Universal preamp with headphone
I made this as
my first project to make the headphone output for the DENON CDP. But I
decided to publish it as universal project for simpe to do preamp.
Anybody can mount it in one afternoon.
This machine has
three stages, all very simple.
The first is a
typical SRPP lampizator , which goes out to the RCA. Thats all, all
line level preamplifier.
which is more demanding in terms of current and power - there are two
next stages. First - a triode amplifier with anode follower circuit,
and second - a cathode follower buffer for 80 Ohm output impedance and
In between the
preamp and head section there is a headphone potentiometer.
If this is not
inside a player but in separate box - the pot should be the first
device after the input sockets, before the lampizator grid input.
I decided to use
ecc88 tube which I like very much. But to go full throttle you may
build a PRO version and use 6H6P tubes.
Of course there
are simple improvements which anybody can add like a MKP bypass of all
electrolytic capacitors and a coil (choke) in place of anode supply
resistors of 1K. The chole should be good to deliver at least 20 mA
Here is a small but excellent pre which I made in 2010