- June 2007
Holy Earthquake, Batman!
K BM-8 Isolation Platform.
By Jeff Dorgay
Aside from friends that have had too much to drink vibration
is your turntable's biggest enemy. The more you can isolate
your table from your environment the more musical detail your
analog rig will be able to resolve.
If you've been in the audio game for sometime now, you know
how many different solutions there are available. I've tried
a few of them myself, with mixed results. I seem to recall
analog maven Michael Fremer reviewing a cool active vibration
base that they use for sensitive laboratory instruments and
was really excited about it until I saw the price tag-about
$8500 bucks (if memory serves me correctly!)
Most of Minus K's customers are scientists. These typically
get used in a laboratory underneath scanning microscopes and
other precision instruments. The resonant frequency of the platform
|Ouch! At that point in time I was listening
to a Rega P25, so I filed that into the more-expensive-
tweak-than-the-gear file and forgot about it, until I
stumbled on to the Minus-K website. At $2795, this is
still not a pocket change item, but for those of you looking
to wring the last bit of performance out of your analog
rig, this may be just what you are after. At about the
price of a pair of mega interconnect cables the BM-8's
price tag is palatable.
The cool thing about the Minus K platform is that it is
a passive device, so that means no vacuum pump and none
of the extra noise that goes with a pump or the complexity
that it brings to the table. After all, the quieter and
more resolving your system gets, the last thing you want
is a pump in the background chugging away!!
Unpack and Adjust
The BM-8 is 18" wide by 20" deep and 4.6" high
so make sure that you have enough room on your shelf or rack,
as well as the ability to support the 35 pounds of the platform
in addition to your turntable. There are three models, to accommodate
equipment from 10-105 pounds. I would suggest to get maximum
performance, if you can match the model you need so that your
table is in the middle to high end of the weight range.
Setup is a breeze, unpack the BM-8, put your turntable on
the platform and unscrew the four red anodized collars. Next,
make sure the vertical position indicator is as close to the
middle of the range as you can get it. You can adjust this
with the crank adjustment that is immediately to the left
of the indicator. I found you can be a little off with this,
but the closer you can get to the middle, the more effective
the BM-8 will be.
Once you have completed this part, nailing the sweet spot
for the vertical softness adjustment will take a bit more
time, but is somewhat of an adjust to taste setting. This
affects the bounciness of the springs in the platform and
again after a lot of listening noticed that by going from
loose to tight will affect the overall sound. As you might
expect going a bit tighter consequently tightens up the sound,
and going a bit more springy gives the overall presentation
a bit warmer feel.
Even if you are a bit off the mark, you should notice a good
degree of improvement and I felt that the more you listen
and make fine adjustments, you will notice a sweet spot where
you are getting the maximum isolation without the presentation
getting too warm or bouncy. Almost like setting VTA, there
is that perfect spot lurking out there!
To be really fair to the BM-8, I used it with six different
turntables: The SME 10, the AVID Volvere, Oracle Delphi V,
Rega P9, VPI Scoutmaster and my favorite budget table, the
SOTA Comet. I wanted to make sure what I heard initially was
happening in a repeatable fashion as well as to see where
the threshold for increased resolution would fall off.
The good news is that the BM-8 worked very well on every
table I put it under. The bad news is that it's 2800 bucks.
However, to put things in perspective, I would spend this
amount of money on one of these before I bought an equally
expensive pair of interconnects or power cord.
Let's start at the bottom and work our
I noticed two major areas of improvement to the analog presentation
with the BM-8 in my system: Tighter, more tuneful bass and
better resolution of low-level detail. Just to make sure I
wasn't going mad, I picked out a wide range of albums to listen
to right in a row and then put the base in and listened again.
I used a lot of standards that perhaps are not the audiophile
standards, but records that I am infinitely familiar with.
The first record I put on was Donald
Fagen's Morph the Cat, because the title track
has fairly loose, whumpy bass. Another favorite in that
department is Thomas Dolby's Aliens Ate My Buick.
Immediately, I noticed the bass tighten up a bit and
it seemed to have a bit more texture. As I spent some
time with some records with acoustic bass, I was definitely
experiencing more texture.
I also noticed a substantial decrease in woofer movement
on my REL subwoofer, I could even leave the dust cover
up on my P9, where in the past that was begging that
devil rumble to sneak in at moderate levels.
Though this was great, the biggest improvement was the in
the area of low-level detail retrieval. I kind of freaked
out from the minute I started listening and the more time
I spent with the BM-8, the more I found myself pulled into
the music. Listening to all of my Doors albums (the DCC versions)
I really enjoyed how much more air was in the presentation;
there was so much detail lurking in these already great LP's!
Again, this was not that subtle of an improvement. I could
really hear my system take a big jump in low level resolution.
This was one of those improvements to your system that makes
you go right to a lot of your favorite records just to get
a quick read on the sound!
Variation on the theme
While vibration is the enemy of all things electronic, I did
try the BM-8 with some electronics as well just to conduct
a thorough investigation.
I got the most improvement with tube electronics first, CD
players second and power amplifiers last. However, I did not
feel that this platform made enough of a difference on any
of my electronics to justify a few more of these for my components
too. Unless you have a really disproportionate amount of disposable
income, I'd just think turntable on this one.
A significant improvement
The BM-8 is not a budget audiophile tweek. But in the world
of 1200 dollar coat racks and little blocks of wood with metal
cups that cost 800 bucks a throw, this is at least a solid
product with some science behind it, that will truly increase
the resolution of your system.
I highly recommend the BM-8 with only one reservation; I
would make this device the icing on the cake of a very good
system. If you have everything else in your system the way
you want it (including room treatments) and are just aching
for a little more performance, I think you will be pleased
with this upgrade. It's not going to turn a budget table into
a mega analog rig, but it will allow you to see further in
to the presentation on a first rate system. I'm kind of thinking
I need one...
version of this article
The Minus K BM-8 isolation platform
Minus K Technology
460 S. Hindry Ave. Unit C
Inglewood, CA 90301