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Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    Dynaco PAS 3 and MK III's

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    gflash

    Posts : 3
    Join date : 2014-01-19

    Dynaco PAS 3 and MK III's

    Post by gflash on Sun Jan 19, 2014 11:13 am

    Hi, I am new to this forum.  I became in interested in tube audio in the early 1990's.  I started with a Audio by Van Alstine rebuild kit for a Stereo 70. I realized the kit was nearly identical to the original circuit but with upgraded parts. I then rebuilt a PAS 3 using the stock circuit boards but used high quality parts and revised phone section. I removed the tone controls and loudness circuit. The switches and knobs are still there but do not do anything.  I then picked up pair of MK III's and rebuilt those.  I had the bases rechromed and painted the transformer covers. The circuit is stock except I have a capacitor board under the chassis to take the load off the quad can capacitor. I have mains close to 130 volts so the input DC voltage to the stock cap was very high. The first two filter sections are handled by the board under the chassis and the stock can cap handles driver tube duties.  Both units are using the same tubes I installed in 1993. The preamp uses NOS 12AX7 and 12X4 tubes, the MK III uses NOS 6AN8's and Sovtek 6550's.  I am running the bias current at 50mAH.  You can see my cabinet has two low speed fans to help keep things cool. I apologize for the dust on the amps, I need to pull them out to clean them.  I have been very pleased with the sound of this system for 20 years.

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