3
X
s
Preamp Owner’s Manual
For your protection please
read the following:
accompanied by much larger heat sinks, and the circuit will now drive
any reasonable load (I have successfully used it to drive my 16 ohm
Lowthers).
The circuits are now completely DC coupled throughout (no
capacitors), and the frequency response is flat to 100 Khz.
The XP-30 could swing enough voltage to drive a balanced follower
output stage to 80 watts rms. The Xs increases that figure to over
150 watts.
Some of the materials have gotten more exotic – the gain stages are
mounted on ceramic circuit boards with gold plating. The channel
motherboards are made of Panasonic Megtron with immersion gold,
which performs about as well as Teflon or Polyamide but without
the adhesion properties. The power supplies use 4 ounce plated-
through high temp FR406.
While the two channels share a chassis, they are isolated on separate
board systems with distance between them, so the crosstalk figures
between channels are as good as the XP-30 separate chassis. Each
channel and the digital control circuits have their own isolated
supplies, each mounted on it’s own board in a separate chassis.
The three separate power supplies use the lowest noise transformers
available from Plitron and they incorporate EMI filters on the AC
line input, secondary output, fast/soft recovery rectifiers, large
storage capacitance and extensive regulation. The active regulation is
both series and shunt types, and is followed by passive filtering using
polypropylene capacitors.
All this in machined aluminum cases. If like me your eyesight is not
what it once was, you will also appreciate the larger display on the
control panel.
It does not automatically follow that more money and more exotic
parts and such will result in a better sounding product. Indeed,
some of things Wayne tried did not work as hoped, although they
measured well enough. Fortunately there was lots of time available,
and the back-and-forth process between Wayne and the four other
listeners assured the finest product we could possibly make.
At this point, I can only say that if you are on a restricted budget you
might be wise to avoid borrowing one of these.
Nelson Pass 2013
