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KT150 Tube Matching

Ok. Educate me. I don't know enough to even be dangerous. What are the critical factors used when matching a set of KT150 tubes, say, to go in an Audio Research amp? Transconductance? Bias current draw? A combination of the two? Is there any spec. or threshold on the variations? Does Audio Research do anything special to match their replacement tube sets? 
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wolf_garcia
6,795 posts
 
"thetubestore.com" has a wealth of info on what's important for tube matching.
jperry
2,485 posts
 
Buy the tubes from Audio Research
knghifi
1,668 posts
 
When shopping for power tubes (NOT NOS), I look for dealers with higher quality and larger supply of tubes for a better match. Upscale states they pay extra for tubes with higher micromhos.  ARC is 2x price of Upscale ... don't think you can go wrong with either. 
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