New Relevance - Idlers

[jls001]

What is sandstone? Is it different from Cudappa ? . I understand that slate is ideal for the plinth as it is softer than granite or marble. I don't know about its availability. Can anyone help?
kuruvilajacob

Cuddapah and sandstone are very different.

I have also read that slate is very good for heavy plinths. But some members here seem to favour sandstone. Slate is softer than either marble or granite. I've seen pics of very fancily made plinths of both marble and granite. So I guess both these materials should also work well. But the current thinking seems to be in using sandwiches of different materials like aluminium (supposed to be quite non-resonant), acrylic (another non-resonant material), and even panzerholz (plywood made under immense pressure and therefore very dense, non-resonant, very hard as to be bullet proof - but availability could be a big problem as it is made only by a German company), and good 'ole plywood (especially the much used Baltic Birch variety) and MDF.

 

[G401fan]

Slate is recommended for plinths, not because it's soft, but because it is a layered sedimentary stone - similar to plywood in a sense - that has the capacity to absorb resonances from the motor unit and the arm. By contrast, cuddappa, marble and granite have solid crystalline structures which are more likely to 'ring' and reflect resonances. That's the theory anyway.

Slate Audio and Oswald Mill seem to have a lot of success with their pre-cut plinths for the Garrards, TD-124 and SP-10. Out here, one would need a mason with a good high-speed cutter to get the cut-out right, as slate is brittle and easily chipped.

 

[jls001]

dude, you know how much its gonna weigh? plus i think a single 30mm slab will be enough to damp any kind of vibrations...

try a getting hold of a 30mm thick slab, you'll know whati mean -- it'll probably be enough to set off hernia!

Don't get hernia. Get a friendly hand to help lift it about:lol: As it is, you already got a screwed up back!

I think even 30mm slab should be more than adequate to drain off all the vibrations from the motor. That said, do get brass footers. I am using magma's brass footers under my 124's CLD and it really helps bring out much better bass impact and makes it more tuneful. I am comparing this to his cereball footers. The cereballs eke out more details but somehow lose out on the bass department. For my listening, I prefer the brass footers under the TT. I have even tried sal wood footers (with rounded bottom instead of pointy bottom) and that definitely killed the life of the music compared to the brass or the ceramics.

All this was with my hybrid power amp which was inherently weak in the lowermost and uppermost frequency extremes. Need to repeat this experiment on a newly acquired class A solid state, everything else being still same (except that I now have to use DIY balanced ICs).

 

[Hiten]

For my DIY TT have been reading a lot about mechanical vibration and resonance. Here is brief summary of what I gather. try to aim for best isolation/dampening of plinths by these basics. Correct me if I am wrong.

- All materials transfer vibrational energy.
-- All mechanical vibrations in any material should be damped, Dampening requires large volume.
-- Some vibrations would be fed back to the source there is no escape from this
-- material used for dampening should be low in density than the source of the vibrations. so as vibrations travels easily in to that material and dampens.
- Conical feets are must or else vibrations would travel from ground to heavy material you are using and amplify them.
- softer materials have low natural resonant fq. metals have high resonants fq. (Depends on Volume and area too) so idea is to have low natural resonant fq. material ideally out of audible fq. range.
-- All materials have natural resonance frequency and mechanical vibrations at those particular frequency amplifies them.

-x-x-

Winds of 35 miles per hours was perfect to amplify and oscillate natural resonance this structure.
Tacoma Narrows disaster Newsreel with audio - YouTube
have fun DIY
Regards

 

[soulforged]

Recently I was approached by this guy from Nagercoil, Tamil Nadu offering me a vintage Garrard SP 25 MK3. He was asking for Rs.20,000 stating that it is an idler wheel based turntable.

I got an old SP 25 MK3 with original packing from a guy here for Rs.500 :yahoo:

It was kept packed for ages at his place and he decided to part with it.

I recently unpacked it and plugged it in, the idler seems to be working fine. Plinth seems solid and in decent shape. Need to check if the cartridge is working...

But I echo your sentiments, the word is out that vinyl is on a resurgance...the result? people trying to make hay while the sun shines...

 

[reubensm]

I got an old SP 25 MK3 with original packing from a guy here for Rs.500 :yahoo:

It was kept packed for ages at his place and he decided to part with it.

I recently unpacked it and plugged it in, the idler seems to be working fine. Plinth seems solid and in decent shape. Need to check if the cartridge is working...

But I echo your sentiments, the word is out that vinyl is on a resurgance...the result? people trying to make hay while the sun shines...

Great Deal...the SP25 series was one of Garrard's most popular series of turntables and a lot are found in India. They are pretty ok for regular use. The advantage they have over most modern turntables are that they are ideal for record collectors as they have all 4 speeds. Congrats on your find.