Philips cd-304 mkII
There is so many Philipses that I am getting lost. Virtually tens and
tens of models. All as ugly as a sin, all looking cheaper than
they
should, and all of them extremely good value for money. Add to the list
all
the clones like Marantz (Philips with 4 x price tag), Grundig, Telefunken, Loewe, Diora,
Blaupunkt, Revox, Studer, etc which used their entire building
blocks like mechanism, display, remote, dac, chassis - everything
including whole PCB's were used at that time (90's) from Philips.
Of course, knowing what we already learned in the process, we focus
only on TDA1541 chips.
That narrows down the choice to a fraction of
the pool, but still tens of models.
304mkII is no exception - it is a fantastic tweaking base.I could name it the first BASE of all players.
The oldest of them all but still very good.
The
mechanism is among the best ever - CDM1, like in applauded MArantz CD-94 and Philips CD-960 for example. It
is a joy to look at, even if compared to the benchmark Sony's 190A or the one
of Kenwood CD-X9010 it looks like a messy prototype.
Just remember - you want MK2 not standard 304 !!!
Note the golden color - all upper PCB is just one huge ground plane of copper.
304MK2 will be the third CD in series in which I found 100nF (0,1uF) SMD capacitors
used as a DAC decoupling function. 14 of them underneath each TDA. The
replacement of these SMD caps with normal mkp ones (but also bigger - 220 or 470 nF) makes the single
biggest sonic difference I heard - arguably bigger than the actual
lampizator job.
Comparison of the removed SMD caps and the new one (the big un)
The combination of the lampization, op-amp upgrade and decoupling cap
tweak takes any
TDA based CD player to the top league, where only Grundigs and Revoxes
used to reside.
The Philips CD630 and Grundig 9000 with the same mod must be one of the
best
CDs at any price that I heard, and considering their 50 Euro price tag
- that must be called the bargain of all times. Marantz 40, 50 and 60 are
almost the same inside, and should be done in the same way. Having said
that, Marantz 60 is nowhere near the build quality of the Philips 304.
In fact, the 304 is arguably better than any revox, even their best -
226S.
Just take the all cast metal chassis, frame and mechanism, all shielded
transport, separate PCB for analog and digital, all metal drawer, all
alu front face (buttons included) and 6 separately regulated power
supplies. That whole thing is very close to the Grundig 9009, taking
the position of the queen ;-)
Crowding of the large MKP caps as SMD replacement - underside of the
TDA1541 chip.
Shielded transport cage
6 separate power supply regulators on a massive heatsink
all metal drawer
CDM one - upside down. This mechanism is a dream !
This player will be lampized externally with I/U conversion by a 80 Ohm resistor.
LAMPIZATION PROCESS
There is no room for power transformer
The drilling in its cast-metal, tank armour body is a nightmare
PCB's are lovely easy to work on.
I used resistor (80 Ohm) as I/U converter - no op-amps at all.
I opted for more powerful tubes - the super 6H1P instead of 6H6P because of higher gain and smaller size.
Pinout is the same, heater current is slightly smaller - 0,6 A instead of 0,75 per tube.
Anode current is 2 mA at 180 V DC voltage (from 110 VAC secondary supply) which in SRPP circuit means 90 V on the anode.
Tubes fit inside, but all power supplies are external in a small box hosting the transformer and PI filters.
Tubes squeezed in ... nice...
The BIG DIFFERENCE is obtained by replacing the under-side SMD
capacitors of the DAC chip with 0,22 uF (220nF) MKP's. I do it with
magnifying glass to solder properly.
I also install same MKP cap as a bypass to all electrolytics
which sit near each chip as the power supply filters to the chips.
I also recommend to replace such old electrolytic caps with new ones - like Oscon, Teapo or Jackcon low esr type.
Here is what a totally instane pen-pal of mine named Paolo from Italy
did with his CD-304. He must be a MAD SCIENTIST (and single) ;-)
Hi Luka
I send you the picture about my job
The trasport working wery well and for my experience is better the tda 1541
Now i have this configuration:
Philips cdm0 with clamper
Zero oversampling
Tda 1540 0r Tda 1541,i can swich it
Up trasformer
Srrp of 6sn7
Crazy what can do the first generation cd philips in my case the sound is wonderfull
For install the tda 1541 is easy,take 4 wire more ground from saa7000 end link to tda 1541.If you are interesting i send you you my diagram
Ciao
Paolo
passcode@libero.it
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