Can I connect an external 4ohm cab to my DSL40 combo?

808alan

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I have a DSL40cr combo and I recently bought a used 1960 lead 2x12 cabinet to go with it. However the previous owner apparently swapped the 16ohm speakers with 8ohm speakers so the cabinet is 4ohms when using both speakers.

My goal here is to use the cabinet as an auxiliary on the other side of the stage while using the internal 16ohm speaker on my side of the stage. But I'm thinking 16ohm + 4ohm is not good to match together. However, what do I know? Literally nothing. So i'm looking for some advice.

A) is it safe and B) is it wise to connect both the internal speaker and this cab to the DSL head?
The back of the amp has inputs for 2x8ohm and 2x16ohm.

IMG_7376.png

if I were to do this, which should I use?

And, if I were to just use a single speaker from the 1960 cab (It has stereo inputs) then I could use one speaker from it at 8 ohm. Would the 8ohm/16ohm combination be better or worse than 4ohm/16ohm?

Or am I just overthinking it and should I just plug it in and shred until it catches on fire?
 

808alan

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If I understand the math here, if I use 16oh and 4ohm together I'd have (16x4) / (16+4) = 3.2 ohms. Is that OK to run out the 2x8ohm output? Or too far off?
Alternately I'd have (16*8) / (16+8) = 5.333 which is closer to 8ohms if I used the single speaker in the cabinet.
 

808alan

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Rewire the two 8ohm in series to get 16 ohm in the 2x12 cab.
Plug internal & external into the 2x16 jacks.
Problem solved.
This cabinet is a little complicated because it has stereo inputs. Plug into the right input, both speakers are in mono @ 4ohms. Plug into the left input, one speaker @ 8ohms. So rewiring to series while keeping the ability to run one speaker only seems more involved, I think I'd need to install a switch as well. Or remove the 2nd jack and lose that option. Looking for a simpler solution, if possible. Seems like using the one 8ohm speaker + 16ohm internal speaker through the 2x8ohm would get my closest match. Just wondering if others have run their speakers with this mismatch without issue.
 

fitz288

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This cabinet is a little complicated because it has stereo inputs. Plug into the right input, both speakers are in mono @ 4ohms. Plug into the left input, one speaker @ 8ohms. So rewiring to series while keeping the ability to run one speaker only seems more involved, I think I'd need to install a switch as well. Or remove the 2nd jack and lose that option. Looking for a simpler solution, if possible. Seems like using the one 8ohm speaker + 16ohm internal speaker through the 2x8ohm would get my closest match. Just wondering if others have run their speakers with this mismatch without issue.
You're over thinking this - no need to change out the stereo/mono jack.
Rewire the mono jack from parallel 4ohm to series 16ohm and put a sticker on it that says 16ohm.
Leave the single @ 8 ohm jack.
 

AdrianDSL

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Do you really need the cab's stereo feature? If not, just tape up the second socket with a big DONTUSE warning, then rewire the 2 in series to the right socket and label it 16ohm.
If you only want to use one of the 2 cab speakers along with the combo one, you plug the 8ohm into a 1x4_2x8ohm socket (1/2 load) and the 16ohm into a 1x8_2x16ohm socket (the other 1/2 load).
 

Jethro Rocker

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This cabinet is a little complicated because it has stereo inputs. Plug into the right input, both speakers are in mono @ 4ohms. Plug into the left input, one speaker @ 8ohms. So rewiring to series while keeping the ability to run one speaker only seems more involved, I think I'd need to install a switch as well. Or remove the 2nd jack and lose that option. Looking for a simpler solution, if possible. Seems like using the one 8ohm speaker + 16ohm internal speaker through the 2x8ohm would get my closest match. Just wondering if others have run their speakers with this mismatch without issue.
No it is not a close enough if you rjn the 4 ohm with, well, anything. If you want to run the 8 and 16, do this.
Plug the 16 into ONE of the 2x16 jacks. Amp is now expecting another as this is a half load.
Plug the 8 knto ONE of the 2x8 jacks. Amp is now expecting to see another speaker there as this is also a half load.
2 half loads equals one full load, no mismatching. It works perfectly well.
Rewire for series amd 16 ohms ro ultimately use both speakers.
 

Dogs of Doom

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This cabinet is a little complicated because it has stereo inputs. Plug into the right input, both speakers are in mono @ 4ohms. Plug into the left input, one speaker @ 8ohms. So rewiring to series while keeping the ability to run one speaker only seems more involved, I think I'd need to install a switch as well. Or remove the 2nd jack and lose that option. Looking for a simpler solution, if possible. Seems like using the one 8ohm speaker + 16ohm internal speaker through the 2x8ohm would get my closest match. Just wondering if others have run their speakers with this mismatch without issue.
lose the option...

the option is only good, if you have 2 source amp's creating a phase between speakers. If you do not have stereo amp's, or are planning on running 2 heads into the cab, that feature is worthless...

Having a pair of speakers that properly match w/ another speaker cab, is 100% more functional...

Using 1 side of the cab, just to run 8 ohm, is purposely running the cab, like it's broken. It is designed to run 2 speakers, it is not designed to run 1 of the 2...

Sometimes people have to realize that adding a bunch of things together, does not make for a better sound. Sometimes it's 1 or the other. Maybe both cab's will sound terrible together. :shrug:

Best bet to try though, is to rewire the 212 cab in series. It is simple. All you do is wire 3 wires, to make a continuous loop. Done...
 

Georgiatec

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Looking for something I don't remember what.
Just rewire the cab to series using one of the inputs, disconnect the other input and bung it up with blu-tack or summat similar. I did this with a 1922 cab that I put two 8 ohm Greenbacks in. I have never needed the stereo option in the 10 years I've had the cab....you won't either.
Do not run your amp with even a slight miss-match it will sound crap then blow your O/T. As others have said you can run one side of the cab into one of the 2 x 8 ohm sockets and your combo speaker into one of the 2 x 16 ohm sockets, but I would just rewire and have all three speakers firing and a useful 16 ohm 2 x 12.
 
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