#1
is it possible to run 2 heads simultaneously through 1 cabinet?
If so what are the limitations? head ohms to cab ohms, mono/stereo cab or head

I dont know if its a stupid question or not but just curious.. everything else I've found is about running 2 heads separately through 1 cab.

another reason im asking is because Im looking at getting a marshall jcm2000 dsl50 and I aready have a jcm 900 50/100 and thought it would be cool to blend the tones together through my orange cab but Im pretty sure its not possible.

EDIT: Also I know that its possible to do it through a 6x12 cab because they are they are powered as a separate 2x12 and 4x12 in 1 body.
Last edited by attheian at Oct 22, 2009,
#2
Sooo you're gonna split your guitar signal into 2... run it into 2 amps, then somehow run the signals from both amps into 1 cab?
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#3
Ya it should be possible, I mean if you're going for distortion it will most likely sound like shit, but otherwise it should work just fine.
#4
basically. If it works without any damage to any of the gear. trying to save myself from having to get another cab to run the second head through.
#5
yes it should work, may have to do some rewiring. as long as impedance is set properly to the amount of speakers, there should be no issue
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#6
I think you're gonna need to rewire the electronics in the cab so that 1 input and its corresponding speakers will be dedicated to 1 amp, whereas another input and its dedicated speakers will be dedicated to another amp.

Unless there's some gear out there which will some how present a load for the amps and combine the 2 signals into 1.

Even if you achieve it... it'll take more than double the effort to dial both amps in.
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#7
Quote by ragingkitty
I think you're gonna need to rewire the electronics in the cab so that 1 input and its corresponding speakers will be dedicated to 1 amp, whereas another input and its dedicated speakers will be dedicated to another amp.

Unless there's some gear out there which will some how present a load for the amps and combine the 2 signals into 1.

Even if you achieve it... it'll take more than double the effort to dial both amps in.



If the cab is run in stereo then it should be fine. Send the signal from one amp to one half of the cab and the signal from the other amp to the other half of the cab.

If its a mono-only cab then the TS is pretty much screwed on this plan unless they can rewire it to run stereo.
#8
if the cab is stereo and the impedance and wattage match up then yeah
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#9
Quote by justinb904
if the cab is stereo and the impedance and wattage match up then yeah


Impedance isn't as big of a deal as people around here make it out to be. As long as the cab rating is equal to or greater than the head rating you will be fine. Be warned though that if the cab is rated higher than the head you will have a bit of volume and tone loss.
#11
Quote by i_am_metalhead
Impedance isn't as big of a deal as people around here make it out to be. As long as the cab rating is equal to or greater than the head rating you will be fine. Be warned though that if the cab is rated higher than the head you will have a bit of volume and tone loss.


so theoretically, two 50watt heads set at 8 ohms into one 16ohm, 120 watt, stereo cab. will allow the output of head1 through 2 speakers and the output of head2 through the other 2?
#13
Quote by i_am_metalhead
If the cab is run in stereo then it should be fine. Send the signal from one amp to one half of the cab and the signal from the other amp to the other half of the cab.

If its a mono-only cab then the TS is pretty much screwed on this plan unless they can rewire it to run stereo.


Ah see... I'd have to confess that I had no idea of the existence of stereo cabs until 2 minutes ago

Quote by attheian
so theoretically, two 50watt heads set at 8 ohms into one 16ohm, 120 watt, stereo cab. will allow the output of head1 through 2 speakers and the output of head2 through the other 2?


Your speaker cab will need to be 4 Ω not 16Ω

Alternatively.... you can set both heads to 16Ω and then run into one 8Ω cab.
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Last edited by ragingkitty at Oct 22, 2009,
#14
Quote by ragingkitty
Ah see... I'd have to confess that I had no idea of the existence of stereo cabs until 2 minutes ago


Well one of the most famous stereo cabs would be the Marshall 1960.

There are two input jacks on the back (one for 16 ohm mono and one for 4 ohm mono) and a switch that turns them into stereo inputs (basically cuts the signal so that two sides are no longer wired together) - it pretty much turns a 4x12 into two vertical 2x12s.
#15
Quote by ragingkitty
Ah see... I'd have to confess that I had no idea of the existence of stereo cabs until 2 minutes ago


Its 4Ω, not 8Ω.



No, he was right if I'm thinking correctly. A 16 ohm cab, when ran in stereo, should be 8 ohms per side - basically like having two 8 ohm 2x12 cabs next to each other.
#16
Quote by i_am_metalhead
Well one of the most famous stereo cabs would be the Marshall 1960.

There are two input jacks on the back (one for 16 ohm mono and one for 4 ohm mono) and a switch that turns them into stereo inputs (basically cuts the signal so that two sides are no longer wired together) - it pretty much turns a 4x12 into two vertical 2x12s.


Now that's something new to me...don't get much vintage stuff here in S. E. Asia. Ya learn something new everyday.

Quote by i_am_metalhead
No, he was right if I'm thinking correctly. A 16 ohm cab, when ran in stereo, should be 8 ohms per side - basically like having two 8 ohm 2x12 cabs next to each other.


I made an amendment to my post... I think I got my maths backwards.

Errr...

This is assuming its a parallel wired cab right?

If its a 16Ω cab... shouldn't 1 side be wired for 32Ω? The combined parallel load would then be 16Ω right?
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Last edited by ragingkitty at Oct 22, 2009,
#17
this is all getting very confusing. infact its making me wonder if I even have my current stack set up correctly.

