I HAVE A 1959 TWEED FENDER CHAMP THATSOUNDS
great except when I turn the volume control past
nine. When the volume goes up that high or higher,
the distortion is buzzy and unmusical. Also, I own
a 1957 Fender Deluxe Reissue. When it is past halfway
up, the low notes seem to compress so hard that
it chops off the front of the note. Any suggestions?
Let’s talk about the Champ first, which is
a single-ended, Class A amplifier. That means
that the signal is being amplified by an output
tube that is drawing either more or less current.
We have all seen a picture of a sound wave
where the top of the wave looks like the hill
and the bottom of the wave looks like a valley.
On a single-ended amp, the tube amplifies the
hill portion of the sound wave by drawing more
current, and it amplifies the valley portion by
drawing less current. As the volume is turned
up, the hills and valleys get larger, so the tube
draws even more current and less current. It
can come to a point where the hill portion of
the tube is drawing as much current as is possible,
and the valley portion is drawing so little
current that it is driven into cutoff—literally,
the bottom of the wave is cut off. This results
in buzzy, homogenized, and non-musical distortion.
Some Champs have more gain than
others depending on whether there is a cathode
bypass capacitor on the first gain stage.
The cathode bypass cap isn’t shown in the
schematic or circuit layout, but many Champs
were shipped with one. If your amp has a cathode
bypass cap, the preamp signal could be
strong enough to drive it into cutoff, which
would explain the buzzy sound when you turn
it up. The solution? You could remove the cathode
bypass cap easily enough, but since it is
only there to boost volume, you can get the
same effect by simply turning your amp down.
Removing the cap would also increase the compression
slightly, but Champs are compressed
sounding enough as is, so I’d recommend leaving
it in place and just running the volume a
With the 1957 Deluxe reissue, compression
can be a real problem. One of the fixes for
this is to replace the tube rectifier with a solidstate
replacement that fits into the same socket.
This will increase the amp’s headroom and give
you a better overall range of clean tones. You
can also use the interactive volume controls to
scoop out the mids and get a better clean sound.
Here’s how to set the controls for piano string
1) Plug your guitar into the #1 input of the
2) Set the volume on the Instrument channel
half way up.
3) Turn the volume control on the Mic channel
all the way up.
4) While playing and listening to your guitar,
readjust the Mic channel volume down a
bit until the best clean tone is achieved. Set
the tone control by ear. It will probably sound
best almost all the way up. This should give
you a pristine clean tone with minimal compression.
—Gerald Weber, Kendrick Amplifiers