l'Audiophile MC Pre-Pre

Folks, with just few resistors, one JFET, one output cap you can build a
step-up device.

12 Volts regulated or accumulator buffered supply

The basic topology is that of the second step-up amplifier by "Maison de
L'Audiophile" of Paris/France.

The first 100R is the cartridge load, which must be adapted for the
cartridge you use. Using a paralleled 1nF cap also makes the circuit immune
against RF noise. The 47R resistor in the source is not necessary, if the
JFET has an IDSS(on) of 2mAmps or less.

As the signals are very sensitive, the voltage must be very clean, a 100 000
uF electrolytic cap for blocking power supply noise, computer grade

favourably, is advisable. Suitable JFETS are 2SK170, 2SK240 (double JFET),
2SK97 (double JFET), sorry only these japanese types are suitable, the
European BC264 and BF254 and so on do not work here (I tried !).

All resistors must be big metall resistors, e.g. Beyschlag 1Watt, or
tantalum resistors. No carbon resistors allowed here, tubes addicts.

The output cap is preferably polystyrene or polypropylene or paper-in-oil,
as you like it, as they are different in sonic balance.

Pacific RIAA Pre - 24V Version


We build the Pre using both the Fet Pre Pre and the Pacific. PSU is 3 X PP3
NIMH Recharables. The Pre Pre get's it's PSU via a dropper resistor and a
2,200uF Decoupling Cap (Black Gate or similar) so that 12V are supplied to
the Pre-Pre.

Later Thorsten