Link function on a cab

[andrewrx7]

Hi,

Apologies for what may seem a daft question, but how do you actually use the LINK connection on the back of a bass cab? I've always ignored it, but curious to know what it is actually for.

Does it mean you can run more than two cabs from a single head (the head has two speaker outs, and can be used with 2x 8ohm cabs)? I am guessing not, since would this not affect the overall impedance of the system back to the head?

Thanks!

[xgsjx]

It depends how many ohms your cabs are & how many ohms your amp will go down to.
If you are using 8 ohm cabs it's a 4 ohm mon load on your amp, then 2 8 ohm cabs is the max (or 1 4 ohm/4 16 ohm cabs). If it's a 2 ohm min load then you'll get 4 8 ohm cabs (or 2 4 ohm cabs). If it's a valve amp then there may be a switch to make it match the load.

[xgsjx]

Oh, & to answer your Q, the "link" on the cab is just the same as using the other speaker out on your amp.

[flyfisher]

There's no fundamental limit on the number of speakers that can be connected to an amp. Think of 1x15, 2x10, 4x10, 8x10 cabs - they've each got a different number of speakers in them but will work perfectly well because the speakers within the cabs have been chosen and connected such that they present an overall 8 or 4 (or whatever) load to the amp.

It also doesn't matter how many speaker outputs an amp has - it can still be connected to any number of cabs/speakers as long as the overal load is within the spec for the amp.

Having said that, in practice cabs are usually 4 or 8 ohms, amps often have two outputs and cabs also often have two connectors - all of which makes things easier when connecting stuff together.

An amp with two outputs can be connected to two cabs, one output to each cab. But it can also be connected to just one of the cabs and a 'link' cable can be used to connect that cab to another cab. Electrically, the two methods of connection are identical - the two cabs are connected in parallel to the amp (note that this only applies to a mono amp - a stereo amp with two outputs is, of course, really just two amps with one output each).

[andrewrx7]

Thanks. I get the principle of overall load on the amp, I believe mine is min load of 4ohms. I also think it is a mono amp. I wasn't sure that if you linked a 2nd cab to the first one (daisy chaining?) the load rating would follow the same rule as if you connected 2 cabs separately to the amp. From what you are suggesting, linking the cabs together is still wired in parallel, so with 2x 8ohm cabs daisy-chained the load on the amp is still 4ohm, and is just fed via one of the outputs. I guess this is not recommended since more current has to flow down the single connecting cable rather than splitting the current into two cables.

I'm sure I read somewhere, that cabs can also be wired such that the linking of two together is in series and not a parallel. How would you know? There is nothing on the cabs to state what kind of wiring has been used for the link socket.

[xgsjx]

Your assumptions are correct.

You can get a [s]Parallel[/s] Series cable made from someone like Bassic Bits (OBBM on here).

Edited November 17, 2011 by xgsjx

[Merton]

[quote name='andrewrx7' timestamp='1321451224' post='1439277']
I'm sure I read somewhere, that cabs can also be wired such that the linking of two together is in series and not a parallel. How would you know? There is nothing on the cabs to state what kind of wiring has been used for the link socket.
[/quote]
For all amps and cabs assume parallel wiring unless stated (some Eden Nemesis gear,for example, has an internal speaker and an external speaker socket wired in series). Series wiring won't cause any problems to a solid state amp, as you'll be increasing the impedance load seen by the amp rather than decreasing it.

[flyfisher]

[quote name='andrewrx7' timestamp='1321451224' post='1439277']
Thanks. I get the principle of overall load on the amp, I believe mine is min load of 4ohms. I also think it is a mono amp. I wasn't sure that if you linked a 2nd cab to the first one (daisy chaining?) the load rating would follow the same rule as if you connected 2 cabs separately to the amp. From what you are suggesting, linking the cabs together is still wired in parallel, so with 2x 8ohm cabs daisy-chained the load on the amp is still 4ohm, and is just fed via one of the outputs. I guess this is not recommended since more current has to flow down the single connecting cable rather than splitting the current into two cables.
[/quote]
Yep, you've got it.

You're also correct that a daisy-chained arrangement will mean more current flowing down the single connecting cable but in practice this is not a problem if you're using a good quality cable. There is another practical consideration of such an arrangement in that if the amp speaker cable develops a fault then both cabs are affected, whereas with two separate cables they would both have to fail before things went quiet. But again, in practice it's not a big issue.



[quote name='andrewrx7' timestamp='1321451224' post='1439277']
I'm sure I read somewhere, that cabs can also be wired such that the linking of two together is in series and not a parallel. How would you know? There is nothing on the cabs to state what kind of wiring has been used for the link socket.
[/quote]
It's certainly possible but not very common in my experience. As mentioned, you'd need special cables or adapters for such a configuration.