The Fender Super 60 packed a
60-watt, dual-6L6 power section
into a compact 1x12 cabinet.
Other features include switchable
clean and gain channels,
treble, mid, bass, and presence
knobs, and spring reverb.
I just started reading your articles and really
find them down-to-earth and informative. I
recently purchased a Fender Super 60 1x12
with red knobs. (Maybe this was produced
during the Rivera era?) I love this little monster’s
clean sound and power. It’s perfect in
smaller venues. However, I’m not happy with
the high-gain channel—it’s not as tight as I
want it. I know the gain on Fender tube amps
is much different from Marshall amps, but
I’m hoping that by replacing the preamp tubes
I could get a little more saturation when the
gain is pushed. But I might be way off and
replacing preamp tubes may not be the answer.
Any suggestions? Thanks!
Thanks for reading my columns
and I’m glad you find them
informative. Your red-knob
Fender Super 60 was designed
in 1988, but it does not appear
to be a Paul Rivera circuit, as the
schematic credits C. Kobylarz as
the engineer on the project. The
amp actually came in three configurations:
head, 1x12 combo,
and a rackmount unit with a
an LED bar graph for power output.
Just in case you didn’t know
how loud you actually were!
As far as the gain structure
of the amp, as I recall the gain
channel on these amps can be a
little loose and grainy. In looking
at the schematic, there are
some modifications I’d try in an
attempt to change these characteristics,
but there may be a
downside to this. (More on that
in a moment.) First, let’s explore
your question about preamp
tubes. This is something you
can easily do and it keeps the
service fee in your pocket.
Changing preamp tubes can
definitely change the characteristics
of an amp, and if you
don’t know the age or condition
of the tubes, it’s probably a
good idea to change them anyway.
An old worn preamp tube
could be responsible for part of
the bad tone you’re experiencing
now. When changing tubes,
sometimes the audible difference
is subtle, but sometimes
it’s much more noticeable. And
that‘s where the fun comes in.
Different preamp tubes
from different manufacturers
sound different. A Chinesemanufactured
tube is typically
considered a brighter tube with
a good deal of gain. A Russianmade
tube is typically fuller
sounding with just slightly
less gain. Most new-old-stock
(NOS) preamp tubes are
thought to be the best sounding
of all, due to the quality of the
materials used back in the day.
My suggestion would be to
do your research by searching
preamp tube characteristics
online. There’s plenty of
information with descriptive
adjectives of different 12AX7
tubes. If possible, purchase a
few different types and experiment
yourself by playing each
one of them.
In your particular case—
where you’re interested in
getting more saturation and
tightening up the overdrive
characteristics—I believe the
tube that will affect that the
most is V101. This is the tube
closest to the input jacks and
is responsible for most of the
amp’s gain. Plugging in each
replacement tube here will give
you a good idea of its characteristics
and if it’s capable of
accomplishing the sonic change
you’re looking for.
Tube prices range from $10
to well over $100 for some
NOS items, so get what you
can afford to experiment with.
Remember you can also use
these tubes in the V102 position,
which is the tone stack and
pre-driver tube. Trying different
tubes here can affect the overall
tone and response of the amp.
By the way, there’s nothing
wrong with mixing different
types of preamp tubes in an
amp. In fact, sometimes you get
the best results with different
brands in different positions. As
an affordable suggestion, I’d recommend
auditioning a Sovtek
12AX7WB, a reissue Mullard
12AX7, and a reissue Tung-Sol
12AX7 in the V101 position
and see where that gets you.
If tube substitution doesn’t
yield the result you’re seeking,
there may be a couple of circuit
modifications you can try, but
here’s where the rub comes in.
You mention really liking the
amp’s clean sound. Since almost
all the Super 60’s circuitry is
shared between both channels,
almost anything done to
improve the quality of the gain
channel will affect the clean
sound as well.
As with most mods, there’s
usually a tradeoff, but here are a
few suggestions if you’re willing
to give them a try. Important:
These mods should be done by
someone qualified and familiar
with working on tube gear, as hazardous
voltages can be present.
Change the value of power
supply resistor R167 from 120k
to 82k. This should raise the
voltage supplied to the V101
plate resistors by approximately
60 volts, increasing the size
of the signal at the plates for
more saturation. The increased
voltage often tends to tighten
things up a bit, too.
Substantially decrease the value
of R103 from 390k to 100k or
less. This will allow more saturation
of the second gain stage.
Change the value of the
capacitors in the tone stack.
While the traditional Fender
values work well for clean tones,
they don’t always sound good
for overdriven tones. Change C6
and C7 from a 0.1 μF and 0.047
μF respectively to .022 μF caps.
This will give the tones more of
a British flavor. If the tones are a
bit too bright or harsh, you can
also experiment with changing
the treble cap C4 from a 100 pF
to a 250 pF value.
These, of course, are only
a few of many possible mods
that could get your amp closer
to what you expect. But, as
with most amps, each mod will
almost always do one thing best,
so you’ll need to experiment to
understand the tradeoffs.
I hope you’re successful in
making your Fender 60 combo
is one of
the godfathers of the
low-wattage amp revolution,
co-founded and was
the principal designer for
Budda Amplification. Jeff recently launched EAST
Amplification, and he can be reached at