New Thiele(s) Day and ohm question

[eecamichael]

I picked up two mint Mesa Thiele cabinets, and to my surprise they have the EVM 12L 200 watt speakers! Jury is still out on them, and I may turn them loose, but my initial thinking is to hook both of them or one up to my Mark IV combo, or just one with the C 90 stock speaker. Other thought would be to use them with the Triaxis and 2:90.

If I am hooking them up to the Mark, the Thieles are both 8 ohms, and the mark has two 4 ohm outs, along with one 8 ohm out, what would be the best way to do this without blowing my stuff up?

 

[>Photi G<]

Unfortunately, running 3 speakers is a nightmare to calculate impedance with. I say if you're gonna run it with your MKIV, run just one Thiele and the internal C90 both into the 4? jacks in your amp. When using it with your TriAxis and 2:90, run them in stereo, with one hooked up to the L output of the 2:90, and the other in the R output, both at 8?.

 

[MrMarkIII]

Not a problem.
Here's a calculator for speaker impedance matching:

http://colomar.com/Shavano/impedance_proc.php

Values entered horizontally are for series connections.
Parallel connections are entered vertically.
Be sure to show all your work. This will be on the final.

Your example:
Row 1 = 1 speaker : 8.00 ohms
( 8.00 ohms total for row)
Row 2 = 1 speaker : 8.00 ohms
( 8.00 ohms total for row)
Row 3 = 1 speaker : 8.00 ohms
( 8.00 ohms total for row)

Connecting Row 1 and Row 2 and Row 3 in Parallel
Total Impedance for this combination = 2.67 ohms

Now that wasn't so hard, was it?

2.67 ohms is do-able, but pretty low. (You would never want to go down to 2 ohms).

Optimally, you should un-plug the combo speaker, and plug each Thiele into a 4 ohm speaker jack on the Mark IV. Or move the combo speaker to a 4 ohm jack, and put one Thiele in the other 4 ohm jack. These two 8 ohm loads in parallel will be 4 ohms total, perfectly safe. Yes, the labeling on the speaker jacks is confusing. Blame Mesa. The label of "4 ohms" on two of the speaker jacks does NOT mean you plug a 4 ohm speaker into them. It means "this is what you get when you plug an 8 ohm speaker into this jack".
Hope this helps

 

[Mark Fore]

Dude... a Mark IV through two Thiele's with EV's is the end of the journey. It just stops there.

 

[JOEY B.]

Dude... a Mark IV through two Thiele's with EV's is the end of the journey. It just stops there.

Almost. :lol: :lol:

Remember to dial the amp in with your ears and not your eyes. This is especially important if you are used to playing Celestion speakers.

 

[Mark Fore]

For me, unless you are a Celestion fanatic, that combination is the one where you can turn any knob, tweak any setting and it just sounds good no matter what; the highs are sweet, the low end is handled, the mids are never in the way. You can explore the tones and just smile in every setting. I'm getting giddy just talking about it. :lol:

 

[nogalian]

How about two EVM Thiele cabs and two Recto 1 x 12's, running one of each on either side of a 2:90? Would the best way be running both speaker sets run thru the 4 ohm outputs of the 2:90? The 2:90 has 2 4 ohm outputs per side I think. (Both the Thiele and the Recto 1 x 12 are 8 ohm cabs) Or, could you run the 8 ohm out of each side of the 2:90 to a Thiele and then run a cable from the Thiele to the Recto 1x12? Or would that blow up my house, or worse my gear???!!

 

[MrMarkIII]

Unless I miss my guess, four 8 ohm cabs in parallel means a total load of two ohms, not recommended.

 

[O==00==O]

Speaker's ohms ratings are not accurate. "8 ohm speakers" are usually 6.xx, 7.xx or possibly 8.xx ohms - so you want to check each one with a DMM before calculating.

I would just unplug the C90 and plug each Thiele into a 4 ohm jack to get an "8 ohm" load, if that's how that amp's speaker jacks are wired.

 

[nogalian]

Yep, I plugged a Thiele and a R 1x12 each into a 4 ohm jack per side on the 2:90, which I think is corrrect, according to the illustrations on most MB manuals. Seems to be workin great.

 

[O==00==O]

Yep, I plugged a Thiele and a R 1x12 each into a 4 ohm jack per side on the 2:90, which I think is corrrect, according to the illustrations on most MB manuals. Seems to be workin great.

The 2:90 is different since it's a stereo amp, it's basically two power amps separated inside that chassis. I wouldn't want to hear about you burning up all 8 6L6s.