An AVID adventure....

[SonicArt]

I guess i'm a sucker for basket cases, or in this case a flimsy wooden crate inside was an AVID Ingenium turntable, well part of one anyway!

A local customer had brought it back from India, missing tonearm, missing the motor drive pod, from what I understand it was in an accident and parts were damaged. No feet either!

 

He had sourced some two piece feet, small alloy puck that sits under the table with a larger alloy cup under it, and 3 ball bearings sitting in their own semi circles holding the two sections aligned. So I pulled the deck apart, well I undid 2 bolts and the rest pretty much fell off

He also had an NOS tonearm from SilverNote, its a 515 series that was made only for Vintageaudio.dk, its quite an old arm and there is no info online about this model. Not having any info or specs on it I was caught out with what the geometry actually was during the initial setup planning and other SilverNote models I found online had 212mm geometry (The table had a Project arm originally so the geometry was for the 9" or 212mm centre to centre).

 

So first thing was to sort out the feet, I felt just sitting the T shaped plinth on top of these feet would be rather precarious, so I suggested boring and countersinking the upper silver section and threading the base so they could be screwed on.

The alloy discs have o'rings in grooves on the top side, so the screws are only just tightened, giving some isolation from the solid alloy T plinth.

 

Once the feet were done I looked at the armboard section, and how we could fit the SilverNote arm base over the flange on the AVID frame. I decided to machine out the inside of the base donut so it would sit over the flange, Only problem was the base donut was not round, had tapered sides, and the end surfaces were not square either!

There is however always a way! A piece of scrap alloy bar turned down so the base was a tight fit allowed me to hold the piece using the only straight section, the centre bore! Now I could face both sides square, and turn down the outside so it was square to the bore.

Pics above before and after, once machining is done I use wet n dry to smooth things out then engineering pads to give a nice brushed finish.

 

I machined the bore out as close as I could to the grub screw bores (locking screws to hold the arm in place) and it was still not enough to fully seat down on the armboard base surface.

So the AVID section was clamped into the mill and milled down a mm to finish things off.

 

Now we are getting somewhere, drop the arm in and it all fits neatly, quick assembly and jee it looks like a turntable! But the arm looks quite big in relation to the spindle distance...

So I went searching and found SilverNote on FB, spoke to Mark (the guy behind the arms) and he hadnt supplied this model to Vintageaudio for quite a few years, turns out its rega geometry, and only Vintageaudio got this particular version of SilverNote's arms..

 

So this stopped me dead in my tracks, and necessitated a rethink on what was needed in order to make it all work (bear in mind customer was on a budget of sorts).

 

Obviously the arm needed to be moved, so some rather more drastic surgery was required to the poor old AVID frame   Next installment is the butchering surgery of the AVID armboard area...

[SonicArt]

So a lot of staring at the AVID frame and some measuring of distances was performed, then a plan was formed to change forever the landscape of the armboard area!

 

First up was machining off the flange so we had a flat surface to work with. That went smoothly, and I was then able to mark out 222mm for the Rega geometry...

And use the boring tool to cut a hole with just enough clearance for the arm base to drop down into, giving us 222+/- spindle to pivot. I then machined up a new arm mounting base and used the two existing holes from the original base to mount it.

The machining came up neat enough, and it wont ever be seen once all assembled.

New armboard in place, it sits flat and square to the frame, and is very secure.

And with the arm fitted into its new bore, fixing points are 2 grub screws at 90deg same as the original factory armboard. I didnt need to machine out the semi circle section for the underneath of the arm lift as the arm needs to be higher than the base in order to achieve VTA, base looks cleaner without cutouts in it too!

 

Next up was the motor system.

 

 

Edited September 5, 2023 by SonicArt

[SonicArt]

Motor drive! A turntable without a motor is well, not really a turntable!   I had a used OL advanced DC drive kit sitting on the shelf, its an early version around 06/07 and had an early motor with it. I had figured out the circuit of the early drives, and replaced all diodes and the two main IC's with new parts, essentially bringing it back into service. The older drives wore over time and would drift speed constantly, a little speed drift was always expected with the OL DC motor kits, but not large changes day to day!

