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The big question of TRANSPORT

CDM1 mechanism transport  Loewe 9000 CDM-ZERO wonderful machine

In this article we will touch a couple of  sensitive points concerning TRANSPORT - its role, quality etc.

1. Bits are just bits or aren't they ?

2. Why separate DAC and Transport ?

3. What sources other than CD transport ?

4. Why do we perceive quality difference between transports ? Why FIFO buffer a'la digital lens does not solve all transport problems ?

5. How to send data? SP/DIF, Toslink, AT&T, I2S  or other ?  What makes a link good or bad ?  Does the word Digital Cable has any sense at all?

6. Tweaking of our old CD player to make it good transport and a giant killer

7. Shigaraki Clone Mania spreads like a bush fire

8. Can we make transports from old champions of mechanics like Philips CDM0 and CDM1 players? Marantz CD 73 for transport, anybody ???   ;-)

9. Digital outputs from  NAIM, and Bang Olufsen 5500

10. Oscilloscope works on everything we can find about the SP/DIF interface, cable and chips. Can we safely turn the adjustment head on the SP/DIF transmitter transformer ?

11. DIGI-Lampizator for the die hard diyers.

12. What if there is no SP/DIF output (digital out) in our CD player, only Toslink fiber optic type ?

The idea behind transport and DAC being separate is that one can try different DACs with his transport. Some people claim that the idea is that separation per se gives improvement which is not true. It is a myth. I believe in one box players because all parts involved in musicmaking are close together and there is no problem. The separations means that the signal has to go through three extra stages without any benefit. If separation was an issue, we can do it by means of a simple and cheap optoisolator chip. But two separate boxes mean that the signal has to go to the transmitter chip, the transmitter interface with transformer etc. and then through cable into a receiver chip and so on. So there are many possibilities of screwing up the signal. I am NOT CONVINCED AT ALL that separation brings any benefits, only problems.
Having said that TODAY, 23 years after the best CD machines were produced, we face the problem of laser failures. So separation gives us an opportunity to buy or build THE BEST DAC money can buy and hold on to it, and the transport - whichever we have - it can be a CD transport, a CD player, a Playstation, a digital tuner, a computer, a LAN receiver - can be substituted and changed.
So having a super - cool DAC separately is not a bad idea. It will serve us forever no matter what happens to the transport. If bits are bits, meaning that if we supply the DAC with an information embedded in ones and zeros - what makes one transport to sound audibly different from another ? This is the key question. Some transports cost as much as a Mercedes car and present extremely sophisticated means of technical competence. Take the Air Forsell transport which suspends the mechanism on an air cushion provided by medical oxygen pump. What an overkill way of achieving nothing. Or is it ?

First of all, let's agree that the digital SP/DIF (Sony-Philips Digital Inter-face) has ONLY - I repeat ONLY - 4 factors of quality:
1. Voltage amplitude
2. Square wave rise time
3. Timing precision
4. Error correction - added data missing from unread pieces of information. This is done by means of digital algorithm which adds missing data by interpolation.

The first factor

 is least important and it is dealt with by means of a resistive voltage divider - two resistors which bring the source 5 V signal to the proper 0,5 V pp.

The second factor

has to do with the cable parameter and transmitter - receiver parameters. For example, the TOSLINK interface of red led is not fast enough.
The only proper way of sending square wave this fast is AES-EBU data interface - a twisted balanced pair plus a shield in 110 Ohm line impedance and with XLR plugs and sockets.

The third factor

Low precisiomn of clock timing causes errors called jitter and it depends on the clock precision, cable parameters and rise time of the square. A Signal slowly rising and slowly falling will have timing errors even if the superclock with 2 ppm tolerances is installed. The CD players I tried had the rise time equal to 1/3rd of the actual pulse width !!!

The fourth factor

 is the most important one and the hardest to correct. We have little influence upon how the laser reads scratched discs and how the vibrations influence laser reading and how the chip interpolates the missing bits. This is where the heavy transports make a difference, isolation tables make a difference, mass loading changes the sound, VRDS clamps make a difference, green pen, snake oil and other tweaks make a difference. In general - the less error data guessing the better. That's why a FIFO data buffers cant make the sound perfect. They correct clock errors, jitter, rise time, signal levels and all that - but cant recover the data lost and guessed - back in the laser reading process.

How is the audio digital data send from a CD player ?

Well, in the Philips machines the chip which produces the SP/DIF signal is the filter SAA7220P/B. On pin 14th there is a "ready" signal.
Consequently in all machines which don't have the digital output like all NAIMs and B&O 5500 we can get the output just by connecting the pin 14th of the SAA7220 to the BNC or RCA digital output socket via a 75 Ohms resistor with a  series cap of 10-100nF.

This signal on pin 14th of SAA7220  is 4 V pp so very strong. The factory solution is that It is sent to the output socket by means of:
- a capacitor decoupler - 100 nF (ceramic is the best).
- a voltage drop divider - in most players it is 560 Ohms and 610 Ohms in series L-pad, creating a halving network.
On the picture below is a different divider as per SAA7220 data sheet, but ALL players which I saw from Philips and marantz had the divider 560 - 610 ohms not 316-91.

I recommend in every player (even the one not used as transport): to float (isolate) SAA7220 leg 14 and take the signal to output by the antenna screened coax cable. REMOVE the noise associated with 5 V DC switching sharply 2 million times per second from the PCB  !!!!!!!

