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Discussion Starter #1 (Edited)
I picked up this Markbass 410 (800w, 4 Ω) cab a couple of days ago.
1- use it the way it is with just the head
2- disconnect two speakers (putting it at 8 ohm) and use it as an extension cab
I'd like to add a switch or a switchable jack to be able to change the impedance from 4 to 8 Ω.
Basically, disconnect two of the speakers.

I grabbed this diagram off of google just as a reference.
How would I wire it to 'disconnect' as apposed to 'stereo'?



Any and all assistance is much appreciated.
Thank you.
 

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The wiring diagram you posted already does that (that's how stereo cabs work).
Input 1 (alone) = All 4 speakers, 4 ohms
Input 2 (alone) = Bottom 2 speakers, 8 ohms (top speakers disconnected from the circuit)

Use input 1 when you want all 4 speakers at 4 ohms. Use input 2 when you want just the bottom two speakers at 8 ohms. The only way it works as a stereo cab is if you use both inputs at the same time.
 
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Discussion Starter #3
Beauties! Thank you.
I forgot to mention, the inputs are speakon.
Do they come 'switchable'?
Do you carry any?
If not, I'm not adverse to installing a switch.
 

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@laristotle I have been looking locally for a supplier of these jacks and QComponents doesn't appear to have them (this pic is from NextGen) and I'm assuming it is one of the jacks you will need.
Personally, I would only buy the Switchcraft brand of jacks....especially with the additional and critical need for dependable switches.



EDIT: You posted just before me. If you can't use Speakon, a suitable switch should be easy to locate at Neutron in Guelph.
 

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Hey Larry
This is what I did when I needed a stereo cabinet...
YES my system uses only 2 speakers BUT you can configure 2 speakers together and work from there.

I got an in industrial toggle switch from Neutron and just followed the signal and got this system
Toggle UP ..
total stereo...plug into one jack and you get that speaker only.
Plug into the other jack and you get the other speaker.
OR use 2 amps and each have their own speaker.
Toggle DOWN
Both speakers are in parallel and you can plug into either jack to get both speakers.

I don't use it now but I do still have the harness if you want to have a look and see at what I did.

Take care
G.

DSC04169.JPG
 

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I've never seen a switching Speakon jack. Doesn't mean they don't exist, though.

I would use a good toggle switch anyways, especially if you're using a tube amp. A switching jack failure may lead to an open circuit scenario. SS amps don't care about that, but tube amps do.
 
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Discussion Starter #7
I don't use it now but I do still have the harness if you want to have a look and see at what I did.
Thanks G.
A pic of the back to see how you wired the switch, or a schem, would be appreciated.
 
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Discussion Starter #8
SS amps don't care about that, but tube amps do.
Apparently it matters with some SS amps, like Markbass.
If I have both cabs running (as it sits now), that would be a 2.6 Ω load.
Which, from I researched, can fry the head.
 

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Apparently it matters with some SS amps, like Markbass.
If I have both cabs running (as it sits now), that would be a 2.6 Ω load.
Which, from I researched, can fry the head.
Oh no doubt, SS amps definitely 'care' about low impedances, or loads close to a short. That's death to many a hard run SS amp. Open circuits aren't though. That's the other end of the spectrum. SS amps will happily run into an open circuit, tube amps not so much. A brief time without a load won't hurt a well made tube amp, but it is risky.

I generally find that switches or switching jacks fail as an open circuit and not a short. Other's experience may be different.
 

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Beauties! Thank you.
I forgot to mention, the inputs are speakon.
Do they come 'switchable'?
Do you carry any?
If not, I'm not adverse to installing a switch.
I've never heard of switchable speakon jacks, but I'm no expert on those. We also don't carry them. McBride/Q-Components may know as they carry several.

Hey Larry
This is what I did when I needed a stereo cabinet...
YES my system uses only 2 speakers BUT you can configure 2 speakers together and work from there.

I got an in industrial toggle switch from Neutron and just followed the signal and got this system
Toggle UP ..
total stereo...plug into one jack and you get that speaker only.
Plug into the other jack and you get the other speaker.
OR use 2 amps and each have their own speaker.
Toggle DOWN
Both speakers are in parallel and you can plug into either jack to get both speakers.
Cool solution. I generally prefer switching jacks as opposed to using a switch. I'm less likely to plug into the wrong jack than I am to leave the switch in the wrong position and mis-load my amp. Of course, that could just be me. :confused:
 

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Thanks G.
A pic of the back to see how you wired the switch, or a schem, would be appreciated.
Ask and ye shall receive Larry...
Please remember that I got the switch first then I used continuity to get a feed that I wanted in the particular switch position.
What Im trying to say is that what I did with that switch may not be universal.

G.
DSC06964.JPG
 

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I like that method better than switching jacks. Switching jacks have enough trouble with small signal levels, never mind trying to run power through them.
Just make sure you check which way on the switch bat is connecting what. It's usually the opposite of what you might expect. For example, in the picture, when the bat is up, the lower set of lugs would be connected.
And you might want some kind of cover on the switch so it can't get bumped during use.
 

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Something like that I think you would have to order from somewhere like mouser or digikey etc.
I was thinking more of just a metal bracket, like this kind of idea:

 
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