+ Post New Thread
Page 2 of 2 FirstFirst 1 2
Results 21 to 36 of 36
  1. #21
    Advanced Member level 5
    Points: 34,834, Level: 45
    Achievements:
    7 years registered Created Blog entry Created Album pictures
    SunnySkyguy's Avatar
    Join Date
    Sep 2007
    Location
    Richmond Hill, ON, Canada
    Posts
    6,729
    Helped
    1679 / 1679
    Points
    34,834
    Level
    45
    Blog Entries
    7

    Re: Who says that TUBES = RETRO?

    With Slew rate limiting and diode soft compression on gain , tube performance can be emulated with solid state design.

    Normal limiting on solid state produces square waves from a single tone which are only odd harmonics and tubes & xfmr's produce limit with even harmonics. A triangle wave makes only even harmonics with no odd harmonics. There is more to it than that, but I have not attempted to emulate it.

    My only tube amp was the Bogan Stereo I had since '70 with my 12" Philips speakers, in cabs. I made with tuned Helmholtz resonators to extend the bass.

    The Bogan final A-B tube stage started to glow with blue corona , I think from spurious oscillations in its last days of use before I replaced it with a Technics unit which always had that solder resin flux smell to it.

    That Bogan with the -15dB contour switch is still today the most sensible alternative to the "loudness" switch used to today. Where the "loudness" switch adds mostly boomy bass, the "contour" switch was used to cut the mid-range when you wanted to cut the sound but maintain the EQ according to human Fletcher-Munchen EQ curves. Our ears tend to be flat EQ near the max levels and then need compensation to cut midrange and lower levels which is exactly what Bogan's design did.


    I loved it, but my buddy who graduated in EE before me had already designed/built tube amps for pre-amp and power amp. They amazed me for low S/N ratio, in fact total silence at max gain. Perfect silence and then the music would vibrate the house with a punchy bass, I had never heard before, until I found a disco in Hull with quad 15" woofers and a rack of DC300's in parallel. It was a 70's vintage RC church converted into a disco, just across the river from Ottawa. I found it late at nite searching for the bass seismic waves.

    Tony in Toronto.
    Last edited by SunnySkyguy; 6th May 2012 at 17:44.
    A best design is easily achieved with good test specs™
    A better question deserves a better answer. ™
    ... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.

    ... Tony Stewart EE since 1975
    - slightly north of Toronto



  2. #22
    Newbie level 4
    Points: 96, Level: 1
    oldskool's Avatar
    Join Date
    Jul 2012
    Posts
    5
    Helped
    0 / 0
    Points
    96
    Level
    1

    Re: Who says that TUBES = RETRO?

    Hi,
    i'm just a plain hobbyist in my 40's building my own tube amps, i'm a single ended fan hence class A, i used to build SS & gainclones, but to me tubes are really special, they are more natural sounding to my ears, no matter what others are against the output transformer limitations, perhaps they have heard those built with a crappy core, the core material of an OPT (output transformer) of tube amps in single ended or push-pull can make or break a tube amp.

    I use Z11 type of core in my projects, another good core is the M6 material. These are just one of the many factors that contributes to a high performance tube amp,



    •   AltAdvertisement

        
       

  3. #23
    Advanced Member level 5
    Points: 11,015, Level: 25

    Join Date
    Apr 2012
    Posts
    1,981
    Helped
    637 / 637
    Points
    11,015
    Level
    25

    Re: Who says that TUBES = RETRO?

    Quote Originally Posted by Audioguru View Post
    I made a mid-quality vacuum tube amplifier in 1961. Its output tubes became unmatched after only a few months and needed to be replaced to have low distortion again. It happened over and over.
    I'm not quite sure what your point is. I have no doubt that you managed to make a really bad valve amp 50 years ago. That doesn't mean that others can't make really good valve amps (then or now).

    Wait a minute! Are you serious about this?:
    output tubes became unmatched after only a few months and needed to be replaced
    If so, can you share the circuit? I'm curious as to how anybody could screw up a valve amp design so badly.


    1 members found this post helpful.

  4. #24
    Newbie level 4
    Points: 96, Level: 1
    oldskool's Avatar
    Join Date
    Jul 2012
    Posts
    5
    Helped
    0 / 0
    Points
    96
    Level
    1

    Re: Who says that TUBES = RETRO?