SP/DIF output
The above is from SAA7220 data sheet. I never found similar application in real life, not even in Philips machines.

The output circuitry and execution is THE SAME on all Philips machines from the cheapest one like Marantz CD40  to the best Marantz CD94 MK1 and MK2, Grundig 9009, and Philips CD 960.  If you need a transport - any Philips will do and will play the same as Marantz CD7.

Then the signal enters the separation and balancing transformer - a small metal  square can near the socket.
The transformer isolates the signal galvanically and creates a free floating balanced voltage source . Even if it is sent then by the coax cable - the signal is not grounded so it travels in both lines - center and screen - all the way to the DAC receiver. 
It would be much much better to install a XLR socket and send the signal via XLR cable with tightly twisted signal wires. RCA is NOT a good way of sending such signal.

This is from Philips paper - description of the output.

Contrary to popular belief, the TOSLINK is inferior way of transmission. It has ADDITIONAL transmitter with own electronics and LED light source and corresponding received with light sensor. Its bandwidth is not fast enough to transmit the signal properly. The TOSLINK interface is NOT USING the direct laser !!! it is a cheap interface. It should be avoided whenever possible.

AT&T is bloody expensive and not popular even if very fast and accurate. The interface alone costs more than the whole transport.

The best way is working on the player to get the signal from the output balancing transformer and add a XLR female socket. The XLR cable can be made of CAT6 LAN cable with twisted pair connected to XLR jewellery of choice. This will transmit the signal in balanced mode isolated from earth and without any cable losses.


signal is a 0,5 V pp square wave. It is VERY FAST. it contains 44 kHZ of samples, each sample is a 16 bits, so it is 16 square impulses, and two channels alternating. So we send 2 x 16 = 32 squares per each sample. Plus some other information embedded like end of word, and clock and checksum. So we have roughly 35 squares times 44,1 thousand = 1,543 million pulses per second.
From Furrier's theorem we know that the square wave is an infinite sum of sine waves of odd harmonics, so if 1,5 meg is our first fundamental frequency, we  need at least 10 harmonics to be represented properly to make a square. This means that we need to send precisely the sine wave bundle which includes clean 1st, 3rd, 5th, 7th, 9th, 11th, 13th 15th and 17th and 19th harmonics
The 19th harmonics of the 1,5 meg is 30 megahertz. That is bloody fast, as fast as radio waves.
It means that there is a big demand on cable quality. What is cable quality? Simply speaking, in order NOT TO attenuate the fast signal the cable must have very low capacitance and inductance. So it must be twisted pair with physical separation of wires and good low loss dielectric. XLO way of twisting springs to mind. Twisted but quite far apart. Third wire - earth - is sent by a separate third wire or screen. The shorter cable the better. XLR made of CAT6 cable should be the best DIY option.

IS2 interface is an option which sounds superior on all equipment which has this option. It makes the data slower, the signal is split into three separate threads: actual data, clock and left-right word separation impulse signal. So we need 3 wires plus earth to send I2S but it is worth it. The SAA7220P/B chip has this format readily available, as well as all receiver chips. It is usually done by means of using computer 9 pin serial RS  socket and a computer LAN cable.

TWEAKING OF A CD PLAYER to make it a killer transport

In order to get a good signal from a CDP we can address a number of issues.

1. Vibrations (mass loading, platforms, deadening, felt mats, sand bags on the PCB, etc.)
2.  Mechanism supply capacitors - upgrade with low ESR and larger sizes
3. Tuning the output transformer - to provide the best square on oscilloscope - just turn the centre core by a screwdriver or better just remove the whole transformer.
4. changing the series capacitor from transmitter side to be ceramics
5. Changing the sockets from RCA to BNC or much better to XLR on both the transport and the DAC while changing the resistor from 75 Ohms to 110. The secondary of the output transformer should be completely floating and connected to XLR only and paralleled with the 110 Ohms.
6. upgrading the cable to a low loss, low capacitance and low inductance. 75 Ohms true wave impedance or better a AES EBU cable XLR with 110 Ohms.
7. Installing a super clock (after market) in the transport and in the DAC
8. Filtering the AC supply by the RFI filter in both the DAC and the transport.
9. Adding the power supply capacitors like os-con sanyo to the digital chips - the demodulator in transport, the digital filter SAA7220, the receiver in the DAC, and the DAC chip itself.


Concerning the drawing above: the saa7220 produces strong output of square wave which we can modify by capacitors, transformer and resistors.
If we have an oscilloscope with at least 30 MHz bandwidth, we can observe the signal. The main thing is to observe it AT THE RECEIVER. It is the END RESULT we are interested in. Not the starting point at leg 14th.
So we can for example omit completely the CD player output transformer, it is not critical, as long as the receiver at the DAC has a transformer (my SATCH DAC has it). We can change the CD player resistor divider to get stronger signal. or even go with full strength of 2,4 V.
The CS8414 and 8416 receiver accepts the signal as strong as 5 V so it is not critical to lower the signal at the output to 0,5 V.
Any series caps in the path are just to eliminate possible DC in the signal, but the signal has no DC so we can omit the capacitors in the path in both transmitter and receiver.
If we don't use the XLR balanced twisted pair - we don't need both transformers at all.

