If you feel more comfortable going with tightly-DC-matched tube sets, that's great - it surely can't hurt, and at the very least it shows that some TLC was put into the selection of your tubes which IMO shows integrity on the part of the seller. AFAIK the only big tube producer who AC-matches is Groove Tubes. b) you really need a huge quantity of 'raw' tubes to end up with a worthwhile number of AC-matched sets, and c) it doesn't always result in a closely-DC-idle-matched set, which can greatly increase the WTF!-factor on resale, especially when top dollar was paid. Getting a set of tubes that makes music in an identical fashion is very much a worthwhile goal IMO, but hardly anyone does it because a) it's difficult to do without a curve tracer, which involves money, possibly a computer w/attendant skill set, etc. Idle DC-matching is really quick and easy to do, and it gives a number that can be readily checked with a meter - but usually it doesn't last, and unless you've got a serious mismatch (which IMO is important mainly for indicating large differences in baseline tube transconductances, which can make a real difference) it really isn't a matter of life and death tone-wise my $.02, YMMV.ĪC matching - now that's a different story. In fact, I've seen sets with much greater idle mismatches that put out very similar full-power currents, and sounded great I'd trade DC current-matching at full power for DC current-matching at idle any day of the week, but I don't know of any tube seller that does this (and what is "full power"? or "idle", for that matter?). Unless you're using a toroidal OT - in which case a bias-servo circuit is in order IMO - 5mA or less DC mismatch won't matter at all IME. I realize you probably won't give a damn what I say but IMO it's quite possible to have a truly matched tube set in a musically-important way (not merely in idling-heat-output) that nonetheless shows significant variances in DC current flow at idle between tubes.
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