Minus K Isolation Platform BM-8

[XV-1]

Wow, I had no idea it is so sensitive. I have not heard this kind of report before about the Minus K. How does one put a level on the turntable platter to confirm that the platter is level? I imagine that the weight of the level itself will throw it all off unless you find the absolute center of the distributed weight and place the level in that exact spot. It sounds too finicky to be a practical solution to turntable isolation.

Actually you have Peter. Pcosta said as much after he sold his a couple of pages back. Spirit aka Marc said as much when he did a quick demo.

Makes sense if you have paid $$ for something like this, you will go to additional lengths to make it work and say it sounds great -- which it does. But I am not sure the finicky nature will be worth it - in my case anyway.

Getting the platter level is quite easy and I use a spirit level over the centre spindle - after the table wobbles around, its seems to go back to the original position - at least horizontally.

I am going to stick with this for a month before returning it to my mate. This should see if I am exaggerating its quirky day to day usability. Sonically its very good.


One thing that is quite cool. When you start the SP10 mk3 platter, the table floats/pulls quickly to the right and back due to the high torque of the famous mk3 motor. same when it stops on a dime - the entire table floats left and forward before coming to a stop.

 

[PeterA]

Actually you have Peter. Pcosta said as much after he sold his a couple of pages back. Spirit aka Marc said as much when he did a quick demo.

What I did not ever read before is that it moves or finds a different level height with just different weight LPs. I know it is finicky, but to move up and down with only 20g is quite something. Perhaps others reported that before, but I did not recall it. Now I am wondering if it is effected by the up/down movement of a cartridge when it tracks a warped LP or an off center spindle hole. Does one need to rebalance it when changing cartridges? I guess one must let it settle down after the SP 10 start up before dropping down the needle.

 

[XV-1]

What I did not ever read before is that it moves or finds a different level height with just different weight LPs. I know it is finicky, but to move up and down with only 20g is quite something. Perhaps others reported that before, but I did not recall it. Now I am wondering if it is effected by the up/down movement of a cartridge when it tracks a warped LP or an off center spindle hole. Does one need to rebalance it when changing cartridges? I guess one must let it settle down after the SP 10 start up before dropping down the needle.

After start up it takes around 2 - 2.5 seconds to stop - so its very quick. I don't really have warped LP's - so can't comment. I don't think it would move as its only 2gm's at the surface of the LP.

Yea, I am really surprised the entire structure goes up or down when going from 120gm down to 90gm or up to 180gm. Another reason why I hate 180gm vinyl

Edit - Dre J said its normal for the entire structure to move up or down depending on the weight of an LP - in some ways it lets you know the unit is working and is very sensitive when isolating vibration

 

[spiritofmusic]

I maintain the MK didn't/couldn't wk for me
My tt was only half the optimal load
Any ballast plate I used to take things up to the limit coloured the sound, three changes never provided anything satisfactory
My tt/arm like many others is loaded asymmetrically, I could never quite optimise things
Which really didn't help my air arm either
A failure in my case
The only positive is the price

 

[pcosta]

It is possible to make the unit less sensitive to movement by adding stiffness with the vertical stiffness adjusting screw. But then you loose the lower Hz isolation. The Minus K website has a picture of my old Minus K BM-8 unit that was custom ordered for High Water Sound. I ended up with it and thought is worked well because the top plate was much bigger than normal. I recently had a BM-1 and didn't like the way it behaved, I perhaps didn't have it loaded to the max, I lost patience with it and sold it for what I paid. I like to play with with different tonearms and resetting the platform would be a real pain.
I truthfully wasn't blown away by what it supposed to offer.

 

[spiritofmusic]

I would have loved to have settled on the MK.
It's multiples of cost less than Stacore and active.
But it's fussiness of use and all round impracticality meant that, at least for tt use, it ruled itself out.
Stacore ended up the winner in my trial v MK and active Kuraka, and by a wide margin, and is now invaluable in my system.
But congrats to anyone who gets the best out of the MK, it's a great price in this limited field.

 

[Mike Lavigne]

I would have loved to have settled on the MK.
It's multiples of cost less than Stacore and active.
But it's fussiness of use and all round impracticality meant that, at least for tt use, it ruled itself out.
Stacore ended up the winner in my trial v MK and active Kuraka, and by a wide margin, and is now invaluable in my system.
But congrats to anyone who gets the best out of the MK, it's a great price in this limited field.

actually it's not active. since it cannot stop and start based on sensing resonance to attenuate. so it's not stiff. in fact, it's the ultimate floater and passive, which why it's so sensitive to exact weight.

 

[spiritofmusic]

Sure Mike.
We now have 4 options.
passive sprung Minus K at entry level
passive hydraulic/CLD hybrid Stacore/Basic/Basic +/Advanced
active Herzan/Accurion/Kuraka
active/passive CLD Taiko Tana.

 

[RedSectorA]

I ve owned the Minus K with three turntables--my observations are:

A: You MUST get the operating weight as close as possible to the total bearing figure of your MK platform--ie say 100 Ib version --then 90Ib up will perform best.

