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In Reply to: Re: Any benefit to lower than maximum watt output for tubes? posted by Ray Moth on February 26, 2007 at 12:29:35:
Ray,ADD to EVERYONE'S list this, with a proper amp ( proper supply of course! ) ...the BEST reason of all !!
*** A lower ( eg: 5/8ths) diss op point will SOUND better, much better!! ***
Manufacturer's stated op points "by the book" ( and NOT MAX ratings N.C. ) sound STRAINED as all get out and I do not like hearing it now at all. On the other hand, op points that are lower sound VERY RELAXED, LUCIOUS, and perhaps even better TIMBRE-WISE and HARMONICALLY.
Now if you have a supply that is conventional, it is SO intrusive upon the music you will very likely miss these nuances. Then you can ( or may have to ) jack UP the tube op point to " make up " for the amp's crummy ( in the way of the music ) power supply, and pretend that you have high fidelity, when in reality its just a kiddie amp.
But with a really GOOD power supply, you can gain a much-relaxed and musical presentation by generally just using the Golden Ratio op point. Now, guess what Ray, this op point stuff is not my idea at all, but ALL THE CREDIT belongs to the person who engineered the marvelous Serious Stereo 2A3 amp, and he GAVE the Forum this information, and much more, last year through my posts!! His name is Dennis Fraker aka "tubewrangler" from Montana.
Very few AA members seemed to follow these prior posts, so two weekends ago, I LISTENED to Greg's 245 amp with all my new low HY, Low DCR, Low C parts added, and then the 245 op points lowered, to gain direct and practcal experience. Greg and I now each have NO DOUBT that the advice previously posted up here was truly " on the money ", re: the supply design and the op points. Greg and I are believers from what we heard, and never again will I push the op point like I USED to do !! Never !! All it took was us listening, with a good amp with a good supply, to rise to a NEW LEVEL in this ART.
400 HZ on up at Greg's home was a pair RCA MI-1443 Field Coils on a big RCA 90 by 40 horns, not a slouch driver and horn combo, to evaluate such changes.
Jeff Medwin
Follow Ups:
I understand that there is a school of thought that power tubes are better run at high voltage and low current. This places less stress on the tube than a higher current. I don't know where the golden ratio comes into the picture - maybe just a coincidence?
Hi Ray,ALL tubes, not just power tubes, run better at lower current AND lower voltages Ray. They sound better, far less strained and are more relaxed sounding. You car engine and lawn mower runs better at 5/8ths throttle, as do many things in nature, hence, the " coincidence " with the Golden Ratio.
and my amp starts sounding like a lawn mower, I'll know whom to blame! ;)
Hi Ray,William Lee and John Hagerman ( on his SE 2A3 amp ) and others use lower op points and prefer them sonically. On SE its dramatic, as the output trannie sees less standing current.
Hard to tell what you will hear, depends upon your circuit and supply implementation and overall execution. But even on stock P-P Paoli 60Ms. I preferred lower op points. Try it and let me know .
Regards !!
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