212 Wiring

Glaw343

Hi everyone, I have a 212 that I'm going to be loading with 2 8 ohm Celestion creamback neos, I was wondering if there's a way of wiring the back plate to have four inputs for a few different options as I would like to be able to use it with 2 amps at the same time and have some impedance options when using it in mono if that makes sense? kind of like the marshall 1960a cabs but without the stupid PCB, would I need some sort of switch like on the marshall? so the inputs would be
1 - mono (series) 16 ohm
2 - mono (parallel) 4 ohm
3 - left speaker 8 ohm to be used with amp 1
4 - right speaker 8 ohm to be used with amp 2
any help you can give me would be greatly appreciated. Cheers.

George.

ICBM

It can be done in exactly the same way as the Marshall using a standard DPDT switch and hard wiring - but the problem with those isn't the PCB or the switch, it's the jack switching contacts, which are unreliable and which you would still have to use.

Probably the best solution is to have two jacks each wired to each speaker and a switch to connect the speakers in series, which would give you a 16-ohm mono cab - usually the most useful. Then if you want to use it at 4 ohms, connect two speaker cables from the amp (assuming it has two jacks) to both speaker inputs.

Alternatively, use the jack switching to connect the speakers in parallel - this isn't as bad from a reliability point of view because the failure mode still means the amp has one speaker as the load - and an external series cable or box to give you the 16-ohm option.

Simplest of all is just to fit two completely separate speaker jacks and get one of these - https://www.thomann.de/gb/palmer_cab_m_merger.htm

Glaw343

@ICBM cheers mate, as usual you've been really helpful. I was thinking I would use speakons rather than jacks as thats what I'm using on pretty much all my cabs at the moment sorry I should have said that, would they be more reliable or would it have the same problem as the jack contacts? I'll definitely check out that cab merger too, that would massively simplify everything. cheers

ICBM

The only switched Speakons I know of are PCB-mount, so that probably wouldn't work anyway - hardwiring to the pins may not be very secure. In theory it would be fine to use the switches though, they're actually properly-rated contacts designed for speaker currents.

maltingsaudio

Using Nl4 speakons you could have +1-1 as your mono either series or parallel wiring then +2-2 as your8 ohm mono for your two amps. Can’t at the moment think of how to do all 3 options without a switch