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It Live's!!

P

Paul Dimaline

12" round member
After 3 weeks without any sounds I could wait no longer. Being in my usual financial state, ie. skint, I was waiting for a big pay day so as I could get myself a nice new MC for my 401/RB300 but I rushed into town after work yesterday and bought the cheapest cartridge I could find, a Orfoton OM5E, and then set to work with the drills, router and sander. A couple of hours later the plinth was finished, arm mounted, cartridge fitted, and we were ready for blast off.
So, what does it sound like? I'll tell you in a moment. Firstly, the story so far.
After trawling the net for plinth designs they seemed to fall into 2 catagories; High mass designs like the Bastin or "sprung" designs like the Lorricraft. Now being a typical DIY'er, I know far more than either of these young upstarts (!!) so decided on a slightly differant approach. Actually, it's simply a combination of the two.
The base is 4 layers of ply cut in a Bastin/Shindo style, ie. each layer with smaller cut outs than the last so as to just clear the motor and othe mechanicals/wiring.
The top plate is cut out as per the template to take the deck and arm and is seperated from the base via "air filled de-couplers", yep, squash balls cut in half to you and me!
So, what we end up with is a light (ish) top plate sitting on a solid, high mass bottom section.
I have enough Birch ply left over to try other designs, and will more than likely do so. I like the look of the Bastin with the extra support at the bottom of the main bearing. I will also look out for some hardwood so as I can try a Lorricraft style. I dont like the look of the skeletal type plinths so I dont have much enthusiasm for trying one, but I may give it a go.
I had to make another spacer for the arm as the one the engineering shop made up was not square. In actual fact, it may have been to high anyway, so i made the new one 12mm instead of 15. I cut a bit of the corner of my kitchen worktop router jig, got to get your prioritys right!
I bought the 401 on ebay and to be quite honest its not in the best of nick. The bearing was virtually dry but a good clean and new oil has done the trick I think, it certainly runs smoothly enough and the platter doesnt rock from side to side much, although it does a little.
The motor on the other hand is a little more worrying. Speed stability is spot on with no drift after a couple of minuites warm up, but is quite noisy, although there is a fair bit of play in the idler wheel bearings so it could be that. If Lorricraft can ever be bothered to return my calls or emails I will talk to them about having some work done.
So, how does it sound? Well, keeping in mind that this is very much a work in progress and has a brand new (very cheap) cartridge it sounds flippin' great. Very differant to my old LP12, stable and solid are words that spring to mind. Bass is much less coloured with far less overhang. At first it seems bass light but I dont think this is the case, it's just alot cleaner down there, notes start and stop in an instant.
Piano is CD like in its stability, there is not the slightest sign of any speed instability at all.
Surface noise is almost non existant. The only fly in the ointment that is obvious is that it doesnt sound quite as good at low volumes at the moment, this is a deck for a detached house!
The best compliment I can pay is that while playing Roger Waters, Radio Kaos, wife asked me to turn it UP!! I'm gonna' like this old gramaphone I can tell!

Paul.
 
Photos, photos and more photos. We want, no, we demand audioporn!
Sounds great. How difficult was the plinth to design and make?
 
Dont panic!!! I am taking photo's of the whole project, it's just that I dont have a digital camera so i have to wait untill I get the film developed and then have it transfered to disc. My plan is to wait untill all the work is done and the end result has been tried and tested and then do a step by step article. I will gladly email pictures to anyone who is interested in the meantime.
The work on the plinth is not hard, although I am a carpenter/joiner so for me that is the easy bit. The most time consuming part upto yet was marking out the cut out in the top plate to take the motor unit. I did it from the dimentions in the manual as I didnt have a full size template to hand. After that its just a matter of following the lines with the jigsaw.
Bugger me, i'll have to stop for a mo'. im just getting to the end of side one of Tubular Bell's and its sounding good!

Paul.
 
Originally posted by Paul Dimaline
High mass designs like the Bastin ...
Click to expand...

Paul,

The Bastin Plinth is not so massive as it first appears, true that when you've added the 401 and an arm you're looking at something that weighs the best part of 20Kg. I have the latest version of the Bastin plinth which is solid and made from birch ply. It's more cunning than that tho', because the each ply layer has a two cuts, almost to the edge of the plinth, to make a break for the 'quarter' of the deck where the arm goes, I have some photos at home that should show this. The cuts are staggered between layers to ensure vertical integrity.

The reasoning behind the Bastin version is that since it's plywood then there is loss as vibrations have to traverse layers. I'm no DYIer, although I did build my first 401 plinth, but I would have felt that if you wished to effectively combine the Bastin and Loricraft approaches, then the suspended/floated part of the deck ought to be the thicker part. i.e. The Motor etc loses it's vibrations in the multiple plywood board layer and the suspension serves to offer isolation from the outside world.

