Vacuum Tube OTL power amp!! - Page 82 - 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 6th October 2012, 08:32 PM   #811
dady is offline dady  Balearic Islands
diyAudio Member
 
dady's Avatar
 
Join Date: Oct 2002
Location: Punta Prima, Menorca, Spain
Send a message via MSN to dady Send a message via Skype™ to dady
LOOKS IMPRESSIVE
__________________
Esteban Bikic
  Reply With Quote
Old 6th October 2012, 08:34 PM   #812
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Cool! Any idea why the toroids are buzzing? Are you for example saturating the core every half cycle - if so some very small power resistors in series with windings might get you out of the woods by limiting the peak current to something more reasonable..

Mechanical buzzing - can you isolate the toroids on sorbothane mats or similar?
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 6th October 2012, 08:44 PM   #813
diyAudio Member
 
Join Date: Mar 2011
Location: Jarna
First i suspected DC from the mains since it sometimes is dead silent and some other times buzz loudly.

A DC-trap didnīt change the behavior.

So either a badly fabricated toroid or something i missed ??
  Reply With Quote
Old 8th October 2012, 05:36 PM   #814
diyAudio Member
 
atmasphere's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by flatheadmurre View Post
First i suspected DC from the mains since it sometimes is dead silent and some other times buzz loudly.

A DC-trap didnīt change the behavior.

So either a badly fabricated toroid or something i missed ??
When you say 'DC trap' this was something on the mains side of the transformer? A set of diodes bypassed by electrolytics? If no, then you need to add this, if yes, noisy transformer.
  Reply With Quote
Old 8th October 2012, 05:39 PM   #815
diyAudio Member
 
Join Date: Mar 2011
Location: Jarna
Yes, tried from 2-7v diode drop on the mains side same result so must be the toroid itself.

OR..???

Strange that it comes and goes.

A noisy toroid could change during heatup, but this comes and goes.
  Reply With Quote
Old 8th October 2012, 09:00 PM   #816
diyAudio Member
 
atmasphere's Avatar
 
Join Date: May 2007
Were the diodes bypassed by electrolytic capacitors?
  Reply With Quote
Old 8th October 2012, 09:22 PM   #817
diyAudio Member
 
Join Date: Mar 2011
Location: Jarna
Yes.

2pcs 10mF back to back.
  Reply With Quote
Old 8th October 2012, 10:53 PM   #818
diyAudio Member
 
atmasphere's Avatar
 
Join Date: May 2007
Hm. I would try something more like 1000uf...
  Reply With Quote
Old 8th October 2012, 11:32 PM   #819
diyAudio Member
 
Join Date: Mar 2011
Location: Jarna
Quote:
Originally Posted by atmasphere View Post
Hm. I would try something more like 1000uf...
Why 1000uF ?

My experience is that nothing below 4700uF works good.

10mF is double that.
  Reply With Quote
Old 9th October 2012, 05:36 PM   #820
diyAudio Member
 
atmasphere's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by flatheadmurre View Post
Why 1000uF ?

My experience is that nothing below 4700uF works good.

10mF is double that.
In the US, the u means 'micro' and quite often 'm' means micro too.

You must mean 'mill' as in milli-farad'?

If that is true then you will simply have to replace the toroid(s) or find some way to isometrically isolate them from the chassis.
  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
FS: Vacuum Tube Monoblock Power Amp Kit cuibono Swap Meet 13 7th May 2011 01:49 AM
Vacuum tube VCO Bitrex Tubes / Valves 1 15th March 2011 01:07 PM
HLLY MK III 3 Vacuum Tube Headphone Amplifier Pre Amp hllyelec Vendor's Bazaar 2 19th July 2009 06:54 AM
S3E Vacuum Tube angsuman Tubes / Valves 12 15th March 2008 06:12 AM
DIY Vacuum tube amp turbo_h4 Tubes / Valves 2 1st July 2004 02:48 AM


New To Site? Need Help?

All times are GMT. The time now is 11:40 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2