2 cabs question

spev11

Happy new year all,
I have an Orange Dark Terror with 3 speaker outputs, 1 16ohm and 2 8ohm, it says to use 1 8hm or 2 16ohm with the 2 8ohm outputs. 
I also have 2 cabs, both 8ohm and both have 2 jack sockets. (they are identical cabs)
for the life of me my brain does not compute that board, the second output is series? So if I use the 16ohm output of the amp to the first cab and then daisy chain the second cab from the first the total impedence will be 16ohm?

Ah god I need a lie down, bikes are much easier to fix

ICBM

The board is parallel. Each cabinet is 8 ohms, so the total load is 4 ohms, which means you can't really use both together with your amp - although you can (use 8 ohm on the amp) as long as you don't crank it into power-stage overdrive. If you do it will still *probably* be OK, although valve life will be shortened and a sudden failure isn't out of the question.

To do it safely, you need to either rewire one of the cabinets so the second jack is in series - separate jacks are easier than trying to do it with the PCB - to make a special cable to do it, or to get one of these -

https://www.palmer-germany.com/en/products/signal-splitter-switcher/5088/cab-m?c=2129

- and use the 16-ohm jack on the amp.

spev11

ta ICBM, brain frazzle is strong today. Ive also got an attenuator (simple Harley Benton one) its got 3 inputs (4 8 and 16 ohm) and a single speaker out,I'm sure I read that post the attenuator being loaded at whatever is sent to it (8 or 16 in this case) the attenuator doesnt care what ohm the speakers are, i'm likely to be wrong or I misread.

ICBM

spev11 said:

ta ICBM, brain frazzle is strong today. Ive also got an attenuator (simple Harley Benton one) its got 3 inputs (4 8 and 16 ohm) and a single speaker out,I'm sure I read that post the attenuator being loaded at whatever is sent to it (8 or 16 in this case) the attenuator doesnt care what ohm the speakers are, i'm likely to be wrong or I misread.

That's correct, provided the attenuator is not bypassed or (sometimes, depending on the design) set to the highest level just short of bypass. The important thing is to match the amp to the attenuator, because the amp 'sees' the attenuator as the load, and can't 'see' the speakers which are beyond it.

So the safest option is to connect the 8-ohm output on the amp to the 8-ohm input on the attenuator, and then from the attenuator to both speaker cabs. That will be safe if you crank the amp up with the attenuator turned down, and also safe if you turn the attenuator up to full volume with the amp down lower.

spev11

brilliant, ta, you are,as always a font of knowledge and help