PS Audio GCPH Owner's Reference Manual - page 12
4826 Sterling Drive, Boulder, CO 80301
Troubleshooting
PH: 720.406.8946 support@psaudio.com www.psaudio.com
15-044-11-1
Rev B
®
Troubleshooting
©2005 PS Audio Inc. All rights reserved.
Owner’s Reference
GCPH Phono Preamplifier
AÊÊUÊÊDÊÊIÊÊO
PÊS
first gain block to the appropriate gain setting you can keep the self noise (hiss) at a minimum. A
good rule of thumb would be to always have the lowest gain setting in the rear that allows the best
combination of noise and undistorted performance while permitting the front panel gain setting to be
in the ½ or ¾ position. Keep in mind that the rear panel gain setting control the input gain block of
the GCPH and the front panel gain setting adjusts the output gain block (after the passive RIAA curve)
of the GCPH.
Hum is a common problem in turntable setups. This is because the cartridge on the turntable acts
like an antenna connected to a very high gain amplifier (the GCPH). To minimize hum, make sure the
turntable is properly grounded and properly shielded interconnects are used between the turntable
and GCPH. Typically, turntables have a separate ground wire to be connected to the green binding
post of the GCPH. If you are experiencing a higher level of hum than expected, try the system with
and without the ground wire attached. It may be necessary to “cheat” the third wire AC ground of the
GCPH with a 3 prong to 2 prong AC adapter in extreme circumstances. This method is not as safe
as leaving the third wire AC ground connected so we do not recommend its use.
Use of shielded cables between the turntable and the GCPH are mandatory. Over the years we’ve
seen all manner of cable constructions that make the system “sound better”. While we are firm
advocates of better cables for the highest-end performance, we are not advocates on unshielded
cables between the turntable and the phono preamplifier. This is just asking for trouble from hum,
his, radio stations etc. We strongly recommended not using anything but the best shielding on the
interconnects. Our Transcendent line of interconnects are perfect for this application and you will not
find a better sounding cable.
Lastly, it may be necessary to ground the headshell to the arm and subsequently to the ground wire.
Some turntable manufacturers neglect to ground the cartridge mounting headshell to the tonearm.
This means the cartridge body is not grounded and will lend itself to acting like an antenna for hum,
hiss, noise and radio stations. If you suspect this is the case, contact your turntable manufacturer for
assistance.
Ground the
Headshell
Hum
Shielded Cables
7