What to do with a TT2?

As long as the suspension allows the sub-chassis some lateral movement in all planes as well as traditional "bounce" (Can't remember how truly piston-like the TT2 is, but the TD125 had some difficulty as does the Gyrodeck I remember), you should be ok.

Shane should confirm, but when tightening the P-clips, it's common for the edges of the cable to be crushed, leaving the center of the cables not fully gripped. With the fig-8 Linn cables this was an issue, but obviously, the fancy cables often used with the Jelco 750 may well be a heck of a lot easier to manage and dress..

Agreed. The cables Linn used were a nightmare for any suspended turntable. If you dress the cable as shown, then the portion that flexes when the chassis moves is straight and interferes less with the movement of the chassis.

I was curious about the recommended height of the platter as the 5mm the manual insist on, seems a little bit high imo.
I have used those 5mm as a point of reference though.

Another issue is that i cant seem to find any references to the correct angle of he motor, when using the external motorcontrol. The belt has tendency to wander about as they spin. I think this is a similar construction to Linn's and would like some furter info on how toadjust this?

Regards Mike

In my experience, the belt should be smooth with no grease or dirt on its surfaces. Rega belts have flashing on from the moulding process and can take an age for this to wear off and the belt to start "rolling" as it runs. It sorts itself out after a few tens of hours and modern Regas have fixed motors in any case..

As to the TT2, I'd suggest cleaning the belt and all driving/driven surfaces with a cleaner (I've used RS switch cleaning solvent but cannot recommend this universally as it may react with the belt compounds). Turn the top platter upside down and after fitting the belt, place the top platter thus. Switch on and watch the belt run. It'll weave up and down until the speed is stable and then should run roughly in the middle of the pulley. I seem to remember the motor can be slightly tilted to get the belt to run correctly, but if it won't, it must be replaced - suppliers of replacement belts?

Your turntable is between twenty five and thirty years old, so it would almost certainly benefit from a new belt. Guy at Puresound has the remaining stock of TT2 spares, including belts, so I'd drop him a PM.

Once you've got the new belt, then as Dave says, the motor plate can be adjusted to get the belt running centrally on the pulley. Make sure the running surfaces of the pulley and sub-platter are clean and free of any rubber residues from the old belt first, then turn the platter upside down, let the motor run for a few minutes to let everything settle down and then look to see where the belt is running on the motor pulley. If the belt the runs high on the pulley, loosen the two front socket head screws on the motor plate by half a turn, then screw down the two grub screws by the same amount to lift the front edge of the motor plate. If it's running low, then undo the two grubscrews by half a turn, then tighten down the two socket head screws by the same amount. Repeat if necessary.

All of this is detailed in the handbook, which can be downloaded from http://www.vinylengine.com/library/heybrook/tt2.shtml if you haven't already got one.

Thanks guys!
It does have a brand new original belt from Pure Sound!
And i have read the manual, but that did not mention the "straight" pulley which is mounted on the TT2's with the TPS external motor control. It does refer to the double speed pulley on my older TT2. However, the older pulley has got a ridge on each of the sections that more or less automatically centers the belt.

So, info on whether to lower the front of the motor when the belt was riding low was exactly what was missing in the manual! :)
Then i suppose the aim is to have the belt riding in the middle of the flat portion of the pulley?

Thanks again!/Mike

Sorry Mike, I didn't twig that yours is the TPS version. I've never had a chance to look at one of those so I don't know what the pulley looks like, but if it has the same arrangement of bolts and grubscrews on the front edge of the motor plate, the principle is the same.

Any chance of a close-up photo of the pulley and motor board?

Absolutely! Sadly it wont be until tomorrow night, but i'll show you with pictures instead!

Regards /Mike

The TPS pulley did just have a single crown as the speed change was effected electronically by adjusting the frequency of the supply to the motor. However a manual speed deck that had been subsequently upgraded by the addition of a TPS might still have the original double crowned pulley in which case I'd assume the smaller crown will be used all of the time and should be the same diameter as the TPS pulley given that the TPS also produces 50 Hz for its 33.33 rpm drive.

May I add that the belt must NOT rub on the pulley shoulders, but as centrally as possible.

