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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


    Keyaki ST-120 build

    et1bill
    et1bill

    Posts : 4
    Join date : 2019-06-11

    Keyaki ST-120 build Empty Keyaki ST-120 build

    Post by et1bill on Sun Sep 15, 2019 1:46 am

    Hi all.  I have been reading this forum for a few years now dreaming about building one of Bob's ST-120 kits.  This year I finally made the leap and ordered the ST-120 kit.  I live and work in Japan and thought it only relevant to change out the stainless chassis and construct my own using Japanese Keyaki Wood.  Its a beautiful hardwood only grown and available in Japan.  The top plate of the chassis is 4mm aluminum plate.  Using the original ST-120 stainless chassis as a template, the top was hand-cut using a drill and dremel.

    Thank you Bob for the great support along the way.  It sounds truly amazing....better than my expectations.

    Here are some photos...I would love to hear your thoughts.  

    Note:  the photo of the wiring is not the final product, but gives an idea of how it was constructed.  I can upload more photos later.

    Best regards,
    Bill

    Keyaki ST-120 build Img_0716
    Keyaki ST-120 build Img_0717
    Keyaki ST-120 build Img_0715
    et1bill
    et1bill

    Posts : 4
    Join date : 2019-06-11

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    Post by et1bill on Sun Sep 15, 2019 1:51 am

    Keyaki ST-120 build 58649611
    Keyaki ST-120 build Img_0719
    Keyaki ST-120 build Img_0718
    et1bill
    et1bill

    Posts : 4
    Join date : 2019-06-11

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    Post by et1bill on Sun Sep 15, 2019 2:04 am

    Updated photos of the rear panel and completed wiring.

    Keyaki ST-120 build Img_0810
    Keyaki ST-120 build Img_0811
    Dave_in_Va
    Dave_in_Va

    Posts : 382
    Join date : 2013-04-02

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    Post by Dave_in_Va on Sun Sep 15, 2019 10:18 am

    I think that's probably the prettiest VTA ST 70/120 I've seen posted here.
    Congrats!
    HarryY
    HarryY

    Posts : 46
    Join date : 2019-07-24
    Location : NY

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    Post by HarryY on Mon Sep 16, 2019 1:41 pm

    That's very pretty.
    Mr C
    Mr C

    Posts : 94
    Join date : 2019-07-11
    Age : 65
    Location : Visalia CA.

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    Post by Mr C on Wed Sep 18, 2019 10:44 pm

    Gorgeous! I have the same SS rectifier. I peeled the labels off and polished it. Turned into some real bling.
    cci1492
    cci1492

    Posts : 316
    Join date : 2016-05-09
    Age : 59
    Location : Bergen County NJ

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    Post by cci1492 on Thu Sep 19, 2019 8:50 am

    Looks amazing, nice work! The extra couple of inches makes this model look so much cleaner underneath. I wonder if Bob offered a plate like that as an available option if it would sell. So in Japan it's 100 VAC for Utility voltage, are you boosting it up a bit? Are you in the 50HZ or 60HZ?
    CletusB
    CletusB

    Posts : 201
    Join date : 2018-02-11
    Age : 65
    Location : Trinidad & Tobago

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    Post by CletusB on Thu Sep 19, 2019 9:40 am

    Congratulations on a superb implementation of a wonderful amplifier!
    CletusB
    CletusB

    Posts : 201
    Join date : 2018-02-11
    Age : 65
    Location : Trinidad & Tobago

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    Post by CletusB on Thu Sep 19, 2019 9:54 am

    cci1492 wrote:Looks amazing, nice work! The extra couple of inches makes this model look so much cleaner underneath. I wonder if Bob offered a plate like that as an available option if it would sell. So in Japan it's 100 VAC for Utility voltage, are you boosting it up a bit? Are you in the 50HZ or 60HZ?

    I considered making and offering such an aftermarket plate set for the amp. It was going to be offered in polished Aluminum, Brass or Stainless steel and was proposed to be CNC Waterjet cut from sheet-stock and silk-screen printed in the necessary areas.  The materials and process in itself was very costly, then there would be exorbitant shipping charges from the Caribbean.  So, another nice project was shelved.
    billinrio
    billinrio

    Posts : 104
    Join date : 2018-01-03

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    Post by billinrio on Thu Sep 19, 2019 10:01 am

    Amazing work. Congratulations!
    avatar
    baseballhack

    Posts : 1
    Join date : 2015-11-22

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    Post by baseballhack on Thu Sep 19, 2019 12:06 pm

    That is simply amazing!!!! One question what is the knob on the top of the chassis connected to the RCA jacks on the back with shielded wire for?
    billinrio
    billinrio

    Posts : 104
    Join date : 2018-01-03

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    Post by billinrio on Thu Sep 19, 2019 12:41 pm

    Do you have speakers for that Heresy box? Question


    Last edited by billinrio on Thu Sep 19, 2019 12:42 pm; edited 1 time in total
    pedrocols
    pedrocols

    Posts : 147
    Join date : 2014-11-24
    Location : Western MA

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    Post by pedrocols on Thu Sep 19, 2019 12:41 pm

    baseballhack wrote:That is simply amazing!!!!  One question what is the knob on the top of the chassis connected to the RCA jacks on the back with shielded wire for?
    That is probably a volume control.
    pedrocols
    pedrocols

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    Join date : 2014-11-24
    Location : Western MA

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    Post by pedrocols on Thu Sep 19, 2019 12:42 pm

    Nicely built!
    et1bill
    et1bill

    Posts : 4
    Join date : 2019-06-11

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    Post by et1bill on Sun Sep 22, 2019 1:44 am

    Thanks for all the kind comments on my build. I really enjoyed building it and wanted somewhat of a showpiece in my living room.

    I hand cut the top plate using regular old drill bits, hole bits, and a dremel cutting wheel. If you get up close there are some flaws in my cuts which is why I used a hammered look spray paint to cover up any imperfections. I had thought about drawing this up in CAD to have someone laser cut the plate. Of course that would look really good, but it didn't seem cost effective. Cutting by hand took me 3 days, but was well worth it.

    The knob is Bob's stepped attenuator option. Since the RCA jacks were relocated to the rear of the cabinet, I used shielded microphone cable to protect the line input signal from unwanted EMI to get the attenuator in the front. Bob recommended the shield be grounded to the driver board and it worked magnificently; no noise, dead silent. I use a Audioengine B1 bluetooth receiver as my line in and play most of my music from the Tidal app. If you have not tried this yet, the premium subscription has HiFi and Master quality music which is quite good. This also allows me to change music and adjust volume from my phone or ipad while sitting on the sofa. The attenuator is almost not necessary using this bluetooth setup.

    Voltage in Japan is 100VAC @ 50hz. I have not noticed any degradation with this voltage/freq.

    I am using a set of Heresy III speakers and they sound amazing with this amp. However, my ears prefer a little more bottom end than these speakers produce and considering adding a subwoofer or two to the set up. Right now I a mulling over what sub and how to tap off the line input to connect them. At the moment I do not use a preamp but probably will build one sometime down the line.
    fredeb
    fredeb

    Posts : 6
    Join date : 2017-04-22

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    Post by fredeb on Sun Sep 22, 2019 4:12 am

    Absolutely beautiful build et1bill ! The cutting is hard work when done by hand , not easy to get as neat as you have done .

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