Posted by Tnuctipun [ 205.188.116.67 ] on April 17, 2005 at 08:39:47:
In Reply to: amp input stage posted by Tnuctipun on April 09, 2005 at 06:42:14:
Hey-Hey!!!,
I removed the 150k grid leak resistors from the input stage of my amp and replaced them with 15k. The 20 cps output Z of my linestage is dictated by its 7.5 uF coupling cap, so a 15:1 ratio of input Z to linestage output Z seemed OK from a filter/freq response POV.
I find the system a bit cleaner now. It's not a big difference, but subtle ones are OK with me at this point. Same type of resistor, a 1/2 watt carbon film from Radio Shack.
After listening for a while, I keep thinking that the change was worth it. A worthwhile deviation from std. practice if a system analysis looks to support the change. I would not suggest trying this if a Dynaco PAS 3 were the linestage. A 12AX7 and .22 uF or so coupling cap is not going to cut it I suspect...
regards,
Douglas
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