Quote:

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Originally Posted by DSJR

May I add that the belt must NOT rub on the pulley shoulders, but as centrally as possible.

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See my last-but-one post! :)

Quote:

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Originally Posted by shane

See my last-but-one post! :)

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I did, but that was relevent to original ones. I thought you'd posted that the later model lost the adjustment? My bad if I'm wrong, apologies...

Right, I've hit a bit of a snag. I removed the subplatter to check the bearing and change the oil, but it seems that the bearing is stuck in the well. I've tried dislodging it with the end of a cotton bud but it's not budging.

Is this a common problem? How serious is it and what can I do to rectify it?

Not really serious as the ball isn't intended to turn. Provided there isn't a flat worn on it it should be fine as is. Just clean the bearing well out as much as you can, add some new lubricant & re-fit the spindle. Do keep the surface of that inner hub clean & free from oil/grease/fingerprints.

If you do want to take the ball out & clean & reposition it, I'd fit a transit bolt to lock the subchassis in place, remove the arm & turn the whole deck over. Tapping the bearing housing (or the whole deck) from underneath should cause it to fall out.

Okey, now let me show you the differences between the earlier TT2 and its double speed pulley and the later TPS external motor control version with its single "straight" pulley.


http://www.ollars.net/hififorum/TT2_0001.JPG
Here is the later pulley, which i belive is quite similar to the one on Linn LP12's


The belt though has a tendency to wander on the pulley, making it difficult to adjust susp. to 100%. Correct me if im wrong but the rubber belt will always strive to the "highest" part of the pulley if it is convex in shape like the pulle on the images further down belonging to the early TT2.


http://www.ollars.net/hififorum/TT2_0002.JPG
This is an extreme picture, but it shows that the belt will almost always be on the verge of the pulley, top or bottom.


Below is the pulley from the early TT2:
http://www.ollars.net/hififorum/TT2_0003.JPG
This has convex belt surfaces and flanges to prevent wandering. It's quite easy to adjust this one to perfect running.


http://www.ollars.net/hififorum/TT2_0004.JPG
This last pic shows the belt in a running state, perfectly centered on the pulley.


I can appreciate the desire "not" to use a convex pulley as imperfections in the drivebelt will always create speed variations to a bigger degree that with a straight pulley... At least imo and theories! :lol:

So, what is the best way to make the belt stay on the flat portion of the pulley on the later version of the TT2?

/Mike

Quote:

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Originally Posted by AlfaGTV

http://www.ollars.net/hififorum/TT2_0002.JPG
This is an extreme picture, but it shows that the belt will almost always be on the verge of the pulley, top or bottom.

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Why do you say that this is an extreme picture? The belt is riding in, essentially, the correct position.

Quote:

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Originally Posted by AlfaGTV

Below is the pulley from the early TT2:
http://www.ollars.net/hififorum/TT2_0003.JPG
This has convex belt surfaces and flanges to prevent wandering. It's quite easy to adjust this one to perfect running.

---

To be honest, I don't see how one is easier to adjust than the other? A strobe is required for the first, but at least it directly adjusts the speed (by adjusting the effective diameter that the belt sees).

Quote:

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Originally Posted by AlfaGTV

I can appreciate the desire "not" to use a convex pulley as imperfections in the drivebelt will always create speed variations to a bigger degree that with a straight pulley... At least imo and theories! :lol:

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No, there is no inherent disadvantage to a crowned drive pulley.

Quote:

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Originally Posted by AlfaGTV

So, what is the best way to make the belt stay on the flat portion of the pulley on the later version of the TT2?

---

Both the drive pulleys you show are effectively the same thing, crowned pulleys. The only difference is that the first allows the profile of the crown to be altered by tilting the vertical axis of the motor relative to the plane of the belt. The second assumes that this mechanical adjustment will be made electrically. Neither pulley solution is better, or worse, than the other in mechanical terms as both achieve belt centring my the same method, and a crowned pulley is the best solution.

However, if everything is accurately machined to a sufficiently high tolerance and the belt produced similarly, belt wander should not be an issue even on a straight sided pulley (unfortunately this is not always true, even for many 'quality' turntables).

