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The
Pure Vinyl User Guide
includes complete information on setting the proper preamplifier gain. Briefly,
you should aim for “Dry” signal level peaks in Pure Vinyl between -20 and -4 dBFS, for the music
that you usually play.
Provided that peaks usually reach these levels, it’s not necessary to have to adjust
the gain setting frequently, or at all. It’s prudent to allow at least 4 to 6 dB of headroom below full scale,
to accommodate unexpectedly loud modulation levels. (At the
low
end of the suggested signal range
above, be certain that a signal peak represents music, and not “pops” or “clicks” from defects in or
contamination on the surface of the LP.)
If your audio interface permits setting nominal input signal levels to consumer or professional
format
(true of professional audio interfaces from Lynx, RME, etc.)
,
first try the consumer (“-10 dbV”)
setting, in conjunction with the minimum gain setting on the Seta.
•
If signal levels remain too high,
set the
input
of the audio interface to professional (“+4 dBu”)
format.
•
If the levels are too low,
increase the gain on the Seta. (For monitoring / playback, if the
output
levels of your interface can be adjusted independently of the input levels, use the +4 dBu setting
for the
output
.)
(The High gain setting on the Seta Model H preamplifier is provided as a convenience for using low-
output moving-coil cartridges with the Model H. The desirable audio reproduction qualities of the Seta
are retained, even at high gain settings, because the Seta design insures that bandwidth is independent of
gain. However, for dedicated use with low-output moving-coil cartridges, the Seta Model L is preferred,
because the noise characteristics of the low impedance, high-bias-current devices used in the Model L are
specifically tailored
to offer quieter operation and wider bandwidth with low-output moving-coil
cartridges than is possible with the circuitry used in the Model H.
Note:
the Model L cannot be used with
high-impedance cartridges such as moving - magnet or “high output” moving coil.)
Note: If you’re accustomed to using conventional phonograph preamplifiers, the
available “Flat” Seta gain settings may seem somewhat lower than usual. However,
they are tailored to using the Seta with Channel D Pure Vinyl’s digital vinyl
compensation curve. The required gain is about 10 to 12 dB less than needed in a
conventional phono preamplifier, because the signal is provided to Pure Vinyl with
treble emphasis (boost) intact.
(Note for the technically knowledgeable: this turns
out to be somewhat less than the maximum 20 dB boost of the RIAA compensation
curve at 20 kHz, due to the frequency balance of most music.)
For example, if you
would normally use a preamplifier gain of 58 dB for your moving-coil cartridge,
then the proper setting on the Seta would be 46 dB. (The Seta with the optional
RIAA hardware compensation module has an overall gain 12 dB higher than the
settings listed in the table.)
Cartridge Balance TRIM Control
The Seta rear panel (optionally front panel mounted) features a unique, precision trim control for
adjusting the inter-channel cartridge balance. The range of the control is 2 dB. The neutral position is with
the slot in the brass actuator oriented vertically. To properly adjust the cartridge balance, use a small
slotted screwdriver while playing a monophonic record (or a record with the music mixed to the center).
Observe the RIAA Balance indicator in the Pure Vinyl application, and adjust the trim control until the
value is close to zero (within ± 0.1 dB is sufficient). This adjustment should only need to be performed
once, and can be left alone, unless or until a new cartridge is later fitted to your turntable. The setting is
not affected by the overall Seta gain.
