Vibraplane vs. Minus k for Turntables

The BM-8 gives vertical transmissibility values that are comparable to Halcyonics' benchtop product (the Micro) in the range >=5 Hz. However, the BM-8's horizontal isolation is significantly less effective than the Halcyonics product. As Tbg points out, there are significant differences between the Minus-k technology, which involves a resonant system, and an active electro-mechanical vibration-suppression system, such as that used by Halcyonics, Herzan, etc.

In most cases, laboratories opt for passive isolation over active. There are two main reasons for this: cost and complexity. Active systems have the edge in applications where settling time is critical - basically these systems behave like overdamped oscillators over a wide frequency band. A downside of active systems is that the cost is proportional to the number of degrees of freedom because of the number of transducers required. Also, feedback loops in such systems become complex; for example, small angular displacements of a payload can generate significant horizontal accelerations. Settling time shouldn't be much of an issue in analog playback as long as the resonant frequency of an isolator is well below that of the tonearm/cartridge combination. Also, for most audio applications, vertical isolation is likely to be much more important than horizontal.

Ten months ago I looked into the Vibraplane, Minus K, and the Halcyonics platforms. The Minus K web site, namely the links to the audio applications, prompted me to lean toward Minus K. It is made in America, utilizes only passive components that won't hold you hostage to a foreign manufacturer to keep your device working.

I began my turntable project needing a 350 lb isolation device. It rose up to more than 600 lbs. My Minus 650 BM 1 will be here in about a week. I've never seen one but the help I received from the folks at Minus K prompted me to opt for their product.

The Library of congress uses them along with Simon York tables for archiving. They looked into the Halcyonics units but chose the Minus K. Keep in mind that they don't have acoustic feedback problems at the Library Of Congress, monitoring is probably done with headphones.

All that said, I don't anticipate problems with horizontal oscillations with a 650 lb table spiked to a concrete floor. The Minus K should have vertical isolation equal to the Halcyonics.

Vibraplane, I checked them out when I saw, "the table only," on Audiogon for $2200, that was a year or so ago.

I found the company that manufactures, and private labels the Vibraplane, and received a quote from the industrial distributor of the product, $1500 without the pump. If you feel that a Vibraplane is your ticket, Google it and save some money.

I'll post after I have it up and running and confess if I've spent my money unwisely.

Ken

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Ken,
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Thanks for sharing your thought process in deciding to get the Minus k. I am leaning towards getting the Minus KWS-3M Vibration Isolation Workstation for my upcoming 220 lb Teres Table. The work station sits at 29 inches high and solves my problem of what stand to use with the Minus k.
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Did you ever consider get the work station or have any conversations with the Minus K people about using a workstation? What type of stand are you planning on using under the Minus k ?
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Do know if the Minus k products have any provision for leveling ?
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Regards,
Larry
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Larry,

All the Minus K vibration isolators have leveling feet. I don't know about the work stations as I never considered purchasing one. They are, however, very robust and will no doubt provide you with a stand second to none with regard to rigidity.

I'll be fabricating a welded tubular steel stand for my table. I want the platter chest high for ease of use. I also need the stand to accommodate the vacuum pump for the platter along with 3 Krell KPE Rerference head amps with the separate power supplies, one for each of the 3 arm-cartridge combos on the table. Since the KPE units only have single ended outputs, it would have been necessary for me to locate the table next to the processor - preamp, something I didn't want to do. The turntable will be across the room from the processor so I have a Krell KCT pre amp directly under the KPEs acting as a selector - preamp that will send the signal via balanced lines to the processor. Since the KCT also has CAST outputs I can use them sometime in the future when I upgrade my HTS 7.1 The remote controlled KCT will also enable me to make direct comparisons among the 3 cartridges as they all track the same groove. Lots of stuff on the stand, it's good the room is on a slab.

Good luck with your TERES project.

Ken

Any updates on the Minus K or Halcyonics platforms?.

I have a similar problem to Dgad, except that nothing happens to my needle, just a low frequency feedback sound if I stamp down close to the turntables.

I might go Dgad's much cheaper route, as I would need to go BM-1 size with the Raven AC-3.