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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


4 posters

    Power Tower

    CletusB
    CletusB


    Posts : 218
    Join date : 2018-02-11
    Age : 67
    Location : Trinidad & Tobago

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    Post by CletusB Sun Jan 08, 2023 1:55 am

    Well, today I "finished" building this power conditioning and distribution system for my stereo system, repurposing an old Mac Pro case donated by a friend.
    Here are the features:
    1. Main AC Latching Relay  (drops out and locks out on a power outage, manually reset)
    2. GFCI
    3. Z-Wave smart-switch (Alexa voice actuated power control)
    4. RFI filtering
    5. Servo Variac automatic mains voltage regulation (Input swing 85Vac to 170Vac, output front panel adjustable, maintains +/-1V of nominal setting)
    6. Digital AC raw mains display
    7. Digital regulated AC output display
    8. Linear 5V 3A regulated DC power supply (for Raspberry Pi/Allo Boss DAC)
    9. Sequenced power-up (2-stage) for the various stereo component groups
    10. AC voltage ramp up (soft start) for tube amp.
    11. Spike protection MOVs

    Works a peach, what I find superbly impressive is the glaring sonic difference upgrading from a 5V 2.5A switch-mode power supply to a linear 5V 3A regulated power supply for my Raspberry Pi3 / Allo Boss DAC / 2TB music server.

    These cases are really awesome when gutted and repurposed for projects.
    A little neatening up to do with some 3D printed bezels around the front outlets, and that should happen tomorrow. Right now I'm just sitting back with a fine Bourbon and enjoying the music.
    Power Tower Power_11

    aguaazul, Dave_in_Va, mijohn and Dale Stevens like this post

    dalemurray
    dalemurray


    Posts : 59
    Join date : 2018-09-25
    Location : Wheaton Illinois

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    Post by dalemurray Mon Jan 09, 2023 4:27 pm

    No photos of the guts?

    I'm currently using a variac to adjust the power to my ST-120. I regularly get 124-127v at the outlet and the ST-120 does not lit it one bit.

    It would be nice to have something to make that adjustment without my involvement.
    CletusB
    CletusB


    Posts : 218
    Join date : 2018-02-11
    Age : 67
    Location : Trinidad & Tobago

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    Post by CletusB Mon Jan 09, 2023 4:35 pm

    dalemurray wrote:No photos of the guts?

    I'm currently using a variac to adjust the power to my ST-120. I regularly get 124-127v at the outlet and the ST-120 does not lit it one bit.

    It would be nice to have something to make that adjustment without my involvement.

    The Servo Variac I'm using is this unit, it works very well. I replaced the internal trimpot with a panel mounted 10-turn 1K pot so I can easily set the output voltage, right at the front.

    Power Tower Stab112
    Power Tower Stab212
    Power Tower Stab312
    dalemurray
    dalemurray


    Posts : 59
    Join date : 2018-09-25
    Location : Wheaton Illinois

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    Post by dalemurray Mon Jan 09, 2023 4:44 pm

    Thanks.
    It would be nice to have something I do not need to monitor to know I'm only delivering 120v to the ST-120.
    gktamps
    gktamps


    Posts : 34
    Join date : 2017-07-30
    Location : Santa Rosa, CA

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    Post by gktamps Mon Jan 09, 2023 5:43 pm

    @CletusB:

    Nice job on your power conditioning/distributing system! Gut shots would be appreciated.

    The automatic voltage regulator is interesting, but it raises questions.

    1. How quickly does it adjust output voltage when there is a change in line voltage?
    2. What is the line voltage variation that causes it to auto-adjust (e.g. 1, 2, 5v)?
    3. Does it adjust output higher for low line voltage? What happens if there is a short duration brown-out - does it drop output voltage quickly enough to protect the load?
    4. I notice it has no AC chassis ground wire at the entrance to the chassis. Are you concerned about not having any grounds to your loads?

    Thanks!
    CletusB
    CletusB


    Posts : 218
    Join date : 2018-02-11
    Age : 67
    Location : Trinidad & Tobago

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    Post by CletusB Mon Jan 09, 2023 5:49 pm

    dalemurray wrote:Thanks.
    It would be nice to have something I do not need to monitor to know I'm only delivering 120v to the ST-120.

    https://bkmiami.com/product/1000va-automatic-voltage-stabilizer/
    CletusB
    CletusB


    Posts : 218
    Join date : 2018-02-11
    Age : 67
    Location : Trinidad & Tobago

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    Post by CletusB Mon Jan 09, 2023 5:59 pm

    gktamps wrote:@CletusB:

    Nice job on your power conditioning/distributing system! Gut shots would be appreciated.

    The automatic voltage regulator is interesting, but it raises questions.

    1.  How quickly does it adjust output voltage when there is a change in line voltage?  It's slow maybe 1.5sec, but fast enough to keep up with our variation due to loads on the grid from nearby factories.
    2.  What is the line voltage variation that causes it to auto-adjust (e.g. 1, 2, 5v)? - ~2v
    3.  Does it adjust output higher for low line voltage? -  Yes  What happens if there is a short duration brown-out - does it drop output voltage quickly enough to protect the load? - My latched relay will drop out clean
    4.  I notice it has no AC chassis ground wire at the entrance to the chassis. Are you concerned about not having any grounds to your loads? I added a ground, GFCI, EMI Filter Etc.

    Thanks!

    This is where it's at:
    Power Tower Power_12

    Power Tower Power_13

    Power Tower Power_14
    Seamus
    Seamus


    Posts : 38
    Join date : 2020-03-17

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    Post by Seamus Mon Jan 09, 2023 7:37 pm

    dalemurray wrote:
    It would be nice to have something I do not need to monitor to know I'm only delivering 120v to the ST-120.

    Even today many power transformers are spec'd @ 115v.

    Line voltage regulation is supposed to be ±5% in the US. 105% of 115 is 121.

    A bucking transformer with a three way switch can provide Line, Line - x and Line - 2x by using a CT transformer for areas with less than stable power.

    See Bucking (And Boosting) Transformers by Rod Elliott

    This Google Image Search give plenty options from utility to HiFi pretty.
    CletusB
    CletusB


    Posts : 218
    Join date : 2018-02-11
    Age : 67
    Location : Trinidad & Tobago

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    Post by CletusB Mon Jan 09, 2023 7:57 pm

    I'm located in the Caribbean (Trinidad) so I used what I could get my hands on locally for this project.  With our power company anything goes, got a plastics extrusion factory right opposite and other factories nearby. On the grid during the day it could be as low as 105V and at night when the factories are off-line as high as 128V. Not really fast changes or spikes, but rather inconsistent overall, right now for instance it's 118V at the outlet and my Servo Variac is holding nicely at the preset 115V)


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