Non Over Sampling modification (NOS)

In December 01 :  (Sensational success of SONY NOS mod - click to jump straight to the point)

february 2008

After looong delay I finally tried the nos. Motivated by impatient friend, as usual.
He wanted a snipit mod plus NOS to squeeze the best sound for the buck from his old but beautiful Marantz CD94-1.
I searched for tips and I found this nice help from DC audio web site:

(also check his excellent list of CDM mechanisms:

Anyway, back to nos modification, it is a very simple process.
In case of TDA 1541 we just build a bypass of digital signal across the chip that precedes the TDA and feeds it with the digital signal - we cut away SAA7220p/B

What over sampling accomplishes is easier removal of sampling frequency components from analogue signal.
In 44 kHz sampling rate, the 44 kHz square wave signal is "dangerously close" to audible  musical 20Hz-20KHz range. It is much easier to filter the "noise" if the difference between the 20-20 and the noise frequency is bigger than only twofold. That's when the clever engineers decided to accelerate the clock on the square wave by 4 or 8 and in this genius simple act - move the noise to completely inaudible range above 100 kHz. The remaining artefacts are easy to filter in the analogue domain.
If we remove this process we bring the noise again to 44 kHz - so it may be audible.

Well, I am not deaf, I am not 100 years old, and I do have one hell of a tweeter - and let me tell you - listening with NON - oversampling - there is NO PROBLEM AT ALL. At least not with TDA1541.
After the mod - the music flows somehow easier, in a more liquid, more natural fashion. It does not loose any of the good quality, none of the power or attack of bass - everything becomes just a little bit better. Don't expect miracles - I said a LITTLE BIT BETTER.
Highly recommended.
See the Marantz mod description in detail.

April 9th.
Encouraged by my first experience - I also modded the next player - the mighty philips CD-880. It also has the usual trio of chips - 7210, 7220 and 1541A-\s1. I followed the instruction of DCAUDIO and the result was really fantastic. The owner, who is a first class opera singer and music lover - with his ears 100 times more trained than mine - just loved the result of this 20 minute mod. Clearly - there is no debate - no return to the over sampled mode. I agree.
But one thing worried me - the mute function got screwed up - there is a small noise when changing tracks and the pause function results in CD reading stopping in the chosen moment BUT THE music still flows. It is like a 0,1 s portion of the track is played in a loop with full volume. The CD mechanism reads just one full circle of the CD and does not forward - but plays this circle audibly.
The recommended trick of bridge from leg 11 to leg 23 does not help. I must further investigate this circuit. But even with this minor inconvenience - the listening enjoyment is increased by a whole new level.
The famous "veil" is removed, a thick veil that is.

May 2008 - I managed to NOS the Marantz CD50 (same as CD40, CD60, and many many more)

This time I paid attention to detail and the mute works properly.
Here comes the instruction proven and tested following the DC AUDIO tips :

1. Locate the "LEG 1" on the underside of 1541 and 7220 chips
2.  on 7220 cut both traces  as close as possible to legs 15 and 16
3. on 1541 cut trace as close as pos on leg 1
4. using a thin wire connect the 1541 and 7220 : leg 1 to 1, 2 to 2, and 3 to 3. 
5. connect the 7220 leg 23 to the other chip - the de-modulator chip 7210 leg 11. In case of the Marantz 40/50/60 - there is a newer chip - the 7310 - a square black spider with 44 legs - 11 on each side of the square. The mute is in this case leg 18 (which looks like floating)
6. sit back and listen.
In case of the SAA7220 and SAA7210 chips - if the mute trick does not work, you must float (isolate) the leg 11 on SAA7210 before connecting it to SAA7220P 's leg 23.


On the photo the chips are identified and their respective legs are marked. Leg one is the one with arrow and circle. Note that the TDA1541 has new decoupling caps - the 14 orange ones above.

nos marantz tda1541a

The demodulator receiver chip SAA7310 has leg 18 important for mute function.
Note that the capacitor upgrade is not finished - the new os-con in the chip power supply has legs uncut.

Non over sampling lampizator

The NOS job completed except the mute wire. In red circles are visible trace cuts.

  my next plan is to add a super-power to the 1541. Meaning - a dedicated power line:

there are 3 power inputs: -15V - leg 15th,  5V  leg 27, 28  and -5V  leg 26th. I could build anew all three  voltages, but there is an easier route for lazy man:

 The 7220 and 7310 are both powered by just one 5V plus. And these chips inject back the noise to this power line.

