myles_rose Posted April 5, 2007 Share Posted April 5, 2007 I just completed a series of tube tests on a number of current production 12AX7 and ECC83 types. Most conventional tube testers do not measure actual gain. They measure things such as emissions or transconductance. Unless one can also measure the plate resistance one cannot know the actual true gain. As a side note, the VTV tube tester which has a scale marked "gain" does not measure actual gain. This scale is some sort of scale that has no actual relationship to any conventional engineering spec. Engineering spec on a 12AX7 states that in a circuit with a TC of 1600, a DC plate current of 1.2 millamps, a plate resistance of 62.5k ohms, and 250 volts on the plates and a 2 volt bias the gain will be 100. Your TC can be lower if your plate resistance is higher and maintain gain as a side note, and visa versa. Typical production 12AX7 tubes today show a gain on average of 75-85 with average typical gain in the low 80s. The JJ ECC83S in this batch (over 100 tubes were tested) had gain of over 90 in most cases, and there were a number of tubes with gain of over 100 in the range of 108+ http://www.groovetubes.com/assets/2177_JJ-ECC83S_040507.jpg Myles S. Rose www.guitaramplifierblueprinting.com www.la-economy.blogspot.com www.facebook.com/mylesr www.twitter.com/myles111us Link to comment Share on other sites More sharing options...
Corner Pocket Posted April 5, 2007 Share Posted April 5, 2007 But how do they sound????? Peace, Paul ---------------------- Link to comment Share on other sites More sharing options...
fantasticsound Posted April 5, 2007 Share Posted April 5, 2007 Ok, Myles, in English for use ignorant players.. How does the gain factor in to real world timbre adjustments. Does it simply add more distortion for those in love with hi-gain amp sounds or are there other considerations that make increased gain from the tube desirable in instances other than balls-to-the-wall, hard rock/heavy metal guitar sounds? It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
miroslav Posted April 5, 2007 Share Posted April 5, 2007 Is higher gain actually "better"...or just another "flavor"? Not sure if it's a relative comparison....but a lot of guys like high output pickups...I prefer lower output pickups. miroslav - miroslavmusic.com "Just because it happened to you, it doesn't mean it's important." Link to comment Share on other sites More sharing options...
myles_rose Posted April 5, 2007 Author Share Posted April 5, 2007 Ok, Myles, in English for use ignorant players.. How does the gain factor in to real world timbre adjustments. Does it simply add more distortion for those in love with hi-gain amp sounds or are there other considerations that make increased gain from the tube desirable in instances other than balls-to-the-wall, hard rock/heavy metal guitar sounds? It sounds more closely to what the amp was designed to sound like in the case of vintage amps. In the case of some new amps with their noisy and complex circuits ... mmany of these moderately priced amps were designed around current production tubes that are sub-par. In any case ... to me, they always sound better, are more fun to play and more lively and touch sensitive. Myles S. Rose www.guitaramplifierblueprinting.com www.la-economy.blogspot.com www.facebook.com/mylesr www.twitter.com/myles111us Link to comment Share on other sites More sharing options...
myles_rose Posted April 5, 2007 Author Share Posted April 5, 2007 Is higher gain actually "better"...or just another "flavor"? Not sure if it's a relative comparison....but a lot of guys like high output pickups...I prefer lower output pickups. See my post reply above Myles S. Rose www.guitaramplifierblueprinting.com www.la-economy.blogspot.com www.facebook.com/mylesr www.twitter.com/myles111us Link to comment Share on other sites More sharing options...
Strategery Posted April 5, 2007 Share Posted April 5, 2007 Good to hear and thanks for providing that info to us. I've purchased and have been a fan of JJ's for a while. They just sound GOOD! Randy "Just play!" Link to comment Share on other sites More sharing options...
Gifthorse Posted April 5, 2007 Share Posted April 5, 2007 I wonder what one of those would sound like on the left side of the Bivalve with a high gain AT7 in the input..? http://flagshipmile.dmusic.com/ http://www.myspace.com/gifthorse Link to comment Share on other sites More sharing options...
mdrs Posted April 6, 2007 Share Posted April 6, 2007 Ok, Myles, in English for use ignorant players.. How does the gain factor in to real world timbre adjustments. Does it simply add more distortion for those in love with hi-gain amp sounds or are there other considerations that make increased gain from the tube desirable in instances other than balls-to-the-wall, hard rock/heavy metal guitar sounds? It sounds more closely to what the amp was designed to sound like in the case of vintage amps. In the case of some new amps with their noisy and complex circuits ... mmany of these moderately priced amps were designed around current production tubes that are sub-par. In any case ... to me, they always sound better, are more fun to play and more lively and touch sensitive. Valuable information. Thanks, Myles. Don "There once was a note, Pure and Easy. Playing so free, like a breath rippling by." http://www.soundclick.com/bands/pagemusic.cfm?bandID=574296 http://www.myspace.com/imdrs Link to comment Share on other sites More sharing options...
fantasticsound Posted April 6, 2007 Share Posted April 6, 2007 Yes, thanks for the answer, Myles. BTW - I just missed your buddy, if he's still with Jake Owen.. But I have an excuse.. it was my wife's birthday and she was not interested. It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
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