Seymour Duncan SFX-03, Twin Tube Classic User Manual

Two Channel Tube Overdrive / Distortion Pedal

Congratulations on your purchase of the Seymour Duncan SFX-03
Twin Tube Classic™. You can start using your Twin Tube Classic right
away after reading the safety precautions on the next page, and

ʼll immediately enjoy the versatility of having two channels of

you
gain and a wide range of great tones. However, you might want
to read through these instructions in their entirety first, to gain
valuable information, that will enhance your enjoyment of your
Twin Tube Classic.

SFX-03

1

Safety Precautions

Hazardous voltages are present. For your protection, and to reduce the risk
of electric shock and danger to personal health, please observe the following
safety precautions when setting up and using your Twin Tube Classic. Most of
this is common sense, but please read it anyway.

Your Twin Tube Classic is designed to work with typical power systems utilizing
a three-prong outlet. To reduce the risk of electric shock, do not plug your
Twin Tube Classic into any other type of power system. Contact your facilities
manager or a qualified electrician if you are not sure what type of power is
supplied to your building or performance stage. Do not use your Twin Tube
Classic with amplifiers or other gear that has two prong AC plugs. Do not
overload wall outlets, extension cords, or multiple power strips as this can result
in a risk of fire or electric shock.

Never open the chassis. Do not attempt to tamper with or service your Twin Tube
Classic yourself. Youʼre just asking for trouble. Opening or removing the cover
may expose you to dangerous voltage or other hazards, which could result
in serious injury or death – not to mention damage to the Twin Tube Classic.
Wouldnʼt that suck? Refer all servicing to qualified service personnel.

Do not block or cover the side vents on your Twin Tube Classic. Never push
objects of any kind through openings in the equipment. No drummer jokes,
please. Dangerous voltages may be present. Conductive foreign objects could
produce a short circuit that could cause fire, electric shock, or damage to your
Twin Tube Classic.

Never place a Twin Tube Classic near a radiator or heat register. Failure to
follow these guidelines can cause overheating and affect the reliability of your
Twin Tube Classic

Unplug your Twin Tube Classic from the wall outlet before cleaning. Do not use
liquid cleaners or aerosol cleaners. Use a damp cloth for cleaning.

Do not use your Twin Tube Classic near water - for example, near a bathtub,
washbowl, kitchen sink, or laundry tub; in a wet basement; near a swimming
pool; on stage with water effects or precipitation; and the like. Do not expose
the Twin Tube Classic to dripping or splashing liquids and do not place objects
filled with liquid on or near your Twin Tube Classic (yes, unfortunately, this
includes bottled malt beverage liquids). And for heaven sakes, donʼt use it while
youʼre sitting on the can… OK, enough of that.

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.

General Information

The Twin Tube Classic is designed for years of solid performance. One of the
secrets is the duet of type 6021 tubes. These sub-miniature dual triodes represent
the pinnacle of tube technology advancement. The 6021s were designed and
manufactured to meet the MIL-E-1 spec for reliability under conditions of severe
shock, vibration and temperature. They provide extremely long service life with
virtually no tendency towards microphonics (see USA Department of Defense
Standards, Test Methods for Electron Tubes). Also, unlike some “tube” stomp
boxes that only use the tubes as a clipping diode, the Twin Tube Classic employs
a 100% vacuum tube signal path with a high voltage power supply. This allows
the tubes to operate to their fullest potential and provides the most gain and the
smoothest tone. The result is the classic tube sound, smooth distortion, and low
order harmonics you expect from a great tube preamp.

Tube Life

The 6021 tubes will typically last many times longer than even the best 12AX7s.
For most Twin Tube Classic owners, this means youʼll never have to change your
tubes. However, nothing lasts forever. Should you find your Twin Tube Classic in
need of new tubes (e.g., exhibiting erratically fluctuating signal levels, spurious
increases in noise, sputtering, low-level whistling, extreme loss in frequency
response), contact Seymour Duncan or your favorite authorized Seymour
Duncan dealer for your options.
Changing tubes on the Twin Tube Classic is more complicated than plugging pins
into a socket and could be dangerous. Make sure a professional does the work.

Do not try changing the tubes yourself.

Two channels means versatility. When coupled with (true) bypass, this effectively
provides three channels: Rhythm, Lead and bypass. Separate gain and volume
controls allow Lead and Rhythm Channel levels to be independently set. The
meticulous internal layout minimizes cross coupling and unwanted circuit
interactions that can be a major problem in high-gain / high-impedance vacuum
tube circuits.

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Explanation of Controls

11

7

8

3

2

1

6
5

4

10

Top Panel

9

1 Rhythm Gain – Inter-stage gain control for the Rhythm Channel. Provides varying
degrees of overdrive and saturation.

2 Rhythm Channel Status Indicator – When lit, it indicates that the Rhythm
Channel is active or staged for activation if the unit is bypassed.

3 Rhythm Volume – Master volume control for Rhythm Channel. Positioned at end
of the gain chain, it regulates the loudness relative to the other channel and to the
bypassed sound.

4 Lead Gain – Inter-stage gain control for the Lead Channel. Provides for varying
degrees of distortion and saturation.

5 Lead Channel Status Indicator – When lit, it indicates that the Lead Channel is
active or staged for activation if the unit is bypassed.

6 Lead Volume – Master volume control for Lead Channel. Positioned at end of the
gain chain, it regulates the loudness relative to the other channel and to the bypassed
sound.

7 Treble – Controls high frequency content in both channels with greatest effect in the
range of 2 KHz to 20 KHz.

8 Bass – Controls low frequency content in both channels with greatest effect in the
range of 40 Hz to 200 Hz.

9 Channel Selector – Selects between the Lead and Rhythm channels. It is possible
to pre-select the gain or volume for a channel when in bypassed mode. This allows the
fl exibility of transitioning from bypass to either channel without having to step through

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different sounds.