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  1. #21
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    Re: Beginner question about experimenting with tubes

    Fair enough, but not all tubes are wimpy little things there are some real monsters out there.
    Cheers, Tony.



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    Re: Beginner question about experimenting with tubes

    Yeah, I know I am aiming really high here, but I can't wait to get to those monsters. There's something about tubes that fascinates me. Just recently, I bought RIAA phono amplifier with tubes for my turntable. I didn't want transistor amplifier.



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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by I14R10 View Post
    I didn't want transistor amplifier.
    You should try to study their datasheets just for fun- at least. Because they are basically voltage sensitive devices, the parameters are reported differently.

    But I personally believe that if you have a decent idea about vacuum tubes and their operation characteristics, you will also be a better transistor engineer.



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    Re: Beginner question about experimenting with tubes

    What did you have in mind by studying their datasheets? When I am buying a transistor I always look at the datasheet.



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    Re: Beginner question about experimenting with tubes

    Tubes are used today in Geetar amplifiers to produce no low frequencies or boomy low frequencies (poor damping of speaker resonances) and no high frequencies like an old AM radio and produce lots of distortion. Tubes soon wear out or fail.

    A transistor amplifier should have no problem producing frequencies lower and higher than you can hear and their extremely low output impedance provides excellent damping of speaker resonances. Their distortion cannot be heard and is so low it is difficult to measure. They last "forever".



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    Re: Beginner question about experimenting with tubes

    All the above evils that Mr Audioguru speaks of are true, but more due to the limitations of the required audio output transformers rather than the vacuum tubes.

    If you find the tubes hard to source, that is nothing compared to trying to find really good audio transformers, as there is no longer a big enough market for such devices.
    Cheers, Tony.



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    Re: Beginner question about experimenting with tubes

    Some circuit examples are in the back of tube manuals like this:
    http://www.tubebooks.org/tubedata/RC30.pdf
    page 693


    2 members found this post helpful.

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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by retrogear View Post
    Some circuit examples are in the back of tube manuals like this:
    http://www.tubebooks.org/tubedata/RC30.pdf
    page 693
    This is a goldmine! Next to Stutters' mill.

    When the transistor was first made, it was commented that the new discovery will help modern hearing aids (I do not have the reference).



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    Re: Beginner question about experimenting with tubes

    So, the tube amplifier for my turntable came today. It uses 6J1 tubes. I've read that they are quite bad. I don't know, to me they sound good. Should I replace them with these http://www.thetubestore.com/Tubes/On...w/JAN-GE-5654W? It says that GE-5654 is replacement for 6J1.



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  10. #30
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    Re: Beginner question about experimenting with tubes

    Treat remarks like "rich warm result, and a sense of 3D space" as highly suspicious. Nothing in the design of a tube can change the tonal quality or spacial content of a sound!

    It's smells of "...uses special resistors with TWO wires for lower noise, interstellar ambiance and higher greatness of upper amounts".

    It might work better, but I would bet that a blind test couldn't tell tell them apart except maybe for a slight difference in volume level.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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    Re: Beginner question about experimenting with tubes

    Yeah, as I said, I can't hear the difference between CD version and vinyl version and I have quite good speakers.



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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by retrogear View Post
    Some circuit examples are in the back of tube manuals like this:
    http://www.tubebooks.org/tubedata/RC30.pdf
    page 693
    I just had time to flip through this. Amazing! This is among the most useful books I ever had the chance to read. You made my day. This is like a Christmas present. Thank you.



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    Re: Beginner question about experimenting with tubes

    Wow, some real nostalgia there.
    I well remember owning an original earlier edition of that book for many years, it was pretty much "the bible" for anyone interested in electronics around the late 1960's early 1970's.
    Last edited by Warpspeed; 27th August 2016 at 01:06.
    Cheers, Tony.



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    Re: Beginner question about experimenting with tubes

    I also have the RCA Receiving Tube Manual.
    The ultimate guide to Vacuum Tubes.
    Other companies also published tube manuals, but none as comprehensive as RCA's.

    Back then when RCA was the world's foremost electronic company.



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  15. #35
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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by I14R10 View Post
    I just had time to flip through this. Amazing! This is among the most useful books I ever had the chance to read. You made my day. This is like a Christmas present. Thank you.
    You're welcome. I still have that manual. I built the 50W amp on page 696 back in the 70's on a tube TV chassis and used it for like 20 years. Cost about $200 for parts back then. Wish I still had it but got tossed :(

    Larry G



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    Re: Beginner question about experimenting with tubes

    The microwave oven is the most widely used vacuum tube producing 1000W (about) of RF power!



  17. #37
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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by c_mitra View Post
    The microwave oven is the most widely used vacuum tube producing 1000W (about) of RF power!
    Yep, had factory training by GE to service those starting back in the 80's. The magnetron tube has a very powerful spiral magnetic field to rotate the electron emission across a sinewave shaped metal housing to generate a high power RF signal guaranteed to sunburn your skin. Power supplied to it is close to 2000 watts AC. Had a coworker who died slumped over the bench when he accidentally contacted the supply when it was live.

    Larry G



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    Re: Beginner question about experimenting with tubes

    Cathode ray tubes are rapidly becoming extinct, but magnetrons and travelling wave tubes will probably be around for a long time yet.
    Really high power radio transmitters still use tubes, its the most economic way to generate tens or hundreds of kilowatts of RF power.
    Cheers, Tony.



  19. #39
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    Re: Beginner question about experimenting with tubes

    Quote Originally Posted by Warpspeed View Post
    Cathode ray tubes are rapidly becoming extinct,
    Include neon display tubes (for advertising) - they are giving way to LED displays. Perhaps in another 5 years there will be none. Nightlife will never be the same again.



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