Series heaters = small problem? - 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 12th May 2007, 04:53 PM   #1
Klimon is offline Klimon  Belgium
diyAudio Member
 
Join Date: Apr 2005
Location: Leuven
Default Series heaters = small problem?

Hi,

Putting the heaters of two 6ck4 (same brand, same construction) in series I get a difference of 0.5V between both tubes (when one gets 6.5V the other one gets 6V); the tubes are responsible for this (I switched them and voltages switched along).

-- Would the 0.5V variation in heater voltage cause a notable difference in output (one channel sounding louder than the other one, the amp is SE)?

-- Would it dramatically affect the lifespan of (the/both) tubes?

If the answer to both questions is "NO", I'll happily live with it as such; both voltages would still be in the recommended region of 6.3 +- 0.3V and I wouldn't need to spend money I don't have anyway.

As before and after; many thanks!!

Simon
  Reply With Quote
Old 12th May 2007, 05:35 PM   #2
diyAudio Member
 
Gold_xyz's Avatar
 
Join Date: Dec 2005
Location: Italy
The difference can not influential it depends on schematics.
(gain, nfb, etc. etc.)
but I suggest a resistor in parallel at tube with the most greater tension,
for balancing power disipation between heater.


Datasheet of 6ck4 (GE) say 6.3 +/- 10% @ 1.25A
http://frank.pocnet.net/sheets/093/6/6CK4.pdf

that means tube can supply from 5.4 to 6.93

__________________
My English originates from here
  Reply With Quote
Old 12th May 2007, 05:48 PM   #3
Klimon is offline Klimon  Belgium
diyAudio Member
 
Join Date: Apr 2005
Location: Leuven
Hi mr. Gold,

Excellent idea, that should indeed solve everything!!!

Thanks a lot / Simon
  Reply With Quote
Old 12th May 2007, 06:29 PM   #4
diyAudio Member
 
Gold_xyz's Avatar
 
Join Date: Dec 2005
Location: Italy
for equalize the power of heaters tube
Attached Images
File Type: gif heaterser.gif (5.6 KB, 127 views)
__________________
My English originates from here
  Reply With Quote
Old 12th May 2007, 07:21 PM   #5
diyAudio Member
 
Gold_xyz's Avatar
 
Join Date: Dec 2005
Location: Italy
If the total current is 1.25A (from datasheet)
and Vsupply 12.5V

P1 = 1.25A * 6.5V = 8.1W
P2 = 1.25A * 6V = 7.5W
(as the light bulbs )

this is already amply accetable.

With a resistor of 100 Ohm (2W)

I = 1.28A
P1 = 7.73W with 6.32V
P2 = 7.83W with 6.15V

I suggest a resistor from 100 Ohm to 180 Ohm 2W in parallel at
tube with the most greater tension.

Also this is enough simply to verify with Pspice.
__________________
My English originates from here
  Reply With Quote
Old 13th May 2007, 11:12 AM   #6
Klimon is offline Klimon  Belgium
diyAudio Member
 
Join Date: Apr 2005
Location: Leuven
You're right, yesterday I experimented with resistor values untill voltages were within 0.1v; 100ohms works well. I'm using a 1W resistor (that's what I've got on hand) though.

Thanks again!

Simon
  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
PL519 Heaters in series blow fuse wiysel Tubes / Valves 5 6th November 2008 11:18 AM
Tube heaters in series. nigelwright7557 Tubes / Valves 5 4th July 2008 09:11 PM
Tube current regulation for series heaters' supply. engels Tubes / Valves 4 5th August 2007 10:49 PM
Physically small rectifier tube with 5V heaters dsavitsk Tubes / Valves 7 14th June 2006 02:47 AM
Series wiring for heaters XZur Tubes / Valves 5 19th December 2005 02:43 AM


New To Site? Need Help?

All times are GMT. The time now is 10:26 PM.


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