I just checked my TT speed with a couple of of DL/printed strobe disks for 60hz.
There is absolutely no "wow".
However, it shows that both speeds are slightly slow by the same exact amount .....probably not enough to even notice.
This is with a new belt, clean pulley and platter... everything lubed and spinning freely.
So I checked my hz and discovered that it's 59.9 hz
My 66 year old brain is having a freeze....... Would that account for the slightly slow reading. or, would that make it appear faster?
There is absolutely no "wow".
However, it shows that both speeds are slightly slow by the same exact amount .....probably not enough to even notice.
This is with a new belt, clean pulley and platter... everything lubed and spinning freely.
So I checked my hz and discovered that it's 59.9 hz
My 66 year old brain is having a freeze....... Would that account for the slightly slow reading. or, would that make it appear faster?
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Is your motor a 60Hz induction type?
If it is then it will track your strobe and always appear slow...drive ratio issue.
If it is some other type of drive that is not derived from line frequency then it would show faster than 59.9Hz if actually accurate.
Either way it seems that it is actually slow.
If it is then it will track your strobe and always appear slow...drive ratio issue.
If it is some other type of drive that is not derived from line frequency then it would show faster than 59.9Hz if actually accurate.
Either way it seems that it is actually slow.
Your line frequency is probably far closer to 60 than 59.9; how good is your counter? Being belt drive, small errors in platter speed are likely. It's almost impossible to get the belt thickness just right for the pulley diameters so the platter speed comes out with no drift.
I found the problem.
The belt guide to change speeds was hitting the belt ever so slightly in both 33 and 45.
Pulling the lever back slightly so the guide does not hit the belt brings the speed up to perfect. .
Tomorrow I will see what I have to do to adjust it to bring it down a hair. .
The belt guide to change speeds was hitting the belt ever so slightly in both 33 and 45.
Pulling the lever back slightly so the guide does not hit the belt brings the speed up to perfect. .
Tomorrow I will see what I have to do to adjust it to bring it down a hair. .
A strobe that operates at mains frequency will always track mains frequency.
The turntable will hopefully turn at the correct speed/frequency.
If this frequency is "locked" to the mains frequency, then the strobe will ALWAYS indicate the SAME speed error.
Only when the TT speed and/or the strobe speed are NOT locked to mains frequency will the strobe indicate changes in the relative speed of strobe to TT rotation.
The turntable will hopefully turn at the correct speed/frequency.
If this frequency is "locked" to the mains frequency, then the strobe will ALWAYS indicate the SAME speed error.
Only when the TT speed and/or the strobe speed are NOT locked to mains frequency will the strobe indicate changes in the relative speed of strobe to TT rotation.
as I remember it, a tiny bit slower speed gives better timing, rythm, and 'sonics'
or ... maybe its really the opposite
just a tiny bit too fast, and all the good musical stuff is gone
and I believe that is a main problem with all modern music 'reproduction'
but with new and better digital technology this may be changing soon
or ... maybe its really the opposite
just a tiny bit too fast, and all the good musical stuff is gone
and I believe that is a main problem with all modern music 'reproduction'
but with new and better digital technology this may be changing soon
Best IMO to playback at the proper speed, obviously if the cutting lathe was running off speed all bets are off unless you have some range of adjustment and know by pitch whether you are on speed or not.
I don't buy that playing off speed is going to be an improvement, but small errors are probably undetectable in practice.
Back when I was restoring my MIT flea TD-124/I basket case I used it as a source for an audio get together, it was running several % slow and while I could tell, apparently I was the only one - the strobe and speed adjustment linkages were not fitted at that time and I had to adjust it manually with a vinyl engine strobe I printed out for the occasion.. The strobe confirmed it was running slow, and reaching under the table to adjust it was a royal pain. Lots of curious looks and comments from the well beered crowd.. lol
I don't buy that playing off speed is going to be an improvement, but small errors are probably undetectable in practice.
Back when I was restoring my MIT flea TD-124/I basket case I used it as a source for an audio get together, it was running several % slow and while I could tell, apparently I was the only one - the strobe and speed adjustment linkages were not fitted at that time and I had to adjust it manually with a vinyl engine strobe I printed out for the occasion.. The strobe confirmed it was running slow, and reaching under the table to adjust it was a royal pain. Lots of curious looks and comments from the well beered crowd.. lol
I just checked my TT speed with a couple of of DL/printed strobe disks for 60hz.
There is absolutely no "wow".
However, it shows that both speeds are slightly slow by the same exact amount .....probably not enough to even notice.
This is with a new belt, clean pulley and platter... everything lubed and spinning freely.
So I checked my hz and discovered that it's 59.9 hz
My 66 year old brain is having a freeze....... Would that account for the slightly slow reading. or, would that make it appear faster?
Unless you're running your own generator, it is NOT 59.9 Hz. To be on the power grid, the generators are all in phase - obviously at the same frequency. The most likely culprit is your metering device needs calibration.
Wow can be far finer than can be measured with a strobe disc. If you can see wow on a strobe disc it will sound really bad.