The transformers are always present in all CD players output. If we want to convert the connection to XLR balanced, the transmitting side needs a transformer with secondary winding completely isolated and connected to XLR pins, and if the DAC has no transformer, we can buy an old CD player on ebay for 20 Euro (defect one) and get the transformer from it. It is a metal square can.

The resistors of 75 or 110 Ohms are not strictly necessary - they are just for approximation of the cable LINE IMPEDANCE (WAVE IMPEDANCE or CHARACTERISTIC IMPEDANCE) . The signal as fast as this is travelling in the cable with the speed close to light, and the cable has a characteristic impedance per meter, and if the receiving point has different impedance - the signal may BOUNCE BACK and travel back and forth as a reflection. It really behaves like a wave. When wave hits the shore - it bounces back.
This causes the receiver to go crazy because it sees more than one signal. It reads the echo of the original.
So a good practice is to use the resistor the same value as the cable characteristic impedance on both transmitter and receiver ends.
Having said that, the RCA connector IS ABSOLUTELY NOT a 75 Ohm impedance connector., So no matter what cable, no matter what transmitter and what receiver - the RCA will cause signal reflections.
The only good solution is BNC connector  (50 Ohms)  or XLR (110 Ohms)
Let's not forget that the resistor at the input is in parallel with the small transformer. So in fact we see at each end not true 75 (110) ohms but this impedance in parallel with the transformer winding impedance plus the parallel impedance on the other side of transformer. So it is very very hard to make a line with the same impedance as the transmitter and receiver point.
Remember, it is NOT IMPORTANT which impedance is at the transmitter or receiver. We don't need to produce exactly 75 or 110 Ohms.
What matters is that the IMPEDANCE OF RECEIVER, of TRANSMITTER and of CABLE WITH PLUGS is the same. It can be 200, 143 or 59 Ohms. As long as it is the same and it does not induce reflections and bouncing.
So in the end - it does not matter what is between the source of the signal and its receiver, as long as at the end we get the clean, sharp digital square wave without reflections.

The last tip - if you decide to keep the chinch RCA connection - just isolate the pin which produces the signal - in case of saa7220 the pin 14, add a coax cable with a screen to take clean signal all the way to the output RCA, (not via PCB traces) and just divide it at the end near RCA by two 500/500 Ohms resistors. Omit all circuitry and the transformer, series caps and original resistor network.
Of all the mechanisms which I know - the SONY KSS190A is the best for transport. Or at least the Philips CDM1 not MK2. but MK1.

Here are some actual real life examples:

SP/DIF output

This is the Sony CDP227ESD :

as you see - according to the red pointer arrows - the signal comes first through the 33 uF electrolytic cap (it seems bad idea anyway), then through the switch (who needs it ???) and then just before the transformer we see a parallel RC network - 100 Ohms and 68p Cap. This is grounded on one side of the primary winding by a cap in series to ground.

On the secondary there is the expected 75 Ohm resistor, but wait a minute ! It is in series, not parallel to the output. And the screen is grounded via another ceramic cap. 0,1 uF.

The above is is the Kenwood CDP 7090 above

As you see the output is not passive, it has amplifier - two transistors. They drive the output. The coax RCA has 0,22 uF in series and a 1:10 divider of 180:22 resistor L-Pad. The expected 75 Ohms is in parallel but the 22 Ohms - in series (reflection attenuator ?)

There is no transformer at all.

SP/DIF output

Above - this is Grundig CD9009 SP/DIF output

This is an output I found in ALL Philips and Grundig machines regardless of price or age. The signal is attenuated roughly 1:2 and then there is the transformer, no grounding, no 75 Ohm resistor, no capacitor. Both transformer windings are simply grounded.

Same as above except that the re is secondary transformer winding grounded via a capacitor.

The above is Marantz CD 94 MK1 and MK2   SP/DIF output

Above: Grundig CD9000 fine arts SP/DIF output

CD transport

Above: Philips CD-753  SP/DIF Output

sony CDP338ESD

Above: Sony CDP-338ESD SP/DIF Output

Above: Denon DCD-960 SP/DIF Output

Testing and experimenting with  SP/DIF output of the Grundig CD9009 Fine Arts player.


SUMMARY of what we learned so far:

there is no one proper way of doing SP/DIF (coax) but the most popular way is the worst - with single ended coax transmission and wrong RCA connectors.
The output circuitry is different in every machine and there are no rules what is best . You can try various approaches as per diagrams above - with a cap, without, with transformer and without, with ground or without. Observe the END RESULT on the DAC side - how good is the scope trace.
I discovered in my Grundig CD9009 / SATCH dac combo that the DAC side RCA socket - when externally grounded - improved the trace by VERY MUCH.
Whether it is audible I dunno but I sleep better having it fixed.

The only proper way of transporting the square wave is the twisted pair and balanced connection via so called AES/EBU XLR cable. It is relatively easy project - 20 minutes of drilling with 24 mm crown bit for XLR sockets and 5 minutes of soldering the transmitter / receiver cabling.

Taking the old CD player to new level of CD transport perfection

In this section we will start to tweak the Grundig CD9009 to became a good transport. It has all critical elements like good chassis, screening, anti vibration arrangements, great power supplies, great Philips CDM1MK2 mechanism, good servos, and a broken DAC section. So lets see what it will take to make it a Theta / Wadia / Levinson killer.

