Zen V4 - 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 9th February 2003, 09:26 PM   #11
Stabist is offline Stabist  Slovenia
diyAudio Member
 
Stabist's Avatar
 
Join Date: Sep 2002
Location: Slovenia
The hum is mechanical - if I put my ear on the top of chassis - you can hear it quite easely ...

The same hum can be also heard on speakers - just that it is even more loud.
BUT - if one interconect is pulled out - almost nothing - speakers are almost silent ...
So - I guess there is a ground problem - there are few things I'll have to inspect - the first one is - there is no 22kR resistor yet .. Then - mr. Nelson allready sugested to ground RCA inputs ..
But - as said - there hasn't been enough time to play with ... And also momentarily the osciloscope is dead So ...

The thing is - the chassis is very compact - and it gets quite crowdy inside - so - Kirc and I must have enough time to try some solutions - it shall be a couple hours job ...
  Reply With Quote
Old 9th February 2003, 09:40 PM   #12
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
OK. In my opinion the only consequent thing you can do against the mechanuical noise i described above.

At the speaker, without a long antenna cable at the input, with normal speakers, you should hear nothing. Zen V2 i hear some hum. Zen V4 - nothing.
  Reply With Quote
Old 9th February 2003, 10:31 PM   #13
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Toroids are very susceptible to crap on the AC line,
particularly DC imposed by lamp dimmer circuits and
such.

Try putting a couple of 10,000 uF caps back to back
(series) on the AC line to the primary to block DC and
see if that doesn't help.
  Reply With Quote
Old 9th February 2003, 10:46 PM   #14
Stabist is offline Stabist  Slovenia
diyAudio Member
 
Stabist's Avatar
 
Join Date: Sep 2002
Location: Slovenia
mr. Nelson I agree - if there is DC component - trannie can get "overmagnetized" - don't know the expression - I mean - B(H) charachteristic and stuff conected with all that ...

Series of 10.000uf caps between AC power cord and trannie if I understood you right?? Hmm - what about voltage of such capacitors?? 230V is quite high - I'm not sure if there are some 230V/10.000uF caps ... - I mean - am I missing something here or ... ?!?
  Reply With Quote
Old 9th February 2003, 11:03 PM   #15
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
10000uF / 63V 4 times in series => 2500uF / 250V ??
  Reply With Quote
Old 9th February 2003, 11:15 PM   #16
Stabist is offline Stabist  Slovenia
diyAudio Member
 
Stabist's Avatar
 
Join Date: Sep 2002
Location: Slovenia
Quote:
Originally posted by till
10000uF / 63V 4 times in series => 2500uF / 250V ??


Hmm - it can be clearly seen that it has been a long long day - and that I should allready be in bed for at least 2 hours ...
I've mixed up serial and paralel .... ... Silly me ...

Oh ... I feel so

I feel soooooooo stupid ...
  Reply With Quote
Old 10th February 2003, 08:55 AM   #17
miguel2 is offline miguel2  Portugal
diyAudio Member
 
Join Date: Jun 2002
Location: Portugal
I tried this weekend a DC trap with a 3300uF/25V cap and 4 diodes as in the figure. I noted that when I turned it up it was silent but then the transformer started to hum again.

I am thinking in putting it in a vacuum oven to get the air trapped inside and then bake it. Does anyone knows the baking temperature for these guys?
Attached Images
File Type: jpg dc trap.jpg (21.9 KB, 568 views)
  Reply With Quote
Old 10th February 2003, 09:09 AM   #18
diyAudio Member
 
Join Date: Feb 2003
Location: Aalborg, Denmark
I really dont under stand why you have theese kind of problems, its just a question about a big enough trafo and enough capitance, then you will not have theese noise/hum problems
Please correct me if im wrong!!
  Reply With Quote
Old 10th February 2003, 09:20 AM   #19
miguel2 is offline miguel2  Portugal
diyAudio Member
 
Join Date: Jun 2002
Location: Portugal
I am using a 800VA toroidal.
Caps are 20000uF per channel.

I do believe my transformer is a bit old but toroids are said to be lifetime guaranteed .
  Reply With Quote
Old 10th February 2003, 09:50 AM   #20
diyAudio Member
 
Join Date: Feb 2003
Location: Aalborg, Denmark
Are you sure it is your transformer that makes the hum?If it is I would not believe in that gaurantee,it could also be the grounding problem or even worse dried out caps!
  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 10:23 PM.


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