Isolation for phono stage

Discussion in 'Audio Hardware' started by bajaed, Oct 13, 2021.

  1. bajaed

    bajaed Forum Resident Thread Starter

    I have a two piece Icon phono stage that weighs about 9 lbs for the power supply and about 6 for the stage.

    Want to try some isolation to see if it makes a difference but don't want to spend $600-$1,000 right now for the high end stuff.

    How are the Vibrapod products for applications like this? Would it be worth trying s neoprene sheet or some sorbethane pucks?
     
  2. Radley

    Radley Forum Resident

    Location:
    San Francisco
    Back in the disco days, the big clubs would build wooden boxes (without lids) maybe 8 inches deep. They would fill them with sand and then place the lid cut maybe a quarter inch short on each side (the lids were marble). Then place the turntable on the box as if it's floating. You have understand turntable feedback was not acceptable even at 115dB plus. One club even took it a step further, they poured a concrete column just to isolate the turntables (the dj booth was on the top floor so they ended up with a pillar maybe 30-35 feet tall.

    If you do build something like a sandbox, you ain't moving too easily once it's filled...
     
    Lowrider75 and Danmar like this.
  3. Bill Hart

    Bill Hart Forum Resident

    Location:
    Austin
    I did a comparison some years ago (not published) of different devices, both coupling and decoupling under the power supply to my phono stage. Among them, Goldmund cones (which I had from years past), Herbies little rubber like cubes (don't remember the name), Aurios (like a captive roller block), some HRS feet with top plates, Stillpoints SS Ultra (whatever) and the Vibrapod (puck and cone). The Aurios was the most forceful on some transients but sounded strident, the others didn't do much one way or the other, except the Vibrapod puck and cone was pretty good and cheap. I wound up with the Stillpoints which had the clarity of the Aurios without the "bite." So, in my book the Vibrapod did a decent job for very little money. This was on my main system, which is linked to in my profile here.
     
    sturgus, Ingenieur and bajaed like this.
  4. B. Scarpia

    B. Scarpia WatchingYouWatchingMe

    Location:
    WNC
    Back 2000-2010 first sorbathane and then sand boxes were were all over every audio board. I found that those vibrapods sucked the life out of electronics and that sandboxes, I built several, did nothing for electronics and dulled the life out of my turntable, HW-19 MK III at that time. Somewhere I have a picture of a KR Audio Kronzilla, or maybe it was a VA-340 on a sand box.

    Speakers on a suspended floor, though, magic!

    Go over to http://www.percyaudio.com/Catalog.pdf Michael Percy and buy a set of the 75 cent EAR C-1002 feet. I use them under all my low level (phono, line stage) builds. 3 Bucks! Try not to spend another $100 as you scroll down to near the bottom of the page to find them.
     
  5. aunitedlemon

    aunitedlemon Music is medicine, dose often.

    +1 for the Vibrapods & cones. I was surprised when they made a noteworthy difference when I placed them under the butcher block style slab I scrapped together for my turntable. Recommended.
    [​IMG]
     
    gakerty likes this.
  6. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    guys he is asking about isolating a phono stage, not a turntable.
    bajeed,
    we trust you and if you notice a difference with whatever you try please let us know!
     
  7. edd2b

    edd2b Well-Known Member

    Location:
    Southsea UK
    I watched an interesting video about the Naim Audio top of the range phono stage, which features a 10mm thick plate of brass below the main pcb. This plate along with the electrical components are floating inside the outer casing. Mass damping with brass appears to be an increasing feature of high end components. I am working on this aspect in my own turntable experiments. One of my decks has two such weights each side of the main bearing in the sub chassis. :agree:

    Agreed this is not a phono stage, but someone did mention pylons and sand!

    When I first bought my Roksan Xerxes record player 30 years ago I also bought one of their asymmetric tripod stands. This tubular steel item did make the deck prone to footfall disturbance on my suspended wood floor.
    There was a 6-700mm void below the floor joists so being suitably obsessed with hifi tweaking I decided to build a square brick pylon for my record deck below the floor. :uhhuh: This was to be 600mm square cemented house bricks raised to about 65mm below the floor joists. I filled the brick square with sand which was plentiful on the ground below the void. I heaved a 600 sq x 50mm thick concrete paving slab on top of the brickwork. Onto the slab I positioned three mini concrete pylons which I cast inside small flower pots. The mini pylons reached just below the floor boards to match the position of the Roksan tripod legs. Above these positions I cut 50mm holes in the floor boards. I then moulded some resin/plaster mix pucks to raise the pylons to the top of floor board level, but with a 7 or 8mm clearance all round from the edge of the holes in the floor. The idea was for the spiked feet of the Roksan tripod to sink through a layer of carpet to locate onto the plaster pucks below.

