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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 Dynakitparts.com products


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sKiZo
Bob Latino
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    Sutherland solid state driver board for the Dynaco ST-70

    Bob Latino
    Bob Latino
    Bob Latino
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    • Post n°1

    Sutherland solid state driver board for the Dynaco ST-70 Empty Sutherland solid state driver board for the Dynaco ST-70

    Post by Bob Latino Wed Jul 30, 2014 8:44 pm

    In the 1980's there was an all solid state driver board for the Dynaco ST-70. The Sutherland board used JFETs and MosFets in combination to drive the output tubes. Although the Sutherland board stopped production in 1990, a company called Nobis Technologies in Wisconsin produced an ST-70 like amp in the 1990's using the Sutherland solid state driver circuit. It was called the Nobis Cantabile and had solid state rectification, an under chassis cap board and an LED system to set the bias. Considering the $1700 price tag on the Nobis Cantabile, not too many were sold. Nobis Technologies ceased production of this amp in about 2004. Every now and then one will show up on Ebay ..

    Bob

    Below are a two photos of an original Dynaco ST-70 modified with a Sutherland board. The last photo is of a production model Nobis Cantabile.

    Sutherland solid state driver board for the Dynaco ST-70 ST-70Sutherland_zpsc28e968a

    Sutherland solid state driver board for the Dynaco ST-70 ST-70Sutherland_2_zpsa9dc438d

    Sutherland solid state driver board for the Dynaco ST-70 111849-nobis_cantabile_tube_amplifier_zps1abc328b
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    sKiZo
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    • Post n°2

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by sKiZo Wed Jul 30, 2014 10:06 pm

    The Nobis is a legitimate high-end tube amp, offering sound quality on a par with many of the better-known companies on the market. If your listening requirements don't include louder-than-hell levels and bass-bass-bass-all-over-the-place, the Nobis Cantabile deserves a serious audition.

    http://www.stereophile.com/tubepoweramps/992nobis/

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    gooch
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    Join date : 2016-03-05
    Location : Florida
    • Post n°3

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by gooch Sat Mar 19, 2016 11:32 am

    Anyone heard that amp? I know someone who has the original Sutherland board still in the box with all the instruction. I wondering if it is worth a try in a ST70. I have a ST70 with the Curcio PWB-3A CCDA DRIVER AMPLIFIER board I did some years back for the most part it sounds good but the bass is not a tight as I would like. Now maybe that just tubes I don't know seeing I don't have another tube amp to compare it to.


    Regards

    Dave
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    Roy Mottram
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    • Post n°4

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by Roy Mottram Sat Mar 19, 2016 12:38 pm

    Dave,
    here's what I wrote back in 1989 when I compared every available ST70 mod . . .

    Sine wave frequency bandwidth was from 5 Hz to 6 KHz, not much better than the stock Dyna. Square waves remained fairly square from about 60 Hz to 3 KHz.
    This mod definitely changed the sound of the amplifier from being warm and rounded, to being more neutral. The music came thru very clean and detailed without being harsh.
    The sound was open without the veiling noted above, although the soundstage seemed to be more recessed. Cymbals and bells were reproduced with a clean airy sound around them. The bass reproduction was about the same as the stock Dyna, probably limited by the power supply. There was a noticeable lack of impact with too much smoothness.
    The dynamics of the music was better but still not as good as the three mods below.
    (VTA, Curcio, GSI)

    Here's a link to the original article . . . http://www.tubes4hifi.com/st70mods.htm
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    gooch
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    • Post n°5

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by gooch Sat Mar 19, 2016 1:59 pm

    Thanks for the info you kinda summed it up as to what I was hearing with the Curcio dry sounding
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    sbradley02
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    • Post n°6

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by sbradley02 Wed Apr 26, 2023 12:01 pm

    I built a Sutherland ST70 back in the 80s, and found it to be an exceptional amplifier. Your comparison between the Sutherland and the VTA is not quite equal in my opinion. The VTA board has additional filter capacitance on the driver board. The Sutherland used a separate optional board under chassis with several hundred uF. Without adding the Sutherland capacitor board, the VTA is way ahead in the power supply area. Sutherland also had an additional kit for bias set which I also had, though this was likely more of a benefit for convenience than sound quality.
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    New2Tubez
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    • Post n°7

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by New2Tubez Thu Apr 27, 2023 3:00 pm

    You’re replying to a 7 year old post…
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    sbradley02
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    • Post n°8

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

    Post by sbradley02 Thu Apr 27, 2023 3:03 pm

    New2Tubez wrote:You’re replying to a 7 year old post…
    I was aware of that. The board was very long out of production when the original post was made.
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    • Post n°9

    Sutherland solid state driver board for the Dynaco ST-70 Empty Re: Sutherland solid state driver board for the Dynaco ST-70

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