To do this we need a fast oscilloscope (mine is 50 MHz)  and a "strong" drawer of resistors.
To be practical and stay on the ground - I will use typical RCA cable and sockets on both sides and see how it can be accommodated to serve as proper transmission media.
I will look at the transport, plugs, cable, receiver and screening as ONE SYSTEM, so my goal is to achieve good transmission as end result, but he process can be freely modified. If it means for example deviating from the norm and using a 50 Ohm cable, add two caps and some spider web with bread - we will try it too.

1. Loading of the signal generating chip - SAA7220p/B on its pin 14

I observed no anomalies when the digital leg 14 of Philips SAA7220P/B chip was unloaded (floating) or loaded with 1 K (as some schematics above) or 300 Ohms, or even 75 Ohms.
I experimented with  various caps in series with and the caps make no difference at all. A 10 nF ceramic seems to be the best choice. Cap or no cap - this is invisible on the scope so I decided to use it because it seems safer (DC decoupling).

The trace seems sharpest and most elegant when the signal is coming out of the SAA7220p/B without any transformer, just via one resistor 75 Ohms and one 10 nF capacitor.
This is THE BEST that I can get out of the Philips based machine. It should apply equally well to thousands of CD players which use Philips chip set.
Compared to original stock version - that trace is perfect !!! The original trace was TOTALLY HORRIBLE !!! Probably due to poor transformer.
The trace on the photo has been taken from the other end - the DAC receiver chip. It INCLUDES in its shape - everything: the SAA7220 chip, the internal cable, the cap/resistor interface, the outgoing, RCA, the 1 m cable, input RCA of the dac, internal cable, input 75 Ohm resistor, and input DAC capacitors 10 nF.
The SONY chipset is described below

SP/DIF output

2. getting from pin 14 to the RCA

I used a shielded piece of wire because this cable potentially is a HUGE noise antenna. The 5 V pp of square wave at 2 MHz is enormous emitter. Shielding is a necessary evil - it adds capacitance which "rounds" the square.


3. Isolation of galvanic contact

I eliminated the transformer and used just capacitor as galvanic isolation on both - transport and receiver side.

4. External cable - coax, telephone twisted pair or CAT 5 ?

On the scope there is little difference.  The cable length  is invisible, while other nuances are very visible. Scope shows everything.

5. Receiver end - transformer or caps ?

Definitely caps. Just ceramic 10 nF or something similar. NO paper in oils please !

6. Absolute level of signal

Please read the data sheet of your receiver chip. The signal is from very wide range - starting at 5 V at the SAA7220 chip to as low as 0,5 V as S/PDIF norm suggests. The Crystal CS841* series tolerate as much as 5 V.
I managed to arrive at: my schematics unloaded by DAC - produces 1,5 V pp. After loading - it is 0,75 V. The signal locks every time.

7. Listening impressions

The modded system sounds better without a shadow of a doubt. The sound is more crisp, better defined, with more background details. Good recordings are now on the verge of hallucinations.

DAC used: Satch without digital input board.

The best story continues on the next page : The DIGI-LAMPIZATOR enters and mops the floor with all other of my  transports!

Next, we will try the shigaraki clone transport - arguably the best there is according to some people who know what they are saying.
Finally - who knows - maybe even a shigaraki digilampized will be made.

some other traces of SP/DIF signal

SP/DIF trace
This is a middle price Harman Kardon HK DVD10  player - actually a nice trace for such a plastic toy.

SPDIF traces

This excellent trace is produced by the Yamaha player - one of their top machines with Sony laser and spinner. Model number CDX-890.

This is the Revox B126. Hmmmmm....

Wow ! Look at THAT ! Bravo Sony. Again and again Sony shows us how things oughta be done. No wonder why - Sony player has a FET transmitting buffer.
Thats why it does need any digilampizator to sound awesome on any DAC.

This quite nice signal is produced by the first and oldest and simplest CD recorder - Philips CDR880. This first generation recorder has no gimmicks - just 1x recording.
The recording sound quality is FANTASTIC. Much better that the Pioneer model 05 that it replaced in my system.

The below is a nice trace made by Pioneer DVD used as a transport aftert bypass of SP/DIF patth:

Pioneer DVD
Nice trace ??

Improving the SONY chipset players

So far I was able to identify the SP/DIF on PHILIPS chip - SAA7220P/B. With my patience and curiosity, I found the SP/DIF also on the Sony setup. So far - only on one chip - CXD1125 leg (pin) 27. Or later models - CXD1165 (also leg 27) Signal is called DOTX by Sony literature.  Since the chip is an SMD type with thin legs - you must be careful to first find a better soldering point - first after the chip pin itself. If not - prepare yourself for microsurgery and THIN THIN soldering job.

Without any mods, the cd players from SONY higher models sound better as transports than any other non-transport specialized machines.
I tried a bypass - from leg 27 to RCA, ar RCA add a 300 Ohms series resistor and then parallel 75 Ohms at RCA . This mode sounds significantly better than stock Sony. Improvement is audible - trebles, bass, width, height, timbres - all improved without doubt. You can try it and just stay with it.
Or do the digilampizator or digifetishizator mod.

Digital Lens Phenomenon.  It guides me closer to the TRUTH about transport sound.

