Lampucerized CD
One of the beautiful features of Lampucera DAC boards is that it is
small and fits in small spaces.
Another good feature is that it just requires one 5 VDC by 50 mA
power supply
On this example I will show how a 40 Euro old Kenwood 4090 player gets
its second life with high end pretensions.
A lampucera board, with full tuning will be implanted inside the CD
player, using its SPDIF signal and parasitic power supply.
The DAC inside is like an Alien inside the belly of Sigourney Weaver.
This is well known player, we like it because of high reliability,
pretty face, great ergonomics, great dot pixel text display, cool
drawer mechanism and low price. And for biiiig empty space inside.
Just what we need.
First step is installation of new RCA sockets. The old ones are de
soldered and removed.
New RCA's must be of course grounded.
second step - lampucera (on the picture - stock unit without tweaking)
is installed on metall hex bolt legs as close as possible to SP/DIF
source.
The two holes on the side are for tube socket.
This is the Lampizator output stage power transformer with a three
capacitor power supply for high voltage (150 VDC) and the heaters in
this system can be AC powered. In Cathode follower triode there is no
hum from AC heaters.
The transformer is mounted in the hole where originally the players
foot was screwed. Now a 4 mm allen key bolt holds the transformer AND
the foot on the other side.
A 820 uF cap and two 100 uF caps are hot melt glued to the transformer.
Resistors are 1 K to smooth the AC pulsation of the anode supply.
Each green cap supplies one anode of the triode - tube halves.
The tube of choice for cathode follower is 6N6P with circa 7 mA current.
This is a quick and dirty power regulated supply - a 7805 regulator
without heatsink is soldered by its center leg to the groind which I
found nearby (a PCB wire jumper)
The left leg of the regulator is supplied from a 12 V DC supply to the
old opamps (opamps are removed now, remember? ) So the 12 V is unused
and available.
Output - right leg of 7805 regulator is connected to electrolytic cap -
2200 uF by 16 V and then sent to Lampucera 5 VDC power input.
Lampucera cground is also connected to the GND with the regulator's
center pin.
Simple innit?
Lampucera has now very pure, double regulated % V supply - just what
the doctor ordered. The player is very happy and we don't need to buid
the whole raw supply from scratch. This one costs 3 Eu.
One tube is installed, triode mode, half tube per channel. Screen is
grounded, heaters are 6,3 VAC supplied between legs 4 and 5.
150 VDC is supplied directly to legs 1 and 6 of the tube.
Each grid gets signal from lampucera DAC chip via two good caps. I used
Tantalums - 47 uF by 6 VDC. Polarization plus towards dac.
Each grid has to see the ground via a 250K - 500 K resistor.
Each cathode has a 330 Ohm resistor to ground.
SCHEMATICS
The cheap plastic sony lookalike transport now provides raw data to
Lampucera which becomes a separate dac but sharing one box with the
landlord Kenwood.
In this way the cheap and overall nice Ken became a giant crunching
machine, with modern, detailed, full blooded sound, full of definition,
space, depth and music.
For many people hearing this 150 Euro (raw cost) job would be a REAL
SHOCK.
I also did the same in one Marantz 67,
one MHZS66 and one other kenwood DPD 5090