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Thread: The State of Vacuum Tubes for the 21st Century

  1. #1
    Join Date: Jan 2008

    Location: Wrexham, North Wales, UK

    Posts: 110,012
    I'm AudioAl'sArbiterForPISHANTO.

    Thumbs up The State of Vacuum Tubes for the 21st Century

    Have a look at this, guys. It is extremely interesting for anyone who uses valves!

    http://www.vacuumtube.com/FAQ1.htm

    I found this bit particularly interesting regarding NOS and current production valves:

    TQR: In terms of audio quality, durability, and technical performance, how would you rank the various manufacturers previously described?

    VTV: I feel that NONE of the current production is exactly as good as genuine premium NOS tubes from Western Europe or the USA. Part of the sound of a really good tube is caused by ultra-pure cathode materials--something Western Electric, M-OV, and other firms strove to use whenever possible, for longevity. You chances are, you will NEVER see that done again, the economics of OEM tube sales won't allow it.

    The largest buyers of tubes are the big guitar-amp makers; Fender, Marshall, Ampeg, Mesa, Peavey and a few others. They drive the market, and they have collectively made it clear that their primary qualification for a tube for use in a guitar amp is low unit cost. They go around shopping for the cheapest tubes which give tolerable reliability in a guitar amp. Many amp companies design their amps around, say super cheap Chinese 6L6GCs and they work just fine. Cathode purity is not important.

    As far as VTV's editors can tell, very few guitar amp makers pretest tubes to find the longest-lived version or brand. Another issue is with cleanliness and vacuum hardness. This is easily traded off at the factory, and the end-user often can't tell--until the tube outgasses and its plate current runs away, destroying the amp! All the current factories are pumping their tubes down for the shortest time they can get away with. Because guitar amps stress the screen grids of output tubes, one can see this as a problem for reliability.

    When a screen gets red-hot, any absorbed gas in it will be emitted. Enough of it, and the tube runs away. Again, OEMs are demanding low cost and quick delivery schedules, so the tubes are not pumped for 2 or 3 hours, as the best factories once did routinely. This is less of a problem with power triodes like 300Bs, but those are not used in guitar amps. Preamp tubes aren't much affected by gas, except for its tendency to shorten cathode life.
    That'll explain why I much prefer the sound of genuine NOS valves, and the older the better!

    But that's just the tip of the iceberg - there's so much great info within this link it's mesmerising!

    Marco.
    Main System

    Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.

    Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.

    Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.

    CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.

    Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.

    Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.

    Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.

    Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.

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  2. #2
    Join Date: Nov 2008

    Location: North Down /Northern Ireland/ UK

    Posts: 19,484
    I'm Neil.

    Default Nice article

    Hi Marco

    Very good article. I would not claim to be a valve expert but a lot of what this article says I have heard of from guys who really know valves. The new Sensor Tung-Sol reissues are very good and I have compared them to NOS Tung-Sols and I prefer the modern ones, 6sn7 and 5881.

    I use the 6sn7 in my Bat power amp and the Bat vk10 se phono stage, they work very well in deed. The 5881 I use in a pair of Audio Innovations series 1000 mk 3 mono amps(much better sound than el34 valves). Very nice amps IMHO.

    Regards D S D L
    Last edited by Spectral Morn; 29-12-2008 at 09:27.

  3. #3
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

    Default

    Yes,seen that before Marco.Interesting stuff.Bad thing about current demand being on the up is it pushes NOS prices up,though in the long term,if it continues,we may see much better quality new valves coming along.No reason why not,with modern technology.Just need enough consumer demand to make it worthwhile for the manufacturers IMHO.

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