AD1865 schematic - 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 18th December 2012, 03:08 PM   #1
diyAudio Member
 
skouliki's Avatar
 
Join Date: Aug 2010
Location: Athens
Default AD1865 schematic

I am planning to build the following AD1865 and cs8416 schematic from pavouk.org because it includes toner transfer pdf's and this makes it really easy.
CS8416 S/PDIF decoder
AD1865 based audio DAC with I2S input and voltage output

Does anyone have any comments on the quality of layout and circuit?
I intend on using Salas regulators and C0G ceramics instead of x7r
Thanks
  Reply With Quote
Old 18th December 2012, 03:40 PM   #2
diyAudio Member
 
Join Date: Apr 2003
Location: Eastern Pennsylvania
1) I notice that the S/PDIF input transformers don't appear to have a D.C. blocking capacitor in series with their primaries. Unless you are sure that your transport's S/PDIF output signal contains no D.C. component, this omission may be distorting (adding jitter to) the received signal.

2) I have some experience with the AD1865 in the Vout configuration. While the sound is okay that way, in my opinion, it's much better in the Iout configuration via a passive resistor I/V (of as high as 330 ohms). The resulting signal voltage can be A.C. coupled (without an intervening active stage) to your linestage input.
__________________
Ken
  Reply With Quote
Old 18th December 2012, 04:10 PM   #3
diyAudio Member
 
skouliki's Avatar
 
Join Date: Aug 2010
Location: Athens
Thanks for the reply Ken.

What value for the capacitor do you suggest?

Pavouk has a schematic for AD1865 with Iout.
Audio DAC with AD1865

I guess i can build both and choose the one that i like best.
  Reply With Quote
Old 18th December 2012, 08:13 PM   #4
diyAudio Member
 
Join Date: Apr 2003
Location: Eastern Pennsylvania
10nF to 100nF should be fine for coupling the S/PDIF transformers. Ideally, caps. featuring low parasitic inductance, such as SMD ceramics, are to be preferred since this signal is wideband. Although, I've used both 22nF NP0/C0G ceramics and 10nF film & foil polypropylene with equal success. I must add that I've not before seen a paralleled dual transformer configuration utilized here, I assume there must be a good reason the designer chose to do so. Perhaps, it's an attempt to produce a composite transformer having a wider bandwidth than either one alone, I'm not sure.

The Iout schematic appears fine to me. All one would need then do is A.C. couple (via a quality capacitor) the resulting signal voltage to a linestage. The DAC signal should be large enough that not much gain would likely be required while the output impedence would be just under 200 ohms, together eliminating the need for the usual DAC active output stage.
__________________
Ken

Last edited by Ken Newton; 18th December 2012 at 08:41 PM.
  Reply With Quote
Old 19th December 2012, 08:51 AM   #5
SSerg is offline SSerg  Russian Federation
diyAudio Member
 
Join Date: Mar 2012
Location: St.Petersburg
Quote:
Originally Posted by Ken Newton View Post
While the sound is okay that way, in my opinion, it's much better in the Iout configuration via a passive resistor I/V.
Yes, I agree. The built-in amplifier is mediocre.
  Reply With Quote
Old 19th December 2012, 09:14 AM   #6
marce is offline marce  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
Location: Blackburn, Lancs
Single sided design is going to be a compramise, best thing you could do is etch it on double sided PCB material and have a complete ground plane on the other side (clearing where throough holes come through)and wire link ground pins to this plane. The good thing about this design is it allows for this, and would be greatly improved as a double sided layout.
  Reply With Quote
Old 19th December 2012, 05:37 PM   #7
diyAudio Member
 
skouliki's Avatar
 
Join Date: Aug 2010
Location: Athens
Thanks everybody for your suggestions.
Creating a double sided version with a ground plane is a very interesting idea (and easy enough for my amateur level).
  Reply With Quote
Old 20th December 2012, 06:47 AM   #8
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 109
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
I'm finding these double sided PTH boards excellent for building DIY DACs on. The pads don't lift off when resoldering, they're nicely robust and due to being PTH both sides are usable for SMT components. Makes for very compact layouts

2X Double Side Prototype PCB Board 5x7 cm Tinned Universal Board FR4 | eBay
__________________
There is surely nothing quite so useless as doing with great efficiency what should not be done at all - Peter Drucker
  Reply With Quote
Old 20th December 2012, 01:43 PM   #9
diyAudio Member
 
skouliki's Avatar
 
Join Date: Aug 2010
Location: Athens
Didnt know these boards existed. They'll be usefull in a lot of projects. Thanks abraxalito
  Reply With Quote
Old 20th December 2012, 01:59 PM   #10
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 109
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
You're welcome - I only discovered them this summer too They are indeed a great DIY resource.
__________________
There is surely nothing quite so useless as doing with great efficiency what should not be done at all - Peter Drucker
  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
AD1865 vs AD1955 toufu Digital Line Level 50 15th April 2012 02:59 AM
Schematic for AD1865 ebay dac? mkanna Digital Line Level 1 13th May 2011 04:26 AM
AD1865-based dac schematic Sandor Digital Line Level 8 16th March 2010 08:01 PM
AD1865 w/ USB? dsavitsk Digital Source 6 28th February 2006 11:47 AM
AD1865 where? avian Digital Source 2 5th January 2004 08:17 AM


New To Site? Need Help?

All times are GMT. The time now is 07:21 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