SP 12 SE

laatsch55

Administrator,
Staff member
Joined
Jan 14, 2011
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74,915
Location
Gillette, Wyo.
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Halfbiass...Electron Herder and Backass Woof
Ya got a point there. I once set chokers on a loggin crew in Oregon. Had to crawl in the crew truck at the end of the first day, and they rolled me out on my doorstep. Great bunch of compassionate and caring people, them loggers.
 

Gepetto

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May 15, 2011
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Sterling, MA
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Old 'Arn Enthusiast
Where are you considering the use of Schottky's in that tube preamp? Generally speaking, Schottky's are low voltage, high current devices. Usually tube gear is the direct opposite of this.
 

mlucitt

Veteran and General Yakker
Joined
Jun 24, 2011
Messages
3,494
Location
Jacksonville, FL
Lee you need a spectrum analyzer to find the origin of that noise. If you can trace it to a 60Hz source or a bad ground creating a junction that resonates at a certain frequency...
 

laatsch55

Administrator,
Staff member
Joined
Jan 14, 2011
Messages
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Gillette, Wyo.
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Halfbiass...Electron Herder and Backass Woof
Joe, I will. I'm so frustrated with it I sent Larrt a 3300 Ser II to hold him off till I'm in a better frame of mind to deal with it. I have a few projects coming I committed to at the end of the year so i have to clean my slate a little. I'm just lucky the Larrt is so understanding.
 

mlucitt

Veteran and General Yakker
Joined
Jun 24, 2011
Messages
3,494
Location
Jacksonville, FL
Chasing the gremlins can be a real pain. I once had bad channel (out of 576) in the SONAR aboard the ship. I finally found a tube that had cracked and let air inside the envelope, but it still glowed! (We used to look for blown tubes by turning the lights out) I found that little sucker, I think it was a JAN Phillips 12AX7WGT, and strung it up on the bulletin board in the Control Room. It swung there for the entire cruise and everyday I laughed at that sucker.

You will be overjoyed when you find the issue. May I suggest the halfway approach, where you look for the noise in the middle of the circuit (disconnecting parts to isolate the "middle"), if you find noise, go back towards the source. If you don't find noise, you go forward halfway again and keep doing that until you can find a small section where there is noise on the output but no noise on the input (with isolated components, as required). It usually works for me.
 
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