TubelabSE left 5842 drift

Green77 · 22nd July 2011, 10:15 AM

Hi all!

Enjoying my TSE with 300b tubes. Think after 20 h that the sound is really good

I have a small problem with my left channel. Nothing i hear but i need to adjust the 175 V at 5842 tube all the time..

After 30 min it has drift +/- 10V while the right channel is steady (+/- 1V).
Maybe it is the tube. I haven't swaped them yet but maybe i do that tonight..

What can do this except for the 5842 tube?

Thanks //Daniel

Evenharmonics · 22nd July 2011, 03:45 PM

Quote:

Originally Posted by Green77

After 30 min it has drift +/- 10V while the right channel is steady (+/- 1V).
Maybe it is the tube. I haven't swaped them yet but maybe i do that tonight.

Both of mine drift in about 10 min. I set it at 175V at that point and it stays there. If yours doesn't drift anymore after 30min, it may be ok.

Green77 · 22nd July 2011, 05:55 PM

i have adjust it 5 times under 30 min..if i check it again after 1 h it has drift +- 10 v

rknize · 23rd July 2011, 02:59 PM

Keep in mind that the 5842 is not fixed bias. If it's drifting it's because the cathode bias and active plate load is compensating for changes in cathode current. It could also be the CCS that's drifting, but that is not likely. Does the CCS have an adequate heat sink?

The drift itself is nothing to worry about, but it could be a sign of some other issue.

Green77 · 23rd July 2011, 03:59 PM

Thanks for your answers. I use the same heatsink for both sides. And there is no drifting on the right side..

rknize · 23rd July 2011, 04:44 PM

Swap tubes. If the drifting follows the tube, you have your answer.

Green77 · 23rd July 2011, 06:06 PM

Thanks, will try that tomorrow..

Green77 · 25th July 2011, 08:30 AM

I had a spare 5842 home. Changed the tube and the problem was gone

Bad tube..
Thanks all! //Daniel

22nd July 2011, 10:15 AM	#1
Green77 diyAudio Member Join Date: May 2007 Location: MJOLBY	TubelabSE left 5842 drift Hi all! Enjoying my TSE with 300b tubes. Think after 20 h that the sound is really good I have a small problem with my left channel. Nothing i hear but i need to adjust the 175 V at 5842 tube all the time.. After 30 min it has drift +/- 10V while the right channel is steady (+/- 1V). Maybe it is the tube. I haven't swaped them yet but maybe i do that tonight.. What can do this except for the 5842 tube? Thanks //Daniel

23rd July 2011, 02:59 PM	#4
rknize diyAudio Member Join Date: Feb 2009 Location: Chicagoland	Keep in mind that the 5842 is not fixed bias. If it's drifting it's because the cathode bias and active plate load is compensating for changes in cathode current. It could also be the CCS that's drifting, but that is not likely. Does the CCS have an adequate heat sink? The drift itself is nothing to worry about, but it could be a sign of some other issue. __________________ Russ http://www.knizefamily.net/russ/cate...ics/tubeaudio/

23rd July 2011, 04:44 PM	#6
rknize diyAudio Member Join Date: Feb 2009 Location: Chicagoland	Swap tubes. If the drifting follows the tube, you have your answer. __________________ Russ http://www.knizefamily.net/russ/cate...ics/tubeaudio/

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22nd July 2011, 05:55 PM	#3
Green77 diyAudio Member Join Date: May 2007 Location: MJOLBY	i have adjust it 5 times under 30 min..if i check it again after 1 h it has drift +- 10 v

23rd July 2011, 03:59 PM	#5
Green77 diyAudio Member Join Date: May 2007 Location: MJOLBY	Thanks for your answers. I use the same heatsink for both sides. And there is no drifting on the right side..

23rd July 2011, 06:06 PM	#7
Green77 diyAudio Member Join Date: May 2007 Location: MJOLBY	Thanks, will try that tomorrow..

25th July 2011, 08:30 AM	#8
Green77 diyAudio Member Join Date: May 2007 Location: MJOLBY	I had a spare 5842 home. Changed the tube and the problem was gone Bad tube.. Thanks all! //Daniel

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