George Roland Posted September 10, 2006 Share Posted September 10, 2006 I have a Dynaco PAS 2 with full Curcio Audio Engineering mods. It has a single 12AX7 tube on the line stage board. I just got 5 Electro-Harmonics 12AX7-EH tubes because mine died. I have been trying them out the last day or two. Every one of the tubes so far tested sounds different on my Klipschorns. Most are noisy enough to produce some hiss, hum, wind or gurgling that is audible from my listening position 12-14 feet from the speakers. I gather there are some of you who have a Dynaco PAS-2 or 3 you are using, and I'm wondering if you have any 12AX7 tubes you would recommednd I try for lower levels of noise? Thanks, George Quote Link to comment Share on other sites More sharing options...
scott0527 Posted September 10, 2006 Share Posted September 10, 2006 What tube did you have in there before? The only new 12ax7 I've used in a stock circuit PAS were JJ Tesla. I had no problems with noise. Quote Link to comment Share on other sites More sharing options...
WPM Posted September 10, 2006 Share Posted September 10, 2006 George, I've been using the new, re-issue, Tung-Sol's with excellent results. To my ears, one of the best new manufactured tubes around... sweet, detailed and coherent from top to bottom. You can't go wrong for the money. William Quote Link to comment Share on other sites More sharing options...
paul cbc Posted September 10, 2006 Share Posted September 10, 2006 The Sovtek 12AX7LPS is a very quiet tube. Cheap too. Good luck! Paul Quote Link to comment Share on other sites More sharing options...
George Roland Posted September 10, 2006 Author Share Posted September 10, 2006 Sorry I didn't make that clear. The Electro-Harmonics 12AX7-EH was the tube supplied by CAE with the upgrade board. Since that was what was supplied, I just thought to replace it when it went south with the same type of tube. George Quote Link to comment Share on other sites More sharing options...
DRBILL Posted September 11, 2006 Share Posted September 11, 2006 I'm going to have the last of my Curcio upgrades on e-bay in a few weeks. Didja ever stop to think that it might not be the tubes? 'Nuf sed. DRBILL Quote Link to comment Share on other sites More sharing options...
George Roland Posted September 11, 2006 Author Share Posted September 11, 2006 Well, yes, I did think about that, but since I'm generally satisfied with the PAS-2, and makings tube changes does make audible differences in the sound, it seemed the economical thing to do to try some different tubes. My experience with tube amps is limited, but I'd be interested in your take on the Curcio modded equipment and what you're using for a preamp. So maybe not enough said? George Quote Link to comment Share on other sites More sharing options...
DRBILL Posted September 12, 2006 Share Posted September 12, 2006 George, I don't find much use in active preamplifiers anymore. After I got Bob Crites tweeters and crossovers for my K-horns, I just didn't feel the need to twiddle with treble and bass controls. I bult a device that would allow me to switch inputs and would regulate volume and balance. This went right to the Mark IIIs. Wonderful. It is like cleaning the haze off a window. I don't do much vinyl. I put a small line amplifier right under the arm. It has the advantage of no line loss or noise gathering. I bought just about every kit Joe had to offer. Nothing survived a year. They did not satisfy. "Occam's Razor" rules! DRBILL Quote Link to comment Share on other sites More sharing options...
George Roland Posted September 13, 2006 Author Share Posted September 13, 2006 DRBILL, Thanks for the reply. I can build a kit because I have steady hands and can solder and follow directions, but I have no electronics background, so I couldn't build anything like what you're describing. I'm dependent on what I can buy from others. In the meantime, I have ordered 4-5 new tubes based on suggestions here and from tube sellers who have provided advice. It should be fun to hear them in a week or so. I am still exploring this whole horn audio business, and I'm intrigued by how sensitive and revealing the Klipschorns are to these kinds of component changes. George Quote Link to comment Share on other sites More sharing options...
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