WM8805 upgrade board (cs8414 pins) - dissapointed - Page 13 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, 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 9th April 2012, 12:51 PM   #121
Account disabled at member's request
 
Join Date: Aug 2007
Quote:
Originally Posted by gfiandy View Post
I couldn't even buy the parts in the uk, never mind wages. However I have noticed parts are easier to buy at high volume prices even in lower volumes in the Chinese markets.

If you are really interested I could do a rough costing to see what it's likely to come out at buying parts from Uk low volume distribution.

Andy
Hi,

I think you don't need to go to that trouble as most people can source parts themselves, and may even prefer to build it themselves.

For me, I'm really looking a for a good PCB with good i2s routing, grounding etc and a buffered output too.

Are you interested in doing a PCB only ? If so, I'm definitely interested.
  Reply With Quote
Old 9th April 2012, 01:10 PM   #122
gfiandy is offline gfiandy  United Kingdom
diyAudio Member
 
gfiandy's Avatar
 
Join Date: Jul 2003
Location: Cambridge UK
That would be my preference, I will need to build at least one up to test it so I need to look at the cost to me. Also I am not a programmer so if the modes you want need software config it might be a problem.

I will have a quick look and see what would be possible.

Incidentally crystal quality is mostly determined by the quality of the quartz and the cut. HC49 crystals can work very well with a High quality quartz and a colipits the cct driven at the correct level and with a LC resonator to optimise the Q of the circuit.

The low profile and SMT packages can make the cut more complex and hence more expensive. I recommend choosing the part via it's specification rather than package type.

Regards,
Andy
  Reply With Quote
Old 9th April 2012, 01:20 PM   #123
Account disabled at member's request
 
Join Date: Aug 2007
Hi,

It seems it will need software control. I wouldn't want a 12Mhz clock because it seems the best clock is either 24Mhz or 27Mhz. Still interested ? :-)

I didn't know you could get different crystal cuts in HC49 - anyone sell SC cut ? No chance I guess... I wrongly assumed they were all rubbish.

I use Euroquartz XO91 a lot - inexpensive and low jitter - so I'll try that first. The datasheet says less than 1ps rms but they don't say over what freq so I guess 10hz. Interestingly, Guido Tent claims the same for his xo module and they sound superb but I don't have a 12Mhz one of those. I have a Valab 12Mhz one to try too.
  Reply With Quote
Old 9th April 2012, 01:50 PM   #124
gfiandy is offline gfiandy  United Kingdom
diyAudio Member
 
gfiandy's Avatar
 
Join Date: Jul 2003
Location: Cambridge UK
I am happy to wire it to a micro connector and put jumpers on to configure it, if you can find someone to program the micro. (I could make it compatible with an Arduno board or something like that. Arduino - Hardware)

Euroquartz do seem to be offering good value at the moment. I have been working with them on a set of high tolerance crystals in 500 Hz steps around 100MHz for a environmental dielectric sensor. They were much cheaper than the nearest competitor and were happy to supply custom parts in 500 off. This was in a low profile ceramic package as the part needs to go in a small enclosure and hostile environmental conditions.

However I don't imagine we will get 500 people together for a custom 24MHz or 12MHz part so I guess it will have to be something off the shelf :-). Still I know some tricks for optimising the performance of clock oscillators.

Regards,
Andy
  Reply With Quote
Old 9th April 2012, 02:11 PM   #125
Account disabled at member's request
 
Join Date: Aug 2007
LCDuino is possible but not by me. Linux Works could probably do it in his lunch break, so I'll ask around and see if I can get a willing volunteer.

SPDIF to I2S is a major part of many DACs so this has gotta get done, and done right eh ?
  Reply With Quote
Old 9th April 2012, 04:33 PM   #126
gfiandy is offline gfiandy  United Kingdom
diyAudio Member
 
gfiandy's Avatar
 
Join Date: Jul 2003
Location: Cambridge UK
As an initial discussion document I have thrown a circuit together. This has not been checked so probably contains lots of errors but at least it provides a concept.

It includes screw terminals for all the I/O signals. Twisted pairs are probably the best way to bring signals in and out. A coax may be needed for the clock input if you use an external clock PCB.

I have put a standard clock OSC on the PCB but can upgrade this if a on board high quality clock option is preferable.

I have put on phono type connectors and optical connectors as I had PCB patterns for them however a BNC is possible but I will have to make the pattern which takes a long time. So I will do this if there is interest.

The board is configured to expect software control. If we want to use all the input then this is required. If a hardware option is wanted I will have to add lots of jumpers to configure it.