So to eliminate the interference and to give each chip a dedicated power supply, I suggest to keep the DAC as it is, but to give a new power to 7220 and 7310 (7210). Just use a 7805 regulator followed by one oscon for each chip.
The 7805 goes like this: left leg to power input - any value between 7 V and 20 V DC. Middle leg to ground, right leg to chip. Keep it as close as possible to chip. Replace the electrolyte in the chip power input for os-con with 150 uF or more by at least 6,3V DC.

I will take raw DC from just after the transformer and first bridge: there is I think 20 V of raw dc. We can also get rid of the output opamps and treat the op-amp power - PLUS 12 V DC as the input to the 7805. This power is now un-used (opamp dead) and it is double regulated !!)

I will put a small choke (coil) on cable leading from my power supply regulator to the DAC chip.
Last step will be the clock  .
By that time the player will be UNBEATABLE.
SEE the description HERE

Non-Oversampling NOS mod of the NAIM cd player CD3 with TDA1541A-S1

In june 2008 I managed to lampize and NOS the funny little player Naim CD3 from NAIM - the British legend.
I found the CD3 to be absolutely fantastic player. After lampization its quality jumped so high, that it reached category Zero above almost all other TDA1541A players.


Naim CD3


The red lines are TRACE CUTS and the yellow cables are signal bridges. That's all !!

Below is the Marantz CD94 MK2 modification to NOS

 (remember - it has  2 DAC chips in mirror signal mode)
The circuitry which we must modify is on the vertical brown PCB on the right hand side of the player. Actually after removal  - the underside is green.

marantz CD94

AND NOW ABOUT NOS for TDA1540 ?????

another worthwhile thing to do.
There are so many wonderful players with TDA1540 - the digitally inferior and musically superior DAC.
Like for example Revox 225, Marantz 73, Loewe CD9000, tens of Grundigs, Philipses, Nakamichi, and many many more.
I am trying this on my Philips CD-104
Recommendation courtesy of Frank Willem de Haan from the Netherlands whom I thank

- remove TDA7030 completely
- in place of TDA7030 connect four wire bridges:

pin 20 - pin 3
pin 17 - pin 10
pin 18 - pin 6
pin 21 - pin 7

- de-solder only pin 16 on SAA7000 with a solder wick and make sure pin 16 "floats", it does not make any contact the circuit board. (or simply cut the trace)
- solder a 1K resistor on top of  SAA7000, between pin 16 and pin 18 (to put SAA7000 in 14 bit mode, because TDA1540 needs 14 bit)

Listen to your CD104 the way the Philips engineers designed the CD player, before they were forced into messing up the sound with oversampling because of  the "16 bit race".

Non destructive, if you want to revert;  remove 4 wires, solder TDA7030 back in place, remove resistor and re-solder SAA7000 pin 16.

[While you are at it with the CD104, remove the "griplets" (small rivets) between top and bottom of the circuit board and replace each one by soldering a piece of wire from top to bottom for better earthing. This is the best advice given to me and has solved almost every problem with the 12 CD 104's that I have stashed around the house]

I tried this recipe on Philips CD104 and Revox B225 and in both cases the improvement is huge. Very much recommended !

Simple, innit ?

NOS for the SONY CDX1088 digital filter

The Sony players like CDP-555ESD , and some others like Nakamichi CDP2-e do not use the SAA7220p/B but instead they use Sony CDX1088 chip.
It basically works the same as the Philips, but it is SMD hence it is hard to solder to its legs.
The CDP-555ESD has 4 times oversampling applied inside the chip that precedes the Philips DAC  TDA1541, which is SONY CXD1088. We can identify the pins which carry I2S signals and bypass the chip by means of a bridge of 3 wires a'la Philips 7220p/B. BUT..... the sony chip is so small and it is SMD that the soldering is too difficult for me. Even with 10 x magnifying glass and a sharp soldering tip I am unable to do it properly.
The tracks leading to and fro this SONY 1088 chip have no other points where I could tap to them. The only possible scenario is to solder to chip legs.
I threw the towel. Sorry. Maybe I will try one day again.

