2 heads to one stereo cab?

  • Thread starter Thread starter Dan G
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Dan G

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Right, I have researched this as far as possible and read all sorts of responses. I'm looking for a definite answer from someone with good knowledge of impedences etc:

Put simply, I have a Mesa stereo 4x12 cab, the mighty VH4 head and a Peavey 6505. For years my live rig has consisted of the VH4 and Mesa cab, but I also really like the tone I get from the 6505. As far as I am aware, the heads and cab are 4,8 or 16ohm. I usually run whichever head I'm using at 8ohm.

Using (say, a Morley) A/B/Y box, can I run both heads into the cab and run them both at the same time?

Or will this damage the head(s)?

I'm looking for a definite answer rather than guessing.

Thanks a lot in advance for any answer or suggestion regarding any of this!

I know the best solution would be to buy another cab (which is something I am considering)
 
Sorry, I don´t know the right English expressions
but the speaker will delete some frequencies by
thierselve.
You maybe will be out of phase with the two amps.
 
Radial Headbone Tonebone VT is the correct solution.

Your Morley will cause a ground loop, the unit above is an A/B AND speaker A/B - so you can use the full cab for both heads.
The only disadvantage: no delays in the loop allowed.

Here's a clip switching forth and back between two modded Marshalls thru the VT:
 
Peter Diezel":xvlwfzqg said:
Sorry, I don´t know the right English expressions
but the speaker will delete some frequencies by
thierselve.
You maybe will be out of phase with the two amps.
Click to expand...


phase canceling? :confused:
 
Not sure if I understood correctly, but I used to have a 6505 with my Herbert, both going into my old Engl 4x12 at the same time and nothing happened...ok, let me rephrase...nothing happened to either of the amps or the cab. :D
 
If you use a good A/B with transformers like a Lehle of course nothing happens, but the ground of the speakers are shared - and both amps have different currents going to ground, so with a cheapo A/B you'll run into a ground loop in many many cases.
Solution is either a good A/B or a line transformer (Palmer).

And then the best overall solution is a unit to use the full cab with both amps . . .

I've tried all solutions over the decades and either you run seperate heads (even then you can run into ground loops with the earth/ground being shared and different amounts of current - the typical problem for rack guys, btw) with seperate cabs or this Tonebone thingy.
 
Do you not still need for both heads to see an impedance load when switched out? I tried something similar with my Mesa and Bogner heads through an old GCX. Kept popping fuses as soon as I switched heads. Figured it had something to do with this. So, I started carrying around another 100 lb cab instead of 4watt fuses!

Steve
 
Both do see a load with the Headbone. Inside there's a 8 Ohm resistor (25 Watts), which acts during the few milliseconds of switching as a load. After the switching (simult. the input is switched) no input = no signal = no load needed anymore, you know . . .
 
To run my Marshall DSL and VH4 together into a stereo Marshall 1960A, I just plugged into the VH4, and then went from the VH4's Thru to the input of the DSL. I set the 1960A for stereo (8 ohms each side), and ran each head's 8 ohm output into one side of the 1960A. Each head only drives two speakers, but it blends pretty well. I had both amps on the same power circuit. I don't know much about ground loops, but I didn't really get any excess noise.
 
These threads always confuse me.

Can I run my Herbert 16 ohm out into one input on my stereo Diezel cab and my VH4 16 ohm out into the other input of my stereo Diezel cab. Essentially like using the one 412 cab like 2 16 ohm 212 cabs?
 
Don't know about the Diezel 4x12" Stereo input impedances, with my Marshall it's 8 Ohms per side. The cab gives a sh.. about which amp is running which input as long as you use the right impedances. Hope that helps?

All answers to the initial question (except for Peter's) were referring to both heads being used alone, as separate sounds instead of running them both at the same time.

Dan should clarify at first what his intention was.

Everything has been answered by Duesentrieb, basically. I'm just interested in Dan's initial thought on this.
 
mhenson42":32ucvkne said:
Can I run my Herbert 16 ohm out into one input on my stereo Diezel cab and my VH4 16 ohm out into the other input of my stereo Diezel cab.
Click to expand...