B: I would not put the TT direct on the MK metal top--I found a slab of Silestone( NOT Slate) or Air dried Maple worked superior to the bare MK surface placement.

C:The MK --as voiced in past threads can be quirky to set in a Balanced position --due to the semi central placement of the spring loaded point--but can be smoothed with patience and diligent adjustment.

D:I tried the Stillpoints as pictured and found them to add an"aggressive metallic" aspect to the sonics that I found troublesome--so I moved them on.

Re the footer Q'--well you can pick ya Poison--we all hear different and favour points of playback in various subjectives--- I do suggest trial carefully --as I found with the Stillpoints my original impression was

hey!-- these are detailed clean precise/etc/etc--but they fatigued and became wearisome in short period--take care here.

So what did I use as well under the TT's?--Marigo Feet-VGood, Combak T-210's--VGood,SMook GDFeet--excellent-- of course you may go "au naturale"and use the supplied ones.

All TTs I've had here were non suspended.

All in all the MK's are excellent units--that have been "seconded" for TT isolation Audio use--they originally came to the fore when Library of Congress selected them

for use under Simon Yorke's modified S10's.

Personal observations only and agree YVMV

Good Listening,

BruceD

I would add Ikea's APTITLIG bamboo cutting boards for resonance control. I've used 2 boards that I cut and glued to size in between my bm-8 and tt, works like a charm and relatively expensive.

Dan

 

[rsorren1]

All, I’m writing to update you on my recent experience with Minus-K BM-1 work station. First, before buying, I read everyone’s comments and experiences here. I really appreciate everyone who commented based on their first-hand experience with the device. I have a terrible problem in my dedicated room with footfalls since the room is located above our garage and frankly, I screwed up when we built the house by not having a more substantive floor. I tried a custom made wall shelf for several months that did not work. With the Sperling L3 TT in use you could not walk around the room at all for fear of knocking the cartridge out of the groove. After reading what everyone wrote and speaking to a good friend of mine who has a BM-8 under his turntable, I decided to call Minus-K and discuss the questions that have been raised. They were fabulous. I sent them pictures of my turntable and spent a total of three hours on phone calls with design engineers and technical sales support before purchasing. They were very clear that I should not put their units on my wall shelf or on any other audio rack. They told me a sturdy table would do but I decided to go for the full workstation to give me the best possible isolation. From notes on this thread I was aware that the unit “rings like a bell” so we factored in the weight of two HRS damping plates that appear to have solved that problem. The working area of the BM-1 is large enough to hold the Sperling so that’s what I ordered. Here is a picture of the final set-up:

As several of you have stated above, the BM-1 works as advertised. It does have some of the “quirks” noted here: when I change albums I have to quickly adjust the crank in front to get the load centered but that takes 5 seconds. When the turntable motor starts, it shakes the table so you have to steady it before you drop the needle. Another 5 seconds. I’m hearing a whole new and improved presentation from the turntable now that it is isolated from the room: much less mid-range coloration, better image clarity, better bass definition. It seems to be working out for me. Again I want to thank all of you for sharing so that I could make an informed decision. Your feedback on this product was very accurate, helpful and allowed me to proceed with eyes open. Thanks.

 

[spiritofmusic]

Great news. I alas was one of those who could never sort out the install so trial was kind of invalidated.
Only the BM-8 is sold in the UK, the 48kg optimal loading version.
So I remained somewhat hampered by positioning of the tt on the platform re centre of gravity. And whatever 18kg loading plate I used to take my 30kg tt weight up to the 48kg required was always audible as a hard ringing.
So, is your Sperling close to the loading limit of the BM-1, and how did you settle on “inaudible” loading plates?
Congrats again on solving the issue.

 

[rsorren1]

Great news. I alas was one of those who could never sort out the install so trial was kind of invalidated.
Only the BM-8 is sold in the UK, the 48kg optimal loading version.
So I remained somewhat hampered by positioning of the tt on the platform re centre of gravity. And whatever 18kg loading plate I used to take my 30kg tt weight up to the 48kg required was always audible as a hard ringing.
So, is your Sperling close to the loading limit of the BM-1, and how did you settle on “inaudible” loading plates?
Congrats again on solving the issue.

Thanks. My TT load with the HRS damping plates are about 90% of the max loading weight. Interestingly when I spoke to the Minus-K engineers, they told me that the VERTICAL performance of the BM-1 is not load dependent. It’s 0.5hz. It’s the HORIZONTAL performance that is dependent on load and to get 0.5hz in the HORIZONTAL you need to be as close to max load as possible. They said that footfalls occur in the vertical and unless the room or house was going to shake side-to-side I should be ok. We still figured out load with TT, motor, motor control unit, and HRS Damping plates and got as close as possible. When I read comments about ringing, I asked about putting damping plates on the BM-1 top plate and they thought that would work well. They emphasized to NOT put anything under the components that was a vibration damping device in series with their table isolation (rubber feet, rubber mat, etc.) since that would affect the performance of the BM-1. It appears to have done the trick.

 

[spiritofmusic]

Well, only needing 10% more to reach optimal is a whole lot less challenging than the nr 40% I had to find.