Pre-amps, Poweramps and Cabs question!

Beecher

As of 4 days time it looks like ill have an all tube ENGL pre-amp/poweramp rackmount combo, so its time to go cab shopping. Now heres where I dont have a clue, the poweramp has 4 outputs, 2 left and right (at 8ohm and 16 ohm respectively). Now I have heard that if I am only using 1 output at a time that I can damage the poweramp (I was givin the analogy of the other output being like a car thats being over-revved). Now something like this framus cab seems to be up my street, as its reasonably priced but seems to have good speakers and as this is gonna be mainly for home recording use a 2x12" seems fine. Can anyone shed some light for me as to (1) will only using 1 output damage the poweramp, (2) can a 2 x 12" be plugged into both outputs (3) if so can that framus do it, or could you point me out one that can. and finally (4) Do i need a power conditioner or can I use this all without one. Thank you for any help, J.

SirLemonhead

You can use only one output if you want. Most rack poweramps have 2 seperate sides each with 2 outputs, as you know. You just don't turn the side you're not using out of standby. It's fine to use only one of the outputs on a side.

The two outputs are for running stereo cabs. So if the poweramp is set to 8 OHMS and you hook up an 8ohm speaker, it'll be ok as the speaker is drawing 8ohms from the poweramp. If you use both jacks, you'd have to have 2 x 4 ohm being drawn..I think. It's late and I can't think but the bottom line is it's ok to use 1 output as long as the cabinet is drawing the amount of Ohms that the poweramp is set to

Not 100% sure if that cab has stereo wiring, but you can just set your poweramp to 8 OHM and wire it up with one cable to one poweramp output.

You don't need a power conditioner, they're just nice to have. Multi outputs and noise reduction if you have a bad power line and whatnot. If you can afford one, it'd be worth having, but otherwise it's not essential.

Eoin Madsen

If you have it on with one side unloaded (no speaker) then the transformer for that side could be damaged. As MasterOfSolos said, if you can leave that side in Standby then you avoid this. But I suspect there's no such option. If so, then yes you need two speaker cabs, or you need a stereo cab - ie, a cab with two separate inputs, one for each side of it. Most standard cabs have two parallel inputs - this won't do. It has to be stereo wired.

If you're using two cabs or a stereo cab, the impedance rating doesn't need to be split. You only need to do that if you load more than one speaker on each side of the amp. So an 8 ohm cab into each 8 ohm jack or a 16 ohm cab into each 16 ohm jack.

Beecher

Thank you guys so much, yup the poweramp has dual standbys, one for each side so that is fantastic! I couldnt be happier now!

Eoin Madsen

Beecher wrote:

Thank you guys so much, yup the poweramp has dual standbys, one for each side so that is fantastic! I couldnt be happier now!

Wow, cool. That's actually pretty unusual from the valve poweramps I've seen.