Using a stereo cab with two heads

[backyardburial]

Hi all, I couldnt find this in a search, but can someone just clarify ohms settings etc if I want to plug in my Single rec head AND my triple rec head into my recto 4x12. I have just got the triple and hopefully I can switch between each head with my AB box in order to really compare the differences between the heads, thanks alot!

 

[fluff191]

You will use the 4ohm output on each head.

 

[coppa]

I would love to hear what you think about the differences between the two

 

[backyardburial]

hmmm, well I plugged the amps into two different wall sockets, and there is massive hum when both amps are on, but I thought this might happen, however Im only getting sound through the single recto. There is buzz from the triples lead when I touch the tip, but no guitar coming through. Any ideas?

 

[stephen sawall]

As for comparing the amps .... every tube and speaker has it's own sound. Even if they look the same.

 

[backyardburial]

Stephen, thanks for that, I had no idea I could turn off the ground. Im pretty sure I have it right, just going from 4 ohm on each amp into the two stereo inputs on the cab. As for the ground thing, I cant see where I turn it off. Do I need to get into the amp to do that? Cant see a switch or anything. Anyway, comparing the two amps: They both have the stock mesa 6l6's and are going through the same recto cab, though tonight they will be going through one recto cab each. I am the proud owner of two half stacks for about two weeks, buy then the single is being sold to pay for the triple

 

[stephen sawall]

On my Tremoverb it is right by the power chord and fuse on the back.

 

[backyardburial]

ahh, you mean just plug into the wall with a two pin ext. cord? that makes sense, cheers

 

[backyardburial]

In the past I have used two amps one marshall and one mesa,each with their own cab, there was a hum but not this bad. I was always a bit worried as our whole jam room runs off two sockets, so they are obviously on the same circuit, but I was also worried about drawing too much power, nothing has happened yet tho....

 

[stephen sawall]

You may have more of a problem ? With the hum.

You want to make sure your amps gets enough power. If they do not they well over work and that can cause a lot of damage to the amp. A lot of smaller power chords do not handle enough power. You want a extension cord that is as thick as the one coming out of the amp.

 

[YellowJacket]

Do you really want to run a 150watt head through a pair of 60watt speakers? I smell cooked voice coil.

 

[sekunda]

I am having a similar ground hum problem... I am running a Roadster head on an open-back 4x12, and a Trem-O-Verb head on a Traditional Rectifier 4x12. I am running a stereo delay pedal with separate A/B sends to each amp for a sweet stereo delay effect, but when the secondary rig is turned on, I am getting the worst hum imaginable. I have tried the ground switch on the Trem-O-Verb in all 3 positions, using different pedals with and without power supplies, so on and so forth with no acceptable solutions. Yet. If you guys have any ideas, please pass them on, and I will let you know if I find any solution that cures it.

 

[backyardburial]

Yellow jacket, I never thought of that, as it turns out I left AB box behind anyway so couldnt hook it up anyway, ended up just jamming with the TR through two cabs. My drummer, who never knows when I have any new gear noticed that his ears were "vibrating" haha, he noticed new amp this time...Im positive neither amp has a ground switch which is a pain in the ***, I think the single is quite old, but the triple is quite new, so who knows when they started putting them on the amps?

 

[stephen sawall]

I am having a similar ground hum problem... I am running a Roadster head on an open-back 4x12, and a Trem-O-Verb head on a Traditional Rectifier 4x12. I am running a stereo delay pedal with separate A/B sends to each amp for a sweet stereo delay effect, but when the secondary rig is turned on, I am getting the worst hum imaginable. I have tried the ground switch on the Trem-O-Verb in all 3 positions, using different pedals with and without power supplies, so on and so forth with no acceptable solutions. Yet. If you guys have any ideas, please pass them on, and I will let you know if I find any solution that cures it.

Welcome to the forum.

 

[backyardburial]

so apparently these 3-2 pin cords are illegal to use in New Zealand! Guy at the shop said I need an isolation transformer, as if I need more **** to lug around! I think I need to stick with one head after all this, thanks for your replies tho all!

