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 15th May 2012, 06:44 AM   #3281
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by MurphyUHF10 View Post
[snip] Once I did this, hum/buzz vanishes almost completely.. [snip]Cheers..
CM
Excellent! Well done!

Quote:
Originally Posted by MurphyUHF10 View Post
[snip] Can the Didden Linear PSU handle an extra 300mA..?? Do you see any issues here with taking power from X3 pin 1 & 2.. At least I wouldn't need to worry about grounding :-)
Cheers..
CM
Sorry, no way! I had to bend over backwards to get that linear supply within the space and dissipation constraints as it is - it gets pretty warm, although not critically. But another 300mA is out of the question.

Quote:
Originally Posted by MurphyUHF10 View Post
[snip] However, when I mute/unmute on the remote, or change volumes etc, I get loud "pop" with every button press on the remote..?
[snip]Cheers..
CM
That's unusual. Can you verify whether there is DC offset at the outputs? If that would be the case, changinging level or muting would change the offset level and that could cause plops. If the offset is low but not very low you get what is called 'zipper noise' but you say plop so I guess it's not subtle.
You can check that without signal.

jan
__________________
Never explain - your friends don't need it and your enemies won't believe you anyway - E. Hubbart
Check out Linear Audio Vol 7
!
  Reply With Quote
Old 15th May 2012, 07:54 AM   #3282
diyAudio Member
 
MurphyUHF10's Avatar
 
Join Date: Oct 2010
Location: Melbourne
Quote:
Originally Posted by janneman View Post
But another 300mA is out of the question.jan
Hi Jan, ok I understand :-(

Quote:
Originally Posted by janneman View Post
Can you verify whether there is DC offset at the outputs?

...You can check that without signal.
Yes, I get about 160mV DC across the output (XLR pin 2 & 3). With LM4562's I get only 1 or 2mV..

The 'Pop" is not subtle. It's very distrubing, especially with no music! With music it's not as bad, but still noticeable. With 4562's, no Pop's, dead quiet in all respects (I can see you grinning)..

Ta
CM
  Reply With Quote
Old 15th May 2012, 08:01 AM   #3283
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by MurphyUHF10 View Post
Yes, I get about 160mV DC across the output (XLR pin 2 & 3). With LM4562's I get only 1 or 2mV..

The 'Pop" is not subtle. It's very distrubing, especially with no music! With music it's not as bad, but still noticeable. With 4562's, no Pop's, dead quiet in all respects (I can see you grinning)..

Ta
CM
I think you just answered your own question. 160mV is unacceptably high in this application.
1 to 2mV is also what I measure.
If you switch level, whether stepping or muting, you change the offset in level as well. Stepping DC sound like, well, pops

There's no practical problem as long as the pops don't blow your speakers, but as you say, it's annoying.
If you really want to continue to use the discrete opamps, you might be able to insert a coupling capacitor on it's output to AC couple it.
But then you're really bending over backwards and you should be really sure it's worthwhile.

jan
__________________
Never explain - your friends don't need it and your enemies won't believe you anyway - E. Hubbart
Check out Linear Audio Vol 7
!
  Reply With Quote
Old 15th May 2012, 08:55 AM   #3284
diyAudio Member
 
MurphyUHF10's Avatar
 
Join Date: Oct 2010
Location: Melbourne
Hi Jan,

Yes, Perhaps I just put these discrete modules back in the drawer for another project..

Worth mentioning however, is that I did receive a reply from Burson,, they suggest shortening the wires from the external power supply to the op-amp modules, and also said to put "local power coupling capacitor across the power pins, 100uF or 200uF Good quality cap".. They have not replied to my query about the high DC offest (as yet). I might try these 2 suggestions,, and after that if I'm still not satisfied,, back in the drawer they go!!

What is a "Good quality local power coupling capacitor"..??

Thanks
CM
  Reply With Quote
Old 15th May 2012, 08:58 AM   #3285
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by MurphyUHF10 View Post
Hi Jan,

Yes, Perhaps I just put these discrete modules back in the drawer for another project..

