Garrard Restoration and Plinth Build!
Thought I'd share the progression over the past week or two with my attempts to restore my 401 and design and build a new plinth as it may prove useful to other Garrard DIYers! The plinth in this thread is one that I will be marketing for RFC eventually but this was the prototype.
I had a pretty decent late model Garrad which I'd built a plinth for a few years back:
I wanted something a bit more contemporary looking with better motor isolation but the first priority was to strip and service the Garrard:
First job was to remove and inspect the main spindle bearing:
As can be seen from the photos, the main spindle was in great shape but the thrust pad has the characteristic flat worn into the phosphor bronze bearing, so I changed it for this:
Much better and very very smooth!
Next was a partial strip down of the motor, starting with removal of the transit clamp and lower clam shell:
The lower bearing is in a spherical housing that should be free to rotate to aid rotor shaft alignment but it was pretty seized up and the bearing itself dry as a bone, so this was freed up and re-lubed using light machine oil to fill the lower bearing welll before re-assembly. The top bearing lubrication was done by applying oil through the holes on the magnetic eddy current disc located beneath the platter (oil lightly sprayed using 3 in 1 direct to the top of the shaft bushing). Linkages were cleaned up and regreased with petroleum grease (note that they are all cadmium coated so never handle them without surgical gloves or similar!!!).
The idler wheel was then removed and reconditioned by taking a slight amount off to get rid of the rounded edges, the bushings re-oiled and everything reassembled. I re-soldered the ground wires to the chassis tag as these had developed a dry joint! (the chassis could have gone "live" and electrocuted someone!!)
Next was reassembly and run in of the new bearing. After a few hours at 78RPM everything was very silent as it should be from the factory, no rumble or idler wheel/motor shaft noise at all (to the naked ear), so a very worthwhile service.
Comments
Template cut and the deck tested for fit before...
...trying out an idea for suspension using sorbothane. I experimented
with various shore hardness and diameters until I got one where using a
stethoscope I could pick up no noise when placed on the temporary timber
supports.
The plinth proper was then started:
Solid Oak blockboard (£170 per metre!). The idea was for a contemporary
high mass skeletal design using my proprietry suspension hemispheres and
designing a locating support routed into the solid oak such that no part of the
deck is in direct contact with the plinth:
Deck fitted:
Turned Black Walnut column supports with inset brass cone adjusters for
levelling the deck:
Testing the suspension and design by using a stethoscope to compare
direct feedback from the deck compared with from the plinth:
I was delighted to find that there is absolutely no noise, not one iota
present on the plinth meaning that it is all but free of unwanted vibration
although the deck when listened to via the stethoscope was almost deafening!
No need whatsoever for an off board arm mount!
Next will be the cutting of the hole for the tonearm, a Hadcock GH242
Cryo which I'll do next week, then fitting of acoustic isolation feet to the
lower plinth and finally the sanding and finishing of the woodwork before
settling back to listen to some tunes again!
Watch this space...completed pictures coming next week with a full report on sonic performance!
Gove might even give you a pass in his new D&T CSE course for it.
Keep up the updates. :-)
Even as Mr Digital, I have a liking for a good 401.
How does your Gyro compare to your 401, I wonder?
[-X
Your fine work and time in posting deserves (a lot) better than Alan and I.
Party at your place.
Those stands have true giant killing potential, shewerly!
The Harbeths aren't as pretty as the Agathons, I'd say.
That cut out by hand could be beyond my modest skills ( though I do know of a good joiner). Also bamboo splinters easily and can be hard to work with.
Good luck with the plinth venture - it will give people another option instead of slate which is everywhere now !
Absolutely bloomin' marvellous. I almost don't care what it sounds like.
Almost.
(As long as when I return the favour I'm not obliged to manufacture my own TT. :-/ )
Not sure if you have considered a Decca - not everyone's cup of tea but a 401/unipivot is I think custom made for one.
I started on my 401 motor at the weekend but struggled with removing the 2 bottom clam nuts - what did you use ?
I oiled the top bearing through the 3 flywheel holes and while it did not make a big sonic difference the eddy brake had to be adjusted back towards the centre confirming the oil had lubed the top bearing.
Thanks