Trace Elliot dumb impedance question

[smarthound]

I'm used to chaining two 8 ohm Trace cabs (a 4x10 and a 1x15) together in series to provide the amp (AH250) with a 4 ohm total, which provides maximum power from the amp's single output.

 

For a smaller setup, I have a BLX130SM combo with a GP7 SM amp section and a single 10" speaker and want to add a 2103H extension, also 8 ohms. The amp has two 8 ohm sockets, one of which is used by the internal speaker.

 

I'm not sure whether simply plugging the extension cab into the second 8 ohm socket provides the optimum 4 ohms total or the amp's output is just fed out in parallel to two 8 ohm speakers, which seems counterproductive.

 

Anyone using a TE combo and an additional cab and knows the best way to get max power out of the setup?

 

[Bill Fitzmaurice]

First off, chaining them in series would be 16 ohms. When amps have two outputs they're almost always wired parallel. That's how you get a 4 ohm load from two 8 ohm cabs.

[warwickhunt]

Plug your extension 8 ohm cab into the other output in the pic, you get your 4 ohm load.

 

[Downunderwonder]

That's going to take half the power and put it through a cab that is twice as efficient. Probably close to the same in and out with the combo speaker as you get solo.

 

You will be able to turn it up to about 4 on the loud knob with impunity. Keep using the earplugs.

[smarthound]

Thanks folks. I realised I'd mixed up series/parallel -  how I managed that I don't know. Because the cabs on my large rig are daisy-chained they look like they're in series - but it's surely wired as parallel connections.

 

As for the amp outputs being parallel to get the 4ohm load, I'm sure you're all correct. It just looked too easy and I started overthinking it!

 

Cheers once again, guys. 

 

The mini-stack will look like this, and I'll probably add my 4502H Bright Box to act as a monitor. (Due to the HFP crossover, its impedance is negligible when in circuit.)

 

Edited July 5 by smarthound