Worth mentioning however, is that I did receive a reply from Burson,, they suggest shortening the wires from the external power supply to the op-amp modules, and also said to put "local power coupling capacitor across the power pins, 100uF or 200uF Good quality cap".. They have not replied to my query about the high DC offest (as yet). I might try these 2 suggestions,, and after that if I'm still not satisfied,, back in the drawer they go!!

What is a "Good quality local power coupling capacitor"..??

Thanks
CM
Yes, a knee-jerk reaction to hum is often throwing cap at it.
Which is unfortunate because I never have seen a hum problem that was solved by capacitors.
Hum and buzz always have a very specific cause and if you fix the cause, you fix the hum/buzz.

jan
__________________
Never explain - your friends don't need it and your enemies won't believe you anyway - E. Hubbart
Check out Linear Audio Vol 7
!
  Reply With Quote
Old 16th May 2012, 04:48 AM   #3286
diyAudio Member
 
Join Date: Apr 2002
Greetings all,

I have acquired the DCX2496, and found this thread. However, before I start sifting through the 300+ posts, I was wondering if someone could list the modifications in order of perceived bang-for-the-buck improvement.

Kindest regards,

M
  Reply With Quote
Old 16th May 2012, 05:05 AM   #3287
diyAudio Member
 
MurphyUHF10's Avatar
 
Join Date: Oct 2010
Location: Melbourne
Quote:
Originally Posted by janneman View Post

160mV is unacceptably high in this application.

jan
Hi Jan,

Thought to mention this, just in case anyone else is facing same issue.

I heard back from Burson regarding the High DC offset.. "The DC offset can be adjust via the small blue trimpot. It does not affect class A operation, or sound quality, only used to adjust DC offset.."

Over the weekend, I will finalise the grounding layout to further minimise hum. I will shorten the "fly leads" and install 100uF & 0.1uf across the power pins (4 & 8) of the Discrete modules, and I will also adjust the DC offset as low as I can get it..

I will report back with some reults in a few days!!

Thanks
CM

Last edited by MurphyUHF10; 16th May 2012 at 05:07 AM. Reason: Typing
  Reply With Quote
Old 16th May 2012, 05:11 AM   #3288
diyAudio Member
 
MurphyUHF10's Avatar
 
Join Date: Oct 2010
Location: Melbourne
Quote:
Originally Posted by mefistofelez View Post
Greetings all,

I have acquired the DCX2496, and found this thread. However, before I start sifting through the 300+ posts, I was wondering if someone could list the modifications in order of perceived bang-for-the-buck improvement.

Kindest regards,

M
Hi M,
Although you seek a quick answer,, it might be best to read through this entire thread!! Treat it like a novel, each night you read 15 or 20 pages :-)

Personally, I have the Didden / Oettle combination, and it works great! But perhaps not "bang for buck".. You will get lots of ideas that are 'bang for buck' if you read through this thread.. It's good fun ;-)

Cheers,
CM
  Reply With Quote
Old 16th May 2012, 11:05 AM   #3289
diyAudio Member
 
autopoiesis's Avatar
 
Join Date: Mar 2007
Hi mefistofelez,

1. Didden Active I/O
2. Didden linear PSU
3. Oettle SRC/clock

This is the order I fitted them, over a couple of years, and in order of increasing subtlety and decreasing cost. I suspect that if you fitted the SRC mod on a stock unit, you might not notice the improvement, and give up. With the other two in place, it was more like icing on the cake.

Value-wise, although the active I/O is not cheap, it does so much to improve not just the sonics, but also the usability of the unit (signal levels, remote control). It's really a quantum leap I would consider essential.

All three are certainly worthwhile, and can be spread over several accounting periods, should WAF be an issue

Have fun!
autop
__________________
A gentleman is a man who can play the accordion but doesn't. ..... Oscar Wilde
  Reply With Quote
Old 18th May 2012, 12:55 AM   #3290
diyAudio Member
 
Join Date: Apr 2002
Hi MurphyUHF10,

I will read it, but I thought that a synopsis would be beneficial, so that I do not get lost.

Hi autopoiesis,

Thank you very much.

Kindest regards,

M
  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



New To Site? Need Help?

All times are GMT. The time now is 06:15 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