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    My VTA ST-120 is on the way .....and other loose ramblings of an old fart

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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Tue Apr 03, 2018 8:45 pm

    Daughter bought a used car and it came with "music"  .....had to troubleshoot that system yesterday and had to endure the gross insult and assault on my ears!
    2x 15" sub-woofers occupy the trunk and blast their way through the backrest of the rear seat. A pair of 6x9" mid-range speakers with coaxial tweeters and a couple dreadful piezos. This thing is driven by a huge and I do mean HUGE power-amp that sports a chrome skull whose eyes light-up red as power indicators. A 4-way electronic crossover manages the splits into that gynormous amp.
    I managed to sort out the initial problem (a disconnected interconnect), then I decided to tweak the x-over some (found every knob turned to the max) and tossed those piezos as far as I could throw.
    Got it to "sound much better" (not sure if that's really a possibility) .....but man, I still consider that rig an insult and rape of my auditory passages.
    But, at the end of the day, she's happy that dad fixed her "music" and I scored a bunch of points! Laughing
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Fri Apr 06, 2018 3:08 pm

    Just got myself a MiniDSP UMIK-1 and Room EQ Wizard.
    So, been playing with it and looking at the response graphs from my three primary listening positions (Studio sweetspot, Dining Table and Living Room):
    Not that I'm really looking to adjust anything at this point, since I really like the sound of it all as is (I just like to be able to quantify stuff).




    The Impedance Plots look like this:
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Fri Apr 06, 2018 5:15 pm

    .....And can arrive at this with a couple tweaks to the passive crossover .....sonically, not sure yet which I prefer (need to walk away from it for a bit)

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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Fri Apr 06, 2018 9:19 pm

    IMHO Best sonic compromise, physically tweaking the passive crossover (instrumentation vs listening) at this time:

    Dogstar

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by Dogstar on Sat Apr 07, 2018 8:57 am

    I'm pretty sure I've heard or read that many tubophiles are of the belief that adding anything solid state into the path of the signal from the source to the speaker detracts from the sonic pleasures of tube sound ...whether it be the preamp or any type of equalization or crossover. Now I've considered using a mini DSP to bi-amp my setup...but I wasn't going to let anyone here know... :-)
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sat Apr 07, 2018 3:46 pm

    Passive crossover ...tweak by changing physical components (inductors, capacitors, resistors, etc.)
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    deepee99

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by deepee99 on Sat Apr 07, 2018 8:23 pm

    CletusB wrote:Passive crossover ...tweak by changing physical components (inductors, capacitors, resistors, etc.)
    Yep. It's work but worth it.
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sat Apr 07, 2018 9:39 pm

    deepee99 wrote:
    CletusB wrote:Passive crossover ...tweak by changing physical components (inductors, capacitors, resistors, etc.)
    Yep. It's work but worth it.
    Hell yeah!! cheers
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sun Apr 08, 2018 7:58 am



    Last edited by CletusB on Sun Apr 08, 2018 8:24 am; edited 1 time in total
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sun Apr 08, 2018 8:20 am

    Got up early and tackled rebuilding my Source Selector / Stepped-Attenuator Box "Zero-Preamp" this morning to allow for more stereo source inputs Very Happy

    Switch Positions:  
    1   BLANK (clamps to ground, used as a "mute")
    2   CD Transport (my trusty Pioneer PD-4500)
    3   Rpi DAC / Server
    4   Feed from the Studio Mixing Console
    5   AUX 1 (available)
    6   AUX 2 (input jacks located on front panel, used for quick input access, eg. hooking-up the signal generator or Smartphone)

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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sun Apr 08, 2018 8:34 am

    Here's a shot of one of my "temporary" Passive Crossovers, it's been "temporary" for nearly 20-years now and has been tweaked and tweaked over the years!  ......but it just sounds so damned good! What a Face
    One day it may get rebuilt with some really high quality components (yeah right!) Laughing

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    corndog71

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by corndog71 on Sun Apr 08, 2018 9:07 pm

    Swapping those iron core chokes with air core and electrolytic caps with film would make that sound better.  Although they may not fit in that box.


    Last edited by corndog71 on Sun Apr 08, 2018 10:17 pm; edited 1 time in total
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sun Apr 08, 2018 9:43 pm

    corndog71 wrote:Swapping those iron core chokes with air core and electrolytic caps with film would make that sound better.  Although they may not fit in. that box.
    Oh yeah, I'm with you on that for sure, and that's been the plan. But it gets kinda pricey to do it right. Will get around to it later this year, when I can free-up some budget again.
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    sKiZo

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by sKiZo on Sun Apr 08, 2018 9:55 pm

    Dogstar wrote:I'm pretty sure I've heard or read that many tubophiles are of the belief that adding anything solid state into the path of the signal from the source to the speaker detracts from the sonic pleasures of tube sound ...whether it be the preamp or any type of equalization or crossover. Now I've considered using a mini DSP to bi-amp my setup...but I wasn't going to let anyone here know... :-)

    I guess I'm safe then - I went with a software approach here, adjusting the digital output of my HTPC before it even gets out of the computer. Cool

    Tried the MiniDSP, but it was a PITA to program. It would also lose the programming every now and then. Grrrrr ... Then went with using the "convolution kernel" built into jRiver Media Center and the same curve I'd been using for the MiniDSP - Room EQ Wizard can export that directly to jRiver. Excellent results, easily as good as the MiniDSP,  and as easy as pointing the software to the curve file on the hard drive. Set it all up a couple years back with no further tweaks required.