 

[Leng]

I use multiple amplifiers as well.

Back when I used two, I experimented with trying all the cheap A/Bs before going for the VooDoo Lab Amp Selector - and I'm sorry to say this, but they all added hum / distortion / a variety of other tonal changes to the amps.

The VooDoo Lab Amp Selector is the only thing that works, and it works flawlessly. It has a ground switch for every output, four outputs, and two inputs. It doesn't color tone at all, and it doesn't add any hum when you get the grounds properly selected.

If you're going to be spending thousands of dollars on amps and cabs and guitars, and hundreds of dollars on effects, you would be out of your mind to use a tone-coloring bone switch or A/B.

And LUCKY YOU! You can get the **** thing for $70 less than myself and many others had to pay for it.

By the way, you should not be plugging any amps into separate outlets if they're all being run by the same guitar, even if those outlets are on the same circuit. In other words, don't use a three-to-two prong adapter. All of your effects, racks, amplifiers, etc. need to be plugged into the same power conditioner.

 

[sekunda]

Welcome to the forum.

You may want to try one of them 3 to 2 ends that are in the google link I have above. This worked for me. The ground lift on my Tremoverb did not.

Thanks for the advise. I ended up just going back to the Trem-O-Verb head and running both cabinets off it and ditching the stereo delay. It just works so much better and its about 60 pounds lighter to take to a gig as well.

 

[backyardburial]

Hey Leng
Thanks a lot, so its cool to run two amps off a four plug? I always thought that was creating the hum, being on the same outlet, but if it's best to do that then it makes it easier.
That box looks pretty sweet, but cant really get one as of now. I'm pretty sure my AB box doesn't affect tone much, but think the original problem I had was putting two heads into one cab, Ill just use two cabs! The ground select on four outputs sounds awesome though, hopefully I'll see one used (probably not in New Zealand though!
Cheers

 

[Leng]

If you don't have a power conditioner, I'd recommend using at least a high quality surge protector. But yes, both amps and all effects should be running off the same outlet, ideally the same conditioner. Most ground loop problems are caused simply because amps are plugged into different outlets.

The back of the Amp Selector looks like this:

The ground lifts are necessary, regardless of whether you're using 2, 3, or 4 amplifiers. I won't go into the details of 3 or 4.

But if you're using 2 amplifiers, you would keep three of the switches in the down position, but flip either the 1 or 2 ground switch into the up position (lifting the ground for one of your amps) and, if you have your amps on, magically hear the hum coming through both your amplifiers instantly subside to absolute silence. And then many wide smiles will be yours as you unleash the tonal possibilities of blending two amplifiers. When running two amps, my favorite thing to do is use a pan pedal - have my Recto on a raunchy modern mode and my Crate on a clean, shimmery tone - then pan between them, giving me the option of going from balls out distortion to none at all smoothly, or staying somewhere in between for certain parts of songs. The effect is simply to die for.

Anyway, all of this information was given to me years ago, and I was not at all happy about it. I still, despite having been warned, tried basically every cheaper A/B in existence along with many different ways of eliminating ground loop hum. And I can tell you, this is the only thing that works and won't damage your amplifiers or totally wreck your tone. And not only will it not wreck it, it won't even touch it.

:!: Just to warn you again, do not plug expensive amplifiers into three-to-two pin adapters. :!: I know this from hanging out in a house full of musicians who don't even have ground holes on their outlets, so they use these adapters on all of their equipment, and it's not pretty how much damage can be done. What's being said here about plugging amps into three-to-two's is a cheap way to fix the ground loop hum problems of having to plug your amps into two different outlets, when the reality is that you should invest in a power conditioner or, at the very least, a good surge protector and an amp selector.

 

[bduersch]

Another consideration (if you want to run both heads in parallel all the time, not necessarily switch between them) is to get an Axess Electronics BS-2 buffer... it has an isolated output to prevent hum and also has a handy phase reverse switch in the off-chance that the amps are not in phase with each other.

--B