Digital lens (it is a proprietary name of a product made in USA) is a simple device - a data buffer. It is actually a fifo piece of RAM with SP/DIF receiver and transmitter. It goes between the transport and a DAC. It is supposed to improve the signal quality by recreating it from scratch.  Interestingly,  The FULCRUM transport  from UK (excellent) has the "lens"  built in.

The data is stored in the RAM for a fraction of a second and so it is "purified" of it's original sins. All history of the signal is "forgotten and forgiven" and from the stored zeros and ones the lens creates new data stream. It uses new clock, own generator of wave form, so the new signal clone has no features of the old one at all.

The rise time is a result of new Lens' transmitter characteristics
The absolute signal level is created in the Lens
The timing (jitter) is a signature of the Lens
The data integrity is perfect - nothing is lost or added.
So far so good, isn't it.
Well, this is where going gets tough. We can accept for a fact that most transports will be improved by the Lens. This multi-thousand dollar (back in the nineties) product does a good job , better than the cheap SP/DIF inside a given CD player.
BUT what is totally puzzling - why transports sound different via the Lens ?  Why we can tell one transport from another? Somehow a signature of transport (like deep bass, wealth of details or smooth sound) are smuggled through the process. From IT perspective this is PURE NONSENSE but it is audible. I heard it when the Micromega Duo mopped the floor with my digilampized Grundig - both via the Lens and without it.

So there we go - I think that we found the truth about transport's sound !
If it is not only the clock, not only the squareness, not only the levels and rise time - there is ONLY ONE ANSWER possible and the answer is INTERPOLATION.
There simply is no other possibility, the process is fairly easy to understand and there is nothing mythical about it .
Bits ARE bits so if one musical piece sounds different from two transports with ideal square wave, it means that the data is NOT IDENTICAL.
Of course it is also possible that there is something else that I am not aware of and INTERPOLATION is not the answer.

Another thought - When i change the output of transport player by means of bypassing the last elements - I do not change data, I do not influence interpolation - and yet the sound changes. It always improves. So the quality is lost in the succeeding stages.

That proves, that the truts is somewhere else. Interpolation alone, rise time, timing, jitter - are ALONE not the answer.

I was making a false assumption, that the CD mechanism picks pretty much all the data. Only SOMETIMES, occasionally when the laser beam hits a scratch or a blemish - the missing data is interpolated.
In computer world, all the data is always perfect, otherwise our bank statements and excel spreadsheets would go bananas. If data is missing on CD ROM - the computer recreates it perfectly from checksum, or if it can't - it displays error message. Or a blue screen of death for those unfortunate folks who did not yet switch to MAC.

The CD playback has no time, no computing power and no means (checksum) to recreate missing data. So it averages the missing sample by looking at the nearest good one. This is obviously not the real true information.
If it was just one sample every now and then, say one per minute, that would be OKAY. But what if the CD misses 30 or 50% of data?
It still plays, I mean if the interpolation works, there will be sound even with 90% of missing data. We need at least two healthy teeth to fix the dentures with 30 false ones.

So the sonic signature of a transport must be a combination of jitter, squareness AND PERCENTAGE OF INTERPOLATED DATA. That answers why Lens does not make all transports sound the same as it should well do.
A burned CD ROM with a text file is THE SAME whether it was created on a IBM, HP or Mac. It has NO HISTORY of the "quality".

That whole speculation, assuming it makes sense, and it does - to me at least, also answers why transports sound different depending on the table, the vibrations, the green pen trick, or the LED light addition. Or say - why different BRAND of CD-ROM blank media sound different. Why is Verbatim better than a noname.

My conclusion is: The amount of interpolation must be HUGE, it is a secret of the industry but they read only a certain percentage of the data, rest is ADDED by the solomon code CIRC chip.
(Later I found oyut that this assumption of mine was wrong. Most of the CD playback is data-perfect.

Below is the Philips explanation, showing the old way - SAA7210 and the new way - SAA7310 demodulator and their respective ways of interpolation of missing samples by filling up the silence with approximate samples.


One consequent conclusion of that reasoning is that the good CD  player must be really well made with attention to details: power supply, motor, vibrations, servo, laser, lens, clock, transmitter, demodulator - everything matters.

Second consequent conclusion (very interesting one) is that the perfect transport would be if we could buy the music as PC file WAV  and play it from hard drive using just low jitter and "good squareness" transmitter. That would eliminate interpolation process and we would significantly get towards bits-are-bits perfection in data transmission.

Going further - if we can communicate with the DAC via I2S format not SP/DIF, we can get rid of the clock problem, jitter, and a lot of squareness problems.

So a perfect transport theoretically exists, we just don't have it and I can't understand why.

A simple experiment which is too difficult for me would be to record the data from transport on HDD and compare  by computer the raw data, not the music.
Just place the 1 second of a Pink Floyd song onto the excel sheet and look at it like accountants do - like a balance sheet review. Or a Visa card monthly statement.

I had once the Cambridge CD3 and it had a LED informing when interpolation kicks in, and despite the CD 3 being otherwise a super high end machine - the LED was always blinking with a speed of a machine gun.
I am sure the LED was driven by one pin of the SAA7210  - namely the pin 36 - ERROR FLAG. It triggers the interpolation. Just add a LED to this leg with 1 k resistor and pull it to the front and try listening. Then try the sandbags, potting soil bags, sorbothyane feet, felt mats, green marker and parrot guano. See if it reduces the blinking.
Maybe someone can design a RS232 interface to use PC as impulse counter so we could actually see the number of errors per second. That would be nice..

