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The Dynaco Tube Audio Forum

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

    ST-120 & Tube Rolling


    Posts : 13
    Join date : 2013-06-24

    ST-120 & Tube Rolling Empty ST-120 & Tube Rolling

    Post by jimmytamp on Sun Sep 29, 2013 2:50 am

    Dear all,

    I'm Jimmy & I'm one of the proud (happy) owner of Bob's ST120 that i acquired few months ago (wired & tested version), thanks Bob for the great job on the amps.

    For the last few weeks I've been doing tube rolling on the driver with the the same stock power tubes (Sovtek KT88) & same rectifiier (NOS Mullard GZ34-7 notch plates).
    All tests are done with the amp's volume control on middle/12 o'clock and with around 12-20 hours of listening/burnt time on each set of driver tubes.
    I hooked up my ST120 to the Denon 2809 & a pair of Klipsch RF62.

    Herewith some insight from me to share:

    1. NOS Mullard ECC82 (Matched-1962).
    I found that the bass/lows are very punchy,clear and details yet not boomy, and to me, i feel that sounds very "tubey" which i like most.
    The highs are very clear and not harsh but the mid-range is a little bit flat (which i like) & it gives a bit further back on the sound stage which i like.
    For me, i will use this for accoustic jazz or anything that have double bass/oboe sound in it as well as any solo instruments (sax,violin,piano, accoustic guitar etc), this will be my first choice on the amp.

    2. The stock Sylvania 6189 (Matched).
    To my surprise it's almost similar with the Mullard above and these will be my second choice.

    3. NOS French RT 12AU7 (Matched)
    I found that these tubes bring all music to front which is very details from lows, mids & highs with wide sound stage (maybe kind of HiDef/3d?). The bass is very clear and no harsh on the high regions.
    It has the "modern" sound & to me it almost similar to my Denon for some reason.
    Even though this one is not my favourites, but i will use this to listen to any classical/concert musics, pop/rock/blues or any live music on stage which will produce details. I have't tried but may be i can use it to watch movie.

    4. Genalex Gold Lion ECC82 (Matched)
    These one are the least of my favorites.
    It bring the mids louder & more details compares to other tubes I've tried. The bass guitar sounds further back even though it's clear but at the same time you can hear the bass drum very punchy and loud.
    The highs are clear and not harsh. It brings the vocal/any solo instrument up front.
    For those who like vocal jazz, these one is suitable for that which bring the singer sounds like he/she is standing in front of you. Not my favorite.

    That's all for now I hope these infos will be usefull for you guys who want to try driver tubes rolling.

    By the way i have EH-KT90, 5U4G and some 12BH7s on the way. I will keep you update once i put those on the amp.

    Cheers all,

      Current date/time is Mon Jul 13, 2020 6:39 pm