guitar speaker / was Re: Tube challenge!

Harry Bissell harrybissell at
Thu Nov 25 21:11:48 CET 1999

The problems come if the speaker load (inductive or otherwise) goes open at any
time. This will overshoot the output transformer and can damage the tubes...

Speakers are really not very "inductive" as loads go. Try to measure the
inductance sometime. They vary from being iron core to sort of air core when the
coil leaves the gap (if you drive that far) so the inductance will go down at
that point.

The biggest problem is if you mismatch the speaker load... ie 4 ohms where 16
was expected. This will hurt the amp...

else: No problems. I completely agree with you, Dave !!!

:^) Harry

DCMagnuson at wrote:

> In a message dated 11/25/99 9:32:34 AM Eastern Standard Time,
> chordman at writes:
> > I've used an 8 ohm wire wound power resistor and never had problems.  I
> >  did this so my buddy who plays lead guitar could get the "amp" sound
> >  without having to mic it.  Much quieter, and no need to stuff the
> >  speaker in a closet with two matresses.
> >
> >  I had heard of this potential damage, but I think it's a myth
> >  created by manufacturers of commercial dummy loads.  (c;
> I suspect the amp will *SOUND* different with a resistive load vs an
> inductive load, but I think it's still safe to operate.  I bet the amp
> doesn't react the same to a dummy load because of the non-linear response of
> speakers... but I have no idea what the difference in sound would be.
> Dave Magnuson
> Independent Music Site

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