Diamond Guitar Pedals BASS COMP User manual

Bass Comp
Optical Compressor pedal
User Manual
v1.00 • June 22, 2008
!
Bass Comp user manual v1.00!1

INTRODUCTION
Thank you for purchasing the Diamond Bass Comp pedal. Although bass players have
been purchasing and using our other pedals for some time, this is our first product de-
signed specifically with you in mind. Offering high quality optical compression and a
simple but effective ‘Tilt’ EQ control with selectable center frequency, the Bass Comp
provides an extended frequency response and high headroom to suit a wide variety of
passive or active 4/5/6 string basses.
We hope you’ll enjoy using this pedal as much as we have enjoyed designing it.
Remember to protect your hearing and wear appropriate hearing protection when play-
ing loud…
DESIGN BACKGROUND
The original Diamond Compressor was released in February, 2005 and quickly became a
hit with guitar players. Soon bass players were adopting the Compressor for its smooth
sound and ease of use. However feedback from bassists soon revealed that the low fre-
quency response of the original design wasn’t ideal, especially for 5 and 6 string players.
In addition, basses with particularly high output active pickups were capable of overload-
ing the input of the original design. After developing a modification of the design for bas-
sists, it was clear that a dedicated bass version was inevitable. Many of the features of the
Diamond Bass Comp are based on feedback from players just like you... thank you all!
FEATURES
•Vactrol opto-isolator variable resistance path as used in high-end studio compressors for
smooth attack and decay characteristics while preserving initial signal transients
•Post compressor ‘Tilt’ EQ provides a very musical tailoring of frequency response - from a
massively fat low end, to a bright solo tone with flat frequency response at the center detent
position.
•Selectable 250Hz or 900Hz EQ tilt point
•Optimized gain staging and use of ultra low noise transistors and opamps in the signal path for
lowest possible noise and extended signal headroom
•Premium audio components, including Rubycon electrolytic capacitors, 2% polypropylene
capacitors and 1% metal film resistors.
•Bi-color LED provides visual indication of depth of compression
•True Bypass operation
!
Bass Comp user manual v1.00!2

A NOTE ABOUT POWERING THE BASS COMP
For maximum headroom and performance, the Bass Comp should be powered using the in-
cluded 18V, positive tip adapter. However, for a situation where the 18V adapter is unavailable,
the Bass Comp can be powered from a standard 9V, negative tip power supply provided the in-
cluded red polarity reversing cable is used. The polarity reverse cable should not be used with
the supplied 18V adapter for normal operation.
Also, please note that if you haven’t played your Bass Comp in a while, it may make some noise
when initially powered up. This is normal. The special capacitors we use to achieve the excellent
low frequency response sometimes need a few minutes to charge. You can continue to play
through the pedal while they warm up without fear of damage.
USAGE NOTES
How the Bass Comp works
Fundamentally, compression acts as a leveling control- leveling the amplitude of notes to
make them similar in volume. There have been many design approaches developed over
the years to accomplish this task. The method used in the Bass Comp utilizes an analog
Vactrol opto-isolator which provides a very smooth compression, retaining the attack
characteristics of the input signal.
Where to place the Bass Comp:
The Bass Comp should be placed either as the first pedal in your chain or very close to
first (e.g. a clean boost or tuner could effectively be placed in front of the Bass Comp).
However, there are no hard and fast rules here, there are interesting possibilities in put-
ting the Bass Comp elsewhere in the chain. Feel free to experiment!
WARRANTY
Diamond Pedals carry a full five year warranty on registered products- make sure to send
us your warranty card! The warranty is simple- if you have a problem, call us and we’ll
make it right. Damage due to misuse is not covered by this warranty, however we will do
everything we can do get your pedal working again. We want you to be happy!
!
Bass Comp user manual v1.00!3

CONTROLS
The Bass Comp is an intuitive pedal and a few moments of adjusting the controls should
be all that is needed to dial in the tone you want.
COMP
This controls the amount of compression to be applied to the instrument signal. Backing
it off all the way gives just a touch of compression on signal peaks, while turning the con-
trol clockwise gives an increasing amount of signal ‘squash’. The compression threshold,
the input signal at which compression begins to take effect, is sensitive to level variations
like pickup output and string attack, experiment with this control for your particular setup
and desired sound.
EQ
The EQ in the Bass Comp is not a typical boost/cut tone control. Instead we’ve incorpo-
rated a ‘tilt’ style EQ first introduced in the 1970’s hi-fi market. The goal of this control is
to provide subtle yet powerful shifts in overall frequency balance, not just a simple dull-
ing or brightening of treble frequencies. You can think of the EQ as a ‘see-saw’ with the
balance point determined by the 250/900Hz switch (see below). Turning the EQ control
counterclockwise provides a boost to low-end frequencies below the tilt point while si-
multaneously providing a gradual decrease in frequencies above the center point. Turning
clockwise from the detent position provides the reverse- a boosting of frequencies above
the tilt point while decreasing those below the tilt point. This control is easy to use and
provides a very musical means of adjusting your overall tone.
250/900 switch
This switch determines the center frequency of the EQ control around which the low and
high frequencies are adjusted. 250Hz or 900Hz can be selected as the ‘tilt’ point. There is
no ‘correct’ setting for this switch- experiment and find the setting that provides the best
tone in your particular setup.
VOL
This adjusts the overall output volume of the Bass Comp. Use this control to match your
clean versus effect level, or use it to provide a boost in volume for those times when you
want the bass to really stand out in a mix.
!
Bass Comp user manual v1.00!4