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Valve Radio Vs Solid State Radio

Discussion in 'Hobby Electronics' started by Kate Fights, I Cry, Apr 29, 2005.

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  1. Just wonder what your personal opinions are
    on which sounds better.

    I have a Kriesler valve based table radio and also
    a table radio that is solid state. But when I listen
    to each I have to admit the old radio gives a far
    richer sound. Sure it's got valves and is bulky but
    it sounds a damn sight better then the smaller all
    transistor cousin.

    I find the other radio gives a slightly harsher tone
    to both music and voice, and even when it is tuned
    in properly too.

    Of course this is just my opinion, and opinion can
    be subjective. Just wondering what others think, but
    for what it's worth I'm still using the older radio
    to listen with.








    --
    John

    Remember the good old 1980s
    When things were so uncomplicated
    I wish I could go back there again
    And everything would be the same

    I've got a ticket to the Moon
    I'll be leaving here any day soon
    Yeah I've got a ticket to the Moon
    But I'd rather see the sunrise in your eyes

    (c)1981 E.L.O.
     
  2. Ken Taylor

    Ken Taylor Guest

    The valve radio has a decent sized speaker and is almost certain to be wider
    bandwidth than a crappy cheap transistor radio, so it will certainly sound
    better. But I wouldn't bother going out and buying one; a decently designed
    and built transistor radio is equally as good.

    Ken
     


  3. Not quite what I was talking about. But interesting all the same.

    Thanks for writing
     


  4. Well in this case they are both table radios just one is
    about half the size of the other and uses solid state
    parts... Though until it dies I'll use the valve one.

    Hell I got it at an auction so may as well get use out of it.
     
  5. Mark Harriss

    Mark Harriss Guest

    Most domestic valve radio was build as a lowest
    common denominator product where every component
    inclusion was argued over. I have an AM Kriesler
    stereo unit with Garrard turntable and electrostatic
    tweeters I rebuilt in 1990: it was full of out of
    tolerance resistors and leaky wax capacitors.

    Possible a larger speaker, a larger case and
    class A audio contributes to the sound. It would
    typically be a single ended class A output stage
    too, likely a pentode stage.

    It's possible to have good sounding valve radio
    Patrick Turner has build a modified one and I
    think has the schematics on his website.
     
  6. Steve Batt

    Steve Batt Guest


    Have you had a listen to the Tivoli Audio model 1 ?
    not cheap at $300 for a mono am/fm table radio, but it does have a beautiful
    sound. I have this 1.

    http://www.tivoliaudio.com/product.php?productid=164&cat=&page=1

    Steve
     
  7. Joerg

    Joerg Guest

    Hello Ken,
    Mostly, yes. But I have an Australian example that even a cheesy
    enclosure can contain an excellent radio: An Astor BPJ from 1959. It's
    in a rather flimsy plastic case but the radio itself is a superb design.
    It offers by far the best AM performance (it's AM only) of any radio I
    have except when compared to professional receivers. So whenever I
    listen to AM it is usually with that old Astor.
    Sometimes I wonder if there is any modern radio with a decently designed
    RF section. Excluding professional gear that people wouldn't place in
    their living quarters I haven't seen one in two decades.

    Regards, Joerg
     
  8. Ken Taylor

    Ken Taylor Guest

    Yer durn tootin'. People obviously just won't pay for a decent AM radio so
    they're no longer built.

    Ken
     
  9. roughplanet

    roughplanet Guest

    Denon have (or had) a couple of tuners in their range; the TU-255 & the
    TU-1500RD, both of which are fine tuners in either AM & FM mode.
    When I bought the TU-255, I had two other tuners; an Audiolab 8000T and a
    McIntosh MR75. The TU-255 was not quite as good as either, so when the
    opportunity arose to trade it in on a TU-1500RD, I did, not really expecting
    it to match either of the other two. I was wrong; it not only matched them,
    but exceeded their performance in terms of sensitivity, selectivity & audio
    quality.
    And best of all, it cost less than half what I subsequently sold the 8000T
    for, and a quarter of the price the MR75 brought on eBay.
    So have a look around for a TU-1500RD. It might be a lightweight, both
    literally and in audiophile terms, but it's performance is quite surprising.

    ruff
     
  10. Phil Allison

    Phil Allison Guest

    "Joerg"...