    Originally Posted by Audioguru
    I made a mid-quality vacuum tube amplifier in 1961. Its output tubes became unmatched after only a few months and needed to be replaced to have low distortion again. It happened over and over.

    wow, that was some 51 years ago, if you began building tube amps at age 20 you're 71 years old now

    output tubes became unmatched after only a few months and needed to be replaced

    i agree with godfreyl, my EL84 SE runs for about 2 hrs per day, it is now 3 years without repair or modifications, considering class A runs hot, always in the high rev

    present day tube amp builders are so lucky, we have high capacitance low ESR caps, solid state rectifiers, high voltage transistors for a cap multiplier, silicon diodes/LEDs for cathode bias, voltage regulators for CCS....what more can you ask for

    again, tube amp performance rely heavily on how it was built, even parts/component lay-out plays an important role, a sloppy build equates to a sloppy performance



    •   AltAdvertisement

        
       

  5. #25
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Who says that TUBES = RETRO?

    My 1961 tubes amplifier was a Heathkit. It had a class-AB output stage and was about 25W per channel.
    I got it tested at the MacIntosh amplifier clinic many times. First the distortion was 25% so I replaced the output tubes and the distortion was reduced to the normal 0.3%. A few months later the distortion was 15% and replacing the tubes again reduced it to normal again. Over and over. I bought American name brand tubes, not Russian or Chinese. The tubes glowed with a purple haze inside so maybe they were over-stressed.

    I still use my 1964 H H Scott solid state FM receiver and it never had a problem.



    •   AltAdvertisement

        
       

  6. #26
    Junior Member level 2
    Points: 101, Level: 1

    Join Date
    Dec 2012
    Location
    Nashville
    Posts
    22
    Helped
    0 / 0
    Points
    101
    Level
    1

    Re: Who says that TUBES = RETRO?

    Quote Originally Posted by Audioguru View Post
    There is an ugly old lady in my neighbourhood who walks her old dog on my street every day. They are boring but are fine.
    There is a pretty young lady who walks her young dog and they are extremely lively and attractive.
    They both do the same thing but are very different.

    The output transformer in a vacuum tube amplifier messes up the high frequency response and provides poor damping of resonances of the speaker. The transformer adds distortion especially at low frequencies. A semiconductor amplifier does not have an output transformer.

    Great analogy!!



  7. #27
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Who says that TUBES = RETRO?

    There is a "high end" audio equipment and parts store near me. Their NOS (New Old Stock) 12AX7 vacuum tubes were $149.99 each but now they are on sale for only $99.99.
    GEEZ! The last time I bought a 12AX7 it cost $2.99.



  8. #28
    Super Moderator
    Points: 81,448, Level: 69
    Achievements:
    7 years registered
    Awards:
    2nd Helpful Member
    betwixt's Avatar
    Join Date
    Jul 2009
    Location
    Aberdyfi, West Wales, UK
    Posts
    13,351
    Helped
    4459 / 4459
    Points
    81,448
    Level
    69

    Re: Who says that TUBES = RETRO?

    You are missing a business opportunity there Audioguru, for $149.99 you could make them yourself and sell them at profit!

    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.



  9. #29
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Who says that TUBES = RETRO?

    Quote Originally Posted by betwixt View Post
    You are missing a business opportunity there Audioguru, for $149.99 you could make them yourself and sell them at profit!
    Maybe. But I think the "retro" store is going bankrupt because nobody buys antique tubes anymore.


    1 members found this post helpful.

  10. #30
    Advanced Member level 5
    Points: 33,525, Level: 44
    Achievements:
    Created Album pictures Created Blog entry 7 years registered
    tpetar's Avatar
    Join Date
    Sep 2010
    Location
    Pancevo-Belgrade, Serbia
    Posts
    6,427
    Helped
    1736 / 1736
    Points
    33,525
    Level
    44

    Re: Who says that TUBES = RETRO?

    Does Anyone from you use this today for new design ?

    I'm just curious, nothing else.
    “Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla



  11. #31
    Administrator
    Points: 38,285, Level: 47
    Achievements:
    Created Album pictures Created Blog entry 7 years registered
    alexan_e's Avatar
    Join Date
    Mar 2008
    Location
    Greece
    Posts
    11,895
    Helped
    2093 / 2093
    Points
    38,285
    Level
    47
    Blog Entries
    6

    Re: Who says that TUBES = RETRO?

    Now I know what I'll buy Audioguru for Christmas...
    A pair of Audionote GakuOn, just $250000 for the pair

    http://www.audionote.co.uk/products/...ku-on_01.shtml



    Level Five, 45 watt Class A parallel single-ended no feedback mono triode power amplifiers with ultra simple fully transformer coupled circuit topology with in-house designed and wound input, driver and output transformers, all Audio Note™ silver wired, AN Perma 50 double C-cored, 2 watt Audio Note™ tantalum resistors, Black Gate™ WKz and NH type capacitors in power supply, Black Gate™ N-type decoupling capacitors, no signal coupling capacitors whatsoever (!), valve compliment, 4 x NOS VT4-C/211, 4 x NOS 5R4WGB, 2 x NOS VT25/10Y
    Please don't make requests for help in private using PM. Create a thread in the forum so that other members can benefit from the posted answers.

