Mark IV into Thiele

[Russ]

Man, I just picked up this KK Audio cabinet that was advertised as a convertible cabinet. The auction had stated open or closed back. To my surprize I found a little panel in the front with two little screws in it. I looked from inside at where the panel would be and saw finish from the outside peeking in. I took the panel off and guess what... The thing is ported as a Thiele cabinet also. I had been pricing Thiele cabinets equipped with the EVM and found them to be in the $275+ range. I was truly elated once I got the cabinet because it was only $120. I don't mind the gray carpet because my rack case is the same stuff. I have migrated the short head into a combo cabinet and now I have a Thiele cabinet to add some punch. I had considered even migrating back to the head cabinet then closing the back of the combo and adding a shelf to act as the port to convert the combo into a Thiele but now I don't have to rig it all. I like the sound of the cabinet more than the open back combo.

What is a good combination to run with the EVM loaded Thiele? It will be in the Combo cabinet so it would have to get decent sound as an open back. I am assuming I want an 8 ohm speaker and run both 4 ohm jacks.

I could run my 4x12 greenback cabinet (that thing just sings). The only thing that I am concerned about would be what I plug into with a mixed load like that. The 4x12 is a 16 ohm cabinet and the EVM is an 8 ohm. I would think I could plug the 4x12 into the 8ohm jack with the EVM in a 4 ohm jack. Can the Mark IV take that load?

I have run the 16 ohm cabinet into the 8 ohm jack before without much volume and it sounds ok but there again I had no other load on the amp either.

I could always just get a 2x12 greenback cabinet...

I think it would be easier though to just get a good 8 ohm speaker and put it in the combo. I have an EVM in there now but would like to color in what the EVM seems to lack. I know some guys think that the EVM is all you need but it just isn't cutting it for me. I have another EVM on its way too so I might make a 2x12 with the EVM that is coming and the other speaker I choose. The second speaker would still be open back in the 2x12 as I would be building a Mark style cabinet.

 

[Tuna141]

I've run my Mark IIC 8OHM combo with a 16Ohm 2x12 and never had a problem - connected same as you mentioned - 4x12 into the 8OHM jack and the 8OHM into the 4OHM jack.

I've also run my Mark IV combo with a 16OM 1x12 V30 speaker and that worked fine too (connected the same as above).

There is a slight volume difference between the speakers, but it is not very noticeable. Besides, different speaker efficiencies contribute to different output volumes, anyway.

You should be fine...

 

[Russ]

Thanks for the response. I figured that would work. I am just a little leary of making out of the ordinary combinations though I do understand Ohm's Law. I am just unsure sometimes about how a transformer or circuit will handle a certain load.

 

[Tuna141]

I've run my Mark IIC 8OHM combo with a 16Ohm 2x12 and never had a problem - connected same as you mentioned - 4x12 into the 8OHM jack and the 8OHM into the 4OHM jack.

I better start "proofing" my posts What I meant to type is "I've run my Mark IIC 8OHM combo with a 16Ohm 4x12 and never had a problem - connected the same as you mentioned - 16 OHM 4x12 into the 8OHM jack and the combo's 8OHM speaker into the 4OHM jack. "

Russ, I'm sure you understood what I was trying to say :lol:

Your set-up should work fine...

 

[Shep]

i hav ran my old marshall cab(75's) and my mesa EVM 200 1x12 once and i found that the little cab made it Way to middy..with the port...

Tom

 

[Russ]

I got it Tuna...

I feel like the 75's sound too scooped naturally but do have some nice bottom though you have to watch your highs or you start squinting and wincing...