    PS - I've ripped my collection (vinyl and all) to digital, but I can use the original source if I'm feeling ambitious, using a parametric EQ. Granted, nowhere near as accurate as what I get from the software solution, but I was able to target the big lumps using the REW printout for satisfactory playback. I just got to remember to turn the PEQ on when needed - and turn it off when not. That can get interesting as most of my problems are at the bottom end, and I end up with double or nothing with a chance of serious boom if I'm not careful.

    GP49

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by GP49 on Sun Apr 08, 2018 10:40 pm

    My subwoofers and their associated amplifiers are solid state, as is the branch of an electronic crossover to feed them. The path to the main speakers is all-tube.

    The CD, cassette and tuner sources are transistor; the CD and cassette just about have to be,
    and FM reception from stations I would listen to is too weak here for any tube tuner I've tried,
    though a Sherwood S-3000 II was good in mono, and I have not tried a Marantz 10B.
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Mon Apr 09, 2018 10:17 pm

    Decided to order a set of Dayton Polyprops to replace the electrolytics in the x-overs ....actually we're trying to fix something that ain't broke!  cause it sounds damned good as is! Shocked

    Will start there, the iron core chokes are operating well below saturation at my audition levels and I very much like the way the system sounds now anyways. But I can certainly justify changing out those old electrolytics now. Even playing for extended periods and loud levels for a recent family gathering here, the old iron-cores held their own very well Very Happy
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sat Apr 14, 2018 8:49 am

    Time to make the music system "Smart"!
    February last year (while recovering from spine surgery  ....I just can't stay still for long), I made the entire house and workshop "Smart", using Samsung's SmartThings and Alexa.  Ever since, we voice and smartphone control the entire house. There's also time based and geofenced automated house configurations for when we've left or returning to the house, along with motion-sensed lighting for certain rooms, and other pre-programmed automated response routines for lighting, security and energy management.
    We have not touched a wall-switch in over a year, seriously!   ....mostly just shout-outs to Alexa when we want something on or off or the TV channel changed!  Very Happy 
    Yesterday, I realized that I went off on a service call and forgot the music-system including the ST-120 on (not good!).
    So, the new project on the white-board, is to get the music-system on the home automation network. I am building a Z-wave relay box that will accomplish this and also give me a nice Volts, Current, Power display, along with a latch-out should power fail (manual reset mandatory).
    Will post some pics here in the upcoming days, although it's really simple.
    Here are some key components:
    https://www.amazon.com/gp/product/B000XU5MEG/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

    https://www.amazon.com/gp/product/B0035YRCR2/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

    https://www.amazon.com/gp/product/B004YW5CWQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1    ---  Not needed - The Smart-Switch has relay switching good to 15A

    https://www.amazon.com/gp/product/B06XRW1ZHK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

    https://www.mouser.com/ProductDetail/TE-Connectivity-Corcom/10VS1?qs=TukW%2FaGuJ4Oeuy%252bp7I%252bJDg%3D%3D

    ...and found these enclosures locally very inexpensive (US$13.00)
    https://articulo.mercadolibre.com.ar/MLA-700581013-caja-de-pase-estanca-ip65-roker-pvc-pr100650-165x165x50mm-_JM

    ....built similar relay boxes for AC control here, so I know they work a peach, but the one for the music-center will be a little more "elegant" Laughing


    Last edited by CletusB on Tue Apr 24, 2018 9:02 am; edited 3 times in total
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Sun Apr 22, 2018 11:31 am

    Now there's been quite a bit of run-time on the system, here's the max logged pwr transformer temp:

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    peterh

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by peterh on Sun Apr 22, 2018 11:49 am

    Cool !
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Mon Apr 23, 2018 2:54 pm

    No more rushing out and forgetting the music system on.  My Smart-Switch, Power Monitor and RFI Filter.
    SmartThings / Alexa has control, I can power On/Off via Local SW, Voice Command, SmartPhone and also powers-down by Geofencing when I am more than 2km away (smart-phone GPS).

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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Mon Apr 23, 2018 3:09 pm

    Bunch of audio caps and XT-60 connectors just came in for upgrading my Linkwitz-Riley Passive Crossover Networks. Making the caps plug-in so I can tweak and roll components.
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Mon Apr 23, 2018 8:18 pm




    Done, and I can detect no sonic difference to the old electrolytics. Glad I did it nonetheless, they'll last and I won't have to worry about them.  Will sweep the frequencies tomorrow and see what the spec analyzer has to say compared to the last sweep  .........yes, I know it's a mess! What a Face
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    corndog71

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by corndog71 on Mon Apr 23, 2018 8:51 pm

    Do you have a schematic of the crossover? Those caps may not make as much of a difference if they’re not in the direct signal path. Plus I’ve used those Dayton caps and while they get the job done, there are more transparent caps out there. Consider Sonicaps in the signal path for a little more air and detail.
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    CletusB

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by CletusB on Mon Apr 23, 2018 9:09 pm

    Well, they're just typical garden variety, Linkwitz-Riley networks, no specific schematic handy.
    A little (marginally) tighter bass response maybe? ...but that's soooo purely subjective, and could be just my mood now or the color of the shirt I'm wearing.
    I love the sound of my system. Thanks, I'm good for now and not going to go chasing something these old 63-year ears can't respond to. Very Happy
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    jfine

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    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

    Post by jfine on Tue Apr 24, 2018 1:03 am

    CletusB wrote:BTW folks, here's an excellent and inexpensive piece of test instrument kit for the lab.

    And here I thought capacitor ESR testers were spendy. Hmmm....

    Sponsored content

    Re: My VTA ST-120 is on the way .....and other loose ramblings of an old fart

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