Valves Are Far From Dead

 

VALVES ARE FAR FROM DEAD

     DESPITE  TRANSISTORS

 

Was the headline 50 years ago in Electronics Weekly’s edition of May 24th 1961.

The story opens:

 

‘The valve is far from dead. It may have shed some of its more routine duties, which have been taken up by the transistor, but new valves are to be seen in plenty.

 

Especially is this true of the industrial market, where many new and improved valve types are to be seen.

 

The demand for quick-heating valves for transmitters is catered for by a range of four types using special cathodes.

 

These new cathodes reach full temperature within one second from switch-on.’

Tags: transistor

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23 Comments

  1. Mike Bryant
    September 13, 2012 20:20

    Sounds like we have a business opportunity then :-)

  2. Keith
    September 13, 2012 18:23

    The good old 813 tetrode would have no problem with that. It was a high power high impedance device and happily ran off a 2.5kV anode voltage.

  3. Mike Bryant
    September 13, 2012 15:20

    I believe there is about 2kV biasing voltage in the Quad unit. I’m not a valve expert so no idea if valves can drive this or not :-)

  4. Stooriefit
    September 13, 2012 12:00

    I think if you were designing the transducer system from front to back you can design a transformerless valve amp system driving electrostatics more simply than you can design a transformerless valve system to drive voice coils (although the latter has been done certainly).
    I think one of the un-tapped advantages of electrostatics (and also peizo-electric drivers like the old Audax gas filled HF units) is that they are voltage transducers, not current transducers like voice coils. My sparkie friends tell me it is easier to design stable voltage control loops than it is current control loops.
    I think electrostatics have always been compromised by the fact they are voltage devices in a current driven world.

  5. Anonymous
    September 13, 2012 09:58

    The original way to get more bass out of Quad electrostatics was to stack them, so you had two electrostatic speakers for each channel.
    Enormous & rather expensive.
    Not to mention that you needed a really large room to get the damn things far enough away from the walls.
    Not ideal for AC/DC type heavy rock, really.

  6. Mike Bryant
    September 12, 2012 19:00

    My uncle had a pair of Quad electrostatics when I was young and the sound was remarkable for the time. However I believe there is yet another transformer in the speaker so you may not be able to eliminate the problems of these totally

  7. Keith
    September 12, 2012 18:14

    Well another way of eliminating output transformers would be to use electrostatic loudspeakers. I’ve never listened to Quads but the interThingy tells me that good bass is a problem?

  8. Stooriefit
    September 12, 2012 16:53

    I think the reason valves sound more acceptable than class D etc is because most of the (comparatively large) distortion is low order, and centred on even harmonics. Not sure that it is microphony, or even anything to do with the valves themselves. Apparently valve amps which can drive low impedance loads without output transformers sound significantly different but I’ve not listened to such a thing myself.
    The ear seems to be good good at ignoring low order even harmonic distortion and interprets it as “warmth” or “body” in the sound, unlike the broad-band quantisation mush, digital filter ringing and phase weirdness you get from power amps designed in the digital age.
    Full disclosure: I run a little ultralinear class AB with EL34s. Its certainly not hi-fi but takes the edge of digitised music and keeps the study warm!

  9. Peter
    September 12, 2012 15:01

    Could it be that the microphonic effect is what people like about valves? It would make each type a different musical instrument with its different vibration modes.

  10. September 12, 2012 13:45

    Years ago I worked with a guy (sadly long since dead) who overcame the problem of the output transformers on valve audio amps by winding a set of high impedance voice coils for his speakers. Hand wound in 50 gauge (1 thou) wire – and centre tapped.

  11. Anonymous
    September 12, 2012 10:33

    Gold plated speaker cables?
    Goodness me, do keep up.
    You need oxygen free silver cables wot have been dynamically aligned to the signal direction at the very least.
    Honest.
    And then there’s the special mains lead with a dynamically aligned block of wood on it that sells for a mere $20k.
    ROTFLMAO.
    Compared with that, a bunch of KT88s running in ultralinear class AB sounds reasonably sensible.

