Melos triode and computer as source: BUZZ BUZZ BUZZ - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 25th November 2007, 07:33 AM   #1
zigo3 is offline zigo3  Italy
diyAudio Member
 
Join Date: Feb 2007
Location: italy
Default Melos triode and computer as source: BUZZ BUZZ BUZZ

Hello
I installed a Melos triode 200 plus stereo power amp in my system and I'm using, for the moment, a NAD 3020i as preamp. No problem if the source is tuner, phono, cdp integrated or dac (mhdtlab Constantine usb plus), but when I connect the DAC to the PC, via USB or spdif is the same, begin a BUZZ. And the buzz remain if I select different sources from the pre. It stops only if I disconnetc the cable to the pc.
And this problem born now with Melos, before, using different SS amps, in different classes, never had problems. And the buzz remain changing different passive loudspeakers.
Please what could be the problem? What can I do to resolve it?

Thankyou very much in advance
  Reply With Quote
Old 25th November 2007, 07:37 AM   #2
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
You have a ground loop. Easiest solutions are a) use a digital transformer on the spdif connection or b) use toslink. Both of these will isolate the computer's ground.
  Reply With Quote
Old 26th November 2007, 05:05 AM   #3
zigo3 is offline zigo3  Italy
diyAudio Member
 
Join Date: Feb 2007
Location: italy
Thankyou very much dsavitsk, I will try it.
I made some test and the BUZZ continue even if I switch off the computer: maybe could be a cable interference too (there is a lot of cable very close)? I will try to isolate each cable too.
  Reply With Quote
Old 26th November 2007, 06:19 AM   #4
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
The computer is still grounded, and probably partially powered, even when off. Try unplugging it.
  Reply With Quote
Old 28th November 2007, 02:11 AM   #5
zigo3 is offline zigo3  Italy
diyAudio Member
 
Join Date: Feb 2007
Location: italy
Quote:
Originally posted by dsavitsk
The computer is still grounded, and probably partially powered, even when off. Try unplugging it.

I unplugged it but the buzz is still there. Maybe because there are other devices self alimentated plugged to it. When I unplug everything the buzz stop. But sometimes it stops when I unplug one device, sometimes when I unplug another: seems that there is a kind of casuality. For sure the buzz is there when all are plugged.

The best result I obtained, for the moment, is using a shielded loudspeaker cable like this http://www.tnt-audio.com/clinica/star.html: I measured the buzz before with the RS meter and was 67db, with this cable it was no more a buzz, but a kind of "breath" and is 56 db. Do you know why? What kind of interference can generate this?
  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
Computer to Amp Buzz Funky971 Solid State 60 26th September 2008 04:21 PM
Buzz Hum Aleph 5 with computer as source, no good results with GLI zigo3 Pass Labs 3 20th February 2008 12:26 PM
Buzz in gainclone, looking for source. kmj Chip Amps 31 19th October 2006 10:21 PM
P06 buzz elco Analogue Source 2 3rd June 2005 11:48 PM
A-75 buzz Dave Varner Pass Labs 3 15th February 2002 01:30 PM


New To Site? Need Help?

All times are GMT. The time now is 03:34 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