Post #43 The Penta KT88SC and Reissue GL's are very close in sound and in price. The SC's are (at least visually)
exact replicas of the
original Genalex Gold Lions. The reissue GL's construction are nothing like the originals, no matter New Sensor's claims about reverse-engineering, blah, blah! If those are your two choices, I'd go for the GL's just because they're easier to resell :yes: Best matching, price, and free shipping on those two is from
www.dougstubes.com. In that price range however, my recommendation would be the S.E.D. KT88's (McIntosh's current OEM KT88) for $170 per super well-matched quad from Gene at
www.conusaudio.com Additional tip when buying matched tubes: If you need a matched pair, buy a matching triplet. If you need two matched pair (or a matched quad) buy
five matched tubes -- this way, if one of the tubes in use ever goes, you'll have an instant matching replacement! If you're feeling really anal, you can rotate them like pre-radial car tires
Post #44 It's nice when you can do instant side-by-side comparisons, but it's also possible to A--B with a short interval of time in between if:
A. You decide beforehand what you want to listen for. With power tubes for instance, bass power, transient accuracy (control/tightness), and low frequency extension (how low does it go!?) Remember to keep everything apples2apples -- levels, source material, etc. A handy feature if your CDP has it, is the 'Repeat' function applied to just a short segment of music. You'll be amazed how much detail your brain 'remembers' when it hears just a small segment of something over and over. Is that what Ravel was trying to tell us when he wrote Bolero? :scratch2:
B.
Take notes as you're listening! Be wordy and describe to yourself what you THINK you're hearing in as many ways as you can. Refer to your notes from "A" when you are listening to "B". Make categories for each session (in the case of power tubes for instance -- power, transients, LF extension.) Use a pencil and paper!! One reason many (TOO many) audiophiles aren't getting the satisfaction out of their systems they might, is simply because they haven't taught themselves how to listen -- that repeat function on your CD player is one of the BEST teaching aids in audio (you see, there really IS a "purpose for everything under Heaven", even the digital format :thmbsp
It also helps (but not absolutely mandatory) to decide beforehand what you're going to listen for! Whatever is especially good (or bad) in a short segment of music or vocals will just pop right out at you!! So many audiophiles DON'T REALLY LISTEN!! It's not hard -- you just have to remember to do it! Listen to a Mozart piano concerto or symphony and try following the instuments that are NOT playing the main melody, but underneath it -- that's a really great listening exercise!
Post #45 John, I'm not doubting you, but this is the first I've heard mention of a Raytheon 5751 BP/WMG with
three micas. The three mica Raytheon black plate 5751's I've run across always had regular wire getters. Are you sure? RE The 50's/60's Syl in 70's cans: they are from one of the Scandinavian countries' Air Force (Sweden, I think) which "juiced" their spare tubes (new OR used) once a year (gave them a jolt of voltage) to check them and keep them up to specs. The date on the can is when that was last done. The Syl TM 5751's with gold pins ALL have gray plates. And they don't sound anything like the black plates (which NEVER have gold pins
) I never tried 7728/7729's. I'd like to if they're not too expensive? Are these direct subs (same specs) as 12AX7/5751's? Never auditioned the RCA 5751 Command Series (DMBP?) going instead directly for the triple micas. How do you compare the two?
Post #46 In the MC275, the V-2 and V-5 are the tubes responsible for amplifying THE SIGNAL which then goes to the 12AT7's and enables
them to regulate (drive) the KT88's grids for delivering power to the speakers. If you think about this carefully, you'll realize that the "amplifying" aspect of a power amplifier occurs in the (little) "gain" stage tubes, not in the power tubes! That's why the 12AX7 #2 and #5 (in the MC275 that is!) have so much influence on sonics. Also true in the MC75, but they only have one gain stage tube per unit.