The gorgeous Paganini !

Well, in the previous page we've talk about the diagram; now it's time to say something about characteristic of the...

Audio Analogue PAGANINI CD player

Later we will talk about the CD player's tuning, and more.

Specifications

Here are the declared (and measured, too!) specs:

DECLARED || Prototype MEASURED

Output audio level: 2 Vrms || chR=2.009, chL=1.999, Delta=0.05dB

Output audio impedance: 200 Ohm

Output digital level: 0.5 Vpp || 0.46

Output digital impedance: 75 Ohm

S/N ratio (with no signal): lin. >90dB, weighed "A" >100dB || "Lin" 98dB, "A"109dB

Effective resolution: >15 bit || 15.7 bit

Dynamic range: >96dB || residual noise: 200nV/SQRT(Hz), eq. to 28uVrms (in a 20>20.000 Hz band)

Frequency response: 20Hz / 20kHz (+/- 0.5 dB) || 20>20.000 / +/- 0.1dB

Linearity: +/- 0.5 dB (0dBr / -90dBr) || +/- 0.1 dB (0dBr / -100dBr)

Channels separation: >90dB (20Hz / 20kHz) || L>R 100dB, R>L 110dB

THD+N (@1kHz): <0.03% from 0dBr to -40dBr, 0.3% @ -60dBr, 3% @ -80dBr

IMD (19kHz + 20kHz): N.D. || <96dB@1kHz

DC offset: N.D. || <10mV (remember there is NO capacitor in series at the output)

Here we have some charts too:

This is the THD vs Out level (0dBr is 2Vrms)

This is the frequency response (measured at 0dBr and -10dBr)

This is the channels separation (measured at 0dBr)

Linearity (hor. axis is "out level", vert. axis is "deviation from ideal" in dB)

The calibration procedure for the CD player

Usually the Paganini is factory calibrated; but if you want to poke into it yourself, or if you need to change the drive, or if you have problems reading some discs (it happens, it happens!), it could be useful to learn the calibration procedure.

NOTE: new drives have a tin jumper to prevent ElectroStatic Discharge on the laser diode. If this is the case, remove it AFTER you have connected all the four headers on the pcb.

As you know (have you downloaded the diagram?) in all the Paganini digital section there is a "half" voltage generator, the output being pin48 of IC210; this voltage (named VC) is used as a virtual "zero" to which all signal are referred; one of these signals is the Focus Error Bias, and this must be exactly equal to VC.

Scope of the VR202 trimmer is to tune the FEbias at the same value of VC.

It is not convenient to measure the latest and to trim the first at the same value; it is more precise if you read directly the "difference" between them.

You need a DVM (at least with 200mV DC fs).

1) remove the tin drop over the "R251" link (between TP209 and TP210) that connects VR201 to pin1 of IC210 (see diagram)

2) put the positive lead of the DVM on TP210 and the negative on TP209 (range is 200mV DC)

3) Paganini is ON and out of Stand-by

4) adjust VR202 until zero reading on the DVM

5) turn off the player

6) join again the "R251" link

Okay, this was the "easy" part.

Now you need to calibrate the gain of the Focus Coil servo system; unlucky for you, there is not a "reading on the DVM" to reach; if the gain is too low simply the drive will refuse to read the CD after two or three attempts; if the gain is too high the CD will work, but all the servo system will be too much "stiff" trying to follow the surface of the disc; this in turn will cause a lot of errors to be generated by the system. You'll hear a lot of mechanical "noise" in this situation: the gain is too high!

A "linear" approach to the problem can be this way:

7) rotate VR201 counter clockwise

8) Paganini is ON and out of the Stand-by; tray is OPEN

9) put a disc and push the OPEN/CLOSE switch

10) as you will see, the CD player will refuse to read the disc, and the written "disc" will appear on the display

11) pushing twice rapidly the same OPEN/CLOSE switch will force a new reading tentative

12) do it several times, every time turning clockwise the FCgain VR201 trimmer

13) at least you'll find a point where the disc is read!

Now you can connect the usually DVM at TP220 and TP221 (AC mode, the lowest range, at least 200mV; better if you have a TRUE RMS, but it's not strictly necessary).

14) you'll read a value between 70mV and 160mV; this value is not the same at the beginning or the end of every disc

15) try several discs, and leave into the ones with the LOWEST value read on the DVM

15bis) if you find a disc that the CD won't read, it will be the LOWEST mV value CD; use it! In this case simply turn even more (very slowly) VR201 until it works, than give half turn more for safety. This ends the calibration procedure.

