QUAD 405 power off noise - Page 2

Tajzmaj · 12th June 2012, 03:18 PM

I'm afraid yes.
Did you check supply voltage at op amp? It should be +-15V. I don't know about 134 op amp but if it draws too much current...
Check datasheet or measure it. And be careful. Don't short something.
If noise bothers you it is possible to install some sort of dc protection using relay which act as power on delay as well. There is plenty of such ideas around. Just google it. Again ,,Bernd Ludwig,, text. It is a lot useful information there.
Cheers

Tajzmaj · 12th June 2012, 03:23 PM

Just to make it easier.
Regards
http://www.desmith.net/NMdS/Electron.../405_Qw_14.pdf

ClassA · 14th June 2012, 01:10 PM

Thanks for all of your help,especially, Tajzmaj.
Now This 405 works fine and sounds good. I think the degraded op-amp might be the root cause.

noSmoking · 23rd June 2012, 02:07 AM

Hi,
I bought a set of boards from Jim's Audio (quad 405),and have been reading what you guys have posted ,Any words of wisdom/changes before I turn on the Iron to build it?

Thanks for your help!

Tajzmaj · 23rd June 2012, 02:14 AM

Hi ..
First one is Ludwig Bernd text for which I already posted link and the other is this one.
So check both and decide.
Cheers, Taj
QUAD 405 Amplifier Information and Modification

noSmoking · 23rd June 2012, 06:53 AM

Hi Tajzmaj,
I will indeed,

Thanks,

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12th June 2012, 03:18 PM	#11
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	I'm afraid yes. Did you check supply voltage at op amp? It should be +-15V. I don't know about 134 op amp but if it draws too much current... Check datasheet or measure it. And be careful. Don't short something. If noise bothers you it is possible to install some sort of dc protection using relay which act as power on delay as well. There is plenty of such ideas around. Just google it. Again ,,Bernd Ludwig,, text. It is a lot useful information there. Cheers

12th June 2012, 03:23 PM	#12
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Just to make it easier. Regards http://www.desmith.net/NMdS/Electron.../405_Qw_14.pdf

14th June 2012, 01:10 PM	#13
ClassA diyAudio Member Join Date: Nov 2005 Location: Taiwan	Thanks for all of your help,especially, Tajzmaj. Now This 405 works fine and sounds good. I think the degraded op-amp might be the root cause.

23rd June 2012, 02:07 AM	#14
noSmoking diyAudio Member Join Date: May 2010 Location: Texas	Hi, I bought a set of boards from Jim's Audio (quad 405),and have been reading what you guys have posted ,Any words of wisdom/changes before I turn on the Iron to build it? Thanks for your help!

23rd June 2012, 02:14 AM	#15
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	Hi .. First one is Ludwig Bernd text for which I already posted link and the other is this one. So check both and decide. Cheers, Taj QUAD 405 Amplifier Information and Modification

23rd June 2012, 06:53 AM	#16
noSmoking diyAudio Member Join Date: May 2010 Location: Texas	Hi Tajzmaj, I will indeed, Thanks,