Interesting. It's pretty much the same as the Linn pulley, and I've never understood the logic behind it. It's not possible to get a flat belt to run centrally on a pulley without a crown. It just won't do it. When I was trying to work out the design of the original pulley, I had to pretty much guess the radius of the crown. All the information I could find (there was no internet in those days, remember) came from research done in Victorian times when factory and farm equipment was driven by flat belts, and it was all pretty vague. You don't need much of a crown and in theory the pulley edges aren't needed, but you have to have something. On the Linn-type pulley, the belt just treats the angle between the flat portion of the pulley and the conical part as a crown and runs on that, as shown perfectly in your second picture. (Brilliant photos, by the way!)
What I could never work out was which diameter to use to calculate the speed. In the end, I think we just tried reducing the diameter by degrees until we got it right.

As far as removing the ball from the bearing is concerned, I wouldn't bother. The ball is aclose fit in the bearing. If you take a new bearing with no oil in, the ball takes about 20 seconds to reach the bottom of the bearing. Introduce some oil, and the oil seals the minute gap around the ball almost perfectly. If you try to force the ball in under these circumstances, the air pressure will force the brass plug out of the bottom of the bearing.Iin the same way, it's almost impossible to remove the ball once there is oil in the beaing because air cannot get past the ball. The only way I've ever managed it is to push the ball and the plug out of the bottom together. Not recommended!

There shouldn't really be any need anyway. Cotton buds or a rolled-up soft clotth will be sufficient.

The diameter of the vertical element of the pulley defines the maximum diameter available and should be a few percent greater than the ideal. The angle of the conical element effectively defines the sensitivity of asjustment.

Having the Linn style pulley (probably where the idea came from?) enables easy fine running speed adjustment. Use a non-mains high frequency strobe (avaiable on ebay I think) like the 300Hz Linn one..

At the time, the TT2 sounded slightly different to the Lp12, and of course, anything that sounded different to the LP12 was automatically worse :( I reckon that these days, the TT2 with modern takes on mat and tonearm, may well be a lot better if truth be told, especially the later model with the outboard motor supply, which I don't remember for some reason (probably because their speakers were being changed at around the same time and we weren't as keen on the new models (probably wrongly, but big Linn/Naim dealers were very narrow minded back then).

Well, it won't be 'a lot' better because in real terms it isn't all that different - but, by the same token, it won't sound all that worse either. However, besides just the superficial design, a lot depends on the concentricity of components, accuracy of machining and tolerances achieved.

Thanks Shane and Guy, that's reassuring. I've been doing a bit of cosmetic work to the turntable (repainting the MDF plinth and polishing the veneer), and have just popped on the arm. Hope to have it up and running later today, I'll post my thoughts and some pics.

Quote:

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Originally Posted by shane

Interesting. It's pretty much the same as the Linn pulley, and I've never understood the logic behind it. It's not possible to get a flat belt to run centrally on a pulley without a crown. It just won't do it. When I was trying to work out the design of the original pulley, I had to pretty much guess the radius of the crown. All the information I could find (there was no internet in those days, remember) came from research done in Victorian times when factory and farm equipment was driven by flat belts, and it was all pretty vague. You don't need much of a crown and in theory the pulley edges aren't needed, but you have to have something. On the Linn-type pulley, the belt just treats the angle between the flat portion of the pulley and the conical part as a crown and runs on that, as shown perfectly in your second picture. (Brilliant photos, by the way!)
What I could never work out was which diameter to use to calculate the speed. In the end, I think we just tried reducing the diameter by degrees until we got it right.

As far as removing the ball from the bearing is concerned, I wouldn't bother. The ball is aclose fit in the bearing. If you take a new bearing with no oil in, the ball takes about 20 seconds to reach the bottom of the bearing. Introduce some oil, and the oil seals the minute gap around the ball almost perfectly. If you try to force the ball in under these circumstances, the air pressure will force the brass plug out of the bottom of the bearing.Iin the same way, it's almost impossible to remove the ball once there is oil in the beaing because air cannot get past the ball. The only way I've ever managed it is to push the ball and the plug out of the bottom together. Not recommended!

There shouldn't really be any need anyway. Cotton buds or a rolled-up soft clotth will be sufficient.

