Duncan 84-40, Owner'S Manual

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GAIN BOOSTS
The 84-40 Tube has two gain boosts, which are activated, by push/pull pots on the overdrive
control of each channel. Pulling out the overdrive control of Channel One actives a subtle 6 dB
boost on both channels. Pulling out the OD control on Channel Two activates a stronger, 10 dB
boosts on Channel Two only. In general, these boosts are designed to get more bottom end,
punch and sustain when using the amplifier at low volumes. As the volume increases, the need
for added low frequency response decreases. Using the boosts at high volume levels may
produce unwanted "mushiness" in the sound.
BRIGHT SWITCH
The bright switch is activated by pulling out the master volume pot of Channel One. This adds
6-12 dB of boost at 6 kHz for more "crispness" and shimmer to the high end of Channel One only.
TONE TIP
Your 84-40 Tube will get the richest, most dynamic tone when the power amp section is working
hard; i.e. when the master volume control is up around 4 or 5. With the preamp volume around
6-7 and the master at 4-5, the 84-40 Tube will produce a punchy "clean" distortion - plenty of
sustain and harmonics, but without too much "fuzz" cluttering up the sound. For maximum
overdrive and distortion, run the preamp volume at 10.
REVERB
Reverb adds a spacious quality to your tone. The reverb control affects both channels. Set for the
amount of reverb you need. BE CAREFUL! Too much reverb may cause feedback. EFFECTS
LOOP
EFFECTS LOOP
The effects loop allows you to place your effects into the signal path after the preamp, for
smoother, quieter operation. To use the effects loop, run a cable from the "send" jack to the input
of your effect device. Then come out of the effect to the "return" of the effect loop.
To switch channels, use the front panel channel selector switch or use a remote footswitch. If you
use a footswitch, you'll need a single pole/single throw on/off type switch. Do not use an FET
momentary type.