Any good TDA1541A DAC kit? - Page 41 - 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 7th March 2012, 06:05 AM   #401
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by abraxalito View Post
I flirted with cap to ground but didn't much like the sound on TDA1543 or TDA1545.
At a guess, either wrong value, wrong capacitor type, ground routing issues...

In a differential system you should have one capacitor across +/- out and one each from each output to ground.

Quote:
Originally Posted by abraxalito View Post
The series inductor I chose was one with a high SRF (above 200MHz) intended for use as a CM choke.
If this "coke" is a 4-terminal device and operates on differential outputs then it is not a "choke" in the traditional sense.

The problem with a choke following an I-Out DAC is that the DAC's voltage compliance (real or datasheet) will be massively exceeded... Luckily enough with the Philips parts and common mode only chokes this not much of an issue.

Ciao T

Last edited by ThorstenL; 7th March 2012 at 06:20 AM.
  Reply With Quote
Old 7th March 2012, 06:11 AM   #402
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: 100
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
Quote:
Originally Posted by ThorstenL View Post
At a guess, either wrong value, wrong capacitor type, ground routing issues...
Yep, all issues considered and looked into at the time.

Quote:
In a differential system you should have one capacitor caross +/- out and one each from each output to ground.
I generally dispense with caps to gnd (Y) in such and just keep the one X-type.

Quote:
If this "coke" is a 4-terminal device and operates on differential outputs then it is not a "choke" in the traditional sense.
Yes and no - it has appreciable leakage inductance.

Quote:
The problem with a choke following an I-Out DAC is that the DAC's voltage compliance (real or datasheet) will be massively exceeded... Luckily enough with the Philips parts and common mode only chokes this not much of an issue.
Yep - this is not a configuration I've been tempted to try - choke straight after I-out DAC.
__________________
When you design something for other people you don't have as much motivation to make it beyond excellent - Woz
  Reply With Quote
Old 9th March 2012, 07:16 PM   #403
diyAudio Member
 
Join Date: Oct 2009
Location: Brunei
Quote:
Originally Posted by s3tup

What about my grounds layout?
I didn't liked the capacitive/inductive coupling of DGND and AGND when they are on top of each other (2-layers), so i decided to move the DGND aside.
By doing this i halved the AGND impedance, got solid AGND layer
But i've got a half-circle loop between -5V and DGND pins with -5V PSU in between. The DAC chip is in center of EMI field produced by currents flowing from -5 to DGND and back given the "right hand rule" is true .
My latest layout (not yet built) also has the ground plane for the digital section next to the analog ground plane on the same layer. The tda is on the edge of the Agnd plane (though completely on that plane), and the dgnd plane connects on the entire left side of the tda to the agnd plane. Both planes are almost not interrupted.

One of my previous layouts had dgnd and agnd connect at the agnd pin of the tda only... Worked quite well.

Ecdesigns has, in his latest versions, completely abandoned this discussion: he uses one big ground plane now!
  Reply With Quote
Old 9th March 2012, 08:02 PM   #404
diyAudio Member
 
Join Date: Apr 2010
Quote:
Originally Posted by ThorstenL View Post
Quote:
Originally Posted by gaetan8888
I've take a look today at the Stereophile web site and I can't find those tests.

Can you tell me, please, where they are in the Stereophile web site ?


They are in the March issue (print).
This review will be posted in the free on-line archives at Home Page | Stereophile.com next Thursday or Friday.

John Atkinson
Editor, Stereophile
  Reply With Quote
Old 9th March 2012, 08:03 PM   #405
diyAudio Member
 
s3tup's Avatar
 
Join Date: Dec 2004
Location: Israel
Damn i've gone thru 5 layouts, and still think i should scrap the current layout and redo it from EMC point of view /since i discovered EMC Information Centre - The EMC Journal (Free in the UK) .
"Balanced" PSU is BS, you need every cap stuck into low impedance ground to work, otherwise it will just pass the spike from V+ to "GND" without any filtering.
I2S wires should be done without DIP sockets to prevent EMC emissions due to impedance mismatch.
"I2S attenuator" should be done in 2 parts, with loading resistors near DAC and series resistors near DF.
Rethink the GND cutouts from "slot antenna" perspective.
And overall layout of connections/wires when the board goes into real-world application.