    Consider reading this before posting : How To Ask Questions The Smart Way



  12. #32
    Advanced Member level 5
    Points: 33,525, Level: 44
    Achievements:
    Created Album pictures Created Blog entry 7 years registered
    tpetar's Avatar
    Join Date
    Sep 2010
    Location
    Pancevo-Belgrade, Serbia
    Posts
    6,427
    Helped
    1736 / 1736
    Points
    33,525
    Level
    44

    Re: Who says that TUBES = RETRO?

    And speakers will bring Santa Claus and put them under the tree for 220K USD :



    http://www.higherfi.com/spkrlist/speakerlist.htm



    - - - Updated - - -

    I suspect on sound in any shape in nature that can be so much good for this speakers, I right now saw 1M and 2M speakers . I dont know who buy this boxes?

    - - - Updated - - -

    What to say after thise zeroes and commas between them, I go to watch some movie and go to sleep.
    “Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla



  13. #33
    Advanced Member level 4
    Points: 6,490, Level: 19

    Join Date
    Feb 2011
    Posts
    1,170
    Helped
    284 / 284
    Points
    6,490
    Level
    19

    Re: Who says that TUBES = RETRO?

    Does Anyone from you use this today for new design ?
    I've never used one, but from just a physics point of view, I'm always interested
    so I obtained a few a while back.

    I have 2 x ECC86, and a ECC91 and a recent Russian 6V6GT, if anyone can
    suggest a project.
    From memory it was going to be a headphone amp and an AM radio at the time.

    A pair of Audionote GakuOn, just $250000 for the pair
    Sometimes I wonder who designs these things!
    If I ever got round to it, personally I'd make it look classical (wood box, hidden
    tubes) rather than some of these metal, glossy, unfriendly modern designs.
    But I guess they have a market, so maybe I'm showing my age!



    •   AltAdvertisement

        
       

  14. #34
    Advanced Member level 5
    Points: 33,525, Level: 44
    Achievements:
    Created Album pictures Created Blog entry 7 years registered
    tpetar's Avatar
    Join Date
    Sep 2010
    Location
    Pancevo-Belgrade, Serbia
    Posts
    6,427
    Helped
    1736 / 1736
    Points
    33,525
    Level
    44

    Re: Who says that TUBES = RETRO?

    I watch on youtube homemade production of tubes, and I must say its very interesting, but just for watching over youtube.

    I have around 40kg of tubes, some of them are very expensive and very rare. That tubes my dad and uncle used when they were young. Also I have two old Texas Instruments programmable calculators with cards, I used them sometimes, but time and needs pushing us into newer sophisticated tech.
    Last edited by tpetar; 6th December 2012 at 01:53.
    “Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla



  15. #35
    Advanced Member level 5
    Points: 53,716, Level: 56
    Achievements:
    7 years registered
    Audioguru's Avatar
    Join Date
    Jan 2008
    Location
    Toronto area of Canada
    Posts
    8,749
    Helped
    2053 / 2053
    Points
    53,716
    Level
    56

    Re: Who says that TUBES = RETRO?

    The store that sells extremely expensive antique vacuum tubes also sell extremely expensive amplifiers with vacuum tubes glowing on top.
    The vacuum tubes are for show since they are not part of the solid state amplifier circuit.



  16. #36
    Administrator
    Points: 38,285, Level: 47
    Achievements:
    Created Album pictures Created Blog entry 7 years registered
    alexan_e's Avatar
    Join Date
    Mar 2008
    Location
    Greece
    Posts
    11,895
    Helped
    2093 / 2093
    Points
    38,285
    Level
    47
    Blog Entries
    6

    Re: Who says that TUBES = RETRO?

    Quote Originally Posted by sky_123 View Post
    Sometimes I wonder who designs these things!
    If I ever got round to it, personally I'd make it look classical (wood box, hidden
    tubes) rather than some of these metal, glossy, unfriendly modern designs.
    But I guess they have a market, so maybe I'm showing my age!
    Apparently it is the glowing exposed tube design that attracts more customers , you don't want to pay all that money for a black box.

    Quote Originally Posted by Audioguru View Post
    The store that sells extremely expensive antique vacuum tubes also sell extremely expensive amplifiers with vacuum tubes glowing on top.
    The vacuum tubes are for show since they are not part of the solid state amplifier circuit.
    Not all designs are hybrid but there are times when tubes are used just for marketing.
    Please don't make requests for help in private using PM. Create a thread in the forum so that other members can benefit from the posted answers.

    Consider reading this before posting : How To Ask Questions The Smart Way



--[[ ]]--