Building A Cab For My Mark V-Advise?

[#2121313]

I have two speakers lying around, both 8 ohms Celestions, one Vintage 30 and one G12T-75.

Two main questions:

1) I like to plug in using 8 ohms, I don't like the tone I get when using 4 ohms, could I technically build one 2 X 12 and fit both speakers in it (as per normal), but then wire each speaker independently keeping them at 8 ohms and plug them into my two 8 ohm jacks of my Mark V head? Basically have a speaker going from each speaker to the 8 ohm jacks on my head, two speakers, two wires, two 8 ohm jacks on my head - will this remain in 8 ohms and run safely?

2) Any tips/suggestions on the type/grade wood that Mesa or Marshall uses to construct their cabs? I know it's plywood, but any specific type, thickness - 3/4"?

Would there be any negatives if I do not tolex it? I only care about tone, not concerned about it getting dinged or anything as it'll stay permanently in my basement...

Any tips would be great - thanks!

 

[ampmagic]

I believe you would have to use the two 4 ohm outs on your amp,using two 4 ohm outs would suggest your amp is looking for two 8 ohm cabs in this case separate speakers are in the same cab,if you went out of your 8 ohm jacks your amp would be looking for two 16 ohm cabs.thats the way i see it.look in the back of the mesa manual it gives different configurations.

 

[MesaGod666]

Just buy a DIEZEL front loaded cab.

It's teh best.

 

[#2121313]

Checkout page 44 here: http://www.mesaboogie.com/manuals/MkV_090626.pdf

You'll see exactly how my amps rear panel is configured, it has two 8 ohm jacks...

 

[MrMarkIII]

Two 8 ohm speakers will ALWAYS WITHOUT FAIL be either 4 ohms (parallel) or 16 ohms (series), jacks be damned.
Sorry, it's just the way electrons work.
Those two 8 ohm jacks are undoubtedly meant for two 16 ohm loads (when using BOTH), just as the two 4 ohm jacks are meant for two eight ohm loads.

 

[#2121313]

Two 8 ohm speakers will ALWAYS WITHOUT FAIL be either 4 ohms (parallel) or 16 ohms (series), jacks be damned.
Sorry, it's just the way electrons work.
Those two 8 ohm jacks are undoubtedly meant for two 16 ohm loads (when using BOTH), just as the two 4 ohm jacks are meant for two eight ohm loads.

Thanks MrMarkIII. Makes sense, but if you look at the rear panel, it has 2 X 4 OHM jacks and 2 X 8 OHM jacks, now under the 4 OHMS it says: "(2X8OHM CABS)" which supports what you are saying, but under the 8 OHM jacks it says: "(COMBO)" this is why I am confused, why does it say combo, what is this in reference to? It should then read "(2X16OHM CABS)" or "(2X4OHM CABS)" but more than likely should be 2X16OHM CAB as 16OHMS seem to be more common...

What do you think they mean by "(COMBO")?

 

[MrMarkIII]

That's where the combo speaker goes.

 

[#2121313]

Why two jacks?

 

[#2121313]

Anyone know where to buy MARINE GRADE BALTIC BIRCH PLYWOOD - does Home Depot have this stuff?

 

[thunda1216]

I have two speakers lying around, both 8 ohms Celestions, one Vintage 30 and one G12T-75.

Two main questions:

1) I like to plug in using 8 ohms, I don't like the tone I get when using 4 ohms, could I technically build one 2 X 12 and fit both speakers in it (as per normal), but then wire each speaker independently keeping them at 8 ohms and plug them into my two 8 ohm jacks of my Mark V head? Basically have a speaker going from each speaker to the 8 ohm jacks on my head, two speakers, two wires, two 8 ohm jacks on my head - will this remain in 8 ohms and run safely?

2) Any tips/suggestions on the type/grade wood that Mesa or Marshall uses to construct their cabs? I know it's plywood, but any specific type, thickness - 3/4"?

Would there be any negatives if I do not tolex it? I only care about tone, not concerned about it getting dinged or anything as it'll stay permanently in my basement...

Any tips would be great - thanks!

Yes, you can run one 8 ohm speaker from each 8 ohm output jack with no problem. That's why they are there. My Heartbreaker has one 16 ohm output jack, two 8 ohms and two 4 ohms output jacks.
Have at it.

ty

 

[#2121313]

Anyone know where to buy MARINE GRADE BALTIC BIRCH PLYWOOD - does Home Depot have this stuff?

Yes but I doubt it's home depot.
I have no idea where in your area.

You could use a good shop grade 3/4" Birch or Maple ply for the cab with no worries. Baltic is expensive ($100+ per 4'x8' sheet) and IMHO overkill.

Hey GTS! I was waiting for you to weigh in on this, I was afraid I was afraid I had lost you over here in the "Modern Era Amps (1991-Present)" section of the board lol

Cool. I was actually wondering if the marine grad was necessary or if there was a decent substitute...considering I do have the speakers already and tools are not an issue I was hoping to keep costs down, kinda the whole point to experimenting with the cab...

So I am assuming shop 3/4" grade will be available at Home Depot?

 

[#2121313]

I have two speakers lying around, both 8 ohms Celestions, one Vintage 30 and one G12T-75.

Two main questions:

1) I like to plug in using 8 ohms, I don't like the tone I get when using 4 ohms, could I technically build one 2 X 12 and fit both speakers in it (as per normal), but then wire each speaker independently keeping them at 8 ohms and plug them into my two 8 ohm jacks of my Mark V head? Basically have a speaker going from each speaker to the 8 ohm jacks on my head, two speakers, two wires, two 8 ohm jacks on my head - will this remain in 8 ohms and run safely?

2) Any tips/suggestions on the type/grade wood that Mesa or Marshall uses to construct their cabs? I know it's plywood, but any specific type, thickness - 3/4"?

Would there be any negatives if I do not tolex it? I only care about tone, not concerned about it getting dinged or anything as it'll stay permanently in my basement...

Any tips would be great - thanks!

Yes, you can run one 8 ohm speaker from each 8 ohm output jack with no problem. That's why they are there. My Heartbreaker has one 16 ohm output jack, two 8 ohms and two 4 ohms output jacks.
Have at it.

ty

Thanks thunda1216 for clarification.

 

[#2121313]

Prefect, thanks for the info GTS!

 

[mrcomputer]

I think I'd snag one of those unloaded, half-open Mesa 2x12 (Vertical) cabs that I always see for sale on eBay. Pop the v30 in the sealed portion. Depending on the vintage of the cab jackplate you can probably wire as stereo (2 x 8ohm) or mono (4-ohms or [possibly] 16-ohms).

But if you really want to build a cabinet, I'd love to see a single 2x12 that incorporates a thiele and a (1x12) half-open (horizontally aligned). You'd want an EVM or C90 for the thiele. Wire it for mono and stereo operation.

jbw