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    passive preamps



    Posts : 1
    Join date : 2010-07-04

    passive preamps

    Post by earless on Sun Jul 04, 2010 4:44 pm

    Hello. Anyone have any experience with passive premps and ST 70s?

    Bob Latino

    Posts : 2383
    Join date : 2008-11-26
    Location : Massachusetts

    Re: passive preamps

    Post by Bob Latino on Mon Jul 05, 2010 9:32 am


    Passive preamps, whether transformer or resistor based, work just fine with all the Dynaco tube amps that I have tried them with. Most CD players are set up for about 2 to 2.1 volt output. Most Dynaco amps only need a little more than 1 volt for full output. Most upgrade driver boards for Dynaco amps will allow the amp to achieve full output with even less input voltage.

    The biggest advantage to a passive is that it nearly always will add less of any "sonic signature" to the music than a powered preamp.


    Last edited by Bob Latino on Tue Jul 06, 2010 5:23 pm; edited 1 time in total


    Posts : 725
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: passive preamps

    Post by GP49 on Tue Jul 06, 2010 4:47 pm

    I can say nothing bad about the performance of going passive with a Dynaco Stereo 70 or other typical tube amplifier. Note that the volume potentiometer (multiple is the best way since not all recordings are ideally balanced left/right) should be of top quality.

    With solid state equipment, the low input impedance "seen" by the source could be a problem. Not all tubed phono stages and output stages on tubed CD players like low input impedances; you'd be setting yourself up for a bass rolloff if the equipment is thus mismatched.

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