# Setting up a stack...



## stever67 (Jun 30, 2008)

So I recently picked up a couple Marshall 1987x heads, both had a PPIMV put in one of the speaker outs. I'm wondering if there's any safe way to run either both heads with two cabs (I have a 1960 A and B cab) or both heads into one cab). 

Help!!


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## keto (May 23, 2006)

Both heads, each with its own cab - an AB/Y pedal. Radial Bigshot, or for a bit more dough, the Bones is totally worth it. I've used both extensively, and find the features on the Bones well worth it.

Both heads + 1 cab = you'd need to stereo wire the cab, so each head had a load at all times - ie, dedicate 2 speakers to one output and the other 2 to another output on the back of the cab. Wired so each set of 2 speakers is independent of the other pair. Then, you could use an AB/Y, just like above, to split the signal from your guitar into the 2 heads.


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## dcole (Oct 8, 2008)

If these aren't vintage babies, put another jack in. There is enough real-estate on the back of those amps to add a hole.


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## stever67 (Jun 30, 2008)

I've been doing the A/B/Y thing. Love the amps but ONE head has plenty of get-up. Both heads at the same time, each I to its own cab, just moves too much air! Fun though! Guess I'll look into getting another jack put back in. It was there once, so it shouldn't be hard to put it back!


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## jb welder (Sep 14, 2010)

Just remember it's the cabs moving the air. Running 2 cabs with one head will not be much quieter than 2 heads and cabs. You are only doubling the power into the same amount of speakers which is only 3db difference, nothing major. It's like a 50W stack vs. a 100W stack, when they're cranked I can't hear much difference .

If you want to run both cabs from one head without adding a jack, why not just use a speaker Y-cable?


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## bcmatt (Aug 25, 2007)

You could also build a little box with 3 jacks wired in parallel. Then you could plug in one amp and both speaker cabs into it with 3 speaker cables.


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## LydianGuitars (Apr 18, 2013)

jb welder said:


> If you want to run both cabs from one head without adding a jack, why not just use a speaker Y-cable?


Exactly... and adjust the impedance on the amp accordingly.


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## stever67 (Jun 30, 2008)

That was kind of what I was wondering...

As for the amount of air - running two heads into two cabs is twice as much power and volume as one head into even two cabs, isn't it (legitimate question - don't mean to sound sarcastic)? I know doubling the "wattage" only generally increases the volume output by a marginal amount (50w vs 100w for example, is not a big volume difference). 

I guess I was just more wondering if it was possible to run one cable with a splitter of some sort from one head to a couple cabs... Thank you all for the feedback so far!! Keep it coming!!!


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## hardasmum (Apr 23, 2008)

Holy Marshalls!!


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## jb welder (Sep 14, 2010)

stever67 said:


> As for the amount of air - running two heads into two cabs is twice as much power and volume as one head into even two cabs, isn't it (legitimate question - don't mean to sound sarcastic)? I know doubling the "wattage" only generally increases the volume output by a marginal amount (50w vs 100w for example, is not a big volume difference).


Actual volume is called SPL (sound pressure level) and is measured in db. Power is measured in watts. They are not the same. For a given speaker arrangement, it takes 10 times the power to make it sound twice as loud to our ears. So double the power is not double the volume. In your example, running 2 heads into 2 cabs (one cab each) versus 1 head into 2 cabs is only doubling the power into the same number of speakers. So if it's 2 50W heads, versus one 50W head, it's just like switching from a 50W head to a 100W. All that you are doing is doubling the wattage into the same number of speakers.



stever67 said:


> I guess I was just more wondering if it was possible to run one cable with a splitter of some sort from one head to a couple cabs...


Yes, it's called a Y-cord, for speaker use it MUST be made with speaker cable. The two cabinets then become in parallel, so you must set the impedance switch on the amp to HALF of a single cabs impedance.


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