ShortScale.org

Doog wrote:

stewart wrote:strange that an ashdown extension cab wouldn't be designed specifically to work with their bass amps... you'd think they'd at least have a switchable output on the amp if they didn't want to make their cabs 4 ohm.

It's very common in amps without an impedance switch or different impedance outputs; that way you can use one or two of their 8 ohm cabinets (resulting in a 4 ohm total load when connected in parallel like that) without any real problems aside from maybe a slight loss of efficiency.

I guess it's just cheaper not having to tap the transformer for different loads.

ah, i see.

Solid state is extremely forgiving when it comes to impedance.

MOST SS amp chips are designed to be most efficient at 2 or 4 ohms, but in guitar amps they're usually run at 4 or 8. Basically, an engineer looks at the size and location of the heatsink on the chip and other factors (frequencies amplified, average volume) and decides how hard the chip should be allowed to work safely. Less ohmage = working harder. Most good SS amps are happy at 4; some shitty ones (Fender Frontman) can only be driven at 8 or more. Some of the best, like Acoustic Image and Henriksen, can be safely run at 2.

Tube amps are a completely different beast, and should really only be run with a matched load. Some new amps are designed to handle impedance mismatches, but the vast majority aren't.

4 ohm minimum needs to be attached, so yes that 8 ohm cab is fine.