A month later I decided to try it. I chose Sony CDP333ESD and I bridged the I2S signal over the CXD1088 . The result was a mixed bag - there was sound audible only at MAX amplifier volume. So the player played OK, but it was somehow muted. I found 3 different MUTE pins on three chips around. I experimented with isolating, floating, grounding of these pins - and no success. The music was audible but probably -60dB. I gave up until someone tells me where I went wrong.

November 2008

Sensational breakthrough application of NOS to Sony

Thanks to the power of internet, I got some help from very kind pen pal Mr. Avinash. He suggested a digital trick which basically changes the internal data protocol between SONY chips which preceded the TDA1541 DAC.
Here is what he says:

I thought I would let you know that I have now successfully made the NOS mod to the Sony CPD 227ESD.  (L.F. > It is also directly applicable to Sony 950, 710, 337ESD, 333ESD ESD, 555 ESD, and probably also to the Nakamichi CDP-2e)
The main issue to solve is that the output of the Sony DSP chip CXD1125 is in the Sony/EIAJ format and not the Philips I2S format. The easiest way to convert the Sony format to the I2S format is to delay the LRCLK signal by 7 bit clock pulses and swap the analogue outputs of the TDA1541A so that what was previously the Left channel ouput becomes the Right channel and vice versa. BCK and DATA can simply bypass the CXD1144P filter chip.
I used a 8 bit serial in, parallel out (SIPO) shift register (74HC164A) chip which costs about 20p in the UK. The input to the chip is the LRCLK signal from the CXD1125 chip and I used the 7th bit as output to the two TDA1541A's. You also have to take a parallel BCK signal to this chip as well as +5V (taken from the CXD1125) and ground. If you take a look at the data sheet, copy attached, you will be able to see how it works.
This gives full volume (and full resolution) on the analogue outputs of the TDA1541A.
I was getting some noise when the CD player was not playing any CD's but this goes away if you switch the Digital Out at the back of the CD player off.
The sound out is analogue like and flowing very much like other NOSed TDA1541A CD players but the 227ESD also appears to have better resolution and clarity. It is a little bit better then my NOSed Marantz CD40 to my ears.
I am listening to it right now and it is sounding very good!!!

On the photo above the pins 14, 9 and 2 are shorted, ready for +5V

The pin connections I used on the 74HC164A are:
Pin 1 - LRCLK from CXD1125 taken from before R540 connection with R540 leg lifted - input clock
Pins 2,9,14 - +5V from Pin 8 of CXD1144P supply line
Pin 7 - Ground
Pin 8 - BCLK from before R542 with R542 leg lifted.. Same signal goes to both TDA chips leg 2 and 2.
Pin 12 - Output LRCLK to the TDA1541A's legs 1 and 1 parallel.  - left-right switch clock
The remaining DATA signal goes from any of the R541 sides of  resistor to both legs 3 of TDA1541 paralleled,
All other pins of the 74HC164A are unused.
This already plays FANTASTIC music but makes some noises on pause.
From Lukasz:

CDP227ESD has all points of interests exposed on upper side of PCB.
We have the BEFORE FILTER points where the digital signal must be captured: Resistors R540, R541, R542 carry data, BCLK and LRCLK signals.
AFTER FILTER there are elements that must be lifted: R553, 555, 556 and 557. L555 (coil in a black box)). I broke them irreversibly by pliers.
DATA goes directly across the FILTER chip. LRCLK goes by means of the new chip 74HC164A which shifts it. BCLK goes across the filter to DAC but on its way it touches 74HC chip pin 8. TDA as usual is operated with legs 1, 2 3 and 4 floated but 2 and 4 are connected. Both DACS are parallel - all respective inputs shorted.

There will be garbage noise when CD is on pause or skipped to next track.
The mute remedy is analog relay mute which used to mute the old signal.
We must find the output relay - the black box near old RCA outputs. We connect the relay's legs marked NO to the RCA outputs.
Before that we must float these relay legs which used to go to old outputs. During mute  period the relays will ground the signal.

Above you see the resistors leading to the two  DACS lifted
(huh, to be precise - they are broken. I admit it. My tricks are irreversible.)

The small black cube MATSUSHITA in the center of the photo is the output muting relay.