Crazy as it may sound, a friend of mine owns a nice transport and the rest of his system is totally extremely revealing, and he noticed a huge improvement when changing the power transformer on the transport for a 100 times bigger one. The oversized transformer did something so right to the sound of the transport that it left ten other transports in dust.
The Fikus Interpolation Theorem" really holds in this case - the transformer probably improved the reaction time of the CD spindle motor, the arm positioning (tracking) and the laser focus motor. They react faster to the commands of the servo controller. There is less read errors and less interpolation. Not to mention squareness which must be better too.

The walkaway message is that bits ARE bits, providing we have all of them.

The walkaway message 2: The whole debate has been  a waste of time, we should get the I2S signal from the demodulator and communicate directly with the DAC by I2S cable. And hence "bypassing all the problems listed above".

A year later

A year later I am not closer to the truth. I have modified over 30 other  transports, all in a carpet bombing fashion - improving everything I can, to achieve something - I don't know exactly what.

The encounter with the CEC transport and the fact of it's didtinctly superiour sound made me think again.
The whole CEC story can be summarized in one line: good sound is achieved when we eliminate rotation variations of speed of CD caused by the moror being non-linear and rotating in frog leap speed bursts of the rotor versus stator. The flywheel plus weak motor are perfect combination.

After modding 20 other DACS in their input receiver section I san conclude that : One of the most important keys to good sound is ... making the receiver chip imput HAPPY. By that I mean - that we must do whatever it takes to make input be happy and play well. Be it signal level, frequency, jitter, timing, squareness, rise time, cable reflections, echoes, etc. Removing 74HC chips, transformers, opamps, switches, caps, relays from both Transport outputs and DAC inputs - greatly purifies the sound. So even passive components do make a difference. Less is more !

What if there is no SP/DIF output (digital out) in our CD player, only Toslink fiber optic type ?

well, if you have a toslink - you are a lucky person. It is as good as having the SP/DIF. The toslink way of data transmission is inferior, but not by much. You are welcome to use it as it is, providing the DAC has such input.
But there is an easy way of converting the toslink to RCA or BNC output.
Just lift that PCB and look on the bottom side of the tosling transmitter. It must have at least three  legs: one is ground, one is +5V DC power supply for the diode, and one is actual SPDIF signal. The toslink uses red light as a way of transmission but the data format is actually SP/DIF. Same thing!!!
So just take the signal from the data leg of the interface and wire it to a newly installed BNC or RCA connecting socket. (drill bit 10 mm). Dont forget to ground it as well. To be on a safe side - use a capacitor in series of the signal - say between 1 nF to 100 nF - type ceramic, foil, mkt, mkp, mks or even tantalum. If the signal seems to overloiad the DAC end, it is possible to add a 75 Ohm resistor between the signal and ground electrodes of the socket (RCA or BNC). This will take care of the excess amplitude and adjust the wave characteristic impedance.
The toslink may continue to work OK. The modd is easy, cheap, innocent  and reversible. 

However be aware that Toslink traces like this :

That square directly from Toslink receiver is bad bad bad. It is a miracle the DAC reads and understands this crap.

Known good transports:


This is an example of an excellent transport machine - from a legendary specialist - TEAC. They produced under their PRO label named TASCAM  some nice transports for broadcasting and studios. Their mechanics were Sony KSA151A  with cast metal VRDS clamp and a wired remote, able to control the timing of CD up to milliseconds.
I did not take the trace photo, sorry.

Below is the home version of the Tascam - its brother - Esoteric P2. I mean the golden player is the brother - not my ugly face.

Audiomeca Mephisto (one of most analog-like  sounding transport)

Made in France by hand by Pierre Lurne - who knows something about turntables.
Mephisto 1 has CDM9 from Philips, lots of shiny acryllic, home made disc clamp (light, wobbly and large) and a bad  transformer for SPDIF.
Personally I love these players. They should come free as a bonus with the purchase of A-N DAC-4 or 5.
I review Mephisto 1 here
and Mephisto 2 here

mephisto transport

CEC TL1X (also under Parasound brand) (the famous belt drive motor)

Nobody is able to explain why the hell belt drive should sound better. If you ask me - I think it's bullshit, just a very appealing differenciator for marketing. ( after  I bought my CEC - I had to eat my socks and apologize - the belt makes sens)
The CEC has been popularized by Stereophile and everyone including yours truly wanted one a while ago. (Goldish one! please Santaclaus !!!)
CEC may be good with belts, but they should learn more about the aesthetics. To me this black box looks like Lenin's tumb, not an object of desire.
Their TL0 - one modell above - looks great but the price tag has printed message (next to the price) that says: whoever buys me must be a drug dealer. (besides - the zero has same electronics as the one, the whole price issue is about marketing and looks).

