death and would hate to lose it's single channel of glorious distortion for an amp with 2 ch.

Also - any suggestions for cheaper amps ($AUD 200-500) with decent cleans to A/B with? Not concerned about headroom - I rarely go above 2 as it is on my amp unless I'm jamming with a drummer.
Quote by SlackerBabbath
My ideal woman would be a grossly overweight woman who would happy go jogging, come home all sweaty and let me put my dick under her armpit while she shuffles a pack of cards.

Stay classy, pit.
#2
Depends how you want to run it.

If you are planning to use 1 cab then you will need a head switcher.

2 cabs then you will just need an AB pedal at the end of your chain.
My Rig:
Maverick F-1, Ibanez RG1527, Schecter Omen 8
Marshall JVM 410H,
Hand built 4x12 w/ V30s
Current board:
PXL LIVE
TU2
WHAMMY IV
MXR M132
MXR M101
TIMMY
NS2
MXR M108
XOTIC EP
TC DREAMSCAPE
DL8
#3
Used Fender Hot Rod Deluxe or Ampeg GVT52-112. Both have gorgeous clean channels.
Squier "VMC" Stratocaster
PRS SE Singlecut
tc electronic polytune
CMAT MODS Signa Drive
Blakemore Effects Deus Ex Machina
DIY gaussmarkov Dr. Boogey
EHX Small Clone
Mooer ShimVerb
DIY Beavis Devolt
T-REX Fuel Tank Chameleon
Ampeg GVT52-112
#4
A simple A/B pedal will allow you to switch between amps, put it after all your effects just before the amps. As stated above that will work if you have two combo amps or two separate speakers for the amps.

If you are planning on two heads sharing the same speaker you can also make that work. First make sure they are both running out to the same impedance speaker, you may have options on the back to choose from, if you can't choose a matching impedance for the amps then you will need two speakers.

Assuming you have matching impedance and you want to run to one speaker you will need to make, or buy, a speaker switch. Making one is pretty easy you just need a DPDT switch and some jacks. ***Note that you can't use a standard A/B pedal for switching speakers unless all it has in it is a DPDT switch, a lot of A/B pedals will have buffered outputs and if you put that between the heads and the speakers it will damage your amps because they are looking for a set impedance load.**

With this operation you would have to hit two switches to change amps one switch to change the amp input from amp A to amp B and one switch to change the speaker input from amp A to amp B.

I would suggest you get a little fender or vox combo for your clean and then all you need is an A/B pedal.
#5
The Fender Hot Rod Deluxe is a great combo. I've seen them for as low as $300 used which is a steal. Usually run around $400 on the used market which is still a great price. Get one of those and an AB pedal and you're set. I used the Whirlwind ABY which also allows you to use both amps simultaneously.
#6
Alright - seems like A/B with a combo amp is the way to go. Cheers lads.

So the A/B sits in the effects loop... Does this mean that both amps will require an effects loop?
Quote by SlackerBabbath
My ideal woman would be a grossly overweight woman who would happy go jogging, come home all sweaty and let me put my dick under her armpit while she shuffles a pack of cards.

Stay classy, pit.
#8
I've got a simple passive ABY box schematic if you want it.

As for the amp, HRD, Blues Jnr, JTM45 clone. The VK has pretty nice cleans too. Well, if you swap out the speaker.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#9
I was recently watching phil x, he has this AB box that also has a thing to reverse polarity (I think that's right) so you can run both amps at the same time with both speakers moving in the right direction, in phase.

That seems like a pretty cool feature.
#10
Yeah man I've seen Phil do that too. ****ing rad. Was that the one where he did it with the AC30 and his sig amp?

Cath I'd love that schem if you could post it here.
Quote by SlackerBabbath
My ideal woman would be a grossly overweight woman who would happy go jogging, come home all sweaty and let me put my dick under her armpit while she shuffles a pack of cards.

Stay classy, pit.
#11
One of the amps was the evil robot, he was in the UK at andertons music shop with chapman and the captain. Talks about his gear and stuff including the AB box he uses.

Hell of a tone he gets, I want to do it with the blackstar HT5R and a peavey classic 50 212 lol, bit different but I'm sure it'll sound good all the same
#12
Here ya go.



The battery is just for the LED's. The 10M resistors are for anti pop.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
Last edited by Cathbard at Dec 17, 2014,
#13
That's sweet Cath - thanks heaps.
Quote by SlackerBabbath
My ideal woman would be a grossly overweight woman who would happy go jogging, come home all sweaty and let me put my dick under her armpit while she shuffles a pack of cards.

Stay classy, pit.
#14
I've used a A/B switch for years, for dual amps and now I use it to run into both channels of my Super Reverb and set them for different tones.

The one thing you'll have a problem with running dual amps is ground hum. Use a ground lifter on one amp to lessen that. that's the plug you plug a grounded cord into and it has no ground pin, normally for using a grounded plug on older outlets without ground holes. NEVER break off the ground pin of your amp's plug. Get a ground lift adapter and use that.

You get the hum because using 2 amps sets up a ground loop. Removing the ground from one solves it, but you also risk getting shocked.

Be sure and check before you play to be sure nothing shocks you, usually it's pretty mild, but if you get a shock, most tube amps have ground reverse switches. Try different combinations till you're not getting shocked. It's no fun to touch your lips to a mic onstage and get hit by a shock from a bad or reversed ground somewhere...I started using a foam wind screen on my mic to eliminate that and the pops I get now and then from P's and B's when singing.
Hmmm...I wonder what this button does...
Last edited by Paleo Pete at Dec 18, 2014,
#15
Just run the AB switch at the end of your effect chain (before any amps, not in the loop), run A out to your Jim Root Terror and whatever cab it's plugged into, run B to a new clean amp. Done. As for a clean amp, like everyone said, the Fender Hot Rod Deluxe is a great little combo, which would be pretty much perfect. It also has two OD sounds (a gain channel with an extra "more gain" switch), both of which will be wildly different OD tones than your Terror. So that'll be cool, for more tone options. Or, if you're only ever going to use cleans from the extra amp, and you don't need it to be very loud, you might even just get a Blues Jr.
#16
@Pete a bit of buzz isn't of huge concern to me. If I was going to record I'd be plugging in the amps individually anyway. Ground lifting + potential for shock just seems risky for a bit of buzz. Thank you for the info though.

@bi cheers mate. Blues Jr seems like the go atm but I'm having trouble finding one cheap here in Aus.
Quote by SlackerBabbath
My ideal woman would be a grossly overweight woman who would happy go jogging, come home all sweaty and let me put my dick under her armpit while she shuffles a pack of cards.

Stay classy, pit.
#17
Your call, but it's enough buzz to be annoying, especially onstage. I'm not talking just a little hum like when you turn on a distortion pedal, it's enough to be worth doing something about it. You'll see when you plug in two amps...

The electrical shock is usually pretty mild, but enough...no any...is enough to worry about. It can usually be eliminated by working with the ground reverse switches. One thing I've been meaning to try is the outlet on the back of my Super Reverb, never used it and it might work better. Since one is plugged into the other it might not create such a bad ground loop.
Hmmm...I wonder what this button does...