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Old 24th February 2013, 01:14 PM   #1
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Default WOW & FLUTTER or maybe something else?

My question is, is there something else that could cause effects that I'm perceiving as wow & flutter? I could be turning into a complete paranoid crackerjack & I'm imagining it all or something is playing tricks on me.

I've tested the speed using 3 different strobes while playing & they all stay stable. If I touch the platter/belt/pulley, I immediately see movement. I have to touch quite hard to get an audible effect as the platter weighs 7 kilo's & the motor seems to have a fair amount of torque.

So, what am I hearing when in normal use? It will be the same passage every time I play the same record. Its not on heavily modulated passages but only on quiet ones. I started a thread about unipivot tonearms as I've never owned & I've basically been able to set the VTA so that the arm isn't resting against the sides & can twist freely side to side, not sure if that's correct. Could it be this wobble?

I'm going to get a laser tachometer & have an aluminium disc punched at work with 4 equally spaced slots so I can use 4 reflective strips as I've read it gives a more accurate reading.

I really hope some one can help. Thanks
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Old 24th February 2013, 04:10 PM   #2
AVWERK is offline AVWERK  United States
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Make sure that the surface the belt touches has no way to slip either by loose contact, oily hands on the belt etc.
Eliminate this issue by taking some rubbing alcohol to clean everything.
Also, how do you know your platter is balanced?
Make sure the platter and plinth are level.
Any of these will create a pitch change


Regards
David
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Old 24th February 2013, 04:43 PM   #3
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Quote:
Originally Posted by AVWERK View Post
Make sure that the surface the belt touches has no way to slip either by loose contact, oily hands on the belt etc.
Eliminate this issue by taking some rubbing alcohol to clean everything.
Also, how do you know your platter is balanced?
Make sure the platter and plinth are level.
Any of these will create a pitch change


Regards
David
I did a bit of research on the forum & found some more suggestions. Rubbing chalk/talc into the belt, cleaning everything etc. Tried all those & still the same. Your platter balance suggestion sounds like its worth investigating. I'll have to devise a way of checking it. I'm playing some Wagner now & the slower passages sound terrible, problem is, if I take it off & put it back, it will be the same passages that sound terrible.

I've used a set of small round spirit levels to level the TT but maybe I should look into that too.

I'll get to work, thanks.
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Old 24th February 2013, 05:16 PM   #4
GoatGuy is offline GoatGuy  United States
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Sorry folks... you're getting pretty clearly into the domain of sacrificing chickens at midnight, and throwing garlic over your left shoulder while playing your records...

None of the (crap) advice about cleaning with alcohol, chalk, pixie dust, kevlar bands, and so on makes the least bit of difference - when your experience has been that the built-in tachometer is as solid as a rock, and moreover the amount of friction it takes from your finger to get it to budge is not "feather" but really significant. Having a super-premium 7 kg platter, a really nice tone arm, having invested (one hopes) in a magnificent cartridge, and a wickedly well shaped diamond ... and you're hearing things?

There was some advice, above about making sure things are level. Not bad advice, really, but again ... you'd have to be "off" by like 5 degrees (which is painfully obvious unless you're stone blind) for that even to make a hint of a difference.

The only thing that I can come up wondering (not trying to be snarky, OK?) ... is whether the vinyl itself - the one you can repeatably "hear the problem on" ... itself is either slightly mis-manufactured, or, intrinsically so. I say this because: the vinyl plastic is a wonder of materials, but like all plastics, it is unavoidably "under tension" as a consequence of it being squirted into a mold, and squeezed with incredible force to have the audio track impressed upon it. It is then cooled rapidly and shuttled around, eventually to get a sleeve and a jacket. Packed in boxes, sitting on shelves in warehouses, who knows how long, at what temperature. Then there's the handlers between ... lots of them! Was it always kept nice and flat and cool? Might it have heated up significantly at some point?

Such heating is what causes subtle rearrangement of the linearity of the tracks. I demonstrated it to an audiophile once - with two identical records, one of which I had intentionally thermally stressed over a few month period (flat as a pancake, between two plywood clamped plates!)

The "wow and flutter" was perfectly audible, and not something anyone could overlook. Yet, the two pieces of vinyl looked exactly the same, no matter how you looked in bright light to detect any warping. This is the point.

