#1
I've had some major G.A.S. lately with amp heads, picking up 4 within the last 6 months to add to the 4 I already had, and I don't foresee it stopping anytime soon. I already have 2 or 3 others in mind that I'd like to pick up.

I've been doing some research on A/B boxes as I have way more amps than cabs. And I'd like to see what people here have used with success.

It will be primarily, if not entirely for home/studio use. So it doesn't need to be super durable, I don't care if there is noise/pop when switching (doesn't need to be seamless), doesn't need a Y function as I don't plan on running more than one amp at a time, and doesn't need to be able to be plugged in as I'll probably won't use it very much and can get away with using a battery. I really just need something inexpensive that doesn't suck tone to switch between amps in my studio. I would prefer it to have lights to indicate which amp is selected.
#2
I've been using the line 6 unit with my Variax. 1\4 to amp XLR to PA for a long time and it works great. I've been getting a few amp heads my self lately and am considering setting up my Dean Icon (LA baggs bridge) a\b with a mojo diamond and another Valve Jr head. I'm looking at the mxr units. 1\4 jacks and indicator lights. Hoping it fits the bill.
Dean Icon PZ
Line 6 Variax 700
Dean V-Wing
Dean ML 79 SilverBurst
MXR M 108
H2O Chorus/Echo
Valve Junior (V3 Head/Cab and Combo)
VHT Special 6
Phonic 620 Power Pod PA
Wampler Super Plextortion
Line 6 Pod HD
Last edited by scott58 at Mar 2, 2017,
#3
Xander_X, just make sure that whatever you choose loads the amps that are powered up so not to burn up your power amp. If you're only powering one amp at a time, you might consider a patch panel vs an A/B switch. It works just like the old phone patch bays that an operator would use. A snake would work too. I'm assuming what you want to be able to do is take a powered head and send it to one or the other of your amps, in other words, you want to be able to go from amp A to cabinet W, X, Y or Z without having to run cables all over the place? You would only use one amp, but one or more cabs? First, you have to remember that the wires are different for guitar than speaker (you probably knew that), so the impedance matching of any switch would have to be the same.

Instead, wire all of the speakers to ports in a single location and mark the ports. Then wire all of your amplifiers to ports one the same board and mark them. Now the board is next to you, and you only need to patch the port for the amp to the port for the speaker. If you have multiple ports for amps, then you would wire them similarly. This can sound confusing, but lets say you have heads A and B. A has two ports because it can run 2 cabinets and B has 4 ports, because it can run 4 cabinets. Now let's say you have 4 cabinets: W, X, Y, and Z. Cabs W and X have 2 ports and cabs Y and Z only have one. You would take speaker cable and make a patch panel that looks like this:

A1 A2 B1 B2 B3 B4
O O O O O O

W1 W2 X1 X2 Y1 Y2
O O O O O O

This can be done with a crappy piece of wood or an old wooden box and you'll need speaker cable and female 1/8" connections. Essentially, what you've done is move your output and input ports next to each other. Then you just take a short patch cable (be sure it's a speaker patch cable and not a guitar patch cable) and make your connections.

This is how bands and studios that have their heads in racks and cabinets somewhere else, yet do a fast switch if necessary. It would look something like this one, except yours would only be speaker cables as that is what you're doing:



This gives you the most versatility and instant growth in the future. I would make sure I had a couple of connections available on the head and cabinet sides for future growth.

Edited to add: there are companies that will make these for you, but to be honest, you can use blanks and do it cheaper. Some folks have gone to using CAT5 because the patch bays are readily available and cheaper. You can google using Ethernet cable for audio. Here's a quick, interesting article for you. https://www.jeffgeerling.com/articles/computing/2015/everything-over-cat5
Last edited by GoldJim at Mar 2, 2017,
#4
BTW, the spacing I tried to use to line up the O's with the labels didn't work, sorry. Hopefully the pic is more useful than my crappy attempt at a graphic.
#5
GoldJim

LOL. I like to keep things simple. Right now, all I want to do it put two heads per cab, and have a way to switch between them without having to reach behind and swap cords. I will be manually swapping the input cable into whichever amp I'm using. Yes, I do realize that instrument and speaker cables are different. But I do appreciate you trying to warn me. You never know who knows what.

If I play out, I USUALLY bring only one amp and one cab, so it's really a moot point other than for simple home use.
#6
Cool. So, something like this M196MXR M196 A/B Box only you need more outputs and inputs? Problem is that these guys are made for multiple instruments. Hmmm...
Last edited by GoldJim at Mar 2, 2017,
#7
I'm confused. you said you want two heads per cab and switch, but you will be swapping the input cable into the amp. Do you mean that you'll be swapping the input cable to the cabinet you'll be using?
#8
GoldJim

Ok ... so hypothetically, say I only have 2 amps; for simplicity we'll say my 6505 and my XXX. And I only have 1 cab. Then say I have NO effects; just going straight from guitar to amp. Both amps are stacked on top of each other and then on top of the cab.

I can then easily take the guitar input out of one amp and put it in the other. However, it's a PITA to get up and around the back of the cab to swap the speaker cables. So I want an simple A/B switch for that.
#9
Don't use a generic A/B for switching amp heads and cabs. The load there is too sensitive, if something goes wrong with the switching or you hit the switch with the amps on, you'll blow up one or both amps. Not worth it. 
The Radial Headbone is designed for stuff like this, but it's expensive (and for good reason, the safe way isn't simple). 

