Does any Audiogon member have a Holbo air-bearing turntable?

For what little it is worth, I am not a fan of MDF in speaker cabinets or in shelving or probably in plinths. Based on personal listening experiences but not done in a "scientific" way.

@lewm 

I am not a fan of MDF

Yes, I was aware of that from previous posts!  However, I think it is better than the chipboard that SME used for my Garrard 301 plinth and motor-board.

Most likely there would be little demand for a cartridge body made of MDF rather than rosewood or other exotics, but would HDF (High Density Fibre-board) be attractive?  Or some other engineered wood like Panzerholz?

Natural wood is a good resonator which is why so many musical instruments and concert halls are made from it.  But resonance is the last thing most designers want from speaker cabinets, and many use MDF because of its inherent vibration damping properties, as well as consistency.

I am not sure whether audiophiles are attracted to turntables and vinyl because of induced vibrations, or despite them!  For now, I am trying to reduce them.

The one-piece motor-board / plinth of the Holbo is made from MDF and I think the Japanese DC motor is directly attached to it.  The plinth probably weighs in at 4.5-kgs so will be a good sink for any vibrations from the motor.  In use, the platter is isolated from the plinth and motor by air and the belt drive, which looks very flimsy to my Garrard eyes.  Nevertheless it seems to spin the 5-kg platter to 33-rpm in about 4 seconds, and brings it to a stop in about the same time.  Without the belt, the stop time is rumoured to be about three minutes.

Unlike the Garrard or say a Wilson Benesch turntable, the Holbo seems to me like a black box full of trade secrets.  Certainly, there are no exploded drawings or white papers!

My eight Sorbothane hemispheres arrived a couple of days ago.  Turns out they do have the 3M self-adhesive bottoms that the local office knew nothing about.  They are very black, very squishy and very,very sticky.  If you found them washed up on a seashore, you’d throw them back in the drink.

There was an option for water resistant ones coated in polyurethane!

Obviously they are much less expensive than something similar encased in stainless steel cans with fancy names ...

It really is amazing what some of these simple, easy to get products can do in relation to the audiofool stuff that costs an arm and a leg!  Trust your ears and not the wallet! 

Finally I got my new Holbo home. 

First, I had to assemble the SolidSteel S3-3 stand which was still sealed in its factory packing.  The instructions could have come from Ikea.  Fortunately I noticed there were three different lengths of connections.  I decided to make up the bottom shelf with its screw-on spikes and was going well until one of the spikes rolled down a crack in my 3-seater reclining leather lounge, which might as well have been a black hole.

A gotcha with the rack is that the top shelf is held on by round threaded plates with nothing to grip on except their flat faces.  I hand tightened by rotating the tube below, repeating downward for each shelf.  Next morning I threw the black hole on its backside and lo and behold it disgorged the remaining spike.

Next, the eight Sorbothane hemispheres were positioned diagonally on the top shelf and I added the two sandstone slabs, separated by a sheet of damping.

Next came the Holbo, which I had unpacked a couple of times before.  It comes almost completely assembled.  You just have to add the tone arm balance weight and the rubber drive band.  And a cartridge, of course.

So I set it on the top slab, putting its three aluminium pucks under its three spiked feet.

By this time, the hemispherical Sorbothane thingos had squished down from over 25-mm to under 15-mm and looked like flattened doughnuts.  They allow gentle movement of the 70-kg sitting on them.

The Holbo has to be pretty level, and its three feet are oddly arranged.  One is centred near the back, one is centred near the right, but the third is front left.  There is a drawing of a foot being adjusted with the supplied screwdriver, but in reality the screwdriver is used as a capstan lever with holes positioned around each foot.  Good for sailors.

I figured it made sense to get the back and left feet adjusted first.  Cunningly aligning my 1.2-m German level with the approximate direction of the feet, I capstanned away at the front foot until it showed level.  Never one to totally trust a spirit-level I flipped it to check the bubble position, Same as before - German you see.  Then I just had to repeat with the right foot, adjusting against the left one and checking against the back one.

Now to hook up the power / air supply using the supplied electric cable and soft plastic air tube.  That’s when I discovered one of the ferrules for the air tube was missing.  Maybe I lost it in Sydney.  Anyway, the tube stayed put on its prong without the ferrule, so I was almost in business.

Time to fit a cartridge, which Holbo makes easy because although the tone arm is captive, it can be loosened and rotated about its long axis. My Shure V15 type III was lying around, so I threaded up the mounting bolts but could not fit the nuts.  The Holbo cartridge mounting pad is about 3-mm thicker than a fixed SME head-shell and the only bolts I had were not quite long enough.

It was too late on Saturday to go shopping and the nearest proper HiFi store did not open on Sunday.  I did try a big hardware store but they start at M3 size bolts, and JB HiFi, which started out selling records and CDs, has all but converted to being a pure white-goods seller.

There was one thing I could still do.  When aligning the tone arm, Holbo instructions are to leave the air running, remove the drive belt and then place the heavy supplied puck on one side of the platter.

I was not sure if this was to double check the level, but it turns out the weight is sufficient to overcome the air pressure and ground the platter, effectively locking it in place.

At this point I spotted the missing ferrule lying on the carpet!  To be continued ...