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Wow and flutter on direct drive turntable

Yunus

Yunus

New Member
Hi everyone,

A friend of mine gave me his turntable last year, Pioneer PL-720.. he said it was working fine before but hasn't been using it for a while so not sure about the condition. I recently moved in to my new flat so finally had the chance to set it up.. unfortunately there's a noticeable and disturbing wow and flutter, you can hear it especially with piano sound, sounds like the music slows down for a very short time and it's waving, happens quite frequently, like once every couple of seconds... I honestly don't know much about turntables and pretty much all the recommendations I can find is about the belt.. However, this model is a direct drive so there's no belt.. Do you have any idea what the problem can be, and any potential fixes?

Thanks in advance
 
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If there's a speed control adjuster, you might try spraying it with some DeOxit contact cleaner. At the very least, try moving it back and forth several times and see if it helps clean it up a little.
 
Make sure that the records you are playing are well-centered so that the tonearm isn't swaying back and forth, which happens at about that 2 second rate. Off center records cause wow at 33 1/3 rpm.
 
Yunus said:
Hi everyone,

A friend of mine gave me his turntable last year, Pioneer PL-720.. he said it was working fine before but hasn't been using it for a while so not sure about the condition. I recently moved in to my new flat so finally had the chance to set it up.. unfortunately there's a noticeable and disturbing wow and flutter, you can hear it especially with piano sound, sounds like the music slows down for a very short time and it's waving, happens quite frequently, like once every couple of seconds... I honestly don't know much about turntables and pretty much all the recommendations I can find is about the belt.. However, this model is a direct drive so there's no belt.. Do you have any idea what the problem can be, and any potential fixes?

Thanks in advance
Click to expand...

does the quartz lock light stay on, or does it flicker, maybe go out when the stylus is lowered?

If so the motor may need some lube.
 
Thank you for all the answers, I appreciate it .. so quartz light is on, there's no flickering or something... And I can confirm that it's not because of the records since I've tried 10 different one, all the same..

@beej thanks a lot, I'll email you..
 
Direct drive tables often have fabulous wow and flutter ratings, but they also often base these ratings, not on actual measurement using records, but on the electronic parameters of the motor and the frequency and error correction circuits Seems like cheating to me - and certainly no physical object ever acts exactly like theory says it will, especially ones that are subject to varying drag, as are turntables. It is true that the test records may have more wow and flutter than the best DD tables, but I'd like to see what the numbers are when they are arrived at in exactly the same way that belt and idler drives are measured. My ears tell me that plenty of DDs are affected by what is on the record.
 
Nat said:
Direct drive tables often have fabulous wow and flutter ratings, but they also often base these ratings, not on actual measurement using records, but on the electronic parameters of the motor and the frequency and error correction circuits Seems like cheating to me - and certainly no physical object ever acts exactly like theory says it will, especially ones that are subject to varying drag, as are turntables. It is true that the test records may have more wow and flutter than the best DD tables, but I'd like to see what the numbers are when they are arrived at in exactly the same way that belt and idler drives are measured. My ears tell me that plenty of DDs are affected by what is on the record.
Click to expand...

They take the measurement from the frequency generator in the motor which is directly proportional to the rotation of the platter.
 
To expand on what JP said, the motor has a frequency generator, it feeds back to the motor controller. Any discrepancies or deviations is corrected on the fly. So reading the W & F from the frequency generator is perfectly valid. Any deviation is going to show up on the frequency generator so it's more likely a more accurate test than a test record.

BillWojo
 
Nat said:
Direct drive tables often have fabulous wow and flutter ratings, but they also often base these ratings, not on actual measurement using records, but on the electronic parameters of the motor and the frequency and error correction circuits Seems like cheating to me - and certainly no physical object ever acts exactly like theory says it will, especially ones that are subject to varying drag, as are turntables. It is true that the test records may have more wow and flutter than the best DD tables, but I'd like to see what the numbers are when they are arrived at in exactly the same way that belt and idler drives are measured. My ears tell me that plenty of DDs are affected by what is on the record.
Click to expand...

Here is a real life report from DD table and test test disk. Captured by PlatterSpeed app.

Screenshot_2021-11-22-22-52-41.png
 
Something I would check is whether the wavering is down to room reflections rather than speed instability. Quite easy to confuse the two and room reflections off hard walls can lead to interference patterns at certain frequencies that seem like speed instability.

To check this listen to the problem records using headphones or with one speaker only with ear close to the speaker. A test record with a continuous tone is the best way for checking.

If the wavering is still there using headphones then it is either the deck or an off centered record. If the wavering disappears then it is likely to be room reflections.
 
cre009 said:
Something I would check is whether the wavering is down to room reflections rather than speed instability. Quite easy to confuse the two and room reflections off hard walls can lead to interference patterns at certain frequencies that seem like speed instability.

To check this listen to the problem records using headphones or with one speaker only with ear close to the speaker. A test record with a continuous tone is the best way for checking.

If the wavering is still there using headphones then it is either the deck or an off centered record. If the wavering disappears then it is likely to be room reflections.
Click to expand...

In my opinion, headphones are the best way to check for errors and problems. Even to rule-out amp issues versus speaker issues.
 
I don't think correction on the fly is the same thing as no error. There is always a delay in error correction, and while it may be miniscule, this is a field in which minute details matter, and not just to the tinfoil hat crowd. DD specs are an important part of their claim to being the best type of table, and it seems unreasonable to accept a theoretical result for one set of turntables while actual measurements are used for the others. This isn't a belt/idler crank complaint - I think the better DDs are outstanding, but I want to see the exact same measurements for all.
You could also simply report the speed constancy of the motor in a belt or idler drive without reference to its interaction with the platter mass and the compliance of the belt or idler, but you would clearly not be reporting on the actual results.
 
Nat said:
I don't think correction on the fly is the same thing as no error. There is always a delay in error correction, and while it may be miniscule, this is a field in which minute details matter, and not just to the tinfoil hat crowd. DD specs are an important part of their claim to being the best type of table, and it seems unreasonable to accept a theoretical result for one set of turntables while actual measurements are used for the others. This isn't a belt/idler crank complaint - I think the better DDs are outstanding, but I want to see the exact same measurements for all.
You could also simply report the speed constancy of the motor in a belt or idler drive without reference to its interaction with the platter mass and the compliance of the belt or idler, but you would clearly not be reporting on the actual results.
Click to expand...

What is theoretical about a direct continuous rotation measurement of the motor?
 
What happens when groove modulations change?
Why do cheap direct drives with light platters not sound as good as substantial ones with massy platters, even though they have great specs?
 
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