---

Quote:

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Originally Posted by YNWaN

Why do you say that this is an extreme picture? The belt is riding in, essentially, the correct position.

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The belt is normally (when running) riding a bit higher, with the lower part of the belt just touching the conical part of the pulley. :rolleyes:

Quote:

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Originally Posted by YNWaN

To be honest, I don't see how one is easier to adjust than the other? A strobe is required for the first, but at least it directly adjusts the speed (by adjusting the effective diameter that the belt sees).

---

You misunderstood, the speed of the turntables is quite correct, with the modern one steady at 33.3-33.5rpm and the older one a little bit higher and with more variations, typically between 33.5-33.9rpm. Checked with a cheapie from fleabay, but accurate enough imo.
The issue is that i want the drive belt to keep its position on the pulleys to make it easier to adjust suspension. And the crown on the pulley makes the belt self-center up to a certain degree.

Quote:

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Originally Posted by YNWaN

No, there is no inherent disadvantage to a crowned drive pulley.

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Let me try and explain my theory:
When the belt makes contact with the crowned pulley, the belt will stretch more in belt center, than on the edges based on the different diameters. No rubber belt is 100% homogenous and this will cause variations in resistance and spring force. Thus introducing more variations in speed than with the straight pulley where the diameter ideally shuld be the same for all parts of the belt? :scratch:

Quote:

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Originally Posted by YNWaN

Both the drive pulleys you show are effectively the same thing, crowned pulleys. The only difference is that the first allows the profile of the crown to be altered by tilting the vertical axis of the motor relative to the plane of the belt. The second assumes that this mechanical adjustment will be made electrically. Neither pulley solution is better, or worse, than the other in mechanical terms as both achieve belt centring my the same method, and a crowned pulley is the best solution.

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I really dont understand what you mean here? Are you referring to adjusting the speed?

Quote:

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Originally Posted by YNWaN

However, if everything is accurately machined to a sufficiently high tolerance and the belt produced similarly, belt wander should not be an issue even on a straight sided pulley (unfortunately this is not always true, even for many 'quality' turntables).

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Nah, you're right. This is mostly a non-issue, but i would like to eliminate any potential sources of concern. :mental:

:cool: and thanks for your input!
/Mike

Once set up, just run the thing for a few hours, which should sort the belt out (possibly stored for decades folded in some way?)

Now watch the price of old TT2's go through the roof!

Quote:

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Originally Posted by AlfaGTV

The belt is normally (when running) riding a bit higher, with the lower part of the belt just touching the conical part of the pulley. :rolleyes:

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Where it specifically rides depends on the exact diameter of the inner platter. There's no need to post a 'rolling your eyes' icon :(, I know what I'm writing about.

Quote:

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Originally Posted by AlfaGTV

You misunderstood, the speed of the turntables is quite correct, with the modern one steady at 33.3-33.5rpm and the older one a little bit higher and with more variations, typically between 33.5-33.9rpm. Checked with a cheapie from fleabay, but accurate enough imo.
The issue is that i want the drive belt to keep its position on the pulleys to make it easier to adjust suspension. And the crown on the pulley makes the belt self-center up to a certain degree.

---

Well, perhaps I do misunderstand you. Both types of pulley are essentially crowned so both should have a self centering quality (assuming the belt is positioned correctly).

Quote:

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Originally Posted by AlfaGTV

Let me try and explain my theory:
When the belt makes contact with the crowned pulley, the belt will stretch more in belt center, than on the edges based on the different diameters. No rubber belt is 100% homogenous and this will cause variations in resistance and spring force. Thus introducing more variations in speed than with the straight pulley where the diameter ideally shuld be the same for all parts of the belt? :scratch:

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Well, it's a theory; however, it's not one I have found to be an issue in practice. Absolute concentricity of the drive pulley and the drive shaft are much bigger issues.

Quote:

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Originally Posted by AlfaGTV

I really dont understand what you mean here? Are you referring to adjusting the speed?

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Yes.

Quote:

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Originally Posted by YNWaN

Where it specifically rides depends on the exact diameter of the inner platter. There's no need to post a 'rolling your eyes' icon :(, I know what I'm writing about.

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Apologies, I was meaning to say that i dont know exactly how to express myself. Not intended to your post in any way!