If it's a stereo cab with enough power handling you can plug one head into each side, perhaps. But this is not a situation for an A/B box. 
#10
Roc8995

I wouldn't have both amps on simultaneously, USUALLY. The idea isn't even for switching up amps immediately. More like, maybe one day I want to play amp 1 and the next day I come into the room and want to play amp 2. Both amps would be set to the cabs OHM rating.

Most of my cabs are 212s with mixed Speakers, so going stereo with them is not really an option.
#11
I still would not recommend it. "Usually" isn't good enough; to be even remotely safe you absolutely have to switch with both amps off, and even then you're trusting that the A/B is direct through and can handle the full output of the amp, which they are not designed to do. 

I get that it's a pain in the ass, but I don't think this is a smart solution. In fact, I'd go the other direction. When I had two heads and only one cab, I removed one of the power cords (they were both IEC connectors) so I had to switch both the power cable and the speaker cable to swap heads. It's slower but it guarantees you're not powering up a head without a load. I think it's worth a few extra seconds to make sure you're not going to smoke one of your heads. 
#12
OK, gotcha. N-Audio makes a solution, and you only need the mono version. If you're in the US, that might be cost prohibitive. Tonebone makes the Headbone Valve Tube Switcher. You and I realize that you're smart enough to turn off the equipment before changing channels, but the solutions proposed assume you're leaving the heads on and the Headbone and N-Audio provide loads so not to blow the amps when disconnected from the speakers. This is really the only "approved" recommendation that I would give.

100% agree with Roc8995, so this next solution is cheaper, but not recommended.

You could use a simple A/B/Y switch where the cab would be on Y and the amps would be A and B. Something like the Electro-Harmonix Nano switchblade which is for doing a myriad of A/B/Y connections, including amps and cabinets. Since You'll be turning things off and switching first, this should fit your needs.
Last edited by GoldJim at Mar 2, 2017,
#13
Careful with the A/B/Y search. EHX was a little weird with the labeling on the switchblade. A/B/Y pedals are just A/B boxes with the Y option being "both" which is a super bad idea in this case. I would not trust any A/B box that does not explicitly state on the product documentation that it is designed to go between head and cab. Not "amp switching." Cab switching. 

Agreed, though - cheaper but not optimal. 
#14
The bottom line is this: if the Tonebone Headbone gets bumped and you switch accidentally, no harm, you just chose the other amp, which might not be on, but the powered amp is still under load and won't burn up. The A/B/Y solution gets bumped, you could potentially blow out your head. We're not talking a couple tubes, we're talking "may as well buy another one" burned out. No one wants to give you the wrong solution. It's why people use loads and patch panels or switchers like the Headbone or N-Audio.

All that said, it's your gear, we're just trying to give you good advice.
#15
And THIS is why I do my research and ASK first. I think I'll just take the time and swap for now. It just means I have to keep a step stool in the room to reach over them.

I may invest in one of the Headbone at some point. It just seems like a lot of money to spend on a convenience.
#16
Quote by Roc8995
Careful with the A/B/Y search. EHX was a little weird with the labeling on the switchblade. A/B/Y pedals are just A/B boxes with the Y option being "both" which is a super bad idea in this case. I would not trust any A/B box that does not explicitly state on the product documentation that it is designed to go between head and cab. Not "amp switching." Cab switching.   Agreed, though - cheaper but not optimal.  


Looking at the drawing for the EHX, unlike others that explicitly say that they will do both A & B, their electrical drawing and write up indicate one or the other, not both. Wouldn't hurt to hit the switch and take a measurement to see if there's ever an A and B position with a multimeter.
#17
I couldn't let it go w/o doing a little more digging, now knowing that I have to look for what you all have mentioned. I'm being told that I could use something like an EHX as long as I keep the amp not in use in Stand By, if not off completely.

Does this sound feasible?
#18
 Feasible, yes. Still wouldn't suggest it, but it's your gear. If you're confident that you'll never mix it up, and the box you get can handle the amp's output, it is a solution. 

GoldJim 
You misunderstand, A/B/Y boxes have two switches, so your options are (a or b) or (both). The EHX does not do this, they just labeled the output strangely. It's not an A/B/Y box and shouldn't be called one. It's an A/B that happens to have the letter Y printed on the top. 
#19
I agree with Roc8995 here. Be very careful or else you will let out the magic smoke that made your amp work and your wallet full.
Guitars:
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Amps:
Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
#20
Quote by Xander_X
And THIS is why I do my research and ASK first. I think I'll just take the time and swap for now. It just means I have to keep a step stool in the room to reach over them.

I may invest in one of the Headbone at some point. It just seems like a lot of money to spend on a convenience.


It's a lot more money to fix an amp (or two) that have been fried because you accidentally forgot to turn one off before turning the other on, or because you forgot to connect the cabinet before trying to blast a power chord.
#21
Quote by Roc8995
 Feasible, yes. Still wouldn't suggest it, but it's your gear. If you're confident that you'll never mix it up, and the box you get can handle the amp's output, it is a solution. 

GoldJim 
You misunderstand, A/B/Y boxes have two switches, so your options are (a or b) or (both). The EHX does not do this, they just labeled the output strangely. It's not an A/B/Y box and shouldn't be called one. It's an A/B that happens to have the letter Y printed on the top. 


Yeah, I was just reading the letter designations on the box. I'm not sure why they labeled Y the way they did except to maybe show that it was either in or out. One could plug a guitar into Y and go out A or B, or one could connect a guitar to A and one to B and go out Y to the amp. Who knows. I realize the box is A/B.