If you wish to go get nice metal plates with tiny holes, and keep fiddling, by all means, this IS the chicken-sacrificing-at-midnight forum! But by the sounds of it - really - you've not got a problem with anything physical in the playback mechanism. Just the recording and its uncertain pedigree-of-treatment.

By the way: I offer a tiny piece of advice re: the tone-arm and its degrees of freedom to move -- adjusting the counterweight to where it "floats freely" (which a good tone-arm-and-cartridge should be able to do), you should be able to touch it slightly to cause it to swing toward the spindle, and see that ... it does. Smoothly, without catches or hitches. Likewise, you should be able to see that it swings back smoothly, and in fact, JUST as smoothly, when nudged the opposite way.

If it catches at any point, or seems not to be really smooth in this motion, then I might suspect the support head.

Also, finally, make sure the needle pressure is as the manufacturer specs it. Though tempting to err on the light side, I've found that there are subtle sonic effects from not flexing the cantilever holding the diamond tip ... the right amount in the magnetic field of the pickup coils. Just set it to where it needs to be, and don't second-guess the specs!

Hope it goes well.

GoatGuy
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Old 24th February 2013, 05:36 PM   #5
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Quote:
Originally Posted by GoatGuy View Post
Sorry folks... you're getting pretty clearly into the domain of sacrificing chickens at midnight, and throwing garlic over your left shoulder while playing your records...

None of the (crap) advice about cleaning with alcohol, chalk, pixie dust, kevlar bands, and so on makes the least bit of difference - when your experience has been that the built-in tachometer is as solid as a rock, and moreover the amount of friction it takes from your finger to get it to budge is not "feather" but really significant. Having a super-premium 7 kg platter, a really nice tone arm, having invested (one hopes) in a magnificent cartridge, and a wickedly well shaped diamond ... and you're hearing things?

There was some advice, above about making sure things are level. Not bad advice, really, but again ... you'd have to be "off" by like 5 degrees (which is painfully obvious unless you're stone blind) for that even to make a hint of a difference.

The only thing that I can come up wondering (not trying to be snarky, OK?) ... is whether the vinyl itself - the one you can repeatably "hear the problem on" ... itself is either slightly mis-manufactured, or, intrinsically so. I say this because: the vinyl plastic is a wonder of materials, but like all plastics, it is unavoidably "under tension" as a consequence of it being squirted into a mold, and squeezed with incredible force to have the audio track impressed upon it. It is then cooled rapidly and shuttled around, eventually to get a sleeve and a jacket. Packed in boxes, sitting on shelves in warehouses, who knows how long, at what temperature. Then there's the handlers between ... lots of them! Was it always kept nice and flat and cool? Might it have heated up significantly at some point?

Such heating is what causes subtle rearrangement of the linearity of the tracks. I demonstrated it to an audiophile once - with two identical records, one of which I had intentionally thermally stressed over a few month period (flat as a pancake, between two plywood clamped plates!)

The "wow and flutter" was perfectly audible, and not something anyone could overlook. Yet, the two pieces of vinyl looked exactly the same, no matter how you looked in bright light to detect any warping. This is the point.

If you wish to go get nice metal plates with tiny holes, and keep fiddling, by all means, this IS the chicken-sacrificing-at-midnight forum! But by the sounds of it - really - you've not got a problem with anything physical in the playback mechanism. Just the recording and its uncertain pedigree-of-treatment.

By the way: I offer a tiny piece of advice re: the tone-arm and its degrees of freedom to move -- adjusting the counterweight to where it "floats freely" (which a good tone-arm-and-cartridge should be able to do), you should be able to touch it slightly to cause it to swing toward the spindle, and see that ... it does. Smoothly, without catches or hitches. Likewise, you should be able to see that it swings back smoothly, and in fact, JUST as smoothly, when nudged the opposite way.

If it catches at any point, or seems not to be really smooth in this motion, then I might suspect the support head.

Also, finally, make sure the needle pressure is as the manufacturer specs it. Though tempting to err on the light side, I've found that there are subtle sonic effects from not flexing the cantilever holding the diamond tip ... the right amount in the magnetic field of the pickup coils. Just set it to where it needs to be, and don't second-guess the specs!

