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Thread: Another change in direction

  1. #11
    Join Date: Mar 2010

    Location: Cardiff

    Posts: 396
    I'm Rockabilly.

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    For the spiritual benefit of viewers intrigued by 300W light bulbs, sweet spot meters and static induction, here's a very well written and entertaining article by Michael Rothacher, hosted on the diyAudio site:

    http://www.diyaudio.com/forums/diyau...-part-1-a.html

    Courtesy of Nelson Pass himself, scoot here for beguilement over the De-Lite amplifier:

    http://www.firstwatt.com/pdf/art_delite.pdf

    "Keep your bias high and your feedback low" compradres.
    Johnny Dodgem.

    Cartridges vintage MMs including Pickering xsv-4000/xsv-3000 : Stanton 881s/D81 : AT140LC/VMN40ML
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  2. #12
    Join Date: May 2009

    Location: Southampton

    Posts: 451
    I'm Rob.

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    Mike has been a great help.
    just trying some foo caps Looking at getting rid of the bulbs,will be trying a 1:1 transformer or some vishay thick film resistors but at £30 a pop dunno,also the CRC PSU will be going CLC

    Q



  3. #13
    Join Date: Jan 2008

    Location: gone

    Posts: 11,519
    I'm gone.

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    How are you finding the Parasound A21 power amp, Rob?

    I love mine to bits - it seems a perfect match for my MBL speakers. It's not too far off my first anniversary with the A21, now!
    .

  4. #14
    Join Date: May 2009

    Location: Southampton

    Posts: 451
    I'm Rob.

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    Quote Originally Posted by jandl100 View Post
    How are you finding the Parasound A21 power amp, Rob?

    I love mine to bits - it seems a perfect match for my MBL speakers. It's not too far off my first anniversary with the A21, now!
    Hi Jerry its a very nice amp,I've always had a softspot for Parasound had a long list of the HCA range couple of 1500's bridged was cool still using a 1205A for surround duties.

    not sure if I'm taxing the A21,just using it to drive my 15" bass bins up to 220Hz.

  5. #15
    Join Date: Jan 2008

    Location: gone

    Posts: 11,519
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    OMG - what a waste!
    .

  6. #16
    Join Date: Jul 2010

    Location: North Cambs UK, Earth, Sol, Orion - Cygnus arm of galaxy

    Posts: 11,166
    I'm MadeOfDeadGiantStarsThatExplodedEonsAgo.

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    Quote Originally Posted by jandl100 View Post
    OMG - what a waste!
    Damn right, keep the MC² 450 for things like that & use the A21 for stereo duties
    Bests, Mark



    "We must believe in free will. We have no choice" Isaac Bashevis Singer

  7. #17
    Join Date: May 2009

    Location: Southampton

    Posts: 451
    I'm Rob.

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    OK OK ,got the picture
    A21 replaced by a serviced Crown DC300A
    Also the power supply has been changed to a CLC from CRC on the SIT's
    Hear from the DIY Audio forum Paul H has been asked to look at a regulated PSU for the amp,should be interesting
    Mine tricked out with Kondo SPc power cables,SPc speaker cable and AN Vx interconnect
    Some fans installed to bring down the temp just replaced with some 1200 rpm silent fans
    The SIT is a funny beast,has a sweet spot dependent on speaker load.


  8. #18
    Join Date: Jul 2010

    Location: North Cambs UK, Earth, Sol, Orion - Cygnus arm of galaxy

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    I'm MadeOfDeadGiantStarsThatExplodedEonsAgo.

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    Quote Originally Posted by RobsterD View Post
    Some fans installed to bring down the temp just replaced with some 1200 rpm silent fans
    The SIT is a funny beast,has a sweet spot dependent on speaker load.

    Well for starters the heatsinks don't have the fins vertical, so they won't be anywhere near as efficient at getting rid of heat... Think of a chimney & how it draws air upwards, vertical fins have the same kind of effect

    I haven't seen the circuit but I'd lay a bet that there is no overall feedback what so ever & it has a high output impedance, so yes, it'll be very dependent on the speaker load

    No idea why the designer didn't substitute the bulbs for a choke as it'd be far more efficient, price maybe & ease of assembly as well as that glowing bottle effect
    Bests, Mark



    "We must believe in free will. We have no choice" Isaac Bashevis Singer

  9. #19
    Join Date: Mar 2010

    Location: Denmark - Struer

    Posts: 343
    I'm Jan.

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    I always get nervous when my amps starts to glow.

    Hmm didn't the EU ban the use of big bulbs
    Jan.

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  10. #20
    Join Date: Apr 2011

    Location: London

    Posts: 4,419
    I'm Robert.

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    Quote Originally Posted by slate View Post
    I always get nervous when my amps starts to glow.

    Hmm didn't the EU ban the use of big bulbs
    Would be the least of my worries - Talk about exposed and vulnerable !

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