Aikido Crackle Hiss Noise Solved

dr._sleep · 24th February 2006, 11:59 PM

Earlier I posted this......

"....I had a crackle and hissing sound {sic in my Aikido preamp} from more than one set of 6N1P's, I rewired the heaters for 12AU7's in the first position and no more crackles

All is well, now..."

WELL< The crackles came back and even though I had searched the signal path with my oscilloscope, I could not identify the crackles as signal noise.

Upon very closer inspection I found the voltage divider I had added to bias the filament up to 60 volts DC had a bad solder joint and was intermittentantly making contact due to vibrations, heat and especially, me, pounding on the preamp out of frustration.

I found the faulty joint while using a voltmeter with the preamp powered up and in the fault mode (thank the tube gods because I had done this several times out of the fault mode) and found there was no elevation of the filament voltage, resoldered the joint and now,

ALL IS WELL.

But I do have 12AU7's in the input position now and leave well enough alone for now. Nothing wrong with the 6N1P's after all.

Live and learn, a very happy

dr._sleep

as we say in medicine "The enemy of good is better"

JojoD818 · 25th February 2006, 12:12 AM

Hi,

This is good info for Aikido builders like me.

Now I know where/what to look for in case my upcoming Aikido develops any crackling sound.

Thanks Doc!

24th February 2006, 11:59 PM	#1
dr._sleep diyAudio Member Join Date: Jul 2005 Location: southern us	Aikido Crackle Hiss Noise Solved Earlier I posted this...... "....I had a crackle and hissing sound {sic in my Aikido preamp} from more than one set of 6N1P's, I rewired the heaters for 12AU7's in the first position and no more crackles All is well, now..." WELL< The crackles came back and even though I had searched the signal path with my oscilloscope, I could not identify the crackles as signal noise. Upon very closer inspection I found the voltage divider I had added to bias the filament up to 60 volts DC had a bad solder joint and was intermittentantly making contact due to vibrations, heat and especially, me, pounding on the preamp out of frustration. I found the faulty joint while using a voltmeter with the preamp powered up and in the fault mode (thank the tube gods because I had done this several times out of the fault mode) and found there was no elevation of the filament voltage, resoldered the joint and now, ALL IS WELL. But I do have 12AU7's in the input position now and leave well enough alone for now. Nothing wrong with the 6N1P's after all. Live and learn, a very happy dr._sleep as we say in medicine "The enemy of good is better"

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25th February 2006, 12:12 AM	#2
JojoD818 diyAudio Moderator Join Date: Mar 2003 Location: diyAudio Special Operations Center	Hi, This is good info for Aikido builders like me. Now I know where/what to look for in case my upcoming Aikido develops any crackling sound. Thanks Doc!

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