Hope it goes well.

GoatGuy
What can I say to all that? I feel like sticking two pencils up my nose & waiting in the corner for the men in white coats to come & pick me up!!!

I tried leveling the platter a little better, using 6, yes 6 spirit levels including general diy ones & still the same.

I am intrigued by the possibility that it could be the recordings. This is the first time I've played this Wagner LP as I just bought it & its the only one that sounds rubbish all the way through. Others have only sounded bad at certain points & certain notes & like I said, when I play that record again it will be the same notes.

My tonearm does exactly what you said so That's one bit of good news.
Now where's my pencils & some chickens???!!!
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Old 24th February 2013, 05:44 PM   #6
SY is offline SY  United States
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Quote:
Originally Posted by GoatGuy View Post
Sorry folks... you're getting pretty clearly into the domain of sacrificing chickens at midnight, and throwing garlic over your left shoulder while playing your records...
And yet... I've fixed problems like this in belt drives for many decades. My last one was my VPI, with a very heavy platter, synchronous motor, and a large O-ring for a belt. The O-ring had a 3" or so section where it had started to get stiffer (from UV-induced crosslinking would be my guess- the TT sat on a shelf near a window and hadn't been run for a couple of years) and this minor mechanical flaw caused easily audible wow. It's not unreasonable to think that periodic slippage from a slick spot on the belt or platter could also have the same effect.
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Old 24th February 2013, 06:03 PM   #7
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Originally Posted by SY View Post
And yet... I've fixed problems like this in belt drives for many decades. My last one was my VPI, with a very heavy platter, synchronous motor, and a large O-ring for a belt. The O-ring had a 3" or so section where it had started to get stiffer (from UV-induced crosslinking would be my guess- the TT sat on a shelf near a window and hadn't been run for a couple of years) and this minor mechanical flaw caused easily audible wow. It's not unreasonable to think that periodic slippage from a slick spot on the belt or platter could also have the same effect.
I agree that a problem like yours could occur but I've tried multiple belts to no avail. I even tried masking tape around the platter because that tape is quite rough, to stop any possible belt slippage & I could still hear variations in speed. Not sure what I could do to check the pulley though. Records definitely aren't slipping as I did the tape test with those too. May be I need a friend round to get a second opinion & make sure i'm not nuts. I've asked my girlfriend to have a listen but in seconds I get that blank expression where all she needs is to pucker her lips & she's a goldfish!!!!
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Old 24th February 2013, 06:45 PM   #8
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I was thinking It could be some sort of tonal imbalance I can hear on certain notes & that's why it repeats every time I listen to that track/LP. Not sure if that's even possible but I'm clutching at straws & running from the white coats!!!
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Old 24th February 2013, 06:49 PM   #9
sreten is offline sreten  United Kingdom
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Hi,

A record with an off centre hole, or oversized hole, so it can't be
seated accurately will give you slow wow whatever you chuck at
the engineering accuracy.

For the truly obsessed you need a Nakamichi TX-1000 or Dragon CT.
They had automatic record centering function via a sensor arm and
rotating cams in the platter connected to a floating topplate.

Overengineering won't improve the W&F of the cutting lathe used,
or the W&F of the mastering tape deck used for older records, you
can't eradicate limitations build into a medium by overbuilding.

rgds, sreten.
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Last edited by sreten; 24th February 2013 at 06:55 PM.
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Old 24th February 2013, 06:55 PM   #10
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Originally Posted by sreten View Post
Hi,

A record with an off centre hole, or oversized hole, so it can't be
seated accurately will give you slow wow whatever you chuck at
the engineering accuracy.

For the truly obsessed you need a Nakamichi TX-1000 or Dragon CT.
They had automatic record centering function via a sensor arm and
rotating cams in the platter connected to a floating topplate.

rgds, sreten.
The off center hole makes a lot of sense, but it seems to happen at least a couple of times on every one of the few records I've got so far. Had a big collection years ago with a Gyrodec but a divorce forced me to get rid of everything & now building it back up again & this is really stopping me from enjoying my new turntable & vinyl after working pretty to buy everything again. Thanks for all the idea's so far. With all this, I still never notice a thing on the strobe disc .

Last edited by Arckivio; 24th February 2013 at 06:57 PM.
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