Yes, that's definitely ok. But I think (as Peter himself stated :cheers: ) there's a good chance that the signals from the different amps are running out of phase and so eliminating portions of the sound which makes the result not feasible for listening - but you should try this yourself and decide then if the sound works for you.
 
Thanks for the responses guys.

To answer Jakob's last post, my intentions were to run BOTH heads at the same time, so you get the blend of the sounds from amps at the same time. Not one or the other.

I'm actually considering getting a second cab instead of putting them through the same 4x12 now. Before peter's suggestion, I hadn't really thought of phase cancellation being an issue.

Also, I have heard about ground loops through the morley...
 
I did it for years .... If out of phase just switch the phase of one side.
It well be out of phase when you use one amp/one cab again and need to switch it back.
There is also a good chance that if you use two amps/two cabs they well be out of phase. I have about a half dozen cabs / dozen amps.
They are not all the same.
The way I check it is I just listen to it both ways. It is very easy to hear.
I always felt splitting the cab was a compromise. It sounds better to me to have a separate cab with each amp when blending amps.
 
What I did was using the Axess Electronics buffer as a splitter (there's a photo of it in this other thread on here).

It has one isolated output and a phase switch. That solved both problems, ground loop hum and phase cancellation.
I had a Laney GH100L and a H&K Triamp mk II running at the same time.
I soon found out that phase cancellation is dependant on individual volume levels of each amp but, most importantly, that it's almost NEVER a 180 degree difference. So I had to deal with some kind of cancellation at any time. Which made me stop using two different amps in the end. But I found great sound combinations for recording, when I had time to really fiddle around with the levels and a phase correlation meter to work out that problem. My final decision to ditch this setup was the inability to use the six sounds of the triamp in combination with the Laney without having phasing problems on at least one of those combinations.

@Stephen: it might be feeling better to use one cab for each amp, but my experience is that when there is a problem with the blended sound coming out of the amps, it will reoccur at the FOH mixing desk. I did sound for a lot of people that used two or more amps (including me, doing our band's soundcheck :-)), and it all comes back together when you send the separately miked amp signals over that ONE pa system :-). But I know what you mean. The amps aren't fighting against each other as the cab frames can resonate separately, thus avoiding frequency loss or sound tampering.
We are a strange breed, aren't we??

The Lehle P-Split is a great little box for using two amps at one time, too. I'm working as a backliner for Iced Earth and Jon Schaffer uses this thing to run his Larry heads simultaneously.
 
I always use two or more amps live ....
Most people do not blend them right so I use a small mixer to get them the sound "I" want. Your right ~ I know.
 
freefall":1k1j0yd3 said:
To run my Marshall DSL and VH4 together into a stereo Marshall 1960A, I just plugged into the VH4, and then went from the VH4's Thru to the input of the DSL. I set the 1960A for stereo (8 ohms each side), and ran each head's 8 ohm output into one side of the 1960A. Each head only drives two speakers, but it blends pretty well. I had both amps on the same power circuit. I don't know much about ground loops, but I didn't really get any excess noise.
Click to expand...

This!!!

Essentially a cab like the Marshall 1960 or any other stereo cab, you can do this no problem. Set the cab to stereo, plug one head into the cab at 8 ohms (one side), and do the same with the other head on the other side. Basically it's like running 2 2x12 cabs. Works out great!!
 
Sometimes it works, sometimes it doesn't. Its not like using 2x2x12. Why

a) the ground between the 2x2x12 is shared (risk of ground loops)
b) what Peter said on top

Not that I wasn't doing it before - this is my version of a "triple super lead" Marshall :D
3amps.jpg

DSL and SLX shared the cab. JMP was loaded down and put into the DSL with a looper . . .

Anyway - you can try that, but I still think that the Headbone solution is better.
 
Interesting! If it is possible, I would like to use the Diezel cab in an A+B connection with the Simul Class 2:90, G-Force,etc.. and then be able to switch to the Herbert in it's mono state. Any other suggestions? Other than a second cab, ;)

TIA
 
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