Congratulations on your efforts, the 401 is a fine deck and I would not ever dream of an LP12 after living with mine for the best part of 6 years now.
 
hi Paul

glad to hear your "beast is up and running ! mine should be a week or two yet.

i have found the cause of the scraping though.................at some point the platter has been "pushed" down onto the chassis of the player and the bearing thrust pad is damaged ,now we are talking less than half a mm hear but it is just enough to let the platter make the slightest contact with the chassis. The problem is being rectified by sending the bearing off to Martin Bastin for his modification. I have decided to build my own plinth from layered birch ply , have any of you got plans , tips or templates .

i am surprised Mick P hasnt given us the benefit of his experience yet


regards BB
 
BB

I have just returned from a fortnight in Spain looking for a retirement home. The weather here is making me suicidal. Yesterday I had a fish lunch in an open restaurant in a sunny 28 degrees and now I am looking out of my study at a wet and dismal dump called Swindon in the autumn. I must have been mad to have come back.

Paul

Congratulations on the 401. You will never sell it.

The Loricraft plinth is a bloody heavy base which uses 4 squash balls to support a relatively light board which houses the TT.

You could easily make one and it will sound a lot better than the old Garrard plinth which were frankly useless. A few of the Loricraft plinths come up on Ebay from time to time and seem to sell for around £100.00.

I have not heard the solid marble plinth but it is reputed to have a different sound, so do what I did, blag a few listens at someones house.

Loricraft highly regard the RB300 but virtually insist that you have the Incognito upgrade carried out on it. Evidently it transforms the sound.

I have gone the whole hog and have fitted a Naim Aro, Prefix and also the Loricraft PSU. The 401 totally murders the LP12 and is up with the Ninja which also trashes your bog standard LP12.

The advantage of the 401 is that it is so easy to live with. It just needs a few drops of oil every 5 years and nothing else.

Once again congratulations.

Regards

Mick
 
but I would have felt that if you wished to effectively combine the Bastin and Loricraft approaches, then the suspended/floated part of the deck ought to be the thicker part.
Click to expand...

Mmmm......that makes sense actually, I think I will try this next. One advantage of splitting the plinth like this is that is sort of modular in concept so is very easy to swap top and bottom sections. I will make a heavy top section and lighter bottom this weekend and have another play around.

I have also just got hold of some lovely Black American Walnut so I could try a Loricraft style, although it's rarther expensive to use as a prototype.


BB

There is THIS design if you have not already seen it, a variation of the Lorricraft plinth I think.
Somewhere on the Naim Forum there is a photo of a bare Bastin plinth, do a search if its working at the moment. The interesting thing about the Bastin type is the support for the main bearing and the motor yoke, something that cant be done if some form of suspention is used obviously.
The trouble is the possibilitys are almost endless and I would rarther listen to it than be constantly messing with it!

If you would like some photo's of my efforts so far I will e-mail them to anyone who is interested.

Paul.
 
I'd be carefull about goint oo heavy on the suspended top half of the plinth.

I can't do the math but I would gues that by adding more weith to the top half of the design (by making it thinker) would possibly drop the resonant frequency of the suspension movement (?) - bear with me I'm stretching my physics knowledge here! :)

Therefore the freqency of the 'bounce' might get too close to things like footfalls etc.

Plus I guess there's a possibility of 'overloading' the squash balls?

Anyway, my plinth designs have all used squash balls (whole not halved) and have sounded great.

This is despite my reading that a squash ball isn't suitable for the job - the logic was squash balls are designed to transfer and release energy quickly, which supposedly made them unsuitable for something like this.....

Richard
 
Richard,
Thank's for the input, as I said earlier the possibilitys are almost endless and at the moment i am sooooo much enjoying re-discovering my record collection I cant be bothered to get out into the garage!
It has cost me bang on £350 to date all in, the most expensive item being the new arm, the cheapest the 2 squash balls, and now that the cartridge has lossened up a tad I must say it is sounding fantastic.
As I like the sound so much at the moment im going to refine the design I have and give it some much needed WAF!
My first idea is to laminate the top plate much like Linn did with the later armboards. This should give the 18mm thick top section some extra stiffness (I have no idea if this is a desirable feature!) without increasing the weight to much. I will also try some sorbothane domes and could also try cones or a mixture of both. A cone or spike close to the motor to ground vibration into the heavy base?
One idea I am keen to try is to decouple the arm from the main board somehow. It is a tad tricky as the Garrard's main casting is so large the Rega arm sits very close, idea's welcome!
Then I can make use of that lovely bit of Walnut I have got hold of to finish it off.

Paul.
 
Paul,

oops - forgot that at the moment I'm using some sorbothane feet at the moment in place of the squash balls. They came from the bottom of a mission isoplat - I just separated them and have used the base as a shelf elsewhere.

This is slightly better than the squash balls - a bit cleaner bass and more open top end - the one area that needs lots of attention on a 401 can be the treble - a TD124 fro example is easier to get right in the treble - but it can't match the 401's mega bass!!

I'm using a RB300 with the Easy Riser adjustable VTA collar - this is very easy to use and is an important feature with the 401 as the platter is much higher than the plinth top.

Apparently the trick to mounting a RB300 is in how tight the nut is at the bottom - if you use a tool it will probably be too tight. As tight as you can by hand is probably about right.