#18
Quote by ragingkitty
Now that's something new to me...don't get much vintage stuff here in S. E. Asia. Ya learn something new everyday.


I made an amendment to my post... I think I got my maths backwards.

Errr...

This is assuming its a parallel wired cab right?

If its a 16Ω cab... shouldn't 1 side be wired for 32Ω? The combined parallel load would then be 16Ω right?



Now you've got my head spinning lol.

I had the math all figured out earlier and now I can't think straight


Edit:

If its a 16 ohm cab then one each side should be rated at 8 ohms, then wired together in series to equal 16 ohms. I can't remember how I figured out the math earlier to get that though lol.


The way you're thinking would be each side wired in series (assuming he has 16 ohm speakers) to equal 32/side. Then if the two sides were wired in parallel you would have a 32 ohm cab (32/2 + 32/2 = 32).
Last edited by i_am_metalhead at Oct 22, 2009,
#19
Quote by attheian
this is all getting very confusing. infact its making me wonder if I even have my current stack set up correctly.



Don't start making changes or decisions until Will and I work this out. Either one of us is correct or both of us are wrong. Let us identify the correct answer before you do anything.

Quote by i_am_metalhead
Now you've got my head spinning lol.

I had the math all figured out earlier and now I can't think straight


haha... I hate impedance settings sometimes...

OK... to make it simple.

if its a 8Ω stereo parallel cab.

One side will need to be wired for 16Ω right?

From my Mark V manual

"The formula for figuring the total impedance in Parallel is the multiplication of the two loads divided by the sum of the two loads - i.e. putting two 8 ohm speakers in Parallel results in a 4 ohm load."

So based on the example above, 16X16=256.

16+16=32

256/32 = 8Ω

So by extending that example.

If he has 2 amps putting out 8 ohm each....

he will need a 4Ω cab

8X8=64

8+8=16

64/16=4Ω
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Last edited by ragingkitty at Oct 22, 2009,
#21
Quote by ragingkitty
Don't start making changes or decisions until Will and I work this out. Either one of us is correct or both of us are wrong. Let us identify the correct answer before you do anything.


no worries, I dont have the second head yet. Its all just making me unsure that my amp is set up correctly with just the one head! If some one could answer me that while these other two rack their brains on the topic at hand Id greatly appreciate it!

jcm 900 50/100 watt has 2 speaker outputs and a impedance switch which reads 8-16(4). The cab is an orange ppc 4x12 240watt RMS with two inputs neither of which are marked.

I have my head set to 100watts with the switch in the 16(4) ohm position. running a single speaker cable from 1 output into the corresponding input on the cab i.e. right to right or left to left.

right? wrong?
#22
Quote by i_am_metalhead
I edited my post - make sure I'm thinking right, lol.


DAMN! Where's someone like Colin when you need him


Doh... now my head is spinning... the additive format is used to determine serial wiring ain't it?
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#23
Quote by ragingkitty
Doh... now my head is spinning... the additive format is used to determine serial wiring ain't it?


I'm just so confused right now its not even funny. Its late (almost 3am) and I've been up since about 8am (so 19 hours, with only about 3 hours of sleep last night). I really couldn't think straight right now if I had to.


TS: Don't give up on this idea or this thread. Your idea is very plausible, its just a matter of making sure you're not using a cab that has a lower impedance rating than the output of your head.

Like I said in a previous post - as long as your cab rating is equal or greater than the rating of your head then you're not gonna fry your OT or anything.
#24
Quote by i_am_metalhead
I'm just so confused right now its not even funny. Its late (almost 3am) and I've been up since about 8am (so 19 hours, with only about 3 hours of sleep last night). I really couldn't think straight right now if I had to.


TS: Don't give up on this idea or this thread. Your idea is very plausible, its just a matter of making sure you're not using a cab that has a lower impedance rating than the output of your head.

Like I said in a previous post - as long as your cab rating is equal or greater than the rating of your head then you're not gonna fry your OT or anything.


Haha... I'll leave the maths until someone comes along to correct us... or tomorrow when you're thinking straight.

Correct, Will has go the cab rating greater than amp part correct.

Quote by attheian
no worries, I dont have the second head yet. Its all just making me unsure that my amp is set up correctly with just the one head! If some one could answer me that while these other two rack their brains on the topic at hand Id greatly appreciate it!

jcm 900 50/100 watt has 2 speaker outputs and a impedance switch which reads 8-16(4). The cab is an orange ppc 4x12 240watt RMS with two inputs neither of which are marked.

I have my head set to 100watts with the switch in the 16(4) ohm position. running a single speaker cable from 1 output into the corresponding input on the cab i.e. right to right or left to left.

right? wrong?


Should be ok... but you'll need to check the impedance of the cab if you want to be sure.

Either call Orange .... or check the speakers and its wiring. I'd recommend you call Orange.
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#25
Should be ok... but you'll need to check the impedance of the cab if you want to be sure.

Either call Orange .... or check the speakers and its wiring. I'd recommend you call Orange.


whoops, The cab is 16ohm. I guess I forgot to mention that.. must have dozed off a little and missed it!
#26
So long as it is 16 output from the amp into a 16 input on the cab it's the best connection.

Will.. where're you? Have you resolved your side of the impedance maths yet?
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