Little Mark 2 speakon not working

[MrTea]

I've got a Little Mark 2 head which I've always used with a jack to jack speaker cable. However my latest cab (PJB Compact 4) only accepts speakon inputs so I dug out a Stag Speakon cable I've had a lying around and tried it. I get no output from the amp into the cab. Using a jack in the same socket on the LM2 works with another cab. That said, I've no reason to suspect the cab is the problem although arguably testing this with another head would be a good suggestion!

I don't have another Speakon cable lying around but before I order another one is there any way to test this will work? The cable seems fine when I loosen the ends and check the cable. The only other thing I could try fairly quickly I guess would be to solder a jack on one end of the cable and leave the speakon on the other.

Any ideas? It's frustrating as it's my only had and I can't try the new cab :-(

Edited August 24, 2017 by MrTea

[MrTea]

As an addition I've hooked this up via another cab like this:

LM2 > Jack cable out of speakon on amp > Mi1x12 jack in > Mi1x12 speakon out > Compact 4 speakon in

And it all seems to work. I think that rules out there being an issue with the speakon cable and the compact 4. Does that mean the speakon connector on the LM2 is broken?

I'd seen another post about these being picky speakon cables - does anyone have any experience with that?

[Bill Fitzmaurice]

Speakons can be wired more than one way. You have to make sure yours is wired correctly on both the amp and the speaker ends to function with the PJB.

[MrTea]

I'm pretty sure this is wired the correct way - the LM2 states 1+ positive \ 1- ground and the cable seems to be wired this way. It does appear to have 4 connectors available inside the speakon connector though (2 are unwired) could this be the issue?

[Bill Fitzmaurice]

What does the PJB show for connections?

[MrTea]

It doesn't say on the back of the cab and I can't seem to find the info online but as noted in my update it works when connecting a speakon cable via another cab (Ashdown Mi12).

Maybe ordering another speakon cable from Amazon where I can easily return it is the easiest thing to do but it 'smells' like that also shouldn't work!

[la bam]

If it helps there are 2 types of speakon.

I got caught out years ago with pa that required different types of speakon.

Of the top of my head something like a nl2f and nl4fc. They're wired differently.

I'm not sure if that will be any help, but maybe worth checking online first?

[Bill Fitzmaurice]

The PJB wiring should be found in the owners manual.

[obbm]

On 99% of bass amps and cabs all Speakons are wired the same using the 1+ and 1- terminals of either 2-pole (NL2) or 4-pole (NL4) connectors. These two types of connector are mechanically and electrically compatible.

One of the exceptions to 1+/1- is some power amps and Ampeg SVT4PRO running in bridged mode which use 1+ and 2+ at the amp end but which still require 1+/1- at the speaker end.

Some PJB cabs double up using 1+ and 2+ for one leg of the cable and 1- and 2- for the other leg. The Compact 4 only uses 1+/1-. I know because I used to have one.

Some PA cabs with crossovers use the 2+/2- connections to drive either tops or subs depending where the crossover is located.

I have had two cases where Speakon cables to MB LM2 amps have gone intermittent. In the first case it was solved by using a 4-pole Speakon instead of a 2-pole. The second instance was never fully resolved. I contacted Neutrik and they offered to provide a new combo socket however as a cheap Amazon sourced cable seemed to work so it was left like that.

I have my suspicions that these early amps used very early versions of the combo Speakon/Jack and that either something is not quite right mechanically or that the contacts weaken over time especially when used with only jacks plugs. In the interest of trying to get to the bottom of the problem I bought a well use 1996 LM2 from a BC member which I now gig with. It works well however it did exhibit the fault on one particular cable. On examination I could find nothing wrong with the plug and certainly nothing wrong with the socket in the amp as it works faultlessly with any other cable. I'm afraid the Jury is out on this one.

To the OP I suggest that you try a totally different Speakon lead. It should not matter whether it is 2-pole (NL2) or 4-pole(NL4). If this doesn't do it then I would have the amp combo socket checked by a reputable amp tech.

[MrTea]

Thanks all. I'll get hold of another speakon cable and give that a go. If it works then I'll maybe do what I expected to be advised to do much earlier and treat myself to one of obbms cables ;-)

Edited August 24, 2017 by MrTea

[Opticaleye]

There was an issue with Lm2 Speakon outputs where they were very fussy about the connectors that went into them. I have one that only works with the cable a certain way round. I labeled the connectors as Amp and Cab. Another lead works with both connectors. This was reported on forums at the time (2008 onwards as I recall)

[yorks5stringer]

[quote name='Opticaleye' timestamp='1503598119' post='3359594']
There was an issue with Lm2 Speakon outputs where they were very fussy about the connectors that went into them. I have one that only works with the cable a certain way round. I labeled the connectors as Amp and Cab. Another lead works with both connectors. This was reported on forums at the time (2008 onwards as I recall)
[/quote]

I will concur, in that I had a LM2 from new that would only work with certain Speakons and not others.

[Woodinblack]

Did you try it the other way round? I have a TC450 amp and 2xTC112 speakers. I have 3 speakon - speakcon leads and the have a piece of tape round the end that goes to the amp. If I put them the other way round I get nothing (I can wire between the speakers either way).

[MrTea]

Thanks all for the help. Ordered a new speakon cable and it works fine - I guess it concludes that the LM2 is fussy about speakon cables.

[yorks5stringer]

[quote name='Woodinblack' timestamp='1503703260' post='3360486']
Did you try it the other way round? I have a TC450 amp and 2xTC112 speakers. I have 3 speakon - speakcon leads and the have a piece of tape round the end that goes to the amp. If I put them the other way round I get nothing (I can wire between the speakers either way).
[/quote]

Exactly the same for me, I gaffa'd the end that worked!