CCS question mA - 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 1st April 2013, 01:57 PM   #1
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Default CCS question mA

I want to adjust my CCS current, right tube draws 2,11mA & left tube draws 2,24mA, Have I to set both tubes to 2mA (I use two separate CCS: one per each tube)?

TIA
Felipe

Last edited by merlin el mago; 1st April 2013 at 02:00 PM.
  Reply With Quote
Old 1st April 2013, 01:59 PM   #2
diyAudio Member
 
Rundmaus's Avatar
 
Join Date: Aug 2005
This is difficult to answer without a little more information.

Schematic? Where is the CCS used? Left/Right concerns two stereo channels?

Rundmaus
  Reply With Quote
Old 1st April 2013, 02:16 PM   #3
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Is the ECC81 mu-follower, attached schematic used & DN2540 schematic used without the VR tube see left up corner.
Attached Images
File Type: png 0D3.png (27.2 KB, 113 views)
File Type: jpg Mufollower2.jpg (41.4 KB, 113 views)
  Reply With Quote
Old 1st April 2013, 02:20 PM   #4
diyAudio Member
 
Join Date: Apr 2003
Location: Southern Tier NY
Merlin,
I would take your current "sense" resistor value, multiply it by 2.25. Using that calculated number for resistor value, I would then parallel a fixed resistance and trim pot of same value to allow you to adjust it precisely to the 2,00 mA you desire. I used 2.25 to give some leeway +/- on the adjustment. You can then measure the combined resistor value and replace with a fixed or leave it as it is to allow you to adjust as required.
__________________
Living Life Doing the Waltz in 4/4 meter.
  Reply With Quote
Old 1st April 2013, 02:23 PM   #5
diyAudio Member
 
Join Date: Apr 2003
Location: Southern Tier NY
I see you schema now. Increase the value of your trimmer.
__________________
Living Life Doing the Waltz in 4/4 meter.
  Reply With Quote
Old 1st April 2013, 02:30 PM   #6
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
5K Trimmer & 4k75 resistor?
  Reply With Quote
Old 1st April 2013, 05:05 PM   #7
diyAudio Member
 
Join Date: Apr 2003
Location: Southern Tier NY
Whats the present value of your trimmer?
__________________
Living Life Doing the Waltz in 4/4 meter.
  Reply With Quote
Old 1st April 2013, 05:52 PM   #8
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
1K trimmer
  Reply With Quote
Old 1st April 2013, 06:04 PM   #9
diyAudio Member
 
Join Date: Apr 2003
Location: Southern Tier NY
2k resistor and 5k trimmer would work better.
Did you read the thread regarding the use of a DN2540 for <10mA? There might be some better circuits for such low currents.

Quote:
Originally Posted by SY View Post
It doesn't matter if it's not constant as long as it's large- see DF96's analysis. Unfortunately, the DN2540's impedance is pretty mediocre at low currents. For the 2mA you're seeking, a bipolar cascode will perform much better.
that is from the CCS fixed bias thread.
__________________
Living Life Doing the Waltz in 4/4 meter.

Last edited by SGregory; 1st April 2013 at 06:08 PM.
  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
4ch. Ma Audio p.s. Subsitution question.... amc32 Car Audio 1 19th December 2011 10:49 PM
For sale: 2 x Fivre 2A3 Single Plate, 60 mA + 44 mA emission on Funke W20 2A3 Maniac Swap Meet 3 1st October 2011 12:18 PM
Crown MA-12000i / MA-5000i / MA-9000i jack2040 Solid State 4 8th March 2011 01:21 PM
CCS question woody Tubes / Valves 16 8th August 2005 07:08 PM
Marantz MA 500 or MA 700 schematic krishu Solid State 0 15th March 2004 01:59 PM


New To Site? Need Help?

All times are GMT. The time now is 09:41 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