The spike/cone thing with the motor sounds interesting..... might be worth a go - I have toyed with mounting the motor on the bottom half of the design - but I'm not sure if this would work???.... plus getting it all lined up would be a little stressful!

Richard
 
Paul

Loricraft have tried everything imaginable and still reckon that squash balls sound the best.

Regards

Mick
 
Does anyone have any drawings or pics of the loricraft plinth,

hi Mick

trust you had a pleasant holiday ?


are those squash balls cut in half and placed round side down ?


regards BB
 
The squash balls are virgo intacto (uncut) and fit into gussets inside the plinth.

Regards

Mick
 
Mick

What 'colour' (spot) are the Loricraft squash balls?

From my squash playing days, I seem to recall that yellows were harder than reds and blues and whites?

I think we should be told.

(I wish you lot would stop going on about 401s, then I might have a chance of getting a bargain one from ebay. All we need now is for Tony L to be '401-converted', and the prices will go through the roof.)
 
Patrick

I have been up early this morning listening to a pile of old 1960's mono trad jazz LP's and they were great. Surprisingly, Acker Bilk came out as the best in my opinion.

I lifted the platter and the squash balls were coloured black.

Regards

Mick
 
I lifted the platter and the squash balls were coloured black.
Click to expand...
I think you'll find they all are, but they should have a little coloured spot on them somewhere too. The yellow spot one's don't bounce at all until they get really warmed up, the others require less warm-up. You probably should have different ones for summer and winter, and for hot and cold climes. Who said 401s don't need tweeking? Sell yours NOW before the market crash ;)
 
Ok, time for an update.

Spent a very usefull 10 minutes talking with Terry at Lorricraft the other day and he put my mind at rest on a number of things. Told me to go buy some sewing machine or gun oil, so I did for the grand old sum of £2.15.
He was very forthcoming with advice, I get the distinct impresion he doesnt need any more work! Anyway it seems the bottom motor bearing cant be oiled without stripping the motor down. All the other bearings can be got at by just removing the platter, but as the motor on my deck seemed quite noisey and the main bearing was bone dry I thought it quite important to address the matter. So, for those wishing to give it a go heres how I did mine.

There is no need to remove any wireing. Remove the screw that holds the eddy curent dial and lift of the actuating arm. Remove the 3 screws that hold the motor yoke to the chassis and carefully juggle the motor away from the chassis, making sure to jiggle the eddy current actuating arm from underneath the wireing. There is enough slack in the wireing to lay the motor assembly on the workbench.
A circlip holds the eddy current magnet to the motor case, remove this and put to one side.
There is a collar with 3 screws that secures the pulley to the motor shaft, slacken the screws and remove the pulley. There are now 3 more screws that hold the eddy current rotor, again slacken and remove.
You will now see 2 small nuts that hold the motor caseings together, but first the 3 suspention springs will need to be unhooked to enable the motor cases to be seperated. These are held in place by a circlip, you will need some long nosed pliers to remove these as space is tight. When all 3 are unhooked remove the 2 nuts holding the case together, I again used long nosed pliers as they are recesed in the case. Lift of the motor case and that will reveal the rotor, lift this out and disasembly is complete.
You can now see the bottom bearing. Put 5 drops of oil in the bearing and replace the rotor, this will force the oil into the felt pads that feed the bearing, repeat this half a dozen times to load the felt pads with oil.
The bearings are of the self centering type, so I put one drop of oil on the bearing housing to aid reasembly. The top bearing can be oiled without disasembly, access is trough the 3 holes in the eddy current rotor.
The self aligning bearings can apparently be difficult to align sometimes, if this is the case, when assembly is complete, run the motor without the pulley and lightly tap the spindle with the handle of a small screwdriver. My bearings went together with no trouble.
Assembly is simply a reversal of dissasembly, getting the suspention springs back in place is fun!

One of my main concerns with the deck when I got it up and running was the motor noise. I pleased to report that now the motor has been recharged with oil it sounds alot quieter. The speed adjuster dial has had to be adjusted a little as the newly oiled deck was running slightly faster than before. The most suprising thing is that the sound of the deck has taken a huge leap forwards, being much cleaner and less muddled in the midrange. All in, a good evenings work and quite straight forward to do if a little fiddly in places.

I've also started work on the Lorricraft type plinth. Keeping in mind I have never seen a Lorricraft plinth in the flesh, so I am only guessing the design from what bits of info I have gathered. I have mitred and glued up the surround and have cut out a new top board. All I can predict at the moment is that it is going to be very, very big. It is looking nice however. More info to come when its finished.

Paul.
 
Never posted an image before, so dont be surprised if this dosnt work!
Finished1.jpg
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Gosh, wonders never cease!
As you can see above i've got the working prototype finished. The British Racing Green paintwork is a bit lurid and the Walnut, once planed up was very disapointing. Still. it will do for a while untill I get around to building the final version.
I'll get back to the computer and sort out some more photos of it being made..

Paul.
 
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