| dr._sleep |
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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| JojoD818 |
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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