The mute works well for no play period, for play period, for fast forward and backward too. Only for the track skip there will be 1/10 th of a second of unwanted signal. Small problem for a great improvement overall.
The sound does improve a LOT. It jumps to the next upper class of playback systems.
Strongly recommended.

In Sony CDP-333ESD with one TDA and CXD1125 demodulator and typical digital filter CXD1088
we go like this: the whole job is done on the bottom of the PCB.
data goes straight from CCD1125 leg 78 (lift R311) to TDA pin 3 (floated)
BCLK goes from pin 76 of the 1125 (trace it to the first breaking point - a jumper or resistor and then float it by lifting that part)  to the pin 8 of the 74HC  and from there straight to TDA pin 2 (joined with 4 and together - floated)
LRCK goes from pin 80 of the 1125 (trace it to the first breaking point - a jumper or resistor and then float it by lifting that part)  to the pin 1 of the 74HC and from pin 12 (output of 74HC) to TDA pin 1 floated.

ABOVE: The 74HC chip in first experimental player 333 ESD. Works from the first time !!!

These are output muting relays to be used in 333ESD
They are already floated.


MC74HC164AD - 8-Bit Serial-Input/Parallel-Output Shift Register

High–Performance Silicon–Gate CMOS
The MC74HC164A is identical in pinout to the LS164. The device inputs are compatible with standard CMOS outputs; with pullup
resistors, they are compatible with LSTTL outputs. The MC74HC164A is an 8–bit, serial–input to parallel–output shift
register. Two serial data inputs, A1 and A2, are provided so that one input may be used as a data enable. Data is entered on each rising edge
of the clock. The active–low asynchronous Reset overrides the Clock and Serial Data inputs.
• Output Drive Capability: 10 LSTTL Loads
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 2 to 6 V
• Low Input Current: 1 mA
• High Noise Immunity Characteristic of CMOS Devices
• In Compliance with the Requirements Defined by JEDEC Standard
No. 7A
• Chip Complexity: 244 FETs or 61 Equivalent Gates



SONY family of ESD players in Non Oversampling mode (NOS)

after experimenting with my two players from that family - namely CDP227ESD and CDP333ESD I drew a conclusion.
1. TDA1541A is a hell of a dac, its full potential is unlimited.
2. The Sony NOS implementation is better than Philips one, to be found in Grundigs, Marantzes and Philipses. The difference must lie either in the laser mechanisms (227 uses KSS151A and 333 uses a better (best) KSS190A or BU1. Or it lies in the fantastic sony demodulator chip - the one which converts laser impulses into proper digital format datastream. Or the difference is a sum of the two above. Anyhow - the sound coming from NOSed and lampized ESD players is totally awesome.
3. Two DAc chips in 227 do sound better than one in 333.
4. 6N2P is best tube I know today for this particular application (in SRPP mode)
5. if you love MUSIC not HiFi - you can not find anything better without financial constraints. I guarantee it.

It is very very hard to impress me with all my experience and knowledge, I was not prepared that there may be such a giant quality leap waiting to be unleashed.
Even SATCH dac, which theoretically is TDA at the limits - is inferior to Sony in NOS mode. That is understandable - SATCH must use SP/DIF process of transmission, and Sony is one box solution which does without SP/DIF at all. All process is direct and very simplified.
As good as Sony 227ESD is on its own, as great as it is with lampizator, after NOS - the sound is drop dead gorgeous. It re-defines my quality ladder, all classifications of sound quality must be downgraded to make room for this new whole class of quality.
The pleasure of listening goes up whole level, the amount of information is beyond my wildest expectations. It is not about bass or trebles, it is about the ease of understanding what is in the recording. The details in background become so easily understandable, the secondary instruments are miked anew. I hate to say the most trivial sentence like "I heard things I never heard before" but that is just that - all intimately known recordings become totally new experience. On general note, all aspects of reproduction become very LOVABLE and right - timbre, color, space, timing, voices are natural, space is wiiiiidddeee, instruments clear, separated, audible. I cant really describe it. It is far above my language skills to tell you how good sound becomes.
From everything I ever heard, the 227 ESD nosed is by far the best sound. This is so good that I would say it is the end of the road. Absolute lack of desire to try improvements. It is what I dreamed about all my life.  I cant even write about it anymore - I rest my case.

NOS for Grundig Fine Arts CD9009

read here at the bottom of the page.

GOOD LINK to read




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