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 12th July 2010, 07:10 PM   #121
diyAudio Member
 
Alastair E's Avatar
 
Join Date: Feb 2004
Location: South Wales
Add another pair if you can please....!
  Reply With Quote
Old 12th July 2010, 11:29 PM   #122
diyAudio Member
 
Join Date: May 2006
Depending on price I would take 4 or more.

Chris
  Reply With Quote
Old 12th July 2010, 11:34 PM   #123
mach1 is offline mach1  Australia
diyAudio Member
 
mach1's Avatar
 
Join Date: Sep 2004
Location: Brisvegas
and another 2 please .
__________________
Au rutti wop-bop-a-loom-bop-a-boom-bam-boom - Richard Penniman
  Reply With Quote
Old 12th July 2010, 11:44 PM   #124
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Hi Rod;

since it is a thingy for a tube gear you may easily use IRF parts biasing them from B+.

Just an advice, for flexibility.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 12th July 2010, 11:49 PM   #125
jims is offline jims  United States
diyAudio Member
 
Join Date: Mar 2007
Hi Rod

I am interested in at least a couple.

Thanks

JimS
  Reply With Quote
Old 13th July 2010, 04:19 AM   #126
diyAudio Member
 
Join Date: Jun 2008
Quote:
Originally Posted by Wavebourn View Post
Hi Rod;

since it is a thingy for a tube gear you may easily use IRF parts biasing them from B+.

Just an advice, for flexibility.
Can you say more?
  Reply With Quote
Old 13th July 2010, 06:57 AM   #127
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by Hearinspace View Post
Can you say more?
Yes, I can.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 13th July 2010, 09:24 AM   #128
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
Hi Anatolij, I thought a lot about FET solutions, but in this circuit, we try to run Vds very low (1.5 .. 2V) to keep the heatsinks cool. The devices work OK, but the capacitance is huge (400pF++ even at little IRF510 level) at low Vds, and changes very rapidly with Vds change (supply ripple).

For best quality DHT heaters, we are trying to make the (ac, small-signal) impedance as large as possible, to keep cathode current from leaking out of the circuit - and from one end of filament to the other. This leakage has a very bad effect on the sound quality, and is one reason that ordinary dc heating made with voltage regulation sounds bad. In fact voltage-controlled dc sounds even worse than ac-heat - no lustre, no sparkle. With voltage regulation, the big capacitor across voltage regulator output (even if 0.1uF) presents direct ac-short-circuit across the filament, and is enough to ruin the quality of DHT-sound.

Anyway, I think you're teasing me about having B+ present before heater can switch ON!!

Last edited by Rod Coleman; 13th July 2010 at 09:40 AM.
  Reply With Quote
Old 13th July 2010, 09:28 AM   #129
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
Good to see the interest in the new board - Thank You!

I'll order as many PCBs as I dare, to keep the cost low!
  Reply With Quote
Old 13th July 2010, 09:36 AM   #130
bravi is offline bravi  New Zealand
diyAudio Member
 
Join Date: Mar 2004
Location: Wellington, New Zealand
Please add my name for 4 boards

B.Ravi
  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
how to wire 6.3VDC heater on a heater with center tap (12.6V series, 6.3V parallel)? jarthel Tubes / Valves 9 14th April 2012 05:36 PM


New To Site? Need Help?

All times are GMT. The time now is 08:16 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