Heater supply - Page 2 - 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 9th April 2012, 07:26 AM   #11
diyAudio Member
 
Join Date: Mar 2012
Thanks Thomas.

My B+ is 100V, so I guess I'd use something like 100k and 25k.
  Reply With Quote
Old 9th April 2012, 07:30 AM   #12
diyAudio Member
 
Vinylsavor's Avatar
 
Join Date: Feb 2002
Location: Lindau
Hi!

Then rather use something like 33k and 10k. Most tubes have a max impedance of 20k spec'ed between heater and cathode. Use 2Watt types or higher

Best regards

Thomas
__________________
http://vinylsavor.blogspot.com/
  Reply With Quote
Old 9th April 2012, 07:55 AM   #13
diyAudio Member
 
Join Date: Mar 2012
Sure, would do.

Thanks.
  Reply With Quote
Old 14th April 2012, 05:02 PM   #14
diyAudio Member
 
Join Date: Mar 2012
Another question.

So I got myself a 6-0-6V transformer (12V CT, not dual secondary). When I use one side of the 6V for the amplifier tube heater and bias it wit B+ as said earlier, can I still tie the cathode of the rectifier tube with the heater with the other side of 6V?

Should I not connect the cathode to the heater on the rectifier tube, since both the heater of the amplifier tube and the rectifier tube is connected through the transformer?

Is it even a good idea to share a transformer like that?

Thanks.
  Reply With Quote
Old 14th April 2012, 05:27 PM   #15
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Why use an EZ81 for 20mA? EZ80 would be a better fit, and use less heater current. Or EZ90/6X4. For 20mA you could almost use an EB91!!
  Reply With Quote
Old 14th April 2012, 07:44 PM   #16
diyAudio Member
 
Join Date: Mar 2012
I am no expert, compared to EZ80, it seems that EZ81 is more widely available? And it's still in production. As for the current, I meant to say 20mA per channel (so 40mA total), and I would like to keep the option of bumping it to 40mA per channel.
  Reply With Quote
Old 14th April 2012, 08:06 PM   #17
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Yes, EZ81 is still in production. Both are widely available in NOS form.
  Reply With Quote
Old 14th April 2012, 08:44 PM   #18
diyAudio Member
 
pauldune's Avatar
 
Join Date: Oct 2009
Location: Netherlands
Am I missing something? If you rectify 6v and buffer with a cap, your voltage will be round 7v, so normally you'll need even less then 6v.

Paul
  Reply With Quote
Old 15th April 2012, 05:51 AM   #19
diyAudio Member
 
Join Date: Mar 2010
You are right, if you bridge rectify and filter 6VAC or 6.3VAC you'll end up with 8.4 to 9VDC unloaded. And that will drop as you increase the number of filaments. So it has to be regulated. But the problem with using the LM317 is that it needs at least 1.5V of headroom so it is likely to drop out. And it's limited to 1.5A or so. So using only 6VAC input isn't safe except for low heater currents. I've had good success with the MIC29750-5.0 regulator (digikey has it) and two 1N914 diodes on the reference pin. Since it is a low dropout regulator, it can regulate with only 350mV of headroom, and supply at least 5A. With such a low headroom, you can mount the regulator to the chassis as a simple heatsink (using an insulator).
  Reply With Quote
Old 15th April 2012, 06:31 AM   #20
diyAudio Member
 
Join Date: Mar 2012
You guys are not reading the earlier post.

I will be feeding AC to the the heater.

But an unrelated question, supposedly I am feeding DC to the heater, would it still be beneficial to bias the heater?

But please answer my earlier questions.

So I got myself a 6-0-6V transformer (12V CT, not dual secondary). When I use one side of the 6V for the amplifier tube heater and bias it wit B+ as said earlier, can I still tie the cathode of the rectifier tube with the heater with the other side of 6V?

Should I not connect the cathode to the heater on the rectifier tube, since both the heater of the amplifier tube and the rectifier tube is connected through the transformer?

Is it even a good idea to share a transformer like that?

Thanks.
  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
Is this OK for a heater supply? blacklight Tubes / Valves 9 12th December 2006 05:58 PM
Is this heater supply OK? Nuuk Tubes / Valves 39 18th August 2006 11:20 PM
Regulated Heater Supply Kashmire Tubes / Valves 6 4th January 2004 02:23 AM
help with heater supply jarthel Tubes / Valves 5 24th July 2003 01:12 PM
heater supply (xformer specs are 6.3V 2.5A) as supply for a power LED? jarthel Tubes / Valves 10 21st July 2003 01:30 PM


New To Site? Need Help?

All times are GMT. The time now is 10:09 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