16) find the LOWEST value track on this disc (it could be the first, the last, or someone in between)

17) While playing this track turn counter clockwise VR201 until the CD will stop; than start again the procedure beginning at point 11

18) after point 13 give half turn more for safety. Play & test all the discs you have. Are they all read? Yes? This ends the calibration procedure.

Note: DO NOT USE "strange" discs, like the compilation your best friend made with the Personal Computer: these discs have an "odd" signal overlapped on the track, or something similar; well, if you put a scope between TP220 and ground you'll see it very high!

Therefore they are not useful for the calibration procedure.

Note (again): if the Paganini reads the disc with strange noisescoming from the drive, it means that the gain is too high; reduce it!

The Sony drive

It could be useful to give a look at the drive, and remember that many Sony units share the same components and/or connections.

CAVEAT! The diagram you find here is not the original, but a "concept" version draw by me.

<--Click here for the "zipped" poscript file

The KSL-2101ABM is a very common device, and you can easy find it as a spare part in your local electronic shop.

If you find other drives with about the same connectors (think to the CD-ROM for PC) you can made some tests by substituting the original.

NOTE: never turn the 2k2 trimmer, or the LASER diode will burn in a while!

If you want to check for the LASER current (and more), go to the following section:

Test points

You already know some of the test points: TP209, TP210, TP220, etc.; one of the most important to check for proper operation of the Paganini CD player is TP207: here you'll find the "eye pattern", that is the Radio Frequency signal recovered from the disc; you need a scope for measuring this, and respect to ground you'll read 1Vpp. This is a typical value for all the Sony chip-set.

Another interesting couple is TP214/TP215: with a Digital Volt Meter in DC voltage mode (2Vfs) you'll read 500mV; this in turn is equivalent to a current of 50mA in the LASER diode.

Always related to the LASER are the TP211 and TP212; the first is the voltage developed between Anode and Cathode of the LASER diode (usually near 1.91V DC respect to ground, but vary with the age of the diode and with the temperature), the second is somewhat related to the light power emitted by the LASER and received by the photodiode; here the voltage is very small: you must read a value near 13mV DC.

As previously stated, TP220 and TP221 are in parallel with the Focus Coil, and here you'll read between 70mV and 160mV AC if you use a standard disc, or between 280mV and 360mV AC if the disc is a "masterized" one. Note: do NOT use an old "analog" meter for measuring the Focus coil AC voltage, because sometimes the reading can be wrong.

Near IC203 there is a very interesting header, named J207 ("TO AA-EC"): here you have at your disposal +5V (pin1), GROUND (pin6), and three digital signals (MNT0>pin3, MNT1>pin4, MNT3>pin5).

Here the mystery is solved: as clearly explained on page 30/31 of the CXD2508 data-sheet you can read these data and know when the system found an error, what kind of error was, and if it has been completely corrected or an interpolation has been used.

AA-EC is Audio Analogue Error Counter, a never born device useful to understand if some mechanical mods are useful or not.

You can read anyway the "status" of these data, even with a scope or "ANDing" them in the proper way.

Near the DAC also there are lots of data available; these are:

DAC Master Clock (DACMCLK) = TP201

Left & Right Clock (LRCK) = TP202

Serial Data (PCMD) = TP203

Serial Clock (BCK) = TP204

Negated Emphasys (NEMPH) = TP205

Mute R & L (MUT2) = TP206

With these data you can decide to use your own new DAC, mounting it on a little PCB.

I remember you the new Audio Analogue MAESTRO CD player, where all is similar to the Paganini except the DAC.

In the power supply section you can measure the DC voltage on the collector of Q403 (the power darlington): you'll find +20V in STOP mode, +18V in PLAY mode, +15V while pressing the FWD or REV buttons, 0V in STAND-BY mode.

The Remote Control

The Remote Control used in the Paganini is a custom model, made for us by the

TOP-UP INDUSTRY CORPORATION

in TAIWAN.

Using it, you'll have more functions than the front panel, but even in this case not all the functions are implemented.

You can try what are the excepted command playing with Rows and Columns around the U1 chip into the RC unit.

<--CLICK here for the electric diagram of the R.C. (141k GIF format)

It works with two AAA size cells (3Vdc), and signals are received very far from the CD player until you are in front of the receiver.

