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    Burn in time

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    Clik2media

    Posts : 40
    Join date : 2009-01-18

    Burn in time

    Post by Clik2media on Wed Apr 01, 2009 8:59 pm

    Is there a burn in time for a new board [all new resistors, capacitors etc]. I put all new metal film resistors, new quad cap, new Solens' on a new 7199 board. And now I "wait for the warm sound". Not saying it sounds bad, it's just not "warm" mmmm?

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Burn in time

    Post by Bob Latino on Wed Apr 01, 2009 10:28 pm

    Hi,

    Which board did you install ?

    Bob

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    Re: Burn in time

    Post by Clik2media on Wed Apr 01, 2009 10:34 pm

    Hi Bob, it's a Tube Dreams St-70 board. Identical to the old layout using 7199 tubes etc. Not worried about the board per se' - because all that is differnt really is modern components. In fact the old board worked fine and sounded better.....LOL
    Just doing all round "upgrading" but left at the basic layout. Used the same tubes I had on the old board yesterday....

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Burn in time

    Post by PeterCapo on Thu Apr 02, 2009 1:04 am

    It might mellow a bit over time, but going from the original carbon comp resistors and paper capacitors to metal film resistors and polypropylene capacitors is always going to sound different from the way it did originally. What you have now is probably how it will remain for the most part.

    To get the sound a bit warmer, you might try carbon film or carbon comp resistors with paper in oil capacitors. Actually, I have heard that Auricap polypropylenes are a bit warmer than your average film cap.

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    Re: Burn in time

    Post by Clik2media on Thu Apr 02, 2009 8:14 am

    Thanks for that Bob, I kinda suspected the sound would be differnt. And that is in part the purpose of my experimentation with the various ST-70's I have.
    Question - and I do have some Auri Caps coming - are the .047 the actual output caps or all 4 caps the .01 and the .047 comprise of output caps.
    Much appreciated

    Mike

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Burn in time

    Post by Bob Latino on Thu Apr 02, 2009 8:25 am

    Hi Mike,

    Actually Peter responded to your question with an answer that is spot on. The carbon composition resistors on the original board give a slightly "mellower" sound. The metal film resistors are more neutral but are quieter and won't drift their value over time like carbon composition resistors usually do.

    I think you are off a decimal point on the Auricaps that you mentioned (.01 and .047 mfd). The original caps on the stock driver board were two .05 (or .047 is OK also) and four .10 main coupling caps. You can probably go one size up with no issues - maybe two .10 and four .22.

    Bob

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    Re: Burn in time

    Post by Clik2media on Thu Apr 02, 2009 8:53 am

    My apologies Peter, I did not pay attention to the author. Not enough coffee yet....LOL
    It was a typo on the mdf vaules as well. So to clarify your response - the .10 are the coupling caps and .047 are the output caps?...am I reading that right?

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Burn in time

    Post by Bob Latino on Thu Apr 02, 2009 9:01 am

    Clik2media wrote:My apologies Peter, I did not pay attention to the author. Not enough coffee yet....LOL
    It was a typo on the mdf vaules as well. So to clarify your response - the .10 are the coupling caps and .047 are the output caps?...am I reading that right?

    Correct .. The four .10 caps are the main coupling capacitors and the two .05 caps are part of the phase splitter/phase inverter circuitry

    Bob


    Last edited by Bob Latino on Fri Apr 24, 2009 8:50 pm; edited 1 time in total

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    Re: Burn in time

    Post by Clik2media on Thu Apr 02, 2009 2:48 pm

    Ok Bob thnx.
    I will post my thoughts on the various cap options.

    thnx again

    Mike

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