Finally, an affordable CD Transport: the Shigaclone story

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iTiberius

iTiberius

Member
Joined 2005
syklab said:
Hi Tibi,
Dr.H did mention that feeding a regulated 2.5VDC to C906 would eliminate the need of exotic cap there. what is your opinion on this? Should we have an additional 2.5V supply for this?

http://www.diyaudio.com/forums/digi...rdable-cd-transport-shigaclone-story-489.html
Click to expand...

Vref is given by LA9242M pin 58.
LA9242M will benefit from two low noise regulators. One is for laser and RF section and I expect that Vref to benefit as well.

What current this new 2.5V regulator need to provide ?

Regards,
Tibi
 
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uncle_leon

uncle_leon

Member
Joined 2007
studiozey.com/
tvicol said:
Here is the schematic of the new shiga.
There are few modifications who will allow you to improve further the performance of this transport:

1. entire LC78601RE audio section removed
2. option to use original oscillator or a low jitter XO, aka Tentlabs.
3. separate power supply for each chip
- external 8V for BTL driver LA6541
- +5v for display IR using build-in LA6541 regulator
- power supply for LA9242M is split in two separate sections. One +5V for RF section - pin 64 -, laser and pin diodes and second +5V for servo and digital section - pin 56.
- last +5V regulator is for LC78601RE
4. option to use two regulated +8V. One will go directly to LA6541, second for cascaded LT1763-5 regulators.
5. 4 button display board
6. s/pdif is on board - R50 and R51

Except display and IR all other +5V regulators are low noise LT1763-5 and will be on main board.
You don't like this approach ? Just strap each regulator section using 0ohm resistors - R25, R44

If you have any observations and/or further modifications you like to be included, please let me know.
Please note that this is not final schematic and during PCB design may suffer further small changes.

Regards,
Tibi
Click to expand...

Great job with the schematic Tibi!

One thing that occurs to me after checking it, is that it still has the bypasses for all the electrolytic caps. One of the basic mods was to remove some of them, because they were detrimental to the sound, so perhaps we could remove them all at this stage? On the other hand, there is naturally no harm in making the room for them on the PCB, and leaving it up to the end user to install them or not (which is probably the best way forward).

Also, am I right in thinking that R6 (100R) should be moved to between C2 and C10?

Edit: another thought just occured to me: are we going to use 2SA608NF and 2SA1342 for Q1, Q2 and Q3, or are we replacing them with some other suitable transistors? I have just checked and both the original types seem to be available - albeit a bit scarce.
 
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Z

zjaakco

Member
Joined 2011
Hi tvicol
If you can make choiches for a final pcb, please consider for separete power supply and room for a decouple cap of 1000uF/16V for the motor-drive ic,
This mean 8V to the transistor, and 2x 8V for the other power pins. It save me (us) a lot of work.
If possible give every power pin a seperate power supply.
This will certain be an improvement.
Regards
zjaakco
 
CeeVee

CeeVee

Member
Joined 2006
Paid Member
As for the regulators, from my testing i found that Salas shunt reg for the 5v or the Bobken reg posted by Peter made a huge change for the better to the sound so either connection for external shunt regulators or on board regs with option to disconnect and use of-board shunts would be my suggestion.
 
S

syklab

Member
Joined 2009
tvicol said:
Vref is given by LA9242M pin 58.
LA9242M will benefit from two low noise regulators. One is for laser and RF section and I expect that Vref to benefit as well.

What current this new 2.5V regulator need to provide ?

Regards,
Tibi
Click to expand...

I havn't done that part of the mod but according to the original poster it only require very low current of few mA. May be someone can fill in more on this.

It was discussed below:
http://www.diyaudio.com/forums/digi...rdable-cd-transport-shigaclone-story-503.html

Regards
 
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iTiberius

iTiberius

Member
Joined 2005
uncle_leon said:
Great job with the schematic Tibi!

One thing that occurs to me after checking it, is that it still has the bypasses for all the electrolytic caps. One of the basic mods was to remove some of them, because they were detrimental to the sound, so perhaps we could remove them all at this stage? On the other hand, there is naturally no harm in making the room for them on the PCB, and leaving it up to the end user to install them or not (which is probably the best way forward).

Also, am I right in thinking that R6 (100R) should be moved to between C2 and C10?

Edit: another thought just occured to me: are we going to use 2SA608NF and 2SA1342 for Q1, Q2 and Q3, or are we replacing them with some other suitable transistors? I have just checked and both the original types seem to be available - albeit a bit scarce.
Click to expand...

Thanks uncle_leon, the drawing is made by jazz35 who work with me on this project and many others.
I agree with you that original ceramic capacitors, due piezoelectric effect, degrade the noise figure and therefore the sound.
However there are also ceramic NP0 capacitors which may be used with good results. I´ll leave user option to chose.

Thanks for observation, you are right, the right place for R6 is between C2 and C10.

I´ll go for original transistors.

Regards,
Tibi
 
iTiberius

iTiberius

Member
Joined 2005
zjaakco said:
Hi tvicol
If you can make choiches for a final pcb, please consider for separete power supply and room for a decouple cap of 1000uF/16V for the motor-drive ic,
This mean 8V to the transistor, and 2x 8V for the other power pins. It save me (us) a lot of work.
If possible give every power pin a seperate power supply.
This will certain be an improvement.
Regards
zjaakco
Click to expand...

OK we´ll use the second power supply to power separately LA6541 pin 24 for a better focus and tracking.
What 1000uF cap would you like to see on board ? I need exact part-numer.

Regards,
Tibi
 
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iTiberius

iTiberius

Member
Joined 2005
massimo said:
Tvicol, may I suggest to consider the AD151 instead of the LT1763? Much less expensive and very good noise figure.
Moreover the cd door switch requires a N.C. button switch that doesen't exist. A logic glue can can be easily added in order to use commonly available N.O. button switches.
Click to expand...

massimo,

Can you please give me a link to AD151 datasheet and a source for component ?

I´m not sure I understand completely what N.O. buttons are you referring too. Do you have a draw ?

Regards,
Tibi
 
iTiberius

iTiberius

Member
Joined 2005
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