Microphonics When Hot, Raytheon CK5842 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 5th September 2005, 05:08 AM   #1
CLS is offline CLS  Taiwan
diyAudio Member
Join Date: Jun 2005
Location: Taiwan
Default Microphonics When Hot, Raytheon CK5842

Hello there,

I built a pre amp based on 5842 (as posted here ).

Using it for a while, I found, after running for 3~4 hours, one of the channel clanking loudly as the stepped attenuator hit the 'off' position.

Then I tried tapping on & unscrewing the chassis, that particular channel would make some sounds on the speaker. (not to mention tapping on the tubes, it's so loud when that problematic tube was hit)

Yes, microphonics!! A big bad one.

I swapped the tubes among channels & the symptom followed that particular tube. I changed that tube & kept trying. By now, I found 2 out of 8 tubes have such problem.

Is this normal on such tubes?
Or they are defected ones?
Is it because the tubes are covered by a conventional box instead of protruding out of the top plate like a "real" tube amp, so the ventilation is insufficient?

Back then when I was building this pre, I'd thought about making the tube sockets "suspended". Somehow I dropped that idea. I should have.
  Reply With Quote
Old 5th September 2005, 05:14 AM   #2
PRR is offline PRR  United States
diyAudio Member
PRR's Avatar
Join Date: Jun 2003
Location: Maine USA
> [i]Is this normal on such tubes?


> Is it because the ....ventilation is insufficient?

  Reply With Quote
Old 5th September 2005, 05:23 AM   #3
CLS is offline CLS  Taiwan
diyAudio Member
Join Date: Jun 2005
Location: Taiwan

Thanks a lot for your quick answer.

I'm always thinking you are one of the coolest guy in this forum
  Reply With Quote


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
Microphonics? Carlp Tubes / Valves 5 28th August 2008 12:19 AM
Microphonics that go away by themselves jlsem Tubes / Valves 2 15th November 2007 07:52 AM
Microphonics........... Alastair E Tubes / Valves 4 3rd June 2005 04:02 PM
VC microphonics significant? capslock Multi-Way 4 13th January 2005 11:18 AM
Microphonics AuroraB Tubes / Valves 2 8th April 2003 05:34 PM

New To Site? Need Help?

All times are GMT. The time now is 07:02 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2