A New Year's tweak - gel isolation platform
I was all worked up over how to isolate my Rega Planar 3 (with upgraded motor) from vibrations.
I had tried all sorts of footers under a one-inch (2.5cm) thick acrylic platform - cork, earthquake pads, mass-loaded vinyl, soft foam, pumice blocks, steel cap nuts, steel spikes and brass footers.
Each material had its own sonic signature - with soft cork the bass sounded fat and flabby while with hard pumice blocks the treble sounded bright and brittle. The tonal balance changed with the footers used - with some materials it was bassy, with others it was bright.
I needed something that would sound neutral - I needed something that was neither too hard nor too soft, neither too springy nor too pliable.
My neurotic mind was working at a very fiery pace as I knew I was hot on the trail of something feasible. Suddenly I realised I needed something that was neither solid nor liquid and very fluidly my thoughts jelled into one eureka moment - I needed gel.
So I ended up in a pharmacy and spotted some Hot/Cold Packs. These are used to reduce body temperature when you have a high fever or to soothe joint pains and muscle aches. You can put the Hot/Cold Pack in the freezer to turn it into a cold pack or heat it in a microwave oven to turn it into a hot pack. When it is frozen, it turns quite hard and softens as it warms up.
At room temperature its viscosity is like that of thick syrup. Drop the pack and it just goes ‘splat’ - it does not bounce at all. In other words, any impact or vibration will be fully absorbed by the gel.
I bought two packs - they are larger than normal and measure 31cm (12.2") by 15cm (5.9") by about 2cm (0.7") thick and can be used as hot/cold pillows. Each cost about RM30.
Back home, I placed the two Hot/Cold Packs next to each other on an Ikea Lack table and put the acrylic platform on top of them and applied some pressure on it to ensure that the platform was level. I used a spirit level to adjust the platform to be as level as possible.
|The Hot/Cold gel packs to be used |
as 'footers' for the isolation platform.
|The acrylic platform was placed on top of the Hot/Cold gel packs.|
|The Rega Planar 3 on the gel isolation platform.|
Then I placed the Rega Planar 3 on the isolation platform with gel ‘footers’ and spun some vinyl. The Planar 3 was fitted with Michael Lim’s acrylic platter and the RB300 tonearm had his end stub with underslung counterweight (which improves sound quality tremendously) and a Rega Exact mm cartridge. Phono preamp was the Creek OBH-15.
I was pleasantly shocked by the sound quality - the bass went deep and tight, the mids were clear and the treble shimmered smoothly. The tonal balance was just right.
The gel isolation platform absorbed vibrations so well that the cartridge was able to extract lots of musical information from the grooves. I heard plenty of details, but the surface noise remained very low.
I played one of the few audiophile LPs that I own - John Coltrane’s Lush Life in 180gm vinyl - and was transported back to the venue where the recordings were made in 1957-58. It was such a sonic treat.
You can make your own gel isolation platform for a few hundred Ringgit - two Hot/Cold gel packs cost around RM60 and the acrylic platform is available for about RM475 from ATS Rack in Amcorp Mall in Petaling Jaya. ATS Rack’s vinyl platform measures 48.2cm (19”) X 38.1cm (15”). A cheaper alternative is to get the acrylic platform from Michael Lim (http://www.lpturntables.blogspot.com/) who sells it at around RM300, but his is smaller at 45cm (17.75") X 36.2cm (14.25") which is the same size as the Rega turntable.
The gel isolation platform works very well for turntables without spring suspension like the Rega. I have not been able to confirm if it works for spring-suspended turntables like the Linn or Oracle. If I have the chance to borrow a spring-suspended turntable to test, I will post the results.
In the meantime I will listen to a few more LPs...
Related posts: http://hi-fi-avenue.blogspot.com/2010/10/rm12-tweak.html