ohms question please?

[vklobucar]

My Marshall Valvestate power amp arrived today and as I was plugging it into some outboard gear (JMP-1 and JFX-1) I could'nt help notice this printed on the back...

"40 watts - 8 ohms (min) per channel"

Huh? since when did a solid state power amp have a minimum ohms requirement?

Does that mean that my stereo 4x12 (4 ohms per channel) must be opened and rewired yet again?

Or will running this amp into it destroy them both?

Help please!

[pebber]

Re: ohms question please?

as a general rule : <u>LOW feeds HIGH</u>

In order to preserve signal level and frequency response, <u>it's important to drive equipment with a source signal that is lower in impedance than the destination equipment's input impedance</u>. If the input impedance of a device is not significantly higher than the source impedance, the signal will be reduced or "loaded down" and its signal to noise ratio and frequency response will suffer

<font color="yellow">translated to your case, this would mean that the destination equipment (stereo) needs to have the same or higher impedance then the 8 Ohm (read: minimum 8 Ohm input impedance for the device your driving)</font>

if you drive the 4 Ohm, the first thing that will happen is that more power will be asked of the output transistors used in the power amp, and it all depends on which transistors used (specifications?) to see what will happen further

[vklobucar]

Re: ohms question please?

Thanks for the info!

So I guess that I would certainly be better off with a 16 ohm stereo cab huh? Especially if I do not wish to take any chances with my power amp?

[jgcable]

Re: ohms question please?

[ QUOTE ]
Thanks for the info!

So I guess that I would certainly be better off with a 16 ohm stereo cab huh? Especially if I do not wish to take any chances with my power amp?

[/ QUOTE ]

Yes. An 8 ohm cab would be the best but 16 ohm would be cool too.

[pebber]

Re: ohms question please?

Well, if u take 1 CABinet, use one with 8 Ohm specification, if u take 2 CABinets, use them with 16 Ohm specification (because the input impedances of both would be in parallel)