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Poor quality distortion in a 6n1p based homebrew

11/11/2004 9:10 PM
Bob Ingram
Poor quality distortion in a 6n1p based homebrew
I built a Gilmore Jr. from a kit http://www.guytronix.com . The overall tone and quality is good until it's cranked into overdrive, then there's some bad sound on the sustained notes especally on the bottom end, kinda fizzy.  
 
I'm thinking that the power tube is the cause, possibly bias or the amount of signal driving it. It's got one 12AX7 in the preamp, a single tone control and the self split 6n1p running at just about 300VDC. Here's the schematic without the values, Guytronix doesn't publish these. http://www.gerhartamps.com/gilmorejr/Gilmore_Jr.pdf  
 
The 6n1p cathode resistor is 330ohms.  
 
Here's a clip of the tone. I used a 5751 in the preamp to lower the amount of gain and it cleaned up a little, still I'm not happy with the distortion.  
 
http://www.patmedia.net/bob-ingram/Gilmore/Clip3_5751_hums.mp3  
 
Any suggestions on what to look at?  
 
Thx in advance.  
 
Bob

 
Replies:
kg bob, you want my opinion? -- 12/16/2004 12:59 PM