I review the CEC 1x here

cec transport TL1


Micromega Duo (with CDM9)

Micromega is a small French firm which had a distinct philosophy - buying simple Philips players and refurbishing them up to a high ticket.
The DUO is a stand alone transport with a toilet-seat-like lid, made of acryllic and  with a CDM9 mechanism.
Despite the fact that every time you want to change the CD you will receive a 25 kiloVolt shock from statics, the DUO is very airy, detailed and musiclal player. Somewhat similar to Mephisto although  the looks don't compare, even after a few drinks.

Theta (based on the Philips video laser disc)

theta transport

I have written about the laserdisc principle in the laserdisc article HERE
I also evaluated the Theta Data Universal Mk2 transport HERE
The quality differenciator is the MONSTROUS motor which has 30 times the torque of the standard CD spindle motor.
Thetas sound distinctly deep, powerful and they are a worldwide reference for bass. So I guess fast reaction  time of the servo and all motors is audible.
If I could hear it on a 50 Euro pioneer laserdisk, and believe me -  I heard the best bass too on this 5000 $ Theta. That's the HEMI V8 6,7L of the transport world.

Kenwood X9010 (cheapest of the good ones). - best construction of all of the above

Read about it HERE

kenwood transport

Wadia makes good CD players and good transports, but make no mistake about it - not THAT special. Definitely, apart from pride of ownership, definitely not worth the money asked.
But I had to mention them because Robert Harley used to drool about everything Wadia, as well as every other writer out there.
Apparently, cutting the most advanced cases for the products from solid blocks of alloy pays. People are ready to buy the story and nobody asks any questions.

Wadia (Teac transport with better case).

Same transport sits inside a 100 Euro Sony CDP227ESD, save for the clamp disk.

wadia transport

Ha!!!! Thats the real Mc.Coy. The best VRDS ever (not counting the Neo) - note - the bridge is metal, not composite. It is shiny, not grey. It is not a flat straight slab of alloy but curvy and ribbed. THATS THE INDICATOR of the best variant. It was used only in 4 players in all history at best.

PS Audio (engineered by fanatics)

Picture missing

In short - PS Audio is how the digital audio should be made, minus the tubes at the end.

Roksan (unorthodox mechanically)

Roksan transport is very tempting, the Persian engineer behind Roksan is a very interesting individual. I just missed the auction by a few dollars and I was just THAT CLOSE to owning this wonderful rebellious product.

roksan transport DP1

Sonic Frontiers 3 with the "eye iris"  lid

This transport, along with the Revox 426 could fight for the title of the sexiest player ever made. Save for the handmade toys from Munich High End show.

MBL made by people who do not care about cost

MBL from Berlin is famous for  their "telephone number" price tags and good products. TOTALLY TUBE FREE I must add.
Since I am not a German dentist, I have no idea how MBL sounds or even looks. I never will.
People who own MBL are NOT the same people who say to me: Lukas, would you like to lampize my player please ?!?

mbl transport

Some other transports worth checking: Shanling T200SACD, SONY777 SACD,  Jadis, Accuphase,  Shigaraki, audiolab, Rega, Audio Alchemy (pictured below)

And now something really good: Audio Note Transport 2 - one of my top picks!

This is actually the Philips CDM 2  PRO kit made properly.
This is my view on teh CDM2PRO

And finally - what is believed to be the BEST TRANSPORT IN THE WORLD - but not the bullshit kind like marble tumb, but real meaningful honest engineering:

Spectral SDR-3000  from USA based on modified VRDS Esoteric (teac/sony colaboration) transport.

spectral sdr-3000

Entrer TEAC NEO Mechanism

It is impossible to drool over the transport issue seriously  without mentioning the newest VRDS NEO from TEAC.
The NEO VRDS is the ONLY new mechanism made in many years. While the whole world is going the MP3 way and DVD, TEAC decided to invest in a "greenfield"
  project of mechanism.

Frankly I am not too thrilled - what I see is the standard good mechanism dressed up with 5 huge chunks of metal. This is hardly a rocket science - but I am okay with that. A 5 kg weight is nice to have, we buy by the eyes anyway. But asking 8000 Euro for it ? Thats another story.
As I heard, management of TEAC decided that they will keep the mechanism for themselves  - they will not give it to OEM. They want to keep price in stratosphere as long as the part of the market which is a) rich and b) impatient - will be saturated. Then of course they will change their mind and they will sell to every OEM that will ask. I can bet that the price of VRDS players will drop 5 x in 2-3 years. But then dear TEAC it will be too late - the world will be riding on HDD systems.
Meanwhile - I will stick to the real heavy weight champions of mechanisms like KSS190, KSS273, and CDM1.
I lost my confidence in VRDS since I saw with my own eyes the bullshit that they sell - as described HERE


SP/DIF and AES/EBU explanation file:

DIGI-Lampizator for the die hard diy'ers.

Stereophile article by Robert Harley

Interesting discussion 1

Interesting discussion 2 - CDM1/2 experiments

LINKS TO DATA SHEET - interesting reading:



Cirrus CS8414.pdf

You can read my transport findings - at the transport battle article HERE

and here is again a link to my transport DIY project:

One year later - fall 2009

I have spent the free evenings worth of 2009 researching the transports. I took different routes and finally a picture started to emerge.

After all what was written above and elsewhere in my page, I can conclude that:

1. There is nothing magical or mystical about the CD transports (dedicated machines) versus CD players with S/PDIF output. There is nothing that sets them apart except the fact, that the Transport is a rare breed, hence it is addressed to demanding audiophiles, and there is a potential chance to make more money.  By removing the DAC and analog stage from a CD  player, and adding some weight to make it look sexy - the price goes up 2x or 5x, depending how greedy is the company.