But you are really saying that the belt position is more or less correct in this image:
http://www.ollars.net/hififorum/TT2_0002.JPG
It is supposed to ride partly on the conical section?

Regards
/Mike

That's OK.

Yes, That's correct, precisely so. The belt is intended to ride on both surfaces - the transition between the two acting as the crown that helps belt stability. As the motor (and therefore the pulley) is tilted the belt runs more, or less, on the vertical element of the pulley; this effectively alters the diameter of the pulley and so changes the gearing and speed of the platter. If the belt runs entirely (or almost entirely) on the vertical section of the pulley the pulley is either slightly too small or the inner platter is slightly too large (relative to each other) - belt tension may also be too high, as may be bearing drag or friction. Ideally, the belt isn't intended to run pretty much as your picture shows.

If it becomes necessary to replace the motor, would the current 24V Rega DC motor be an option? As I understand it the early Regas used the same AC synchronous motor as the TT2, the new motor is meant to be backward-compatible. This would potentially give the option of adding the TTPSU for speed control... Just a thought!

Well, here she is after a hard day's work...

Slideshow

Quote:

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Originally Posted by surayne

Well, here she is after a hard day's work...

Slideshow

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Brilliant! Looks brand new. :)

Quote:

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Originally Posted by surayne

Well, here she is after a hard day's work...

Slideshow

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Looks a million dollars!

Quote:

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Originally Posted by YNWaN

With respect, isn't 'critics corner' the section of the forum in which to raise such issues?

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Why? The question is relevant to this thread. Why make everyone fart around looking for the answer somewhere else?

I can't think of any reason why it shouldn't work, and I'd be really interested to hear if it was worthwhile.

Quote:

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Originally Posted by shane

Why? The question is relevant to this thread. Why make everyone fart around looking for the answer somewhere else?

I can't think of any reason why it shouldn't work, and I'd be really interested to hear if it was worthwhile.

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There has been a bit of confusion I'm afraid, my post was a response to another post that has subsequently been deleted (that post was about rising eBay prices).

Quote:

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Originally Posted by surayne

If it becomes necessary to replace the motor, would the current 24V Rega DC motor be an option? As I understand it the early Regas used the same AC synchronous motor as the TT2, the new motor is meant to be backward-compatible. This would potentially give the option of adding the TTPSU for speed control... Just a thought!

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The old philips motor is still available when scavenging the net. I looked into that while my TPS was being serviced.
Great pics by the way! Now, lets hear bout your impressions!

Regards Mike

Impressions are very, very good. I'm using the same cart as I did on my P3-24 but there is more detail, more depth and width to the soundstage and better imaging. Bass was a little wooly at first but I played about with VTA and it seems to have settled. Speed stability seems spot on, I couldn't pick up any audible wow or flutter.

My other half looked up when I popped on a 180g pressing of Nick Drake's Pink Moon and said "My God, it sounds like he's right in front of me playing!" - what more could you ask for? :)

I did have a little issue with the tonearm lift, it seemed to drop like a stone. I opened it up and popped a few drops of the damping oil into the mechanism and it's much better now. Fiddly little screws though. I've not experimented with damping the arm itself yet, but I'm not sure there's a need with the DL-160.

Mike, I don't need a new motor, but I might be tempted to try a change for the heck of it at some point. The current Rega motor is meant to be quieter and more stable than the older generation, and runs at the same frequency. I assume that I'd have to remove the pulley from the end of the motor on the TT2 and fit it on to the new motor, which might be fun. Finding a place for the PCB and inputs would also be interesting, but possible I'm sure!

Alright then! Great to hear you are satisfied!
As for my own older TT2, it is about to receive a Valhalla powersupply! :stalks:
Have you heard about such an abomination!

I believe, when comparing my two, the power supply/motor makes a big difference in performance.

Regards /Mike

A Valhalla supply that's still working? :eek:

Quote:

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Originally Posted by surayne

I assume that I'd have to remove the pulley from the end of the motor on the TT2 and fit it on to the new motor, which might be fun.

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If you decide to try this out let me know, I think I've got a spare pulley knocking around somewhere which would save you messing around with the existing motor. I recall that trying to pull the pulley off the motor often left you with the pulley and shaft in one hand and the remains of the motor in the other!

