What to do with a TT2?

[pure sound]

Hello everyone, this is my first post in this forum, the first thing that I use an online translator and I hope you understand me well, also apologizing for it. I'm very interesting thread carefully. I'm trying to perfect my rotation TT2 pulley as shown in the photo, I have not even set to 100%, just mention that you have to completely redesign the suspension. In this way the suspension works in a more natural way. What you say about it?

I presume this is a different, longer belt?

Incidentally with regard to the image of the 'TPS' pulley further up the thread. I have a bag of genuine 'TPS' pulleys here and they don't look like that. That does look like a Linn part which would be surprising as I'd have expected the size to be wrong if working with the smaller TT2 inner hub.

The TPS pulleys have a single, curved 'crown' and a flange above & below.


Lovely job restoring that TT2 Surayne.

Not sure about the blue mat though!

[YNWaN]

I presume this is a different, longer belt?

Mmm...exactly my own thought - that belt is already pretty tight on the TT2 and will be very tight indeed if stretched in that manner.

Incidentally with regard to the image of the 'TPS' pulley further up the thread. I have a bag of genuine 'TPS' pulleys here and they don't look like that. That does look like a Linn part which would be surprising as I'd have expected the size to be wrong if working with the smaller TT2 inner hub.

That doesn't surprise me. As you say, it looks like the Linn pulley - exceedingly so in fact. It seems likely that a Linn motor and associated pulley have been fitted at some time in the past. No doubt this helps explain why correct speed is not achieved with the belt running on the crown.

Lovely job restoring that TT2 Surayne.

Not sure about the blue mat though!

Indeed (on both counts )

[AlfaGTV]

The TPS pulleys have a single, curved 'crown' and a flange above & below.

Guy, could you please measure the diameter of the pulley on the "official" part?
AFAIK this is the motor and pulley this TT2 was shipped with, but as i am not the first owner i cannot say for sure...

And, i have never had an issue with the speed on either of my TT2's. My apologies for being unclear in that case.
The reason for asking questions is that i want the belt to run in a steady position on the pulley, whether its a Linn or Heybrook
Reason: Suspension is influenced by belt position.

Regards
/Mike

[YNWaN]

Hmm.. the belt should run steady with both designs of pulley, irrespective of speed - is this not the case then?

I have both the Linn and Heybrook parts here - will measure them later for you.

[pure sound]

the 50 Hz twin speed pulley seems to be 16.63 mm in diameter on its 33.33 rpm crown.

I think the bag of TPS pulleys must be up in the loft with the other parts. If I get a chance I'll try to find one later today.

[AlfaGTV]

Hmm.. the belt should run steady with both designs of pulley, irrespective of speed - is this not the case then?
...

I wasn't able to get the belt steady running on the TPS pulley at first, as my ambition was to make it run on the flat portion of the pulley...


But as i have learned from you guys, the belt should be running on the verge of the conical section. And I have also managed to get it to run steady there recently!
So, my problems are solved, thank you all!

However, i was intrigued by Pure Sound Guy's question whether the pulley was the original.

So i measured the pulleys:
TPS, Pulley: 16.6mm
TPS, Platter: 129.99mm
Gearing: 7.830723:1

Old, Pulley 33rpm: 16.9mm (on the highest part)
Old, pulley 45rpm: 22.95mm
Old, Platter: 130.05mm
Gearing: 7.695266:1
Gearing (45rpm): 5.666667:1

The syncronous motors for 110V AC does 250rpm @50Hz which means:
TPS: ~32rpm
Old: ~32.5rpm
Old@45rpm: ~44.1rpm

Anyone got an explanation to why my math is not matching the speed requirements, and also IRL measurements?
Or is it simply the fact that the belt is not running entirely on the widest part of the pulley?
(which would mean that the pulley has a little bit smaller diameter as far as the belt sees it?)

Best regards/Mike

[sq225917]

belt effects.

[pure sound]

Indeed. Try adding the belt thickness (1mm) to each diameter & then calculate your gearing, ie the gearing is based on the sizes following the centre line of the belt.

(stretched slightly over the driving pulley & hub it may actually be slightly less than 1mm).

I suspect that the proper TPS pulley diameter will be the same as the 50Hz 33.33 rpm diameter (ie 16.63mm) but I'll need to dig one out to confirm this.

[AlfaGTV]

Ahh, of course! The belt thickness will affect also.
When adding 1mm to both diamters the results are far more accurate, though a little too high.

Thx, now i can sleep again at night..

[DSJR]

Please get a proper strobe!