Finally, an affordable CD Transport: the Shigaclone story - Page 546 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 27th February 2012, 06:48 PM   #5451
tvicol is offline tvicol  Romania
vicol-audio.ro
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Send a message via Yahoo to tvicol Send a message via Skype™ to tvicol
Quote:
Originally Posted by TheGimp View Post
Hmmm. Actually a couple of resistors and a transistor would work just as well.

The only advantage of inverting the signal is to eliminate the NC switch and use all NO switches.

This simplifies the BOM and makes purchasing parts easier at the expense of the additional resistors and transistor.

With regards to the ADP151, one could pre-regulate the 8V supply down to 5V with a 7805 to generate a supply that is supportive. Again, it adds components. However if 8V tolerant low noise regulators are difficult to source it may be worth investigating.
Maybe we'll make room for something like this on PCB, but I'll try to keep balance between options and price on the side of price. Also a very complicate PCB with lot of options will confuse DIY-ers.

Regards,
Tibi
  Reply With Quote
Old 27th February 2012, 07:11 PM   #5452
tvicol is offline tvicol  Romania
vicol-audio.ro
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Send a message via Yahoo to tvicol Send a message via Skype™ to tvicol
Quote:
Originally Posted by Nomdi View Post
A L7941 is a serious outsider to replace a 7805...
@tibi : could you consider to add 2 capacitors
to replace the ceramic resonator with a regular quartz ?
Good a low cost upgrade to my mind...
Nomdi,

Please a datasheet for L7941 ?
Actually the resonator will no more be used in this project.
This is already reflected in schematic I'll post in few moments.

Thanks & Regards,
Tibi
  Reply With Quote
Old 27th February 2012, 07:41 PM   #5453
tvicol is offline tvicol  Romania
vicol-audio.ro
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Send a message via Yahoo to tvicol Send a message via Skype™ to tvicol
Schematic with latest changes.

- ADP151 low noise regulator for Vref=2.5V
- separate power supply for each pin on LA6541. I don't have LA6541 detailed internal connections, hope this will bring us separate BTL for focus&track from motors.
- N.C. switch is on the display board
- instead ceramic resonator a citizen cristal is in place
- all other small error drawings have been corrected

From now will start to work on PCB, but remain open to any other observation/suggestions.
Thank you !

Regards,
Tibi
Attached Files
File Type: pdf shigaclone_diyaudio_27022012.pdf (117.5 KB, 234 views)

Last edited by tvicol; 27th February 2012 at 07:47 PM.
  Reply With Quote
Old 28th February 2012, 10:14 PM   #5454
diyAudio Member
 
skippyboy's Avatar
 
Join Date: Jun 2008
Location: nsw
Found this, is it of any use for the Shigaclone project or am i off track.
CD rom drive control
CD ROM drive controller board products AR | eBay
  Reply With Quote
Old 29th February 2012, 03:39 AM   #5455
TheGimp is offline TheGimp  United States
diyAudio Member
 
TheGimp's Avatar
 
Join Date: Aug 2009
Location: Johnson City, TN
I think that is designed to interface to an IDE CD rom drive. It uses a microprocessor to talk through the IDE interface to operate the drive.

Third pix from the bottom shows the back side with what looks like an IDE connector.

Last pix looks like a housing with the controller, a ps and the CD rom drive in the bottom.
  Reply With Quote
Old 29th February 2012, 06:57 PM   #5456
tvicol is offline tvicol  Romania
vicol-audio.ro
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Send a message via Yahoo to tvicol Send a message via Skype™ to tvicol
I had a look on the schematic from this post Finally, an affordable CD Transport: the Shigaclone story
I don't get why Vref from regulator output need to go back to Vref from LA9242.
Is there any feed-back in place ?

Regards,
Tibi
  Reply With Quote
Old 29th February 2012, 07:31 PM   #5457
diyAudio Member
 
Join Date: Jan 2006
Location: Ireland
Added my name to the list. This is a very commendable project - well done to all concerned.


Fran
  Reply With Quote
Old 29th February 2012, 07:35 PM   #5458
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by tvicol View Post
I had a look on the schematic from this post Finally, an affordable CD Transport: the Shigaclone story
I don't get why Vref from regulator output need to go back to Vref from LA9242.
Is there any feed-back in place ?

Regards,
Tibi
From my understanding its based on a feedback loop that monitors and regulates the vref signal from the LA9242
  Reply With Quote
Old 29th February 2012, 08:05 PM   #5459
tvicol is offline tvicol  Romania
vicol-audio.ro
diyAudio Member
 
tvicol's Avatar
 
Join Date: Jan 2005
Location: Bucharest
Send a message via Yahoo to tvicol Send a message via Skype™ to tvicol
Quote:
Originally Posted by apoopoo999 View Post
From my understanding its based on a feedback loop that monitors and regulates the vref signal from the LA9242
In LA9242 datasheeton page 16, you will see that Vref is made with a differential stage who mirror a low current resistive reference to a high current reference (see npn/pnp complementary pair).
I don't see any reason to use Vref LA9242 in a feedback loop with a low noise regulator.
In fact this will inject Vref La9242 noise back to C906.
A more elegant solution could be to inject at pin 57 a low noise low current reference.
Can you please disconnect regulator and C906 from LA9242 Vref pin ?
I expect better results.

Regards,
Tibi

Last edited by tvicol; 29th February 2012 at 08:18 PM.
  Reply With Quote
Old 29th February 2012, 08:30 PM   #5460
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by tvicol View Post
In LA9242 datasheeton page 16, you will see that Vref is made with a differential stage who mirror a low current resistive reference to a high current reference (see npn/pnp complementary pair).
I don't see any reason to use Vref LA9242 in a feedback loop with a low noise regulator.
In fact this will inject Vref La9242 noise back to C906.
A more elegant solution could be to inject at pin 57 a low noise low current reference.
Can you please disconnect regulator and C906 from LA9242 Vref pin ?
I expect better results.

Regards,
Tibi
I really didnt notice any improvement when I implemented the regulator to C906. I will disconnect it tonight and see if I notice any change in sound.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 01:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2