Aikido headphone amp startup noise - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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 26th January 2009, 11:56 AM   #1
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Default Aikido headphone amp startup noise

I have my breadboarded Aikido headphone amplifier playing music for some time now, and while it sounds fabulous it has a nasty habit of sending crackling noises through my headphones for about 30sec. after I switch it on...
The crackling/popping sets in after about 10secs and then completely stops after about 25-30secs. It is not rythmic but rather random so I don't think it is oscillation.

My Aikido is built with the Broskie boards, uses 6CG7 and 6H30 tubes, output transformers and a toroid psu with ss rectification and voltage doubler (to generate B+ out of a 2x55V toroid). Heaters are fed by a regulated supply.

Q. What can I do to get rid of the crackling noise on start up?
Q. Attached is a screenshot of my psu configuration. Anything wrong with that, like the value of the caps in the doubler (was thinking of putting much smaller film types in there...)?

Thank you as always!
Attached Images
File Type: jpg cap42.jpg (15.9 KB, 255 views)
  Reply With Quote
Old 26th January 2009, 02:10 PM   #2
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
I'm not an expert here and I'm sure you'll get good advice but I'm thinking if you have SS power supply this crackling could be the B+ power surge going through the tubes before they have warmed up sufficiently.

I have 2 tranny and 2 switches. I switch on the heaters first for a good 30 seconds before hitting the B+.
  Reply With Quote
Old 26th January 2009, 07:31 PM   #3
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Quote:
I'm not an expert here and I'm sure you'll get good advice but I'm thinking if you have SS power supply this crackling could be the B+ power surge going through the tubes before they have warmed up sufficiently.
Thanks Brit for your reply. I was thinking exactly that since the crackling somehow seems to correspond with small noises coming from the tube.

Did you put the switch in the + side or the ground??
  Reply With Quote
Old 26th January 2009, 08:14 PM   #4
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Quote:
Did you put the switch in the + side or the ground??
I have one tranny for the heaters and the other for the B+ only.

On each primary of the tranny I have a switch on one cable and a fuse on the other. Basically between the mains and the tranny.

The secondary windings go direct to the heaters(AC).
  Reply With Quote
Old 26th January 2009, 11:29 PM   #5
diyAudio Member
 
boywonder's Avatar
 
Join Date: Jan 2008
Location: So.Cal.
My recently (almost) completed Aikido has some small crackling/popping and a slight DC offset for the first 5 seconds or so of warm-up.

I recently added this power on mute circuit (simple and adjustable from a few seconds to 30+ seconds) and so far it works like the cat's pajama's.

Suitable relay for delay cicuit

Nothing added to the sig path, it just shorts the preamp outputs for however many seconds you want depending on the setting of the trim pot. I'm actually shorting the outputs through 150 ohm R's.
  Reply With Quote
Old 27th January 2009, 01:13 PM   #6
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Thanks boywonder, that is something for further inverstigation.

Since I am using two toroids for HV and heaters I will try the "switch-solution" first...
  Reply With Quote
Old 30th January 2009, 07:08 PM   #7
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Quote:
Since I am using two toroids for HV and heaters I will try the "switch-solution" first...
Done, and it works.
I am switching B+ after about 30 sec, and the amplifier stays quiet like the proverbial church mouse...
  Reply With Quote
Old 30th January 2009, 10:05 PM   #8
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Quote:
Done, and it works. I am switching B+ after about 30 sec, and the amplifier stays quiet like the proverbial church mouse...
Great news.

I'm a total newbie and it feels good to have helped someone else out. I'm the one always asking questions
  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
Need Help eliminating hum on a Aikido headphone amp wonsup Headphone Systems 36 14th November 2009 09:29 PM
Aikido Headphone Amp lordearl Headphone Systems 2 14th June 2007 03:19 PM
my aikido headphone amp - almost there jarthel Headphone Systems 5 27th April 2007 02:07 PM
Aikido Headphone Amp (new board) -=Zepplock=- Headphone Systems 9 2nd October 2006 06:19 AM
recommended tubes for aikido headphone amp jarthel Headphone Systems 0 22nd May 2006 12:54 AM


New To Site? Need Help?

All times are GMT. The time now is 10:05 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