There is nothing more to a transport versus CD  -  the same mechanism as in equivalent player, then the demodulator chip (the same), then the S/PDIF generating chip - Philips saa7220 or Sony CXD1125. After that the square wave goes via a long trace or wire and ends up in the output shaping circuit consisting of: a series cap (unnecessary) , a L pad of two resistors (questionable at best) and a separation transformer (unnecessary, cheap shit).  Transports are built the same way. The only improvement is that there may be more vibration damping, better power supply (dedicated to the S/PDIF function) and more attention to detail. But that same attention can apply to CD player. We can do it at home to our Denon, Sony or Marantz.

2. I have demonstrated that by improving the power supply to the digital PCB we can improve the sound. I modded this way the Philips CD940 with great result, and then the Mephisto 1 - fantastic result, and recently the CEC TL-1X - also great result.  All these players gained quality in every imaginable aspect thanks to adding separate  supply line (5V) per each consumer (chip) individually. I dont like players where 5 chips, two motors, laser and servo - all use one 5V source.

3. I am sure that a single ended connection is best for S/PDIF signal. I do not like toslink and I don't like AES/EBU either.
The "pro" looking AES/EBU connection is using XLR and it looks OH SO PROFESSIONAL WOWIE ZOWIE.  We buy by the eyes. But the AES/EBU is not invented to be better. It is invented to be LONG DISTANCE.
The RS422  industrial data transmission from which AES/EBU derives can travel as long as 1,8 km (over one mile) on the twisted pair balanced cable. The S/PDIF in coax cable can travel up to few single meters.  THAT IS THE DIFFERENCE. But the S/PDIF signal on both ends exists ONLY as simple single ended asymetrical signal. We must make it balanced artificially by means of adding a balancing transformer which badly distorts the signal. Then we use in our systems one metre cable (not one mile !) and we must use de-symmertization transformer on other end again. That's two unnecessary transformers, two too many for me.
In analog systems, the ballanced XLR has more meaning - as described HERE, but in digital - the signal itself is never trully ballanced, it is the sending media that is ballanced to make long distance possible.

so why is the AES/EBU sounding better on many transport/dac combos ?

Answer is easy. Because the S/PDIF on all transports that I have seen, and I have analyzed about 40 different ones - is made wrongly and it uses an ugly separation transformer as well. So in that scenario - S/PDIF can not beat AES/EBU because they both have the biggest limiting factor - the transformer.

That is leading me to fourth conclusion:

4.  The digital output and input transformer is unnecessary and can be disposed of without penalty or consequences. I tried it in every player including the CEC, Mephisto, Theta and all - and every time I had consistent result - increase of transparency, detail, scene depth, improved bass and removal of veil. None negative effects were observed so far.

That conclusion is explaining the AES/EBU phenomenon : in S/PDIF we can remove both transformers, but on AES/EBU we can not. So a modified S/PDIF beats AES/EBU. Plus - we dont need aes/ebu IN THE FIRST PLACE because it is just a normal SPDIF with doubled up mirror signal by transformer.

One may ask: Why is every manufacturer insisting on installation of series caps and also separation transformers in CD player transport and DAC and why is Mr. Fikus telling it is unnecessary?
That is a good question. When I ask others - what is the separation transformer for? they answer me: it is there to separate. Separate what? I ask -  They say : to separate the grounds. Why ? Well, because the grounds must be separated.
Then I ask: what is the capacitor for ?
They answer: son, the capacitor is there to isolate. Isolate what?   I ask...
Well, isolate noises or protect from spikes.
What noises? - answer is Digital noises.

So shortly speaking, nobody has a clue what to answer. NOBODY.  They are in the fog of stereotypes and meaningless talk.

This is the likely scenario how it happened.
Some engineers met back in 1982 in Eindhoven in the meeting room (as the name suggests) and they decided that they want to move the DAC away from the transport and that they want to standardize the format. But they had no clue how to do it because they were audio analog engineers.
So the  boss decided to call the guys from another department downstairs - from data transmission department. They found Mike, the guy who sends industrial controll and automation signals over the distance. Mike knew how he does it for the transmission across the factory grounds or the airport - he uses a transformer to separate the grounds from one building to another. The potential difference between earth in two buildings separated by few miles can reach huge levels. So a transformer is a natural choice. The caps takes care of DC component if any. So far so good. So mike decided he would recommend doing the same in CD players. The CD player engineer greeted that advice with applause ,  thanked Mike  and the solution was wrtitten in stone and thats how it started.

Then the followers copied what Phiips / Sony did without questioning the solution. The transformer had to be there - full stop.

So I am telling you now - REMOVE THE TRANSFORMER. Mike was wrong. Remove the capacitor and let the square be square.
You would not believe but any digital PCB - from CD player, computer, playstation or another device has HUNDREDS of digital chips inside. They have tens of pins each, and every pin may have a square data signal, and these thousands of connections on that PCB are directly talking to each other. AND THEY DO WITHOUT transformers and caps. Why all of a sudden should 3 feet of S/PDIF connection need the same precaution as the long distance connector ? I don't know.

Enough said.

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