    With the carpet relaid the whole construction was invisible, but with the record deck and tripod correctly positioned, it was completely isolated from floor board movement. You could hit the floor with a sledge hammer close to the tripod and the deck playing wouldn’t react in the slightest. :righton: Although I couldn’t say that it improved actual sound quality, it didn’t seem to detract as far as I could tell at that time. The key here is that sand was not the main isolator, but was placed inside to damp down any echo inside the brickwork.

    The only snag came when I eventually wanted to re-arrange the lounge furniture, but I couldn’t easily move the turntable and pylon! :doh: :laugh: The pylon is still there, but the deck HAS moved over time and onto a different symmetrical tripod support system so I would have to reposition the holes in the floor to re-evaluate the benefits today. ;)
     
    Last edited: Oct 13, 2021
  8. patient_ot

    patient_ot Senior Member

    Location:
    USA
    I'm not sure a component like a phono stage necessarily needs isolation. Then again I don't run a tube phono stage. At least the vibrapods are fairly affordable, and even if they do nothing you can probably repurpose them for some other task.

    I would say for a phono stage equipment placement (away from sources of potential interference) is probably more important than putting an isolation device under the casework.

    Turntables are a totally different story obviously...
     
    aunitedlemon likes this.
  9. bajaed

    bajaed Forum Resident Thread Starter

    I went ahead and ordered some vibrapods for the 2 piece phono stage and my Rogue amp. For about $60 for 12, it's not an expensive experiment.
     
    aunitedlemon likes this.
  10. edd2b

    edd2b Well-Known Member

    Location:
    Southsea UK
    I got called away mid post before I could finish here, but......bajaed you could try to obtain a big enough thick solid brass plate, place isolating feet at each corner then just sit your phono stage on top. I would place the PS on a separate support. :shh:
     
  11. Ingenieur

    Ingenieur Going with the flow...

    Location:
    PA
    If you use these (or similar concept) make sure you get the right ones for the weight.

    also find the center of mass, or balance point
    Put each pod the same distance from it

    Assuming 4 pods
    for 6 pounds you want 6/4 = 1.5 lb each
    the 50 durometer is rated 1 to 1.8

    9 lb, 2.25 lb each, the 70
    1.8 to 3.6

    0.75" Dia Sorbothane Hemisphere Rubber Bumper Non-Skid Feet with Adhesive
     
    bajaed likes this.
  12. bajaed

    bajaed Forum Resident Thread Starter

    Thanks. I went over the weight of each component with the guy I ordered them from and he matched the right vibrapods to the component. The Rogue has more of it's weight in the back so he adjusted the type of pods for that as well.
    I'll try these alone then maybe add the cones later to see if they make a difference.
     
    Ingenieur likes this.
  13. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    i like that they supply a percentage of compression as a means to make sure they are being effective.
    What is the problem statement for the application?
    What are the design goals?
    What testing validates the design?
     
    Ingenieur likes this.
  14. Bill Hart

    Bill Hart Forum Resident

    Location:
    Austin
    I normally don't like sorbothane directly under a component, but when used as part of a larger set up, holding a rack or platform, it can isolate without sounding too "damped." Application may be more tricky though.
    I spoke to Sorbothane and got the correct durometer for my upstairs clothes washing machine (a/k/a "washing machine"). It's fun to watch it vibrate without heavy oscillations through the floor. Figure that's a 400lb load and I think you need to hit the sweet spot for whatever overall load you are damping to get the most out of them.
    Even my Minus K uses Sorbothane strips to connect the top of the internal (swaying and spring reinforced) mechanism to the top plate of the unit itself.
     
  15. brockgaw

    brockgaw Forum Resident

    I found that Vibrapods+cones , when installed correctly (face up or down), would allow components to slide around on the steel balls. Used them with remote operated devices and not CDPs or turntables. Keep in mind that my components sit on hardwood shelving.
     

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