Problems arise when you have an angle of more than 45 degree in whatever direction.

Hints & Tricks

It is quite oblivious that some simple mods are possible, e.g. change of the loading motor's speed (tune the R226/R227 ratio); but for some deep analysis you need some test discs.

I can recommend some:

Discs with & without physical errors for testing servo circuits and errors correction capability:

Philips SBC 426/426A (2 discs)

Grundig 72008-376.00 (2 discs)

Panasonic CDT 016

Pierre Verany PV.788031/PV.788032 (2 discs)

Sony YEDS 3-702-529-01

Konig CD 5441

Discs with standard signals for measuring THD and more:

Konig CD 5443

CBS (Standard Test Disc) CD-1

EIAJ (Standard Test Disc) CD-1 (YGDS 13)

Japan Audio Society Test Disc CD-1 (YDDS 2)

Philips Test Sample 3 (410 055-2)

Technics CD Test Disc 1 (SH-CD001)

Sony YEDS 3-703-811-01

Sony YEDS 3-702-101-01

Sony Test CD Type 3 (YEDS-7)

Sony Test CD Type ? (YEDS-18) 3-702-101-01

Denon GES-9092

Denon 38C39-7147

DHFI 410 741-2

Divox CDXUE-84

Mozart editrice (Terni- Italy) CD MZT 10001-2 (warning: in my disc there is a glitch in track 10 at time 24S)

Stereophile TEST CD2 STPH 004-2

Stereophile TEST CD3 STPH 006-2

Surely there will be many test discs on the market; a simple search in the WEB with the words "+test +disc" gave me many pages like these:

http://www.digital-recordings.com/cdcheck/cdcheck.html

http://www.abex.com.sg/cd.htm

http://www.tmd.co.jp/eng/tmddisk1.htm

http://www.ee.washington.edu/conselec/CE/reports/Group.3/cbs_cd1.html

When you'll have a sufficient number of test discs, you can start an interesting adventure over the .....

Tuning of the time constants

Yes, the Paganini (like ALL the CD players) is full of servo circuits, and this means that there are some time constants (in other words: some RC groups) that needs to be "tailored" in order to obtain best performances even with "horror" discs.

We've made of our best, but if you have time for build the "AA-EC device" you can play with different RC values and see if the errors grows or not.

Here a list of components to play with:

C202

R201,C203

C204

R219, R220, C222, C223

C227

C225, R222, R221, C224

C216

C213, C214

C215

C238, R238

R240, C239

C240, R241

C241, R242, C242, R243

For a tuning procedure you need a dual channel FFT analyzer (e.g.: HP3562A) and a good knowledge of how a servo circuit works (Hint: trim the gain up to a "critical Q" response).

You find some info (by Sony) clicking here (thanks, Santo); unluckily is not a complete procedure, but is a good starting point.

Some last words

It remains to talk about the "test" condition: something happens if you power the Paganini while pressing the FWD button: the system seems to enter in a "test" mode, but nothing of importantance really happens.

Nevertheless there is a "test" mode in IC301 also: you have to tie down pin24 and try to power the Paganini.

Sony is quite miserly about this kind of information, so I cannot help you; try by yourself!

Another important question is the output resistor R7(R107): in some recent productions I've seen that this resistor has been substitute with a "zero" Ohm resistor (a piece of wire, in other words).

Well, I absolutely disagree with this procedure; it's always a good rule to be concerned with capacitive loads (e.g.: long & strange cables, etc.) with a series resistor, and with this no "ringing" in the square wave corners are possible.

Not only: if the zero Ohm resistor is used, the Paganini spend all his "Stand-by" time with IC1 (IC101) shorted to ground; nothing of really "dramatic" happens, but the internal temperature balance of the chip will not be the best at the wake-up, and some minutes will needed for coming back in a normal steady state situation.

Listen carefully: open the Paganini and take a look inside: if you don't find the resistors (they are WELWYN RC55Y, the colour is black) eradicate the fakes and put real resistors!
It could be useful to have a list of the material needed for the Paganini: here you find the provisional document in Word (zipped) format.

At the end of this long page I suggest to read this useful site:

the Sci.Electronics.Repair FAQ under the voice CD Player.

I hope you have found these page interesting; please let me know your remarks, and do not hesitate to contact me for whatever question you should have.

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