Amp Switching?

[rccCrawler]

I'm considering getting another 50w VM head, and I'm trying to figure out (from a position of ZERO experience) what this will work like in a live situation, if I set it up for an amp switch A/B.

I currently have a 50w head, and 2 2X12 cabinets (greenbacks). I leave the head at our practice room. I bought the 2nd cabinet so I wouldn't have to haul the cabinet back and forth. That made it a lot easier. Then eventually I got tired of hauling the head back and forth, so I just leave it where it is (it is in the drummer's house and is quite safe). Now all I have to take to rehearsal is my guitars.

Plus I thought I can hook up both cabinets when we play live, for better 'personal monitor' sound.

Naturally, now my sound at home for practicing sucks.

More importantly, when I practice at home, a lot of that centers around the control manipulation that I need to do, such as turning off and on certain effects, and most of all getting use to pup and vol changes within a song. My home setup does not even come close to reproducing the dynamics I get with the VM head, so it is very hard to practice this because it is not responding like the live setup exactly.

So I am thinking of getting another 50w head for home. This way, I will have the same setup at my house as I do live, and I can practice the parts correctly. When we play out, I will have a backup head (currently I cross my fingers).

Then I got to thinking that when playing live I could set up an amp A/B, and set up the second head with a bit of a volume and detail boost, and voila! I'd have a 'solo boost'.

However, I've never used an amp a/b before, so I have some questions:

1. What kind of switch should I use? Tonebone?
2. Is the switching silent and seemless? ie: if it pops or delays when the switch is made, it would be useless for this function..... right?
3. Is it OK to leave the amp that is NOT being used connected up this way - ie: it won't hurt it, as long as it is still plugged into the cabinets, right?
4. My cabinets have 2 inputs each (16 ohm cabs, if that matters). So I am assuming it would be OK to plug one head into each input, and only having one head driving the cab at once.... right?

Any experience in this type of setup would be appreciated. Sorry for the newbie questions.

[gitarenkraak]

what you need is a tonebone headswitcher, you can safely use two heads into one cabinet 8)

[rccCrawler]

OK, I just looked that up. Looks good, except..... it only allows the use of one external cabinet.... I suppose there is some sort of splitter to drive two cabs from the one output.....

can anyone who has used this pedal tell me if there is any switching noise or delay when switching? Is it suitable for switching mid-song?

[kissfanps]

I am a little confused. You want to switch between heads and use 2 2x12s together with each head?

[rccCrawler]

Correct.

After reading up on the head switcher from tonebone, i'm thinking there should be an easier way to do this. I don't like the delay that supposedly is induced when switching heads.

The connections are actually not difficult, because my cabinets both have 2 inputs. So I would connect both cabinets to both heads. Again I am assuming this will not induce a problem, as long as only one head is actually actively driving the cabinets at once.

So all I am really switching is the INPUT, from one amp head to another. I want to do it instantly (no delay), with no switching sounds.

Sounds simple, right?

My buddy runs a similar setup, but he does it by using a stereo chorus pedal, which allows the use of A, B, or A+B amps. That would be OK with me as well, except that it might be a tonesucker.

[spikei]

hi, if you plug in to a 2x12 cab like a 1936 for eg, at 16 ohms, i think you only use one speaker. you need to check that out.

[rccCrawler]

Yes, that's true on some cabinets, but on my avatars, they are both wired the same. I will check by I'm pretty sure there is just 2 inputs to the same speaker wiring.

I just checked out Loop Master. I think all I need is an A/B switch. However, I'm concerned by two things:

1. Popping noises when switching channels
2. Ground hum or other such noise

Anyone ever simply use an A/B switch to switch between two amps? Is it possible to switch mid-song without popping or other switching sounds? Did you find ground and/or hum problems were induced when using this setup?

[kissfanps]

You are going to need more than an AB in this case because you are switch loads from one head to another. You can't run an amp with out a load attached or u will probably blow the output tranny. You will need some sort of dummy load, which is where the tonebone (or something like it) comes in.

[Riffraff]

Just use one cab with each head and you can use a simple A/B switch. I'm doing the same thing right now with my 2266 and a 1959SLP-RI. No noise, no popping and instant switching when I stomp on the pedal.

[kissfanps]

Just use one cab with each head and you can use a simple A/B switch. I'm doing the same thing right now with my 2266 and a 1959SLP-RI. No noise, no popping and instant switching when I stomp on the pedal.

Yes that is the simple thing to do, but I think rcc wants the benefit of using one 2x12 for the crowd and the other as his monitor

[kissfanps]

I think this may work
Set each head to 8ohms
plug both into the tonebone set to 8ohms
take the out of the tonebone and split it using a PARALLEL splitter
pop each split signal into the 16ohm mono jack on each cab

Anyone?

[rccCrawler]

Kiss is right, i want to use both cabs with both heads.

Kiss, when you say you cannot run a head without a load, do you mean an INPUT load, or an OUTPUT load?

As both heads are constantly plugged into both cabinets, in effect don't they both have an OUTPUT load on them? I know you cannot run a head without a load connected to the speaker output, but in this case, isn't there always a connection to a speaker output for both heads?

But if you mean a load (signal) on the INPUT to the amp, then you are right - one head would always be getting no input signal ....... this represents a damage problem for the amp not receiving the input signal?

Thanks again for anyone's help.

[surfnorthwest]

I use a Voodoo Labs Amp switcher, it is a excellent piece of gear. The switcher allows for up to four different amps to be used individually or at the same time.

Simple take head 1 and hook it up to the cabinet you want and select the proper impedence, do this for amp 2 next. Then place the amp selctor as the last thing in your chain.

Guitar>effect boxes>Guitar input on Amp Slector>

then run a seprate cable to each head from the outputs of the amp selector. Fire up both amps and use the amp selectors footswitch to toggle between each amp or to run them together for a stereo effect. There is no added noise from this and no pops/clicks when changing. You also can adjust the output to each amp on the amp selector. IMO it is exactly what you are looking for.

[kissfanps]

I mean a load on the output of the head (i.e. the speaker).

I don't think it is wise to have two amps running on the same load at the same time, which is what you are talking about doing. I am not too sure what happens, but it sounds like a problem.

In any event, you need to make sure how your cab is wired. This depends on the impedance of the speakers. Chances are your speakers are 16ohms. When you only plug into one of the jacks you are running the speakers in parallel making the total impedance 8hms (so your amp should be set to 8 ohms). When you have a cable in each jack, the connection is probably broken so you can run stereo (ie. two amps each set to 16ohms). This is of course based on the assumption that your speakers are rated at 16ohms. If they are rated at 8ohms the wiring probably differs.

[kissfanps]

I use a Voodoo Labs Amp switcher, it is a excellent piece of gear. The switcher allows for up to four different amps to be used individually or at the same time.

Simple take head 1 and hook it up to the cabinet you want and select the proper impedence, do this for amp 2 next. Then place the amp selctor as the last thing in your chain.

Guitar>effect boxes>Guitar input on Amp Slector>

then run a seprate cable to each head from the outputs of the amp selector. Fire up both amps and use the amp selectors footswitch to toggle between each amp or to run them together for a stereo effect. There is no added noise from this and no pops/clicks when changing. You also can adjust the output to each amp on the amp selector. IMO it is exactly what you are looking for.

The voodoo is cool device for a multi amp set up. However, the problem here is that rcc want to have sound coming out of both 2x12s all the time and that sound supplied by one amp at a time.

Edit: This means the switching will have to take place on the output of the amp not the input. But a device to split the guitar signal to the input amp will be needed to avoid ground loops.