Isonoe feet for Technics SL 1200/10

[KC Jones]

Try this.

Here's what I do to all my threaded inserts, metal to metal threads etc. Get a roll of plumbers PTFE tape, (couple of £'s) and wrap a few turns round each thread before screwing in, this will give a snug damped fit and remove any play and vibrations etc. It has lots uses and is easy to remove too.
Cheers

[Qwin]

KC Jones - Yes the PTFE tape will do the same as the silicone sealant would.

CageyH- The foam boss that is used can be compressed between your fingers, I've tried it. We are only compressing the foam by a max of 3mm when we install the feet so yes the feet are attached loosely by only a few threads (6 to 9mm). When the deck is stood on the feet it takes the weight off the foam so it is actually sitting on the metal threads that are engaged. It is easy for it to wiggle about, try it if you don't believe me.

This is a completley crap way of attaching anything, let alone an isolation system. Because of varying production tolerances some thread matches are going to be better than others but it will never be tight. as soon as you apply enough presure to defeat the foam you reach a point where you are changing the direction of loading on the threads from a pull to a push and any play in the threads will be felt as a rattle.
I noticed this as soon as I fitted one, I was curious about how the rubber bands would feel under load and as I said earlier I applied a light pressure with the palm of my hand. I was immediately concerned by the way that it felt, to the point that I double checked I had understood the instructions and fitted them correctly.

If you look at speaker spikes, they usually have a lock nut, this is not to stop the spike unscrewing, it is to pull up the threads tight and stop any rattle or they won't work very well and the speaker would wobble about on the loose spikes. Its a similar thing with the way the Isonoes are fitted. The weight of the deck is greater than the pressure applied by the foam so it sits on the thread in a similar way to the spike situation.
If you say yours don't rattle, this may be because you have only looked at this when there is no weight on the foot and light foam pressure is taking up any play. Things may be different when you push against the foot as I did. The easy test is to remove the foam compleatly insert the foot 6 to 9mm and try wiggeling it with your fingers.

Even when fitted this way they will probably perform better than the stock foot, but not in my opinion as effective as they could be if held in the deck more securely.
I will definately not be fitting them as the instructions suggest.

[keiron99]

Even when fitted this way they will probably perform better than the stock foot, but not in my opinion as effective as they could be if held in the deck more securely.
I will definately not be fitting them as the instructions suggest.

I have to be honest, when I installed mine, I didn't notice any difference in the sound at all.

But then, I don't hear any difference when I change mats either...

[CageyH]

KC Jones - Yes the PTFE tape will do the same as the silicone sealant would.

CageyH- The foam boss that is used can be compressed between your fingers, I've tried it. We are only compressing the foam by a max of 3mm when we install the feet so yes the feet are attached loosely by only a few threads (6 to 9mm). When the deck is stood on the feet it takes the weight off the foam so it is actually sitting on the metal threads that are engaged. It is easy for it to wiggle about, try it if you don't believe me.

This is a completley crap way of attaching anything, let alone an isolation system. Because of varying production tolerances some thread matches are going to be better than others but it will never be tight. as soon as you apply enough presure to defeat the foam you reach a point where you are changing the direction of loading on the threads from a pull to a push and any play in the threads will be felt as a rattle.
I noticed this as soon as I fitted one, I was curious about how the rubber bands would feel under load and as I said earlier I applied a light pressure with the palm of my hand. I was immediately concerned by the way that it felt, to the point that I double checked I had understood the instructions and fitted them correctly.

If you look at speaker spikes, they usually have a lock nut, this is not to stop the spike unscrewing, it is to pull up the threads tight and stop any rattle or they won't work very well and the speaker would wobble about on the loose spikes. Its a similar thing with the way the Isonoes are fitted. The weight of the deck is greater than the pressure applied by the foam so it sits on the thread in a similar way to the spike situation.
If you say yours don't rattle, this may be because you have only looked at this when there is no weight on the foot and light foam pressure is taking up any play. Things may be different when you push against the foot as I did. The easy test is to remove the foam compleatly insert the foot 6 to 9mm and try wiggeling it with your fingers.

Even when fitted this way they will probably perform better than the stock foot, but not in my opinion as effective as they could be if held in the deck more securely.
I will definately not be fitting them as the instructions suggest.

I wound them in by hand until there was no rattle, and wound others in further until the deck was level. I didn't read the instructions supplied.

[Qwin]

Again kevin - No rattle when you screw it up as the foam is applying light pressure. This is defeated when you put the weight of the deck on it.

I think the important thing here is to recognise that the foam is not contributing acoustically in any way as the weight sits on the securing bolts thread.

Plus when you take the rattle out of the threads, using PTFE tape or whatever you are making the attachment more secure between the deck and the centre hub of the foot.

So why not ditch the foam compleatly and use a nylon spacer that is bolted up nice and tight?

I've just orderd some nylon penny washers, M6 x 23.6mm dia to do just that.

Edit: Sorry Kevin forgot You are using tape on the threads which should Improve things.

[CageyH]

A nylon spacer, or a lock nut?
Could this issue be pronounced with the T nuts you are using, or is this on one of your other decks?

[keiron99]

So why not ditch the foam compleatly and use a nylon spacer that is bolted up nice and tight?

I just read about someone doing this on another forum.

Obviously then you can't use the feet to adjust how level the deck is.

Will you be placing it on an adjustable shelf?

[Qwin]

Kevin - just a plain M6 Nylon penny washer about 23mm diameter and 1.5mm thick in place of the foam bush.
I don't have a problem with the threads going in further due to the reduced spacer.
I am using t-nuts which may have a greater clearance (loosness) on the bolt thread but beleive me the T-nuts are not moving, they were staked onto counter bored holes in the plywood sandwhich so cant push out, plus the pilot hole for the threaded part was deliberately drilled 0.5mm undersize so they are an interferance fit, had to be driven in hard, are the long nosed version with 15mm of thread and dont move at all.

Keiron - It is worth noting that the manufacturers suggest the foam bush should not be compressed more than 3mm in the instructions. Bear this in mind when using them for leveling.
I think the foam is there purely to try and prevent the chatter in the threads which it fails miserably at doing under load, the whole principle is just wrong and I can't see the foam serving any useful purpose. Even removing it and fitting a locknut would be a big improvement in my opinion and useable for levelling. Yes I have an adjustable shelf.