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some 5150 notes

5/6/2003 5:23 PM
Joe N.
some 5150 notes
Well I broke out the soldering iron to try and get this thing to sound a little better. The first thing I tried was lowering the plate resistors to 100K, and removing one stage of gain for a cthode follower, lowering the 39K cathode resistor to 10K, replace the first .022 coupling cap to .0047uf and replaced the 330K grid to ground resistor to 2.2M. When I fired her up, I just got a high pitched squeeling sound. Too much gain.  
I then put the 39K back in, and replaced the 2.2M with a 220K. I fired her up, and got the squeeling when the gain pot was turned 3/4 of the way up. the squeeling went away when I turned the gain pot up all the way. Sounded like crap.  
I then replaced that 220K with a 470K, and changed the first plate resistor to 220K. Sounded worse.  
Changed the plate resistor back to 100K, and changes the first cathode bypass cap to 10uf, and put in some el-34's sounded a little better especially when turned up, but still a bit icepicky  
the squeal is still there with the preamp volume around 1-3 'o'clock, but goes a way around noon or dimed. and my master has a shitty taper, on one, it is loud as hell.  
I'm running out of ideas, does anyone have any?  
Joe N

 
Replies:
KB Heres the best tip ! Trash that pie... -- 5/6/2003 7:36 PM