Full stack with 16 ohm and 8 ohm cabs possible?

piranha_2001

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Hi!

I've got a question! Is it possible to run a 16 ohm cab AND a 8 ohm cab as full stack through a Marshall DSL50?

I bought two vintage 1968 London City cabinets (both with celestion 25watt pré rola's). They sound AMAZING! When I checked the speakers, it said 8 ohm on the speakers of one cabinet (in contrary to what the dimwit seller told me).

Now I was wondering... If I had two 16 ohm cabs, I'ld set my amp at 8 ohm and plug the two 16 ohm cab each in the 8 ohm input of my Marshall DSL.

Now the biggest question I bother you guys for is: Would it damage my amp, if I'ld run my DSL50 as fullstack with the cabs at diffrent ohmage?! I don't know, because when I plug in the 8 ohm cab only, I'ld plug it into the 8 ohm input. (so with the fullstack going, that would be in the same input, right?!)
 

dynabite

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That would equal 5.3 ohms with mismatched power distribution, better off matching the 2 cabs.
 

Adwex

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You'll risk damaging the output transformer, a costly repair.


Hmmm, I could swear I saw the same question on the Marshall forum.
 

NYPV

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Don't do it. They gotta match
You can run: 1- 16 ohm cab
1- 8 ohm cab
1- 4 ohm cab
2-8 ohm cabs
2- 16 ohm cabs
 

dwagar

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how about just wiring up 2-8ohm speakers in that cab, ie running it as a 2x12 at 16ohm?
 

Big John

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That DSL 50 is probably putting out 60-80 actual watts if you run it dimed, depending on tubes, wall voltage and bias setting. That means with just one 4x12, each speaker in the cab will see 20w at most. That's about the point where the vocal magic is happening with 25w Celestions. Why even use another 4x12?
 

NYPV

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how about just wiring up 2-8ohm speakers in that cab, ie running it as a 2x12 at 16ohm?

Theres a thought, but could blow runnin just 2
Runnin one cab makes better sense as far as speaker wattage
 

axepilot

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That would equal 5.3 ohms with mismatched power distribution, better off matching the 2 cabs.

I haven't crunched the numbers, but I'll take you word for it.

That said......................if the OP daisy chains the cabs for a 5.3 ohm total load, he can safely run those speakers from the 4 ohm mono out on the amp. A difference on 1.3 ohms will not kill the amp.
 

Atomic

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Hi!

I've got a question! Is it possible to run a 16 ohm cab AND a 8 ohm cab as full stack through a Marshall DSL50?

I bought two vintage 1968 London City cabinets (both with celestion 25watt pré rola's). They sound AMAZING! When I checked the speakers, it said 8 ohm on the speakers of one cabinet (in contrary to what the dimwit seller told me).

Now I was wondering... If I had two 16 ohm cabs, I'ld set my amp at 8 ohm and plug the two 16 ohm cab each in the 8 ohm input of my Marshall DSL.

Now the biggest question I bother you guys for is: Would it damage my amp, if I'ld run my DSL50 as fullstack with the cabs at diffrent ohmage?! I don't know, because when I plug in the 8 ohm cab only, I'ld plug it into the 8 ohm input. (so with the fullstack going, that would be in the same input, right?!)

after rereading your question.. im unsure as to whether you are stating that your cabinet is 8 ohms, or each individual speaker is 8 ohms.. that will change the answers entirely.
 

axepilot

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Reads to me as cabinets, not individual speakers.
 

dwagar

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I read it as cabs as well, a 16ohm cab being 4-16ohm speakers, and the 8 ohm cab being 4-8ohm speakers.
 

dwagar

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Theres a thought, but could blow runnin just 2
Runnin one cab makes better sense as far as speaker wattage

no, he'd be running 6 - 4 in one cab and 2 in the other cab. But I can't remember how the power divides up that way.

Do you think he'd be running this puppy dimed anyway?
 

NYPV

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I haven't crunched the numbers, but I'll take you word for it.

That said......................if the OP daisy chains the cabs for a 5.3 ohm total load, he can safely run those speakers from the 4 ohm mono out on the amp. A difference on 1.3 ohms will not kill the amp.

The 8 ohm cab would use twice the power of the 16, and be louder. But probably an OK mismatch if you had to
 

Atomic

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When I checked the speakers, it said 8 ohm on the speakers of one cabinet (in contrary to what the dimwit seller told me).

this is where my question was raised.

if your speakers are 8ohms each, and you have a 4x12 cab, you can still have an 8 ohm total cabinet load.. but you can also have 2 and 4 depending on how its wired.

The 8 ohm cab would use twice the power of the 16, and be louder. But probably an OK mismatch if you had to

that is not entirely correct.
when the impedance of the load and output are matched, then you will have maximum efficiency and yield. no matter if the circuit is 4-4 8-8 or 16-16. in tube amps its not advisable to mismatch impedance. this is why there are usually multiple taps available for use. if you connect a load that is MORE than the tap its connected to, the power output will decrease, and you risk creating a feedback loop that can damage the amplifier. vise versa if you connect a speaker load that is LESS than the tap its connected to, then you cause the amplifier to work less efficiently. you end up burning up more power in the output section than you get driving the speaker.. which can cause lots of nasty things to happen.

in the days of solid state generally you could go up but not down. for example a 4 ohm output could drive 8 and 16 with no real problems. you would have a reduction in power by about 20%, but no real noticeable drop in volume. remember, you have to cut your total output power by a factor of about 10 before you hear any perceptible reduction in volume.
 

piranha_2001

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hi

thanks for the reply's! I will clarify my question. I have 2 cabinets. one is 16 ohm (4x12'') and one 8 ohm (4x12''). I would like to have it Fullstack for better sound spreading.
 

NYPV

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hi

thanks for the reply's! I will clarify my question. I have 2 cabinets. one is 16 ohm (4x12'') and one 8 ohm (4x12''). I would like to have it Fullstack for better sound spreading.

OK what about switching 2 speakers from one cab to another and vice versa. 2-8 oms parallel =4 ohms ; 2-16 ohm parallel =8 ohm ; now connecting all 4 series/parallel would yield 12 ohms per cab. Connect to head as though runnning 2- 8 ohm cabs. Cabs will have a balanced load. It will be slightly less efficient but as long as the cab impedence is higher than the amps output impedence, its a safe mismatch.
 

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