decoupling TDA1541A - Page 9 - 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 15th January 2011, 04:14 AM   #81
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by martin clark View Post
Eric - here is a typical Naim implementation:

Click the image to open in full size.

- It's not clear in my pic, but the caps return to a ground plane tied to the dac's own 0v plane.
Also note how Naim has cut slot's into the groundplane to ensure the elctrons behave themselves and only go where they are supposed to.

Naim is actually not a bad place to learn about layout. They always where pretty switched on.

I once serviced a pair of active speaker with pre-naim Julian Vererker electronics, in my days at MVE London, even then the layout was impressive.

I have never been the greatest fan of Naim's sound, but that they sounded comparatively SO GOOD while always using SO PEDESTRIAN circuitry is likely down to as a large degree to layout as it is to the powersupplies.

Ciao T
  Reply With Quote
Old 15th January 2011, 07:41 AM   #82
diyAudio Member
 
Eric Juaneda's Avatar
 
Join Date: Dec 2006
Location: Avignon, France
Default Decoupling TDA1541A S1 by NAIM AUDIO

Thanks Martin, thanks ThorstenL for those details.

Quote:
Originally Posted by ThorstenL View Post
I have never been the greatest fan of Naim's sound, but that they sounded comparatively SO GOOD while always using SO PEDESTRIAN circuitry is likely down to as a large degree to layout as it is to the powersupplies.
Sure. I remember a preamplifier with wonderful 300VA transformer and tantalum capacitors in the signal path

I push contrast on the picture to see details.
Attached Images
File Type: jpg TDA1541A_S1_NAIM.jpg (142.9 KB, 824 views)
__________________
Eric Juaneda - tech.Juaneda.com - Junilabs.com
  Reply With Quote
Old 24th April 2011, 06:18 AM   #83
diyAudio Member
 
Join Date: Feb 2005
I also played with those decoupling caps and currently have a rather weird setup but based on the idea that the decoupling caps might function better if accompanied by a snubber!!
Yes, well, it did seem promising back then, so I decided to try with the "fastest" (sorry) caps that I had that were Rifa styrene pfe216 (not the 225s), those big blue plastic case ones, and stood them on their ends (yes, long leads!) and added the snubbers of 1n47 + 0.165 (2 x 0.33 SMD in //) across each one (1n47 is also pfe216) and it works ridiculously well.

The decoupling cap range appears to be 125 -> 133nF (ended up at 128nF +/- 0.5nF) and with the standard 470pF cap on pins 16/17 reduced to 410pF Rifa Styrene pfe216, there didn't seem any difference and it was expected! (It could also be my less than rigorous scientific methods!)

And on pins 13/18 I also found that 4u7 is the "sweet-spot" for my old ears and ended up with the Mundorf Supreme (or Obbligato) which also has ridiculouly long leads.

Without having good clocks, DEM overdrive, best power supplies, I doubt that much technical significance can be attributed to my efforts, but it is rather curious that such outlandish disregard for accepted good engineering would work at all well.
The output stage for my much abused "ol' banger" is an upgraded clone of the original PassLabs D1 o/p stage, not the original IC stage in the player

For a reference, I do know the sound of both the big Zanden and the Abbington CD777 quite well.

Amazing, nearly 30 years after original design and many of us still prefer this rather basic digital circuit, altho I'm into the recent ESS Sabre dac now (Ackodac)

Incidently, could anyone advise if there are any of the NAIM based pcbs available for a new version of the 1541A dac (NOS) still available?
__________________
... jh
  Reply With Quote
Old 25th June 2011, 03:29 AM   #84
gabdx is offline gabdx  Canada
diyAudio Member
 
Join Date: Jan 2008
Everyone seems to have their own recipe without any adverse effects. I went with polycarbonate decoupling and the analogmetric dac produces noise when playing loud passages. Might be the clock or the cs8412.
  Reply With Quote
Old 25th June 2011, 03:59 AM   #85
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by gabdx View Post
Everyone seems to have their own recipe without any adverse effects. I went with polycarbonate decoupling and the analogmetric dac produces noise when playing loud passages. Might be the clock or the cs8412.
I think you need to tell us more than "polycarbonate decoupling", we may be able to help.

Ciao T
  Reply With Quote
Old 25th June 2011, 01:13 PM   #86
gabdx is offline gabdx  Canada
diyAudio Member
 
Join Date: Jan 2008
Hi Thorsten, I used MKC 0.1uf but I don't think it causes any problem. On the contrary it sounds very good. Unfortunately there is some noise buildup/interference when the dac plays loud passages like if the sound was clipping badly.
  Reply With Quote
Old 25th June 2011, 04:11 PM   #87
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by gabdx View Post
Hi Thorsten, I used MKC 0.1uf but I don't think it causes any problem. On the contrary it sounds very good. Unfortunately there is some noise buildup/interference when the dac plays loud passages like if the sound was clipping badly.
Do you have a schematic for the thing?

Ciao T
  Reply With Quote
Old 26th June 2011, 08:36 AM   #88
marce is offline marce  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
Location: Blackburn, Lancs
Ther is a whole wealth of information out there regarding decoupling capacitors and dogital lay out, it is not a misystery and it is not open to fanciful ideas. It is based on hard exidence and years of doing digital designs. I posted some links earlier regarding decoupling and how they work and how to implement it.
SLOTS in ground planes, dont do them, unless you realy know why you are putting them there, you can cause more problems than you solve, and even if there are slots on the ground on a top layer there may not be slots on inner ground planes. A contigous ground plane is best these days. So I would not reccomend trying to guess why someone at Naim has don what they have done, but reasearch and read stuff like Henry Ott, Electormagetic compatability Engineering; or stuff by Howard Johnson to name 2 of many sources, and look around at Engineering Based PCB froums.
  Reply With Quote
Old 29th June 2011, 01:59 AM   #89
gabdx is offline gabdx  Canada
diyAudio Member
 
Join Date: Jan 2008
Here is the schematic picture.
Click the image to open in full size.
  Reply With Quote
Old 29th June 2011, 02:11 AM   #90
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: 98
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
I'm surprised to see AD797 as I/V in a real-world design rather than in a manufacturer's datasheet Also IME, the 2n2 fb cap is way too high for decent sound. Try substituting an LM6171 for the AD797 and reducing the 2n2 to 10pF then tell us you hear no difference.
__________________
It doesn't have to take the form of a conspiracy, rather a consensus... James H Kunstler
  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
TDA1541A decoupling capacitors value Zoran Digital Source 25 22nd April 2010 09:18 PM
Styroflex caps for TDA1541A decoupling? Andypairo Digital Source 30 21st May 2004 06:38 PM
TDA1541A and the 14 decoupling caps Bricolo Digital Source 46 3rd December 2003 08:07 PM


New To Site? Need Help?

All times are GMT. The time now is 04:02 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