Ohms for 2x12 recto cab speakers

[Mark Fore]

I was wondering, the recto cabs are 8 ohm cabs so are the V30's each 8 ohms or 16 ohms wired to 8 ohms for the cab? The reason I ask is because I have a couple extra 8 ohm EVM-12L's that I would like to put one of each in my recto 2x12's to get that mix. Has anyone tried this?

Or if I put both in a 2x12 that are each 8 ohms, what are my wiring options? Thanks!

(I know I could remove the back and check, but this would save me the trouble... thanks guys)

 

[boogietone]

I have a recto 2X12. It originally had two V30's that were 16 ohms each wired
in parallel making the cabinet a total load of 8 ohms. I swapped out the V30's for
EV12L's that were 8 ohms each. I wired the EV's in parallel like the V30's were
so now the cabinet has a total load of 4 ohms. Hope this helps.
Sounds great BTW!

 

[Mark Fore]

Perfect... thanks! I think what I'm going to do is swap out both speakers in one recto 2x12 cab. I'll stack the V30 cab on top of the EV 2x12 cab for the mix. Otherwise I'll end up with a 6 ohm cab and I don't even want to know what that would do. Thanks again!

 

[Mark Fore]

Oh wait... I won't be able to stack them as the 4 ohm cab will then become 2 ohms. I'll have to use it as a standalone cab.

 

[boogietone]

You can get 16 ohm V30's. Two in a 2X12 cab will get you 8 ohms in parallel.

edited:
I think I got a little confused. Disregard this post.

 

[boogietone]

I don't know what the rear panel of a recto looks like
but on a MarkIV there is a jack for an 8 ohm load and
two jacks for 4 ohm loads. Using both 4 ohm jacks at the
same time with an 8 ohm load in each jack the amp sees 4 ohms
due to the 4 ohm jacks being wired in parallel. But, you can run
an 8 ohm load into the 8 ohm jack and one 4 ohm load into one of
the 4 ohm jacks. I used to do this with my MKIV combo. The combo's
8 ohm speaker went to the 8 ohm jack and the 4 ohm 2X12 cab I
have went to one the 4 ohm jacks. Make sense? So, my question to
you is, can you run the same set up?

 

[domct203]

If you use two 8-ohm speakers wired in series the 2X12 cabinet will be 16-ohms.

This is how my Avatar 2X12's are. One cab has two 8-ohm Hellatone 60's wired in series for 16-ohms, the other has two 8-ohm Mesa Black Shadow C90's wired in series for 16-ohms also. When used together in parallel the total load is 8-ohms. This allows me to also add my 8-ohm Recto 4X12 in parallel for all three cabinets at a 4-ohm total load.

I found this to be the most versatile for me. If I want to run one 16-ohm 2X12, I plug straight into the 16-ohm jack on the amp. If I want to add the second 16-ohm 2X12 I daisy chain them (parallel) to 8-ohms and plug into the 8-ohm jack on the amp. If I want to run the 8-ohm Recto cab and one 16-ohm 2X12 cab I plug the 8-ohm Recto into the 4-ohm jack on the amp and the 16-ohm 2X12 into the 8-ohm jack. To run all three cabs I plug the 8-ohm Recto cab into the 4-ohm jack on the amp, then daisy chain the two 16-ohm 2X12's to 8-ohm and plug that into the other 4-ohm jack on the amp.

These are all CORRECT impedence matches that were confirmed by Mesa.

The poster running the 8-ohm and 4-ohm cab setup is pushing a 2.6-ohm load, IMO stressing the output tranny. Mesa's trannys are very strong and may run fine for years like that, but I personally would not run lower than a 4-ohms total speaker load, which is the lowest output transformer tap per the schematic.

Dom

 

[boogietone]

I thought that you could run one 4 ohm load into one 4 ohm jack and one 8 ohm load into
the 8 ohm jack. The 8 ohm jack and 4 ohm jack are not wired in parallel as I understand.
Only the two 4 ohm jacks are wired in parallel.

 

[domct203]

I thought that you could run one 4 ohm load into one 4 ohm jack and one 8 ohm load into
the 8 ohm jack. The 8 ohm jack and 4 ohm jack are not wired in parallel as I understand.
Only the two 4 ohm jacks are wired in parallel.

When I called Mesa about running my 16-ohm and 8-ohm cabs together I was told to "half the ohms" and plug the 16-ohm cab into the 8-ohm jack and the 8-ohm cab into the 4-ohm jack to keep the output section balanced and reduce excess wear on the output tubes. Mesa said this was a "safe mis-match" for my Roadster. Your DC-5 may be different though.

Dom