guitar speaker / was Re: Tube challenge!

Christophe Stoelinga cstoel at
Wed Nov 24 17:25:58 CET 1999

> I've found that the biggest contributor to *that* tone is the power amp
> stage, which is why I hook up the Red Box to the speaker outputs and then
> to a 75W 8ohm power resistor (required for a tube power amp).  It doesn't
> sound sweet until the master level is about two; set it to five and turn
> the down the Red Box's level at the mixer and you can get that screaming
> tone at low levels, but keep your hands off that resistor...  So if you're
> only using a preamp, no matter what direct box you use you're only halfway
> there.
You should be carefull with this.
Lots of tube amp end stages can get broken if not loaded with the right
(complex-)impedance. the outputtransformer needs to be connected to another
inductor or large voltage spikes can appear at the output. 
I've got a book with circuit diagrams (it's in dutch...) but i never tried


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