PLEASE!
The Power And The Glory
Sometimes attenuators get a bad reputation
for blowing up amps. There may have been
some questionable designs in the past that
put amps at risk, but these days there are a
lot of great choices available that are safe
to use. While I personally have never blown
an amp while using an attenuator, I do know
that if you dime your amp, any parts that
are stressed are going to be exposed. And
most of us running attenuators are using
them because we like the tone of the amp
full up, or close to that. Before you fear the
attenuator will blow the output transformer
on your favorite vintage amp, it might be
wise to take it to a qualified tech and have
it tuned up. What you may have thought of
as a solid and safe amp (because you run
an overdrive pedal in front of it with the volume on 3) could be teetering on the edge
of destruction if you ramp it up. How are the
tubes and tube sockets? What about the filter
caps (especially on vintage amps)? Is it properly biased? So many things need to be right
when you run an amp full out, just like a car
in the Indy 500. And don’t let anyone tell you
that vintage Marshalls, Hiwatts and the like
weren’t designed to be run on 10. They were,
and players have been using them that way
for decades! Besides, even at a volume of 6, 7
or 8, you’re dealing with some serious power,
so take care of your amp and know its running
order before plugging it into an attenuator, or
a speaker cabinet for that matter.
such as the Ultimate Attenuator, are designed
to accommodate any impedance amp. Every
one of these will put their particular tonal
stamp on the amp tone due to the various
types of attenuation being used. These tonal
variations are the subject of much heated
debate in various forums, but that discussion
is outside of the scope of this article.
as you match the attenuator to your amp
like you would a speaker cabinet, you’ll be
in good shape… you’d never run a Hiwatt
DR- 103 full up through a 1x12 Celestion
greenback cab unless you had a death wish
for the speaker and the amp!
Power handling is of utmost concern. You
don’t ever want to use an attenuator that
can’t take the juice of your amp. A 100-watt
tube amp is easily capable of pushing out
150-watts or more peak power, so check
with the manufacturer to see what it can
handle before plugging in your favorite amp.
Personally, I’ve used a Hot Plate for over a
decade with my 50- and 100-watt heads and
have never had an issue with them dimed
for hours on end, five days a week. As long
Load Up
Many attenuators have extra features on
them that can be used for more than just volume reduction. Units like the THD Hot Plate
and Weber MASS can be used as a dummy
speaker load, allowing you to run the amp
without a speaker cabinet. This is an invaluable tool for safely being able to set bias,
check operating voltages or anything that
requires the amp to be running to diagnose.
Prior to specific dummy load devices, techs
have used everything from light bulbs to
giant resistors to dissipate power while
Matching Up Impedance and
Power Ratings
To get the best tone and safest performance
out of your attenuator, make certain that you
are accounting for the power rating of your
amp, as well as the impedance that it’s set to.
The good news is most high-powered tube
amplifiers have selectable impedance settings
to accommodate various speaker cabinets.
Some amps are designed with dedicated 4-,
8- and 16-ohm speaker outputs, while amps
like Marshalls have always had a switch or
plug that sets the impedance. Attenuators, as
in the case of the THD Hot Plate, offer individual models specifically tailored for 2, 2. 7,
4, 8 and 16 ohms, while other units like the
Weber MASS have adjustable impedance settings all in one unit ( 2, 4, 8, 16). Others still,
