Ohm mismatches....

[manicguitarist2]

So ur sayin I would have to get speaker wire with 2 guitR jacks either end?

Sam

Yes. They will supply it with the head and cab.

[thomasross20]

Not read thread.. is this just basic resistive loading? E.g. Load should match source for max power transfer... or at least be greater than source (unless buffered source)?

[manicguitarist2]

Not read thread.. is this just basic resistive loading? E.g. Load should match source for max power transfer... or at least be greater than source (unless buffered source)?

Kinda, but generally, a valve power amp is a current source and a solid state is a voltage source - and that has implications for loading and safety.

[thomasross20]

So valve amp Rout = HIGH so load must be low (to sink all current) and vice-versa for solid-state?
What main implications? Short-circuit protection for valve outs etc?

[manicguitarist2]

So valve amp Rout = HIGH so load must be low (to sink all current) and vice-versa for solid-state?
What main implications? Short-circuit protection for valve outs etc?

if you have too high a load with valves, being a current source it will generate a high voltage which could cause sparking or melt the circuit or damage the transformer.

In general, too high a load is safer than too low with a solid state amp and the converse with valve. But better to match the impedance.

[thomasross20]

Cool, thanks!

[Russell_a]

Is there any way i can rewire a cab to go from 8 ohms to 16 ohms?

BTW its the framus 2x12, rated at 8ohms...

[manicguitarist2]

Is there any way i can rewire a cab to go from 8 ohms to 16 ohms?

BTW its the framus 2x12, rated at 8ohms...

Not without changing the speakers.

[Russell_a]

Bugger... Thanks anyway!

[ecc83]

Is there any way i can rewire a cab to go from 8 ohms to 16 ohms?

BTW its the framus 2x12, rated at 8ohms...

Russell;
If you load a 16 Ohm tap on an amp with an 8Ohm cab that is not a serious "mismatch". Yes, the valves will see a lower load than is optimum and you will probably get distortion at a lower power level, a big amp >30W say might even pop an HT fuse if you give it the full beans for some time but if you just want to noodle at home or check out an 8R cab...No harm IMHO.

Dave.