Parallel TDA1541A DAC Noise - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 March 2010, 08:41 PM   #1
pftrvlr is offline pftrvlr  United States
diyAudio Member
 
Join Date: Feb 2007
Location: SoCal
Default Parallel TDA1541A DAC Noise

I got this parallel tda1541a DAC off ebay and have been playing with it for three weeks now. The DAC uses two parallel tda1541a chips. The I/V is a discrete current mirror circuit. Outputs from two tda1541a are wired directly to the I/V input

The DAC is working all fine with a single tda1541 in either of the socket. But when both tda1541 are plugged in, I can heard apparent noise/distortion - especially in the quieter music passages. The noise is not present when it is not playing music or it is between the gap of tracks. I switched different tda1541 chips in and out, some particular matches of tda1541 produce less noise, however it can not eliminate the noise completely.

This has led me to wonder if the I/V circuit is sensitive to matches of the tda1541a chips. Or two tda1541a may be in contention for bias current? Anybody has similar experience? Maybe each tda1541 need to be biased separately?
  Reply With Quote
Old 28th March 2010, 10:57 PM   #2
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
My guess: each output has a nominal current. Parallel them on the same load (that's 1/2 of the single version one) and one of them will be forced to output more current while the other less - because of the inherent small diffecences.
You should build different I/V stages and parallel the outputs.
If you kept the same I/V load, then both of them will be out of the nominal current range.

Last edited by SoNic_real_one; 28th March 2010 at 11:03 PM.
  Reply With Quote
Old 16th January 2016, 05:52 PM   #3
Mike P is offline Mike P  United Kingdom
diyAudio Member
 
Join Date: Jan 2012
I recently fitted a pair of the new Burson Supreme V5 discrete op amps (duals) to my Sony 337ESD CD player which has parallel TDA1541 DACs and I'm getting exactly the problem described by pftrvlr. If I swap back to a 'normal' IC op amp such as JRC5532 or OPA2604 the problem disappears.

Any ideas?
  Reply With Quote
Old 19th January 2016, 11:23 AM   #4
diyAudio Member
 
Join Date: Jun 2011
Location: SCOTLAND
Quote:
Originally Posted by pftrvlr View Post
I got this parallel tda1541a DAC off ebay and have been playing with it for three weeks now. The DAC uses two parallel tda1541a chips. The I/V is a discrete current mirror circuit. Outputs from two tda1541a are wired directly to the I/V input

The DAC is working all fine with a single tda1541 in either of the socket. But when both tda1541 are plugged in, I can heard apparent noise/distortion - especially in the quieter music passages. The noise is not present when it is not playing music or it is between the gap of tracks. I switched different tda1541 chips in and out, some particular matches of tda1541 produce less noise, however it can not eliminate the noise completely.

This has led me to wonder if the I/V circuit is sensitive to matches of the tda1541a chips. Or two tda1541a may be in contention for bias current? Anybody has similar experience? Maybe each tda1541 need to be biased separately?
I also bought a parallel TDA1541 dac but rewired one to receive inverted data using a spare inverter on the board. In NOS mode with the SAA7220 removed, and using Sowter 9545 transformers and no other filtering or active devices between transformer and passive volume control. I am very happy with the results and of course, no noise issues.

The sound is much preferred over an Audio Note Dac1 (AD1865) and an ES9023 Sabre dac.

Perhaps you should try this method, although you will need a differential I/V stage or use transformers.
  Reply With Quote
Old 20th January 2016, 10:41 PM   #5
pftrvlr is offline pftrvlr  United States
diyAudio Member
 
Join Date: Feb 2007
Location: SoCal
I no longer have the parallel tda1541a dac. Some of the things I did is here:

- Paralleled TDA1541 NOS/OS DAC -

I agree with betterman. Me too is big fan of transformer output. Currently my main DAC is a parallel ES9018 with transformer + resistor only output stage. I am so far happy. See here:

Dual ESS Sabre ES9018 DAC with Transformer Output ? Capstone Project
  Reply With Quote
Old 5th November 2016, 06:44 PM   #6
diyAudio Member
 
Join Date: Jun 2011
Location: SCOTLAND
Quote:
Originally Posted by pftrvlr View Post
I no longer have the parallel tda1541a dac. Some of the things I did is here:

- Paralleled TDA1541 NOS/OS DAC -

I agree with betterman. Me too is big fan of transformer output. Currently my main DAC is a parallel ES9018 with transformer + resistor only output stage. I am so far happy. See here:

Dual ESS Sabre ES9018 DAC with Transformer Output ? Capstone Project
Yes I have the same issues now I have reconnected the dacs for parallel working.
However I noticed that pins 16 and 17 of the dacs, which are stated by Philips as not connected, are connected.