    ** Ever heard of AFC ( automatic frequency control) ??




    ................ Phil
     
  11. Ken Taylor wrote:


    < snip >




    Speaking of AM whatever happened to AM Stereo?
     
  12. Lord Garth

    Lord Garth Guest

  13. Joerg

    Joerg Guest

    Hello Phil,
    ROFL.

    Actually when you turn AFC on it gets even worse. Then the tuner hangs
    on to a strong station for more than 400kHz. In my opinion AFC was a
    kludge, probably invented because some folks couldn't figure out how to
    design a stable oscillator.

    Regards, Joerg
     
  14. Joerg

    Joerg Guest

    Hello Kate,
    Living in the US where AM stereo was very popular on car radios all I
    can say is that the typical new rig from the store doesn't have AM
    stereo. Seems like it's fizzling.

    Most AM stations are talk radio or programming to small ethnic groups.
    Neither would care much for stereo.

    Regards, Joerg
     
  15. Joerg

    Joerg Guest

    Hello Ruff,
    Thanks for the hint. The price is reasonable as well, I believe around
    $250-300. But my wife doesn't like the old tower stacks where every
    module of a stereo system had to have their own enclosure.

    Then again, why not just connect the old tube set to the stereo? That
    gives superb AM performance at next to nothing in cost.

    The real topper is a 2nd hand communications receiver with crystal
    filters. With some luck it won't cost more than the Denon but then you
    have a setup that's almost as good as the station monitors. Also, I
    somtimes use that to listen in single sideband mode when fading gets
    bad. That way I can enjoy programming that is almost unintelligible on
    even a good AM radio.

    Regards, Joerg
     
  16. Phil Allison

    Phil Allison Guest

    "Joerg"
    ** The point is that AFC creates an effect like that of a very broad IF when
    this is not the case.


    ** No - the AFC is counteracting your attempts to re-tune the radio - it
    needs to be disabled when tuning.

    In any case - a broad IF is *required* for low distortion on the FM band -
    plus you will not hear adjacent channel signals along with the wanted one
    since the FM "capture effect" prevents that.


    ** So the dial says - but the local oscillator frequency has been pulled
    in the opposite direction to the tuning dial.


    ** Variable VHF oscillators stable to within +/- 20 kHz over the room temp
    plus internal gear temp range are indeed a design challenge, especially in
    the case of varicap ( non tuning gang) tuners. However, AFC compensates for
    oscillator drift and mistuning for very little cost.

    Modern FM tuners ( since the 1980s) have their tuning frequencies derived
    from a crystal time base so drift is eliminated.



    ........... Phil
     
  17. I have a 1986 Ford Laser with the standard radio.
    It is a rotten performer, and no doubt the
    radio and audio sections are minimalist chips, the
    worst that chip technology can offer, and just
    what the fucking bean counters at Ford are delighted with.

    But nearly all the domestic FM tuners made after 1970 with chips are
    fairly good, although I far prefer my all tube
    home made fully tubed FM tuner which includes a tubes stereo decoder.

    The FM medium is inherently suited for good separation of stations
    since they are 300 kHz apart and the maximum deviation is +/- 75 kHz.

    But with AM, the stations are at 9 kHz apart, and the RF sections of AM
    sets are receivers are almost all limited to about 6 kHz of RF bw.
    This results in 3 kHz of audio bw, and this was standard in all the old tubed
    AM sets.
    The modulation applied to some station transmitters is -3 db at 9 kHz,
    maybe not all though, but the RF bw of the receiver cuts the possible response.

    If you try to listen to to distant stations only 9 kHz apart,
    then the set with reduced RF bw will give good separation.

    But two distant stations both modulated with 9 kHz of bw would interfere
    badly with each other if you have a wide bw receiver.

    To avoid the interference, the station count would have to be halved,
    so stations were 18 kHz apart.

