Mark IV 8 into a 16 1x12 cab, is it safe?

[C-Martin]

I hate to ask this question but i've always just matched the impedance and never tried to figure out what is safe and what isn't as i would always get contradicting info from different people. Some people say it's safe to go from a 8Ω amp into a 16Ω cab and others say it will screw your amps tranny.

I want to grab a V30 cab, the Orange PPC112, do to some recordings in my small home setup when i can't go half way across town to go to the studio to plug into a 2x12 or 4x12. My initial idea was to grab a Randall ISO cab but i figured i could use baffles and a 1x12 cab for about the same results if not better or at least less boxy. The PPC is only 16ohm and the amps i'd be using are my Mark IV which only has 4 and 8 ohm outs, Marshall JTM 45 and Vox Night Train which both have 8 and 16 ohm outputs. The recto cab is 8ohm's and would seem to be perfect match for my setup but i don't want to pay 500$ + Taxes for the freaking overpriced 1x12 Recto, i could get a used 4x12 for that price but that would be overkill for a smaller room.

Will the Orange PPC112 be fine with the Mark plugged into it at 8ohm? It's a combo and there's a 8ohm C90 speaker in it, is there a way i can plug both, maybe split the load or something? i really don't know how this works when not matching impedance...

 

[mva801]

16 is fine. I pulled this text from my Mark V manual:

MESA/Boogie amplifiers can handle 4 and 8 ohms effectively. Never run below 4 ohms in a tube amplifier unless you are absolutely certain that the system can handle it properly; this can cause damage to the Output transformer. A few amplifiers can handle 2 ohms effectively without damaging them ( for example the MESA’S Bass 400+ ).You can always have a higher resistance ( 16 ohms, for example ) without damaging results, but too low of a resistance will likely cause problems

MIS-MATCHING: When running a higher resistance ( for example: 8 ohm output into 16 ohm cabinet ), a slightly different feel and response will be eminent. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is a result of the amplifier running a bit cooler. Sometimes when using more than one cabinet a mismatch will be the only option.

 

[C-Martin]

16 is fine. I pulled this text from my Mark V manual:

MESA/Boogie amplifiers can handle 4 and 8 ohms effectively. Never run below 4 ohms in a tube amplifier unless you are absolutely certain that the system can handle it properly; this can cause damage to the Output transformer. A few amplifiers can handle 2 ohms effectively without damaging them ( for example the MESA’S Bass 400+ ).You can always have a higher resistance ( 16 ohms, for example ) without damaging results, but too low of a resistance will likely cause problems

MIS-MATCHING: When running a higher resistance ( for example: 8 ohm output into 16 ohm cabinet ), a slightly different feel and response will be eminent. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is a result of the amplifier running a bit cooler. Sometimes when using more than one cabinet a mismatch will be the only option.

Sweet, so it'll work fine but with a slight compromise in sound. Doesn't sound too bad of a compromise tbh, i think i could live with a bit less output and a bit of a darker/smoother tone. So there is no risk of damaging the amp or straining it? I mostly concerned about not causing harm to my Mark IV since it's sort of a collection piece now that it's not in production anymore...

Any one here have direct experience with this type of situation?

 

[006]

I know Mesa says explicitly in some manuals that they encourage mis-matching the Ω to get different feels.

 

[TheWinterSnow]

I felt the need to chime in. The issue electrically running an 8 ohm amp into a 16 ohm amp is that the inductance "kick" of the tranny will be a little higher, but is still much lower than the dielectric (the breakdown voltage) of the wire insulation of the tranny. The actual effect on the tubes is that they run cooler. If you have a 120W 8 ohm amp into a 16 ohm cab, you will have a 60W amp. it will change your tone, yes, and your tubes will actually last longer.

 

[C-Martin]

I felt the need to chime in. The issue electrically running an 8 ohm amp into a 16 ohm amp is that the inductance "kick" of the tranny will be a little higher, but is still much lower than the dielectric (the breakdown voltage) of the wire insulation of the tranny. The actual effect on the tubes is that they run cooler. If you have a 120W 8 ohm amp into a 16 ohm cab, you will have a 60W amp. it will change your tone, yes, and your tubes will actually last longer.

Thanks for the info. Although you lost me a bit with the technical terms, i think i understood. So your saying i wouldn't be harming anything but i'd be putting less strain on the amps tube and more on the tranny than if it was running with matched impedance? Isn't it worse to strain the tranny more than the tubes?

The half power result from this is interesting. The Mark IV is rated 85 Watt when using Simul-Class, Penthode and Full Power mode, this means it would be running at 42.5 Watt and i could drive that V30 on full power without any risk, since it's a 60 Watt speaker. I generally run it in Simul-Class and Triode resulting in 70 Watt (According to the manual) so i'd actually be feeding 35 Watt's to the speaker?

Also, how big of a difference in tone are we talking about? Is it just a subtle differences that can be EQ'ed to sound how a Mark IV should sound or does it change the character of the sound so much that i'm not going to recognize it anymore?

 

[DeclanWhite]

amp = people, cab = car

you can fit 8 people in a car that holds 16 people, but you cant fit 16 people in a car that holds 8 or the car (tranny) breaks

 

[bryan_kilco]

amp = people, cab = car

you can fit 8 people in a car that holds 16 people, but you cant fit 16 people in a car that holds 8 or the car (tranny) breaks

This is exactly how I was "taught".

I run my Mark IV 8 ohm speaker out to a 16 ohm rated 5150 cab. Done so for years and never had a problem.

 

[Skinny Viking]

amp = people, cab = car

you can fit 8 people in a car that holds 16 people, but you cant fit 16 people in a car that holds 8 or the car (tranny) breaks

why did no one ever explain it like this to me before?

 

[bryan_kilco]

why did no one ever explain it like this to me before?

The same thing I thought about 5 years ago. I ALWAYS got confused with Ohms and someone explained it this way and I guess it's a decent quick analogy to remember and help save amps.

 

[mva801]

amp = people, cab = car

you can fit 8 people in a car that holds 16 people, but you cant fit 16 people in a car that holds 8 or the car (tranny) breaks

Dude that's a great analogy!

I have a Rectifier 2x12 that I run the Mark V through at home, but when I take it to the studio we have a couple Marshall 16ohm cabs. I record through those all the time. Like the manual says, the difference is small, and if you feel it's a bit darker, then up the treble a smidgeon. TBH I think the guitar and player make a WAY bigger difference in the sound than running into a cab with higher impedance...

I'd say if you can get that orange for significantly less $ than the mesa, then the 8-16 difference should not detract you at all from making the purchase...

 

[C-Martin]

Yeah, i can get the Orange for 150$ less than the Mesa so i'm glad the ohm miss match won't be anything risky for my amp. I am gonna go ahead and grab the the Orange then. Thanks for the help guys.

 

[mickrich]

I often run my MK4 into Orange or Marshall 4x12 cab.
As has been said, as long as your cab impedance isn't lower than the power expects you are good to go.