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A new belt for the Linn LP12

Still rock solid at 33.3, much reduced variability at 45, flicking between 45.0 and 45.1. Better than yesterday, but if you know the Mober, not rock solid.
 
wylton said:
So, I've tried to adjust the speed of my LP12/Lingo 1 with the Blue Belt.

Yesterday, I gave up. It started at -1.2% and I tried incremental changes; outer screw 1/4 turn acw, inner screw 1/4 cw, noting each adjustment, but in the end, I lost track of where I was.

So, a fresh start this morning. This time, I unscrewed both screws until they weren't touching the motor, then back in until they both touched and re-tested. I got -1.18% Then I incrementally adjusted the screws 1/8 turn at a time, and the best I've achieved so far is -0.49%. I've been double checking with a strobe too & I have tried reversing the belt inside out too. I have found that just as I'm getting close, the belt starts to rub on the belt guide, so I have to back off.

For whatever reason, the Blue Belt requires entirely different settings as compared to the Linn belt. I should mention that this is the first time that I have attempted to adjust the speed on the LP12.
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Mmmm, something not right, I always found that small changes of angle gave large changes is speed.
 
wylton said:
So, despite the above & in the belief, that for now, I'll get no better, I tried a disc. Greens Keepers - Bring in your face & Low & sweet (What's your man got to do with gan), mostly because I've played it a lot recently and it sounded totally ace-tastic (is that a word?)! Rhythm was right on the nail with a lovely low end thump, nice metallic ring to the percussion & well defined imaging. This is without reference to the £50 Linn belt and with the Lingo mk1 rather than my preferred Norton AirPower. I didn't detect any loss compared to the Lin belt & in any case, it's too much of a PITA at the moment to try changing belts, but in isolation, it does sound very good indeed; I'll try a few more records...
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Ace-tastic is most definitely a word! Is there any difference with the Norton? At least that would rule out the lingo, the 1 is getting a little long in the tooth…..
 
wylton said:
Not tried it this morning, but during the initial set-up yesterday, there wasn't much between them in terms of speed and wow & flutter & in any case the Lingo was fairly recently serviced.
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Ah, ‘fraid I’m out of ideas then. Mine has definitely settled down with running. Today is rock solid at both 33.3 and 45, whereas when first fitted the Mober really wasn’t happy at 45. How many hours running have you given it? I left mine running at 33.3 overnight last night (by mistake I should add, old and one to many reds)
 
Has anyone got a theory as to why the blue belt seems to run a little slower on the LP12? To my mind there are only two possible reasons; a) it is slightly thinner in cross-section*, or b) it may be a little ‘sticky’ from new and add a little drag (this being my best theory to date for the initial noise on the 124 that recedes so dramatically after ‘break-in’).

*I have no idea if this is true or not, but I do understand that when a material bends around a curved surface it does so at the mid-point of its thickness, i.e. the outer surface stretches, the inner surface contracts, the middle stays where it was, so replacing a thick belt with a thin belt, or vice versa, actually effects the drive ratio and therefore the speed. Again this is very obvious with fast-running drive systems like the TD-124. This is also why accurately sizing a pair of JR149 grilles isn’t as simple as one might think!
 
wylton said:
@Mike P gives some clues as to the differences between the various belts here;

"The LP12 belt has progressed through three versions:

Initial prototype - 165mm diameter and 4mm width. IIRC this is the version @flatpopely has.

Mk1 - The length stayed at 165mm diameter but the width was increased to 5mm. IIRC this is the version @linnfomaniac83 has.

It was observed that the 165mm belt ran about 1% slower than the genuine Linn belt on a standard Axis or LP12 set-up. This itself is not a problem at all since the speed can be adjusted back up again marginally. When using a Radikal the speed will automatically always be kept perfect.

Mk2 - I decided to increase the length of the LP12 belt very marginally to 167.5mm. The slightly longer belt creates less 'drag' and runs a fraction faster on a standard set-up and so needs less speed adjustment. It is of little consequence but I wanted to make the belts as perfect as possible.

For people using a Radikal there is no advantage to the Mk2 belt and no disadvantage to the Mk1 (remember the difference is tiny) and so rather than keep people waiting for the Mk2 to come into stock I sent some Radikal users the MK1."

I'm wondering if the difference in width could be the issue? The increase from 4mm to 5mm may be the reason that I find mine rubbing on the guide if I adjust the pully too much. I'll be testing shorter version soon, but from the above, I'm not sure if that will make any difference.
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It's certainly not a bad shout and I'll happily send you a 4mm width belt if you'd like to try one. However, the vast majority of the LP12 belts I've sent out have all been 5mm and to my knowledge nobody else has reported your problem with the belt rubbing on the belt guide.
 
If I had a tenner for every customer that came in the shop with a bent motor flange that had ‘absolutely no idea’ how it could ever have ended up like that.

I reckon they bend themselves, or it’s a Linn conspiracy to encourage upgrades.
 
david ellwood said:
If I had a tenner for every customer that came in the shop with a bent motor flange that had ‘absolutely no idea’ how it could ever have ended up like that.

I reckon they bend themselves, or it’s a Linn conspiracy to encourage upgrades.
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Never heard of that David, but you obviously know more than me. Can you explain how this can happen? Cheers, Matt.
 
david ellwood said:
If I had a tenner for every customer that came in the shop with a bent motor flange that had ‘absolutely no idea’ how it could ever have ended up like that.

I reckon they bend themselves, or it’s a Linn conspiracy to encourage upgrades.
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I just knew that a Linn advocate would put it down to user error. I withdraw any further interest in commenting on the Blue Belt. Sorry @Mike P
 
Wylton , I wasn’t saying you had been heavy handed or that there was anything wrong with your motor.

Just that it’s a very common issue that occurs without any apparent cause.
 
Mike P said:
It's certainly not a bad shout and I'll happily send you a 4mm width belt if you'd like to try one. However, the vast majority of the LP12 belts I've sent out have all been 5mm and to my knowledge nobody else has reported your problem with the belt rubbing on the belt guide.
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That 1mm less belt width could make all the difference in circa 1.2% speed diff
 
The Bish said:
How do you mean Matt? Mine is slow like Wylton's and am giving a good long run in before listening or adjusting - you mentioned yours was rock solid upthread, has that changed?
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Well, it was rock solid, but late this afternoon the Mober started to struggle at 33.3, as I put a record on.Sounded terrible. Went back to the Linn belt, with no issues.
 
I’d love to know what was actually happening. Did you try running the Linn with the platter on upside down to see how the belt was running?
 
I run a mober with blue belt and with thick silicon oil in bearing so much more drag to overcome than standard, no issue here.
 
Tony L said:
I’d love to know what was actually happening. Did you try running the Linn with the platter on upside down to see how the belt was running?
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Hi, yes, did all the normal things. Was rock solid at 33.3 with the Mober, so I decided to play a record. Used the Technics last night and this morning, so the Superline was well warmed up. As soon as the needle dropped, the Mober was all over the place, settled down a bit, but was never really happy (for Mober users, display didn’t go off, flicking between 33.3 and 33.6)
 
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