The Dynaco Tube Audio Forum

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


    Completed VTA ST120 2018

    Share
    Kramer
    Kramer

    Posts : 51
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Completed VTA ST120 2018

    Post by Kramer on Mon May 14, 2018 12:27 pm

    Ordered the st120 Kit earlier in the year, has been completed for a few months now and I find myself listening more and more. I got the auto bias board installed recently, highly reccomended to everyone. Figured I would share some photos of the completed, for now, amp.

    It is powering a pair of 1982 Klipschorn loud speakers I was lucky to find a good deal on. I took some time rewiring the drivers and had some new crossovers built.

    Here is the amp with flat black transformers, I used some 3m thermal tape and heatsinks I had around on the back of the power transformer to keep it cooler in the summer.









    The new crossovers that I had built. Deans superX


    Klipschorns with original Crossovers



    Let me know what you guys think, still want to build some larger wood horns to replace the k-400's.
    crkohut
    crkohut

    Posts : 17
    Join date : 2016-11-02
    Age : 57
    Location : Sudbury, Ontario, Canada

    Re: Completed VTA ST120 2018

    Post by crkohut on Thu May 17, 2018 3:51 pm

    Nice!! Both the amp and crossovers!
    avatar
    Surfing1

    Posts : 1
    Join date : 2018-05-25

    Re: Completed VTA ST120 2018

    Post by Surfing1 on Fri May 25, 2018 2:37 am

    Well done, I’m getting ready to build up a 120 myself to drive some BW DM-603’s........should be fun
    Kramer
    Kramer

    Posts : 51
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Re: Completed VTA ST120 2018

    Post by Kramer on Sun Aug 05, 2018 12:02 pm



    Adding the bias-board with fuses and solid state rectifier really cleaned up a bunch of distortion. Made a new set of interconnects using Neotech LEST as signal wire, KLEI absolute harmony plugs, and silver plated copper neutral. They sound very nice.



    http://www.image99.net/blog/files/category-002ahelix-speaker-cable.html
    These cables are all very nice and cheap to build. Greatly improved my listening experience. If your going DIY I highly suggest giving them a shot.
    avatar
    Ed Chambers

    Posts : 9
    Join date : 2017-06-20

    Maintenance?

    Post by Ed Chambers on Mon Jan 14, 2019 7:12 pm

    About 18 months ago I built one of Bob Latino’s VTA 120 amps. I’ve been totally pleased; it has performed flawlessly. I have heard and read recently that tube amps should be taken to an expert every few years or so for maintenance or adjustments. Allegedly, (unlike solid state) their performance degrades as they age. I have checked the bias of the output tubes every six months with minimal adjustment needed. Should I worry that my amp will need maintenance as the hours accumulate? Ed.
    avatar
    Dale Stevens

    Posts : 98
    Join date : 2014-07-06
    Age : 69
    Location : Loris, SC

    Re: Completed VTA ST120 2018

    Post by Dale Stevens on Mon Jan 14, 2019 9:22 pm

    Kramer, what are the two jacks in the middle beside the power cord in the rear? Dale
    bbqjoe
    bbqjoe

    Posts : 98
    Join date : 2018-12-03

    Re: Completed VTA ST120 2018

    Post by bbqjoe on Tue Jan 15, 2019 1:18 am

    Dale Stevens wrote:Kramer, what are the two jacks in the middle beside the power cord in the rear? Dale

    I'm betting a dollar they're additional outputs, maybe for subwoofers?

    I also affixed some heat sink action.
    I only did it on the power transformer though, as I find the other two don't get nearly as warm.
    Kramer
    Kramer

    Posts : 51
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Re: Completed VTA ST120 2018

    Post by Kramer on Tue Jan 15, 2019 12:32 pm

    Dale Stevens wrote:Kramer, what are the two jacks in the middle beside the power cord in the rear? Dale

    They're connections for subwoofers, inside the amp the wires are tightly twisted and go around the bottom of the chassis to the front where they connect to the signal after the attenuator before the CCS board. Wired that way I can adjust the volume of my entire system using the one knob. I don't get any hum from the wire or location of the jacks.
    avatar
    Ed Chambers

    Posts : 9
    Join date : 2017-06-20

    Re: Completed VTA ST120 2018

    Post by Ed Chambers on Tue Jan 15, 2019 2:23 pm

    I apologize for inserting my message above about maintenance. I meant to start a new topic. Ed Chambers
    Kramer
    Kramer

    Posts : 51
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Re: Completed VTA ST120 2018

    Post by Kramer on Tue Jan 15, 2019 2:46 pm

    Ed Chambers wrote:I apologize for inserting my message above about maintenance.   I meant to start a new topic.    Ed Chambers

    Not a problem, the amp shouldn't really need maintenance outside of wiping it down of dust and keeping the bias in check. If you recently built the amp you may want to check over the solder joints after a year just to make sure they all still look solid. Electrolytic capacitors drift out of factory spec over the course of 20 years and should be replaced eventually.
    avatar
    Ed Chambers

    Posts : 9
    Join date : 2017-06-20

    Re: Completed VTA ST120 2018

    Post by Ed Chambers on Tue Jan 15, 2019 6:57 pm

    Thanks Kramer. I suppose modern capacitors are much better than those of the 60s, but don’t last forever. Ed

    Sponsored content

    Re: Completed VTA ST120 2018

    Post by Sponsored content


      Current date/time is Thu Feb 21, 2019 1:07 pm