  12. Keith
    September 11, 2012 19:05

    The big problem with valves was not the valves themselves, but the bulky and heavy transformers required. All those amperes that low voltage heaters required needed a big transformer. Power supplies were crude and usually had a big choke. And then to match the high impedance output of valves to a low impedance speaker you needed yet more massive transformers.
    Not to say I don’t like the things though, I grew up with them and have a soft spot for them.

  13. Anonymous
    September 11, 2012 18:02

    Ah, you boring realist! Leave us believers alone and divulge in our endless source of audiophoolery miracle’s equipment’s.

  14. Fred Dart
    September 11, 2012 15:48

    Yes, so you spend a lot of dosh buying an expensive valve based amplifer togther with a mega expensive turntable and cartridge to play vinyl records as opposed to digital media to wallow in the “pure” sound and non of these transistor amplifiers of course.
    So far so good – but the precious vinyl records that you are playing, well they’ve probably been cut using using transistor based equipment. So, what’s the point ? Keep buying the gold plated speaker cables folks – you know it makes a difference !
    In these days of DSP generated audio, I’m sure we could have settings that replicated valve sound, for the nostalgic. For much less than a grand anyway.

  15. Anonymous
    September 11, 2012 13:37

    Considering the price of NOS KT88, KT66, etc. the East is the only option.
    Allegedly the Russian variants are superior to the Asian variety.
    And have you seen the price of the transformers?
    One can quite easily blow a grand on a stereo Williamson just for the transformers.

  16. Pitchfork
    September 11, 2012 13:09

    All valves now come from the ‘East’ & if you want quality go to a specialist supplier like Watford Valves who really know their stuff. If Eric Clapton & Brian May amongst many others get their’s from them then you know that they are good

  17. Mike Bryant
    September 11, 2012 13:03

    An audio system that amused me recently had a pair of ‘as good as it gets’ AKM 24bit D-A converters driving MOSFET amplifiers which then fed the grids of a pair of EL34s.

  18. Mikkel
    September 11, 2012 12:30

    EL84s are not just for guitar amps. I saw many expensive EL84 hifi amps at this year’s CES. And old EL84 amps like the Leak Stereo 20 sound great.

  19. Mark Inskip
    September 11, 2012 12:28

    ECC83s and EL34a in my son’s Marshall amp (which replaced a solid-state modelling amp a couple of years ago).

  20. Anonymous
    September 11, 2012 12:08

    To be honest, it is hard to justify whether valves hold a candle against solid-state equivalents, objectively measured, until the ‘equivalence’ is defined.
    For amplifiers with an equal number of active devices – valves versus transistors – I’d back the valve circuit as having the better spec. For amplifiers of equal cost to build, I’d back the solid-state version. For amplifiers of equal physical size, I’d back the SS. For amplifiers which have incurred equal development cost, I’d back the valve (might be controversial here!)
    Don’t forget that solid-state technology has had massive investment, far more than valve.

  21. Terry
    September 11, 2012 11:28

    You can get EL84s from RS components now.
    It would be interesting to know when valves disappeared and then reappeared in the RS catalogue. But EL84s aren’t really for hifi, more suited to getting that classic guitar sound. Soft clipping is something that valves do rather well.

  22. Anonymous
    September 11, 2012 10:33

    Ah.
    The warm glow of a nice KT88.
    Assuming that you can still get a nice KT88 and not some dodgy far eastern copy.

  23. Anonymous
    September 11, 2012 07:23

    Right. Tubes are still popular in audio. Looks retro and quite cozy with the glow. :-)
    http://www.inherentmirth.com/1mirthpics/lafayette4.jpg
    Though, they can’t hold a candle objectively measured and compared with a solid state equivalent.

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