Have you ever noticed, when looking at photos of ’60s guitar heroes like Eric Clapton and
Jimi Hendrix, the old-fashioned spiral cords
connecting their guitars and amps? At the
time, most guitarists used these cables not
for tonal reasons, but because they looked
cool and the choice of instrument cables
was very limited. From our modern point of
view, these cables were low quality with lousy
shielding, but back in the golden days of
electric guitar, they were it.
Wiring diagram courtesy of Seymour Duncan Pickups and used by permission. Seymour Duncan and the stylized S are registered trademarks of Seymour Duncan Pickups.
As you likely know, the longer you run your
cable, the more top end and transparency
you’ll lose in your guitar signal. Today’s guitar
cables offer a capacitance of approximately
100pF each meter, which is very low and
allows for long cable runs without killing all
the top end—some ultra-low capacitance
cables measure as low as 60pF per meter.
But vintage cables (which I measured after
purchasing a large cache of ’60s NOS spiral
cords on eBay) could have a capacitance of
up to 400pF each meter!
These cables had an immense influence on the
tone of the day, as even short spiral cords took
away a lot of top-end bite. The use of 30-foot
spiral cords to connect guitars and amps result-
ed in a "warmer" sound (i.e., less top end) than
we are used to today. That translated into a
slightly muffled clean sound, frequently leaving
guitarists to crank the treble on their amps or
plug in a treble booster to make up the difference. It also resulted in a monstrous overdriven
sound, especially with vintage single-coil pick-
ups. And isn’t that what we’re trying to achieve
today when we play with distortion?
Such cables have been out of production for
many years. Modern spiral cords are high-quality, low-capacitance designs that only mimic
the appearance of the old cables for a retro
look on stage. But it is a fact that these vintage
cables are an important part of the sound we
know and love from classic records. Realizing
that Jimi Hendrix would sound different with
a modern guitar cable, I thought it was time
to figure out how to simulate these vintage
cables, without unplugging our modern ones.
This seems very easy to do at first glance—
simply add some capacitance with an additional capacitor. But proper placement of the
capacitor is crucial for this mod. If the mod
is switched off, we want it completely out of
the circuit, so we can enjoy the transparent
tone our modern guitar cables provide. But
when the mod is engaged, we want a full
simulation of that ’60s tone, warts and all.
So let’s start with some recommended cap
values for simulating varying lengths of vintage coiled cable:
10-foot (3 meters): 1nF
15-foot (4.5 meters): 1.5nF
20-foot (6 meters): 2.2nF
30-foot (9 meters): 3.3nF
Ultra-long: 4.7nF
I chose standard values, so you should have
no problem getting these caps from any local
electronic store or online supplier. Keep in
mind your cap selection can further influence
the tone. Personally, I feel that the modern,
cheap ceramic caps sound closest to the old
guitar cables, but naturally you can also try
silver mica caps, film and foil caps, or anything in between.
To perform this mod, you need one of the
caps mentioned above and a SPST on/off
switch (you can also use a push/pull or push/
push pot). As I mentioned earlier, it’s all about
placement, so take a look at the diagram. If
you want to be more flexible, you can use an
on/off/on switch and choose between two
caps—I recommend 1.5n and 4.7n for three
completely different tones. And if you want to
go wild, you can also use a rotary switch with
several caps for an ultra-flexible guitar. And
remember, if you use a film and foil cap, con-
nect the outside foil end to ground (see last
month’s column for details).
From a technical point of view, the added
capacitance is shifting down the resonance
frequency of the Strat pickups, so they sound
fatter when using overdrive. This is exactly
the reason why a lot of vintage-voiced distortion and fuzz boxes use an additional cap at
the input section—the resulting overdrive
tone is fat and warm. This mod works best
with typical vintage Strat pickups or a typical
vintage PAF. Modern high-output pickups
don’t sound very good with this mod. If you
want to make your Strat sound more Les
Paulish, try a 4.7n for the additional cap. Your
Strat will sound very muffled when playing
clean, but ultra-fat and punchy when using
overdrive! I wouldn’t recommend any values
higher than 4.7n.
Keep in mind that only a small roll back of the
guitar’s volume pot will cut a lot of highs right
from the start. Additionally, if you use a treble
bleed network that works perfectly with your
modern cable, it will stop working with the
vintage cable mod because it is now mismatched. But that’s the nature of the beast
with this simple, yet effective mod. A lot of
players have told me this mod is one of the
most usable out there, so make sure to give it
a try. Until next month, keep on modding!
Dirk Wacker
Dirk Wacker lives in Germany and has been addicted to
all kinds of guitars since the age of 5. He is fascinated by
anything related to old Fender guitars and amps. He plays
country, rockabilly, surf, and Nashville styles in two bands,
works regularly as a studio musician for a local studio,
and writes for several guitar mags. He is also a hardcore
DIY-er for guitars, amps, and stompboxes, and he runs an
extensive webpage—
singlecoil.com—on the subject.