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Quick Start Guide
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15-044-11-1
Rev B
®
Quick Start Guide
©2005 PS Audio Inc. All rights reserved.
Owner’s Reference
GCPH Phono Preamplifier
AÊÊUÊÊDÊÊIÊÊO
PÊS
is a very high gain input with an RIAA curve built in and was designed for the turntable only. You can
use any high level input for the GCPH, regardless of its nomenclature.
Once the GCPH has been connected to both the turntable and the preamplifier or power amplifier,
turn the system on. Make sure the front panel gain control is all the way down (counterclockwise)
and turn it up only after setting the rear panel gain and input impedance selectors. Changing these
selectors can send some pretty loud thumps through the system, so make sure either the preamplifier
volume is down or the GCPH front panel gain control is down when adjusting them.
Depending on the type of cartridge you are using, moving coil or moving magnet, set the rear and
front panel gain and impedance settings appropriately at this time. The gain selection of the GCPH
is accomplished by adjusting both amplifier stages inside the GCPH to best advantage. The GCPH
is built from two gain blocks with a passive RIAA curve between them. The rear panel fixed gain and
impedance selectors control the input gain block and the front panel gain control adjusts the second
output gain block (it is NOT an attenuator but rather a gain adjustment of the Gain Cell). By optimizing
both the input and output gain blocks for best noise and sonics, you can customize your GCPH for
the best performance.
To set the gain and impedance for a moving coil cartridge, use the higher gain settings and the
lower impedance settings. Moving coil cartridges typically have lower output than moving magnet
cartridges. The best way to adjust the gain of a moving coil cartridge is to first choose the coarse
setting of the input gain block from the rear panel gain selector. Choices are 48/54/60/66dB. We
recommend starting with 54dB to 60dB and then using the front panel second gain block adjuster
to tweak in the gain value. If you choose a rear panel coarse gain setting that requires the front panel
gain control to be close to either extreme of its range, minimum or maximum, change the rear panel
coarse selector up or down in gain to allow the front panel control to be somewhere in the middle or
upper ¾ of its range for best performance for best sonics.
Moving coil cartridges typically require lower impedance settings to properly damp the high frequencies
of the moving coil. Most moving coil cartridge manufacturers recommend either the 10 Ohm or 100
Ohm settings and we would recommend the 100 Ohm setting as a good starting point if you are
unfamiliar with the sound of your moving coil cartridge. Raising the impedance will reduce the coil
damping and increase the high frequency output of the coil.
Many vinyl lovers tend to ignore this basic low impedance tenant of a moving coil cartridge and prefer
the more open top end achieved by raising the impedance to the 1k or even the 47K position reserved
for moving magnet cartridges. This practice is perfectly acceptable with the GCPH. However, many
moving coil cartridges will sound overly bright at this higher impedance setting and so require either
a lower impedance setting or careful adjustment of the VTA (vertical tracking angle) of the turntable to
reduce the brightness. Typically a negative rake (where the rear pivot point of the arm is lower than the
head shell where the cartridge is mounted) on the VTA will produce a less bright sound.
To set the gain and impedance of a moving magnet cartridge, use the lowest gain setting and the
highest impedance. Moving magnet cartridges should be set to 48dB on the rear panel gain selector
and should only be used at the 47K impedance setting. Using a lower impedance setting for a moving
coil cartridge will result in a dull sounding top end and is not recommended.
Using a
Higher Than
Recommended
Impedance for a
Moving Coil
Adjusting a
Moving Coil
Cartridge
Adjusting a
Moving Magnet
Cartridge
Set the Gain and
Impedance
3