Sound problem with Zen 4 - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 31st August 2003, 11:26 AM   #11
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
in case the amp is quiet with no cable connected and makes noise with the cable connected it should be a problem with your ground. How did you connect the ground / shield of the cable? Read the article at passlabs about ground loops.

IMO it doesn´t matter if you have some volts more or less at the regulator. Just try to distribute the zehner in a way the voltage at right and left channel is about the same.
  Reply With Quote
Old 4th September 2003, 04:01 PM   #12
Buhl is offline Buhl  Denmark
diyAudio Member
 
Buhl's Avatar
 
Join Date: May 2002
Location: Aalborg, Denmark
Quote:
Originally posted by till
in case the amp is quiet with no cable connected and makes noise with the cable connected it should be a problem with your ground. How did you connect the ground / shield of the cable? Read the article at passlabs about ground loops.

IMO it doesn´t matter if you have some volts more or less at the regulator. Just try to distribute the zehner in a way the voltage at right and left channel is about the same.

The amp is wired as it should ( I suppose) - I use two bridges (200V, 25 A), one pr. channal, and then a 47,000 uF pr. channal. Unregulated ground is connected to ground on the amp board, to where the RCA-phone's ground/sheild also is connected.

I have tried to make a cable from the balanced XLR from my DAC, where I use pin 2 and 3 (positive and negative) ending up as live and shield in a RCA phone jack - then there is much, much less noise - this is bad though, as my dac does not have a volume potmeter

I use the same powerstrip for the amp and CD player, as stated in the article - earth is virtually non exixting in older houses in denmark - we have a HPFI-relais that deals with power trouble - so earthing is also out of the question.

Is there really noting to do, but to live with the noise ?

I have removed the zener-string on both channals now, and read 42-43 volts on regulated supply (47 volts unregulated - 4 volts) - I suppose thats OK ?

Cheers !
Hans
  Reply With Quote
Old 4th September 2003, 04:17 PM   #13
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
I should not tell, i build some amps without real grounding, and there is not that much noise.

Without the zehners you have no a capacintance multiplyer, its also ok. But with the zehers and and a little less voltage than in Nelsons articles there is also no problem.

I´m afraid for help we need more information. Without some detailed pictures of the amp nobody else than you will find the source of hum.
  Reply With Quote
Old 7th September 2003, 09:56 AM   #14
Buhl is offline Buhl  Denmark
diyAudio Member
 
Buhl's Avatar
 
Join Date: May 2002
Location: Aalborg, Denmark
Default Problem solved !!!!

I feel so embaressed - but it was so simple after all...
Last nigth (0430) I was out having a few beers ( still to many ), and was discussing DIY with a engineering student from my university - "should I try to run both channels of one unregulated supply ??" - "That migth help..." he answerd - so home at around 0500 in the morning I got to work, and bugger me if it didnt work !!!

Im so happy ! - Thanx to everyone who has stuck up with my silly questions......especially Till - Vielen Dank !

Now I have to finish that BLS....so I guess Ill be back

/Cheers !

Hans
  Reply With Quote
Old 7th September 2003, 11:19 AM   #15
diyAudio Member
 
Shoog's Avatar
 
Join Date: Aug 2002
Location: Eire
I just observed that you have a perfectly silent amp with no input plugged in. I had the same on my Zen2. It has nothing to do with your grounding. I had the venerable Nelson Pass point out to me that with nothing on the input, the amp pulls the output low, so producing nearly no output (hence no noise). In this case the lack of noise is a red herring and should not be used when troubleshooting.

I had shielding problems with my torroidal transformer. Encasing it in copper with a tag to earth sorted that one out.

Regulation of the power supply is a nice touch, but you will probably notice no difference with just the cap multiplier, and the amp will run cooler.



Shoog
  Reply With Quote
Old 29th September 2003, 08:19 AM   #16
diyAudio Member
 
Super_BQ's Avatar
 
Join Date: Sep 2001
Location: New Zealand / Canada
Send a message via ICQ to Super_BQ Send a message via Yahoo to Super_BQ
Hans,

Did you finished building your Zen v4 Balanced? I've ordered the PCB and got enough parts for them but wasn't quite sure how the boards are wired up.

Brendon
__________________
Yellow People for a Yellow World
Vote for Super_BQ, the Asian Alternative
  Reply With Quote
Old 29th September 2003, 03:16 PM   #17
Buhl is offline Buhl  Denmark
diyAudio Member
 
Buhl's Avatar
 
Join Date: May 2002
Location: Aalborg, Denmark
Default Balanced Zen4

Quote:
Originally posted by Super_BQ
Hans,

Did you finished building your Zen v4 Balanced? I've ordered the PCB and got enough parts for them but wasn't quite sure how the boards are wired up.

Brendon

Hi Brendon
No, I'm still searching for aluminium to cope with the double amount of heat for balanced operation. But, I belive that the cabeling it self should not be to difficult.

This is how I think it should be done:

1. tie both input gound together, and connect it to the shield in the xlr-connector.

2. Connect one of the channels positive RCA to negative in the XLR-connector(the "cold" one), and the other RCA-positive(signal) to the "hot" XLR-pin.

3. connect the two ground output connectors to each other with heavy duty cable, to avoid current flowing through the input cables(according to Nelsons article).

4. Drain the balanced output acros the two remaining output terminals (remember that this amp inverts the input signal).


I belive this is whats needed to run balanced, but I wont put my head on the block, if you know what I mean, cause ive not tried it yet......


BTW - your site about the SoZ got me into DIY in the first place!!
Happy building & keep DIY !!


Cheers !
Hans
  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
HK AVR335 problem (no sound) mattau2000 Solid State 3 13th January 2009 06:26 PM
Arcam Delta 290 Sound Problem phil_79 Solid State 6 10th August 2008 09:57 AM
CD Player Sound Problem dart56 Digital Source 0 11th February 2008 03:03 AM
A problem of cracking sound amp gaetan8888 Solid State 15 8th July 2007 07:41 PM
TDA 1541A zero oversampling dac sound problem Saso Digital Source 21 29th February 2004 08:06 PM


New To Site? Need Help?

All times are GMT. The time now is 09:31 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