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

    Stepped Attenuation


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    Post by Maintarget on Thu May 30, 2013 10:01 pm

    I'm in the process of assembling a VTA ST-120 and am considering installing a Gold Point Mini-V attenuator in place of the kit supplied unit, I'm seeking opinions, suggestions are there better alternatives?
    I'm more concerned with sound quality than cost to a point (Point were I won't end up in the dog house) Very Happy

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    Post by hawaii.ken on Thu May 30, 2013 10:58 pm

    $149 is a good price, I might get one myself.

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    Post by sKiZo on Fri May 31, 2013 12:20 am

    How about dual mono? Gives you balance also ...

    Bob Latino
    Bob Latino

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    Post by Bob Latino on Fri May 31, 2013 8:14 am

    The Goldpoint Mini V stepped attenuator is 32 mm high. The VTA stepped attenuator is 24 mm high and is a close fit as it is into the space available. I am not sure that the Goldpoint would fit into the space available without banging into the driver board or the bottom cover?

    Both attenuators use gold plated contacts, SMD resistors and "make before break" contacts. The Goldpoint is a 24 step attenuator and the VTA is a 21 stepped unit. The Goldpoint costs 3 times the price ($150) of the VTA stepped attenuator ($50).

    Personally, I don't think that for 3X the price of the VTA stepped attenuator that the Goldpoint would sound any better.


    VTA stepped attenuator - limited clearance to driver board (about 1/16 of an inch) ...

    Stepped Attenuation St70_atten

    VTA Stepped attenuator with dust shield removed to show SMD resistors.

    Stepped Attenuation SMDphotocloseup

    The Goldpoint Mini V is in the top row on the right ...

    Stepped Attenuation Dims_rear_new_mv


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    Post by Maintarget on Fri May 31, 2013 12:39 pm

    I didn't know the quality of the kit supplied attenuator, now that I do I agree with Bob why spend 3 times the amount for the same quality & results.
    Thanks Bob.

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    Post by arledgsc on Sun Jun 02, 2013 1:22 pm

    The parts supplied with the kit are great and meet the requirements for functionality, quality, and affordability.  But I am a circuit modder and will try almost anything that makes logical sense and not ridiculous.

    I have installed the Gold Point Mini-V (dual 50k) in my ST-120 with the low-gain VTA board.  I was looking for more range (less change) around the 12 o'clock position as that is my sweet spot for listening usually.  I don't use a preamp so this attenuator is my sole volume control.  Like Bob mentioned the Mini-V is much bigger than the supplied attenuator and will interfere with the circuit board.  I had to file the slot opening slightly (down and wider) so the Mini-V would clear the circuit board and fit through the slot opening.  There are high voltages in this area so full attention is needed.  Doesn't take a lot of filing but the chassis is strong so be prepared to do this for a while until just right.  Then, for reassurance I placed double sided tape on the VTA board below the two Gold Point Elma circuit boards.  If the Mini-V moves it will rest upon the tape.

    It is very tight fit but does make it OK even with the bottom cover reinstalled.  Sounds great and have more range.  I am going to open the amp up again soon to try some different coupling capacitors (modder addiction is powerful).  I'll snap a photo at that time. Scott

    **EDIT**  Here's an inside picture with the Gold Point Mini-V and coupling cap change.        
    ST-120 Attenuator/ Recap

    Last edited by arledgsc on Mon Jun 17, 2013 10:12 am; edited 1 time in total

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    Post by mantha3 on Fri Jun 14, 2013 10:27 am

    I have a ST120 and built with the attenuator from Bob.  It is a nice attenuator and I would not hesitate to use it.  Another idea

    You may want to not go with the attenuator on the ST120...

    I like the passive preamp.  I just built a DCB1 Hot Rod from DIY Audio.  It is an Attenuator with a DCB1 Buffer that can drive two outputs.  Unity Gain Buffer 

    I run a Khozmo Attenuator on it.  These are pretty nice and I'd buy it again.  The preamp has no input selector and has 2 outputs as I use a subwoofer on and off at times.

    The DCB1 has a nice transparent passive pre sound that matches up well with the ST120.

    Idea talk here..  Sorry to deviate.  Attenuator was the topic and the attenuator with a buffer stage was my idea of response I guess.  Many different buffers

    Stepped Attenuation P1030576_zps9c8f36c3

    Stepped Attenuation P1030584_zps3239f62c

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