nakamichi CD4 player /  AD-1864N

March 29 2008

I remember my student's years, when compact cassette was the media that ruled, and the absolute dream of us, young audiophiles used to be the ultimate of cassette players - the NAKAMICHI. The king of them all. My God, they were so much better than the other players, that I can't even describe it. All these three head, five motor mechanics, dolbyC, oh Lord.
Anyway - NAKAMICHI is a bloody legend - period. (I used to have the 480, and dreamed about THE DRAGON!)

nakamichi cd4

To my joy, I just found on the ebay a CD player with a minor fault, but otherwise spotless as brand new.
I never tried the CD from the legend - so I bought it.

A smartie as I am, I repaired it in 5 minutes and voila - there it is - the absolute stunning looking NAKAMICHI player - just screaming at me - "take me I am yours, lampize me, lampize me hard !!!"

A look inside the Nakamichi CD4 player

cd player4 nakamichi lampizator

The face plate - believe it or not - is all metal, including the drawer part.

nakamichi 4CD

The general view under the hood - very typical 1990's look of Japanese players - NOTHING is highendish about it, nothing legendary either - just an OKAY player, like many sanyos, sonys, toshibas, jvc's, yamahas and kenwoods. I did not notice any shiny contribution from nakamichi R&D department.

The transport is a middle range sony KSS210A: with good laser but low end mechanics.

kss-210A sony laser

sony laser

The power supply is based on one small transformer, and just ONE voltage regulator. Compared to say SONY CDP227ESD this is just a joke. Sony has a regulator per every individual chip.

Small and cheap transformer, they could have done better really.

Now the DAC part - I am excited because this is an unknown to me 18 bit DAC from Analogue Devices - just one stereo chip AD-1864N.

Good sign - just one op-amp per channel! I like this minimalistic output stage. And no ceramic caps for high frequency killing. Another point for CD4.

I test the remote - despite the sony laser, and sony servo - the remote from SONY does not work. It must be proprietary coded.


As we can see above, there are voltage outputs which are normally used in the player, and the conversion is inside by op-amps. The signal comes out of the op-amps on legs 8 and 17 respectively.
There is no possibility for balancing the signal. It is SE only.
The DATA SHEET is here: DATA

We will use the proper kosher I out - current outputs - by cutting away all circuitry from legs 4 and 21. This signal will feed straight to the lampizator input.
New electrolytic caps go between legs 9-13 and 16-13 observing proper polarity. (I use os-cons)


This is very easy job really. There is plenty of empty space for transformer, power supplies, cables, tubes and everything else. Shall one want to replace the clock - there is easy access to the standard japanese quartz - the 16,9 Meg.


lampizator trafo

Lampizator Power transformer happily sitting in it's new home

Two caps with an X on top are the digital section supply - these get replaced for os-cons or black-gates or ultimately - a 10 uF MKP/MKS caps.

os-con sanyo

 New os-cons in place.

output stage

on this blurred image we can identify the two blue caps - these are for analog part of the DAC (op-amps which we don't use at all). The green ones are for the output stage opamps.
The long black thing between the green caps is the double op-amp.

lampization stealing points
The bottom side of DAC chip - we can see legs 4 and 21 marked with black marker lines.
These legs must be isolated(floated)  from other circuitry.

The cut traces were leading from the right leg to the right and from the left to the left.
You can see the cuts near the tapping points.

The red wire is obviously the ground. It is connected to tube ground (leg 9)

The current of signal will flow like this: DAC leg - wire - tube leg 7 - resistor 300 Ohm, tube leg 9 -> DAC earth via red wire. The voltage drop on resistor will control the tube grids and get amplified.

The tube (one) is installed inside, as well as new RCA on the back plate.

THE TUBE SCHEMATICS: (I used 6DJ8 from Amperex (usa) which I found in my drawer.
this is a double triode - with:
U power = 155V DC, R anode = 25K, U Anode = 60 V DC, I anode = 4 mA, Rcathode = 500 Ohms, R grid = 270 Ohms, U grid = -1V, capacitor - from anode to RCA - 2,7 uF/400V.
Heaters: DC - C1=10000 uF, R=1 Ohm, UAC=6,3V, UDC=6,3V, I=300mA, C2=10 000 uF.

Full installation of Lampizator

nakamichi player4


The sound of lampized Nakamichi CD Player 4  is very very nice, although it did not bring me on my knees. It was a safe all-round sound, very natural, un-fatiguing, liquid and un-digital. It was missing in the detail and depth departments compared to the best players.
(A year later - I would have chosen a more suitable tube - the 6N2P from Russia. )
 I think that after some longer time I liked it more and more for complete lack of harshness and aggression.
Not that it was dull and boring - far from that - but this is the sound you can have all day and never have enough. Classical music really benefits from this character. All is in harmony and beautiful.
Considering very low price of this player, plenty of space, no noises, no hiss, no pops, no nasty surprises, great looks, metal face, cult status of the brand etc. - it is very recommended for amateur lampization fans. It simply can't go wrong.

READ ABOUT THE OTHER NAKAMICHI CDP2-e with LAMPIZATOR (an even better machine)