Marshall DSL 40CR and extension cabinet

[JAMESAK51]

Hello all!!
I just bought a Marshall DSL 40CR. I have a 2 x 12 Marshall extension cabinet. The combo speaker is 16 ohms and the extension cabinet is 8 ohms. I'm wondering if there's a safe way to run all 3 speakers?
I apologize if I'm posting this in the wrong section.
Thanks all in advance for any input!!
Here are some pics of the back of the amp and extension cabinet.
Best wishes!!
Jim

 

[efstop]

Um, no. It's either/or. Unplug the combo speaker cable and plug the cab into an 8 ohm jack. I think Marshall warns against using multiple speaker jacks (unless you are using the 2 x 8 = 4 ohm or the 2 x 16 = 8 ohm jacks.)

If you wired them in parallel, they'd be a 5.33 ohm draw. In series, they'd be a 24 ohm draw.

2 x 12" ought to be plenty

 

[JAMESAK51]

Thanks efstop!! That's what I figured!! It's always fun to experiment with different speakers and cabinets but not at the risk of damaging an amp.
Thanks again for your input!!
Jim

 

[efstop]

Thanks efstop!! That's what I figured!! It's always fun to experiment with different speakers and cabinets but not at the risk of damaging an amp.
Thanks again for your input!!
Jim

No worries! Been there, myself! I custom made a series cable so I could plug two 8 ohm cabs into my DSL1HR that's 16 ohm only.

 

[Roxy13]

Right, if you want to run your combo speaker and an extension cab together you will need a 16 ohm cab. I have my Marshall DSL40c running that way.

 

[efstop]

Right, if you want to run your combo speaker and an extension cab together you will need a 16 ohm cab. I have my Marshall DSL40c running that way.

With the right cables, I could hook up my three 112 cabs to my mini Jubilee and run it as a 4 x 12 (two Greenbacks, a V30 and a G12H Anniversary.)

 

[JAMESAK51]

Thanks Roxy13!!
Just to experiment I disconnected one of the speakers in the 2 x 12 extension cab and tried that along with the combo speaker. I like it!! Much fuller sound!! Definitely sounds better than running just the 2 x 12 cab by itself.

 

[tzd]

From the DSL40CR manual:

WARNING: Although the amplifier has five speaker outputs, never attempt to connect more speaker cabinets than rated.

The safe combinations are: 1x16 Ohm, 1x8 Ohm, 2x16 Ohm, 1x4 Ohm or 2x8 Ohm only.

Any other speaker cabinet configuration may stress the power amplifier section and in extreme cases may lead to valve and/or output transformer failure.

NEVER use DSL100HR or DSL40CR without a speaker load.

 

[JAMESAK51]

Thanks for your reply tzd!! The way I have it now is 2x16 Ohm

 

[tzd]

Your MX212 cab has 2x16 Ohm speakers wired in parallel, giving it an effective impedance of 8 Ohms at the cabinet's jack.

If you wish to use the DSL40CR's internal 16 Ohm speaker together with your MX212 cab, you could either:

a. Rewire the MS212 cab to disconnect one of the two speakers, so that your MX212 cab becomes effectively a 1x16 Ohm speaker, and your DSL40CR provides the other 1x16 Ohm speaker, both connected to the 2x16 Ohm outputs of the amp.

b. Change the two speakers in MS212 cab to 2x 8 Ohm speakers wired in series, so your MX212 cab is effectively a 16 Ohm cab with 2 speakers, and your DSL40CR provides the other 1x16 Ohm speaker, both connected to the 2x16 Ohm outputs of the amp. Then you will be driving 3 speakers effectively.

 

[JAMESAK51]

Hi tdz!!
For now I did disconnect one of the speakers in the cab and am running that along with the combo speaker. I like the sound and fullness. At some point in the future I might change the two cab speakers out with a couple of 8 ohms and run 3 speakers. For now I like the sound!!
Thanks for your input!!
Jim