    Anyway AM radios are a compromise on selectivity needed for
    long distance listening, and fidelity need for locals.
    A wide bw RF section in an AM radio is harder to build,
    but they only suits local station reception with stations at 45kHz minimum
    apart.

    Ppl here have cited other fancy tuners, but nearly all the
    AM sections of AM/FM tuners are also quite hopeless with
    3 kHz or less of measured AF bw due to their
    small RF bw within.
    Why anyone would ever bother with the crackly hissy
    interference ridden sound of distant AM station listening is beyond me.
    They should all be made with a wider band width RF section.
    In fact the RF section should consist of a double tuned bandpass circuit and
    the
    IF section should have a ceramic filter with 18 khz of BW,
    and then we get the best from AM with modern devices.

    The radios I have made for myself use double tuned two section
    LC inputs before the frequency converter tube,
    then have R strapped across the IFT coils to lower
    the Q of the IF transformers, and one has variable IF coil spacing, and then I
    get the
    18 kHz of IF bw needed before one can get 9 kHz of audio bw.
    Then I have a +/- 6 dB tine control, mandatory with AM radio
    since HF audio content is variable.
    Radio National here in the ACT on 846 kHz sounds magnificent.
    Music programs are fine.

    With old standard sets, boosting the treble with a tone control might possibly
    stretch the response to 4 kHz. But old tube sets usually had only a treble cut
    adjust knob.
    The speakers were current driven from a
    beam tetrode, a 6V6, and the response of the 6" speakers of 1960
    gave increasing output as F rose, so some slight further extension
    of the HF due to speaker rise compensated the response, so
    maybe 5 khz on a good day, wind permitting was obtained from
    a tube AM set.
    I have measured dozens of them and repaired and tweaked many.

    I don't treasure any old AM sets as they were presented as standard.
    All were crap.

    All need serious mods before one removes the horrendous thd levels
    and bw limitations.

    Most of the SS AM tuners which followed the tube sets were far worse
    than tube sets because their RF/IF pass bands were
    even narrower than the tube sets since they used single coil auto
    IF transformers, with one tuned LC, rather than two,
    critically coupled to give a flatter pass band.
    Only 3 tuned circuits were involved, and this gave very poor
    "skirt" selectivity, which means that attenuation of powerful local stations
    45 kHz apart is inadequate.
    The SS tuners using discrete transistors had a limited dynamic range compared
    to valves,
    and the distortions were worse in the amplifier stages and the
    use of a single transistor as an oscillator and frequency converter wasn't
    as good as the heptode or or triode hexode like the 6BE6 or 12AN7
    used so effectively when tubes were king.


    The effect of the invasion of Australia by cheap Japanese transistor
    radios made people even more used to the worst possible sound.
    I never ever purchased such crap.

    If you want really good A reception, you have to search carefully
    for tuners which guarantee at least 9 kHz of audio bw
    for local station reception.
    Unless a tuner specifies the AM audio bw id 9 kHz, assume is the usual
    2 kHz so often found.

    While some kits were offered in the past, I know of no standard sets available
    right now
    which do the business properly on AM.

    To easily get 25 kHz bw from each of IFTs in an old tube set, one would really
    need to have 2.5 MHz IF frequency rather than 455 kHz, the standard F for
    over 60 years. And you'd want 3 IFTs, but this was something that
    no accountant would ever allow a 1950's radio maker provide.

    The history of AM is one about how to keep most people fooled most of the time.

    Patrick Turner.
     
  18. Communications radios are terrible performers if you
    want decent local station performance; they are deliberately
    selective, and most without more than a maximum of 3 khz of AF bw.

    Sure, OK for DX.

    What is the measured and guaranteed AF response from the Denon
    using AM and local stations, if the station modulation
    or test signal has 20 kHz of flat level AF modulation?

    Patrick Turner.
     
  19. roughplanet

    roughplanet Guest

    Ask Denon.

    ruff
     
  20. roughplanet

    roughplanet Guest

    Very handy for FM satellite reception where Doppler shift means that the
    frequency appears to move constantly. Both my R-9000 & R-8500 have it & I
    wouldn't want either of them without it.

    ruff
     
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