Although I've not heard one, I'm told that the TPS makes a big difference. Makes sense really, anything that feeds the motor with a clean sinewave rather than the crap that comes out of a mains socket will reduce motor vibration and clean up the sound. I'd thought of using a Valhalla supply myself (not that I actually have a TT2 at the moment, but this thread's had me searching ebay), but they're a bit pricey. I did see an artical somewhere about a Naim Armageddon clone which I might dig out some time which seemed a lot simpler.

Quote:

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Originally Posted by shane

If you decide to try this out let me know, I think I've got a spare pulley knocking around somewhere which would save you messing around with the existing motor. I recall that trying to pull the pulley off the motor often left you with the pulley and shaft in one hand and the remains of the motor in the other!

Although I've not heard one, I'm told that the TPS makes a big difference. Makes sense really, anything that feeds the motor with a clean sinewave rather than the crap that comes out of a mains socket will reduce motor vibration and clean up the sound. I'd thought of using a Valhalla supply myself (not that I actually have a TT2 at the moment, but this thread's had me searching ebay), but they're a bit pricey. I did see an artical somewhere about a Naim Armageddon clone which I might dig out some time which seemed a lot simpler.

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Yeeaargh! That doesn't sound particularly pleasant, I'll definitely take you up on that offer if I go down this route, Shane.

From what I can tell from a few days of intense Googling, there are the following options for a PSU upgrade:

1) Naim Armageddon clone. Will probably cost around £100 all in with a decent case, the circuit design looks fairly simple. You won't have speed control though.

2) Valhalla, but it's getting a little old now, so I personally wouldn't go down this route. Around £50-80 I think?

3) The Hercules / MOSE combo. Will give external speed control as well. Cost is around £300.

4) Motor replacement with a Rega 24V version, and use an external Rega TTPSU. Should give external speed control as well as a new, more stable motor and decent regulated, external PSU. Cost is £120 for the motor and £200 for the TTPSU if bought new (I'll probably look for a used older version that tends to go for around £100). The downside to this is of course that installation will probably be more complex.

5) Other external PSUs like the Origin Live, etc. are available but most seem to go for over £400 and I can't see the point, really.

Just to watch out for ease of pulley replacement. Shane and Guy could advise here :)

In my experience, adding a high current mains filter to the stock motor "supply" does a similar job to the Valhalla kit, believe it or not. I'm sure a properly phase-adjusted external supply would be far better again though, as the Lingo used to be (how much for an early Lingo?)

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?

Hola!
Well, why not? There are some advantages and some disadvantages IMO.

It is not impossible to get a "perfect" bounce in a TT2, somewhat difficult though. The biggest issue i've had is the tone arm cable dressing which was tricky when using RB-301 and OL Silver which both have quite thick and cumbersome cabling.

Your idea gives two main advantages as i see it:
You eliminate the pulling of the drive belt in one direction, which
1. Lessens drag on the bearing
2. Simplifies suspension adjustment

The disadvantages are:
1. Quite small belt contact surface, opens up for speed drifting?
2. Addition of another bearing which will influence by introducing rumble?

I have seen photos of people adding a second motor to their turntables though, in the same position as you suggest. That will also solve the above problems, but introduce others instead such as increased complexity etc. etc.

Good to see some ingenous ideas though!

/Mike

Quote:

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Originally Posted by mafrega

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?

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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! ;)

Quote:

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Originally Posted by pure sound

I presume this is a different, longer belt?

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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.

Quote:

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Originally Posted by pure sound

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.

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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.

Quote:

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Originally Posted by pure sound

Lovely job restoring that TT2 Surayne.

Not sure about the blue mat though! ;)

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Indeed (on both counts :))

Quote:

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Originally Posted by pure sound

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

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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 :D
Reason: Suspension is influenced by belt position.

Regards
/Mike

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.

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.

Quote:

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Originally Posted by YNWaN

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

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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...
:brickwall:

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? :mental:
(which would mean that the pulley has a little bit smaller diameter as far as the belt sees it?)

Best regards/Mike

belt effects.

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.

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.. :lol:

Please get a proper strobe!