re: hooking two tube amps together to power a stereo

[FedUp]

Is there anyway to take two guitar tube amps and use them to power a
stereo system?
For example:

1. Fender tube head powers left stereo channel
2. Marshall tube head powers right stereo channel

What kind of preamp is available that could work with #1 and #2?
Or, is this an impossible idea?

Thanks for any ideas on this.

--- Entfred

[JWV Miller]

On Sep 24, 8:53=A0am, FedUp > wrote:
> Is there anyway to take two guitar tube amps and use them to power a
> stereo system?
> For example:
>
> 1. Fender tube head powers left stereo channel
> 2. Marshall tube head powers right stereo channel
>
> What kind of preamp is available that could work with #1 and #2?
> Or, is this an impossible idea?
>
> Thanks for any ideas on this.
>
> --- Entfred

Sure but why would you want to do this. Guitar amplifiers have low
fidelity and will have considerable distortion when run at high power
levels. This provides the unique and to many people the preferred
sound of an electric guitar. For general musical playback this is
extremely undesirable since the resulting intermodulation distortion
will be very objectionable to a great many listeners.

[[email protected]]

On Sep 24, 8:53=A0am, FedUp > wrote:
> Is there anyway to take two guitar tube amps and use them to power a
> stereo system?
> For example:
>
> 1. Fender tube head powers left stereo channel
> 2. Marshall tube head powers right stereo channel
>
> What kind of preamp is available that could work with #1 and #2?
> Or, is this an impossible idea?

First the short answer:

Yes, you can do this. And any decent pre-amp with a line-level output
may be used to feed the power-amp. You will have to use a fixed output
level from the pre-amp (Line Out), not the variable output unless you
are very careful on how you adjust both the volume controls.

Now the longer answer.

Most guitar electronics are best described as "interesting" when it
comes to actually playing music. In many cases, what goes out is at
best the first cousin of what goes in and in many cases not even from
the same family. But not all cases.

Writing for myself and my direct experience with the species, a friend
of mine brought me two classic Marshall amps about a year ago, both in
type and vintage (both late 70s all-tube units) that were simply not
working. Hum, buzz, and it would not pass any signal. For the record,
I am a audio person. He brought them to me as I know a bit about
servicing tube stuff, but until that moment I had never touched a
guitar amp. He is poor, I don't charge for my hobby, so it works out.
So, what did I do but treat one just as I would an audio amp. Cleaned
up the power-supply, cleaned up the rectifier circuit, cleaned up the
internal caps, resistors and other junk in the circuit, pretty much
replaced all the passive components with good resistors and caps and
installed a dual-element fuse rated at much closer to the actual full-
load draw (~6A) than the beast (15A) that was in there. What came out
was a reasonably OK tube amp that would push at 100% of the rated load
at about 5% THD. And he could use the controls to add additional
effects if he wished. The other one I simply replaced the individual
bad components with or-equal to factory. It was at about 10% THD
already at about 90% of rating, and promptly blew the D/E fuse after
that.

He opted for both being given the "full" treatement. I am quite sure
that many - even most - would have opted for the or-equal treatment.

Point being that guitar amps do not require high-fidelity as their
first goal. They are to make noise and (presumably) not burn up while
doing so. At very low levels they may be reasonably accurate - but at
any volume, not so much.

Peter Wieck
Melrose Park, PA

[FedUp]

I was thinking of experimenting with this for the "warmth" of the tube
amps - not to get guitar harmonic overdrive distortion.

[ quote snipped -- dsr ]