Ferrite beads and common mode chokes should be placed everywhere, at least on the points of I/O connections on the board, to prevent EMI emissions/fishing.
Every current should be returned to it's source, otherwise it will find it's way back thru air/other circuit paths affecting the performance of DAC surrounding.

Common ground for D and A sides of DAC is reasonable in many ways. Less EMC due to solid ground, the D and A parts of 1541 are probably capacitively coupled much better than our GND impedance. Therefore, the more impedance we add to GND pins, the less current the GND will catch, and more A to D interference will be there.

GND layers should expand to PCB edges, much futher than other wires, so GND could catch and return emitted EM fields.

Every EM transmitter is a receiver too, in same frequencies and same power, therefore, fighting EM emissions reward us with lower EM fishing too.

I know i'll end-up with solid single GND, and PSU layed-out on one side of the board
  Reply With Quote
Old 10th March 2012, 04:42 AM   #406
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
I picked up a red barron PCB 'cause I won't have time to build a PCB for a while.

I was planning on using SMD caps for decoupling by grinding the solder mask off the top layer ground plain. Then I saw that the i-outs are routed right under the TDA1541 cutting the groundplain in half.

I am thinking of removing the mask off that area under theath completely and soldering a thick piece of coper foil underneath the TDA. Going to be a PITA.

Click the image to open in full size.

Last edited by regal; 10th March 2012 at 04:44 AM.
  Reply With Quote
Old 10th March 2012, 05:09 AM   #407
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by regal View Post
I picked up a red barron PCB 'cause I won't have time to build a PCB for a while.

I was planning on using SMD caps for decoupling by grinding the solder mask off the top layer ground plain. Then I saw that the i-outs are routed right under the TDA1541 cutting the groundplain in half.

I am thinking of removing the mask off that area under theath completely and soldering a thick piece of coper foil underneath the TDA.
Go for it.

Or just use my suggested Veroboard method. If you have enough silverfoil you can even make an all silver DAC that way...

Ciao T
  Reply With Quote
Old 10th March 2012, 06:04 AM   #408
diyAudio Member
 
Join Date: Apr 2007
Quote:
Originally Posted by StereoEditor View Post
This review will be posted in the free on-line archives at Home Page | Stereophile.com next Thursday or Friday.

John Atkinson
Editor, Stereophile
Hello

Thank you Mr Atkinson

Are you going to the Montreal Hi-Fi Show (Salon Son & Image) this year ?

Bye

Gaetan
  Reply With Quote
Old 10th March 2012, 12:00 PM   #409
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
OT posts and insults removed. Warnings given. Keep it civil, gentleman.
  Reply With Quote
Old 10th March 2012, 11:39 PM   #410
diyAudio Member
 
s3tup's Avatar
 
Join Date: Dec 2004
Location: Israel
This one goes to production tomorrow, unless i'll find something to fix at mornin' coffee.

- Added some ferrite beads on power rails
- A bit of cutouts around PS ferrites to lower parasitic capacitance around 'em.
- Changed reg bypass caps to electrolytics, as LM317/337 have no love for low impedance on their outputs, but they want some caps to stay stable.
- Some graphics added.
- AGND/DGND could be stitched together with a bit of solder around plane edges.
- Pad for foil-screen grounding. You can glue a ribbon of foil around 1541, and solder it to the pad. Aaargh, DGND or AGND?! Okay, ive added the same "pad" on DGND side too. /not in pic/
- A tiny pad for I2S att resistors, pretty optional, as i had no place to mount them in a good way, and i didn't want to pass traces under resistor's belly due to parasitic capacitance. The resistors could be mounted on their side, between I2S pins and a spot on DGND.
Attached Images
File Type: png DAC_1541_V008.png (174.2 KB, 420 views)

Last edited by s3tup; 10th March 2012 at 11:45 PM.
  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
Raindrop Hui TDA1541A DAC Kit wushuliu Swap Meet 25 21st November 2013 10:07 AM
which clock for analogmetric tda1541A dac kit Chilli6565 Digital Source 4 6th May 2010 12:41 PM
FS: AYA DAC Rev 2.0b TDA1541A Non-Oversampling DAC kit or complete krishu Swap Meet 0 17th December 2009 09:33 AM
Recommend a DIY tda1541a dac kit? boidos Digital Line Level 2 6th August 2009 01:43 PM
TDA1541A Chineese DAC KIT UV101 Digital Source 8 10th February 2009 10:46 AM


New To Site? Need Help?

All times are GMT. The time now is 04:42 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