I have buffered the inputs and outputs, the inputs may need termination resistors depending on the speed at which the signal is being driven. However depending on the source impedance this could cause the logic level to be too low so they may need to be removed.

As I said this is just a first draft and in no way intended to be considered complete or checked.

Comments welcome.

Regards,
Andy
Attached Files
File Type: pdf Schematic Prints.pdf (81.8 KB, 84 views)
  Reply With Quote
Old 9th April 2012, 04:49 PM   #127
Account disabled at member's request
 
Join Date: Aug 2007
Fast !

The datasheet says the clock must be between 12 and 24, or 27Mhz but you have noted 11.2896 ?

No pulse transformers on the inputs ?

It might be on this thread, or elsewhere, but it seems the higher clock freq is better.

On the thread here,
Wolfson WM8805 I2S to TDA1541A NOS
it was noted that performance improved considerably with an xo, and this is very credible of course, so perhaps you should design it around smd ( like XO91 ) or Tent labs dip, plus any clock circuit improvement possible.

Finally, all the decent regs these days are tsot, like the adp151, so you should design for this I think.

Other than that, hopefully others more knowledgeable than me will comment...

Thanks !

BTW I didn't check the pin connections but I assume you did ;-)

Last edited by KlipschKid; 9th April 2012 at 04:55 PM.
  Reply With Quote
Old 9th April 2012, 05:06 PM   #128
gfiandy is offline gfiandy  United Kingdom
diyAudio Member
 
gfiandy's Avatar
 
Join Date: Jul 2003
Location: Cambridge UK
Hi,

Crystal came from an old design and I forgot to update the freq. I'm not sure I have a XO91 PCB footprint but I can make one if that is the preferable part. Also if you intend to use the on board oscillator I will design a discrete osc circuit to run it rather than use the CMOS one inside the WM8805. I imagined from your description that you would use an off board osc so didn't bother putting any effort into the on-boad osc.

PSU was also one I had available but I can easily change it to a ADP151.

I have used these parts before so unless the pins have moved they should be OK.

Driver software is the biggest problem and how to debug the board.

Regards,
Andrew
  Reply With Quote
Old 9th April 2012, 05:40 PM   #129
gfiandy is offline gfiandy  United Kingdom
diyAudio Member
 
gfiandy's Avatar
 
Join Date: Jul 2003
Location: Cambridge UK
My experience of pulse transformers has been mixed. They don't always seem to improve the situation but I guess they do provide isolation to DC and L.F noise such as ground loops.

Do you have a part in mind as I haven't used any recently so don't know what's good. I think it was a Schott 22133 I used last time but I don't know where I could buy them in low volumes.

Regards,
Andrew
  Reply With Quote
Old 10th April 2012, 04:27 AM   #130
Account disabled at member's request
 
Join Date: Aug 2007
Hi,

I'd definitely want the option of onboard xo, and ideally it should have smd pads for 5x7 xo (and smaller- there are some tiny ones available in japan with ultra low jitter) and also holes for a square dip package like Tent labs/feeding in an external clock.

The clock should get its own reg and again that would be tsot for adp150 or tps79333dbvr or similar. I don't know if/how a clock output can be improved but if you know a tried and tested way then that would be awesome. Of course, low jitter is the main goal.

An alternative to the reg is to use a potential divider (say 5.1K and 22K) to drop 5v to 4V and feed that into the base of a bc550 with a 100uF cap from the base to ground. This gives 3.3V output and it's a a very effective noise killer.

Pulse transformers - off the top of my head so maybe my part nos might be wrong - the Newava s2283 is great and the Murata DA101C is also very good.

I forgot to say, for input, I think some people might be okay with RCA but I'm not. So, let's say one optical toslink for PC, two bnc for cd and digital player, and one rca for the couldn't-care-less-must-be-convenient people ? Perhaps an XLR is going to be necessary too if this board is going to become popular. Sorry if this is more work but it's really a must.

Thanks !
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: NOS Quad TDA1543 + CS8414 SPDIF DAC Board pftrvlr Swap Meet 5 8th June 2010 01:00 AM
FS: NOS Quad TDA1543 + CS8414 SPDIF DAC Board pftrvlr Swap Meet 3 20th April 2010 08:06 AM
FS: NOS Quad TDA1543 + CS8414 SPDIF DAC Board pftrvlr Swap Meet 0 26th July 2009 09:28 PM
Micro Jacks and Micro Pins for board-board connection jazzist Parts 1 12th May 2008 04:02 PM
Selling CS8414 to CS8412 converter board spencer Swap Meet 8 1st May 2007 08:08 AM


New To Site? Need Help?

All times are GMT. The time now is 10:12 AM.


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