 

The AVID table needed a motor pod, it needed to be simple and within a tight budget, yet still function correctly. Alloy was chosen as the motor pod needs a reasonable amount of weight to stabilise it when in use, and the cost of aluminum slugs is no more than alternative materials in plastics, and making a steel pod with screw on top and bottom plates is more time consuming for not much less material cost.

 

The alloy pod is machined from solid 90mm diameter bar stock, a 35mm bore is machined up into the base, with a 9mm hole for the base of the drive pulley to sit in,

The OL motor comes with screws and o'rings, and I decided this was the most cost effective way to mount the motor. Using an OL motor plate as a guide made it super quick to mark out the holes and bore then in the mill, countersinking them cleans up the look of the pod.

The end result is a very neat looking motor pod that weighs around 1.5kg!  The top section is approx 6mm thick with the screws countersunk 3.5mm and sitting on the o'rings, with the holes slightly oversize the screws do not touch the pod itself.

 

I machined up a new motor pulley with a concave belt groove to better carry the factory round belt supplied by the owner.

Time to test out the drive system! Quick positioning of the motor for a reasonable belt tension, then I popped the platter on with its clamp, set the phone to "TT SPEED" app, and fired it up. Adjusted the speed to 33.4 after letting it run a few mins, then hit the go button to see what sort of wow figures we would get. (Speed is not my concern at this stage, the apps are not speed accurate, always around 0.1rpm faster than actual, but they are useful to get like for like tests and for wow figures).

 

I noticed the belt did not want to run steady around the subplatter, it moved up and down a little no matter what position it was in, rotating it, warming it up a bit, still ended up with 0.14%+ in wow.

 

This was not acceptable, had to be a better way to drive the table. I then knocked up a new pulley shaped for flat belts, I have tooling ground that gives me concave or convex shapes for making Delrin pulleys, very handy! Dug around in the part box and found a new belt that was a little longer than the factory one, but still suitable for the AVID.

 

Flat belt conversion as shown above, the belt sits on the subplatter with plenty of room to spare, and runs very smoothly.

So a little adjusting of motor position and drop the platter back on for some more tests.

End result, wow reading down to a best of 0.04% with an average of 0.06%, I think we should be happy with that.

 

Testing out of the way I popped a VM95SH onto the arm and discovered that the huge cartridge clips get in the way of alignment and stop the cartridge from being able to rotate into correct position, fouling against the side of the arm tube....

 

So I removed them one by one, replacing with some very small gold plated copper clips, these give much more room to move and alignment was achieved with no further pain!

 

So NOW I could sit down for a bit of a listen, there is some hum going on and hang on, something is not quite right with this stage, why is the piano over there???

 

Yet another issue with this so called NOS arm, something up with the earth and channels are back to front! No issue with the DIN cable I was using, so has to be the internal arm wiring. No chance it was me replacing the clips as I did them one by one to make sure of that!

 

So arm came off, again, and a quick measure confirmed left was right on the male DIN socket. Slipping out the foam bung in the end of the tube under the headshell exposed a tatty frayed earth wire, and andother earth wire soldered into a C shape that my guess should have been under the rear nut of the screw holding the headshell on! (so thats why that screw was a little loose when I did a quick initial check of fasteners)...

The frayed wire was under the front screw, ok that works, clean up the wire, twist and solder the end, and join it to the actual earth wire floating around inside. Bingo we have continuity between the headshell and the ground pin on the DIN!

Next up remove the clips one by one and swap the heatshrink colour over so we have correct left and right...( you can see how much of a sucker I am for basket cases!).

 

OK, finally back together, reconnected, cartridge back on, no hum through my DIN cable, and it sounds really quite good! A very nice end result and with the Shibata cartridge it really sings, the ball bearing feet seem to work ok, rapping on the shelf during playback was subdued through the table, less than other rigid decks I have worked on.

I think the owner will find it quite an enjoyable table once he fits his own cartridge!