There is a 470pf cap on pin 16 to 0v so I am wondering whether the noise is due to differences in the oscillator frequency (nominally 200kHz)?

Might try a variable capacitor on one to see what happens.

(My I/V stage is an AD844 with 100r//10n on pin 5, capacitively coupled to an OPA627 buffer driving the transformer. )
  Reply With Quote
Old 7th November 2016, 05:57 AM   #7
Account disabled at member's request
 
Join Date: Jun 2015
Location: It varies
Quote:
Originally Posted by batteryman View Post
Yes I have the same issues now I have reconnected the dacs for parallel working.
However I noticed that pins 16 and 17 of the dacs, which are stated by Philips as not connected, are connected.

There is a 470pf cap on pin 16 to 0v so I am wondering whether the noise is due to differences in the oscillator frequency (nominally 200kHz)?
This is schema for //1541A DAC which works, I had one here maybe 10 years ago now. Note the arrangement with the cap across respective pins 16 &17, and with 16 on each chip shorted together at junction SYN (but you can try without this junction if you like)

470pF across each chip pin 16 & 17, short pin 16 of both chips together - and that is all (NO reference to 0V from pins 16 or 17)


LH/S
Attached Images
File Type: jpg tda1541a-ckt-rev1.2.jpg (349.9 KB, 187 views)

Last edited by Ludwig Haus; 7th November 2016 at 06:07 AM.
  Reply With Quote
Old 7th November 2016, 07:57 AM   #8
diyAudio Member
 
Join Date: Jun 2011
Location: SCOTLAND
Quote:
Originally Posted by Ludwig Haus View Post
This is schema for //1541A DAC which works, I had one here maybe 10 years ago now. Note the arrangement with the cap across respective pins 16 &17, and with 16 on each chip shorted together at junction SYN (but you can try without this junction if you like)

470pF across each chip pin 16 & 17, short pin 16 of both chips together - and that is all (NO reference to 0V from pins 16 or 17)


LH/S
Thanks I will try that.

The schematic I have shows the syn point on pin 16 on each dac but currently they are not connected to each other. There is a 470pf capacitor and I was incorrect to say it was connected to ground, it was indeed between pins 16 & 17.
  Reply With Quote
Old 7th November 2016, 10:06 AM   #9
diyAudio Member
 
QSerraTico_Tico's Avatar
 
Join Date: Oct 2004
I got these noise problems in NOS mode and never could get rid of it.
So I am using a digital filter now.
  Reply With Quote
Old 7th November 2016, 10:10 AM   #10
diyAudio Member
 
Join Date: Jun 2011
Location: SCOTLAND
Quote:
Originally Posted by QSerraTico_Tico View Post
I got these noise problems in NOS mode and never could get rid of it.
So I am using a digital filter now.
Did you try linking dac pin 16s?
  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
Parallel TDA1541A non-o/s DAC Kits siu sin man tho Digital Source 89 14th February 2011 04:05 PM
FS: AYA DAC Rev 2.0b TDA1541A Non-Oversampling DAC kit or complete krishu Swap Meet 0 17th December 2009 10:33 AM
Parallel TDA1541A ... some clarifications required skje Digital Source 3 25th March 2008 02:11 PM
Only noise from TDA1541A based Sphinx Project 3 DAC Lucas Unger Digital Source 10 10th June 2006 01:53 PM
How many TDA1541A are needed in parallel to achieve double crown standard ? Blitz Digital Source 39 26th January 2004 02:26 PM


New To Site? Need Help?

All times are GMT. The time now is 08:10 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki