My Upcoming Anologue front end

So the time is coming to stick it all together, still a while yet but the majority of parts have arrived.

First the Cornet Mk2 -




Essentialy the same as the first Cornet, but with a few changes. The CCS is now on the board and not a lash together as before. More space on the board aswell.
The large alluminium can type caps are 51UF polyprop in oil, these are to replace the electrolytics for B+ bypass.
Elna Cerafines, 10,000UF for the heater supply. Signal coupling will be TRT Dynamicaps with Mcap for decoupling.
resistors in the IRIAA stage are Kiwame, Mills non-inductive wire wound for the power side of things.
CCS caps are blackgate.
Copper chassis was sourced from Ebay US. Very well made from 1.5mm copper with copper welded seams.
Valves are Mullard NOS ECC82/83 in the amplification. B+ rectification is a Mazda 5Y3GB.
I suspect a liberal sprinkling of ERS will be used between power and signal sections of the board.


The TT -




Platter is an 80mm think Scheu (Germany) item, with inverted bearing from the same source.
Motor is also supplied by Scheu, a DC PLL controled item.
Plinth is a circular piece of slate. 250mm diameter and 55mm thick (looking for a coating/wax suitable to give a deep finish)

The arm will sit ontop of its own stand. Stand will be made from solid brass with adjustable spike feet.
Cones for the plinth will be brass again.
Motor will be housed in a circular alluminium box. The motor box will be standing on a seperate shelf

The arm will be an RB300 with mods -
Michelle Tecno weight
Incognito rewire.
VTA adjuster isn't decided yet, but the OL sliding one is looking favourite.
Cart is a DV 10X5.

Support for the TT is a wall shelf, i will probably try to borrow a pnuematic support of some kind to try with it. If i like the result i will be sourcing one to use.

So, there ya go, its finally coming together

 

oops,
maybe i should of posted in DIY

 

Penance, Im at this moment decorating my bathroom in natural stone. Im about to use a product that you may like to investigate.

It is a product thats available from any high quality tiling shop which seals and impregnates natural stone.

It will give a gloss type effect, and will also mean that grease, oil can be wiped off. Its designed for things like slate, marble, quartz etc.

NB Deck is looking good. What are you going to do for the armboard/height of the armboard etc?

 

Hi Chris

Do you have a name for the product?

The arm will sit on top of a circular brass stand, probably with an OL sliding VTA adjuster. Also adjustable brass cones for it to sit on. All to my own design

 

Looking good. I'd be interested to hear how it sounds, the Scheu kits look really interesting. If it isn't a rude question, how much were the Scheu bits?

-- Ian

 

Hi Ian

I'll also be interested to hear how it sounds
Hopfuly no nasties!

From memory i think i paid around £400. That was for platter, bearing, oil, string stuff, motor with switches etc. Also included shipping.
Chris Fieckhert is the guy that deals with english customers, very helpful chap.

 

That sounds like a very reasonable price. Get it finished quick and tell me if it's any good!

-- Ian

 

im trying
although it will be effect of both phono amp and new TT. But i may keep my existing amp until i finish the deck, or vice versa.
Just being held up on obtaining the materials i need at a reasonable cost.

 

Deck's looking good Just wondering though (and this sounds like such a dumb question I'm sure I must be misunderstanding you) - if the arm is going in its own stand how do you stop it wondering around in relation to the platter, messing up cart and arm alignment?

Also re the Scheu stuff - presumably you going to have to build/machine the motor case yourself? Do Scheu supply one already cased? Also you went with the super thick platter - are the thinner ones much cheaper?

Just curious as I can feel a winter project coming on once I've got the attic room retro thing sorted out.

 

Great minds think alike

 

The arm will be on top of a solid lump of brass, wieghing around 10kilos, so that aint gunna move. apart from that the arm will be set up as per usual, just need attention with the spindle to arm distance.

Scheu do supply a cased motor, around 300 euro's i think, works out cheaper for me to fabricate my own.

Yep, thinner platters are cheaper. I have a Scheu pricelist in .PDF at home, i can mail if you want.

 

all looks great, keep posted on how it does, Andy, good luck with it.

 

If you would please, that'd be great, ta very much .

So are you going to make up some kind of spacer to fit between the deck block and the arm block to aid setup/resetup? Just that it strikes me that if either the deck or the arm base move even by a fraction of a mm it could throw things out. still 10kGs is a lot and I guess the deck can't move if the little cups the cones are sitting on are stuck to the shelf/base.

 

I may make a spacer tool to aid setup, but it wont be permanent.
The idea of a seperate arm base (wich is used by some comercial decks) is to help isolate plinth borne vibration from the arm. So any permanent fixing between the 2 defeats the idea.
I cant see there being a problem, arm base being around 10kg and plinth/platter around 15kg.
And i dont have any little terrors that will play with it


edit - Mr Ants, you have PM

 

forgot to mention

I'll be making a weight for the deck aswell, probably brass or lead loaded alluminium. may work may not, but minimal cost to try.

 

So do you That makes sense - I wasn't thinking of something permanent - like you say it'd miss the point. But some kind of lump, you can squeeze between the two to check every now and again would make life easier and give peace of mind I guess.

I guess you'll need to make sure that whatever you sit these things on it'll need to be dead flat though and not too shiny/slippy.

 

I have a 'special' Seismic Sink rated to 60 kg that we could try. How heavy is that TT gonna be?

 

Not sure on final weight Chris, but i doubt it will be 60kilo's.
Wouldnt mind trying it when the decks finished

Mr Ants

im thinking of a tool like this --

Code:

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So the circular profile at one end would be a fit for the bearing base and at the other end would fit the arm stand, if the diameters of the cutouts are measured with the spindle/arm distance used than it would set them apart correctly. Hope that explained it well.

 

"The arm will be on top of a solid lump of brass, wieghing around 10kilos, so that aint gunna move. apart from that the arm will be set up as per usual, just need attention with the spindle to arm distance."

Yes It will move.It will vibrate at a different frequency to the platter and deck, which is not a good thing.A tonearm does need a solid connection to the bearing you do not want things vibrating all over the place.If joined the resonante frequencys will be similair.If the platter is moving one way(microscopicly) and the arm another it going to effect the sound.
Also the record will want to drag the arm with it around the deck.Doesn't matter how heavy your brass is it will not be solid unless it is physical fixed , this will be an atomic bond, much stronger than the weight of the brass pressing into the wooden surface its resting on.
A solution would be to bolt both the subschassis and arm mount to the wooden top you have.
Your cones are designed to couple the main deck to it solidly anyway.
The reason motors are seperate are because they vibrate at a higer level and at certain frequencies that will be different to the bearing ,platter and arm what ever you do.
The level or vibration goes down as it looses energy traveling down through its mount into the shelf and back up it the bearing and arm.
I would do a little more research into turntable design before commiting to anything expensive.

 

You mention using weight to stop things moving.
What you have to remmember is that atomic bonds (when you screw or clamp things together thats what you get)are stronger than the weight of gravity.
Also the frequencies you need to be "scared" of are small and will ripple through metal weights.Good turntable desgin seaks to get things vibrating at "good" frequencies as you cant eliminate vibration by mass.