Since we can be pretty certain your 60 Hz really is 60 Hz, you could have a slightly small motor pulley (if the table uses a synchronous motor) or if it uses a variable speed DC motor, the regulator is a little off.
I worked on turn tables may years ago and can tell you nearly everyone complained of _slghtly_ slow but nobody complained it it was a percent or more fast.
G²
I used just a "Kill A watt"
BTW, assuming that the TT uses line hz to lock in motor speed, if you then read the speed with a light bulb with the same hz error, wouldn't the speed still indicate correct?
Correct me if I'm wrong .
In any event it was just the belt lightly rubbing on the guide that caused the slight slowdown .
I'm now happy with the speed. I'm actually surprised how stable it is.
BTW, assuming that the TT uses line hz to lock in motor speed, if you then read the speed with a light bulb with the same hz error, wouldn't the speed still indicate correct?
Correct me if I'm wrong .
In any event it was just the belt lightly rubbing on the guide that caused the slight slowdown .
I'm now happy with the speed. I'm actually surprised how stable it is.
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You are wrong.Unless you're running your own generator, it is NOT 59.9 Hz. To be on the power grid, the generators are all in phase - obviously at the same frequency. The most likely culprit is your metering device needs calibration.
Wow can be far finer than can be measured with a strobe disc. If you can see wow on a strobe disc it will sound really bad.
Since we can be pretty certain your 60 Hz really is 60 Hz, you could have a slightly small motor pulley (if the table uses a synchronous motor) or if it uses a variable speed DC motor, the regulator is a little off.
I worked on turn tables may years ago and can tell you nearly everyone complained of _slghtly_ slow but nobody complained it it was a percent or more fast.
G²
The mains frequency varies each time the load changes.
The load changes all the time.
Therefore the frequency changes all the time.
I used just a "Kill A watt"
BTW, assuming that the TT uses line hz to lock in motor speed, if you then read the speed with a light bulb with the same hz error, wouldn't the speed still indicate correct?
Correct me if I'm wrong .
In any event it was just the belt lightly rubbing on the guide that caused the slight slowdown .
I'm now happy with the speed. I'm actually surprised how stable it is.
You're correct. Using a line timed strobe like a neon bulb would read the same as the line frequency changed which was why I mentioned DC dervos.
G²
Turntable speed measurement
There seems to be a lot of lively discussion on this site regarding turntable speed and stability. I became interested when designing a digital PSU to control the platter speed and was confronted with the problem of measurement: Stobes are only slow/fast indicators and somewhat awkward to use and handheld tachs are too inaccurate and subject to movement. I eventually built a digital tach with 0.001RPM resolution.
I soon discovered that most of the PSU's out there were too coarse (0.1RPM steps) to dial in the speed of the platter. The PSU I was working on had 0.01RPM steps which was better, but the next thing I noticed was no matter how close I initially dialed in the speed, it would slowly drift upwards (~0.25 RPM) over a 30-45 minute interval. Since the tach has a serial output, I connected the two together, and the platter now stays within ±0.005RPM, no matter how long it runs.
There seems to be a lot of lively discussion on this site regarding turntable speed and stability. I became interested when designing a digital PSU to control the platter speed and was confronted with the problem of measurement: Stobes are only slow/fast indicators and somewhat awkward to use and handheld tachs are too inaccurate and subject to movement. I eventually built a digital tach with 0.001RPM resolution.
I soon discovered that most of the PSU's out there were too coarse (0.1RPM steps) to dial in the speed of the platter. The PSU I was working on had 0.01RPM steps which was better, but the next thing I noticed was no matter how close I initially dialed in the speed, it would slowly drift upwards (~0.25 RPM) over a 30-45 minute interval. Since the tach has a serial output, I connected the two together, and the platter now stays within ±0.005RPM, no matter how long it runs.
Attachments
as I remember it, a tiny bit slower speed gives better timing, rythm, and 'sonics'
or ... maybe its really the opposite
just a tiny bit too fast, and all the good musical stuff is gone
and I believe that is a main problem with all modern music 'reproduction'
but with new and better digital technology this may be changing soon
Interesting theory.
This must be the reason why all Regas run slightly too fast.
Best IMO to playback at the proper speed, obviously if the cutting lathe was running off speed all bets are off unless you have some range of adjustment and know by pitch whether you are on speed or not.
I don't buy that playing off speed is going to be an improvement, but small errors are probably undetectable in practice.
...
agree
Actually, it hsa been my experience that slightly too slow is more notice noticeable than slightly too fast.
Slightly too fast can often just make something seem just a bit more lively somehow but, slightly too slow can really get your
attention in some songs as the music seems to "drag" somehow .
Slightly too fast can often just make something seem just a bit more lively somehow but, slightly too slow can really get your
attention in some songs as the music seems to "drag" somehow .
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when I said 'slow', it sounds like being misunderstood
'slowish' means 'inaudible'
it should not be heard as 'slow'
but its where the music begins to breathe, and sound 'airy and liguid''
and in the same manner, 'faster' should not be audible as being too fast either
it does give the music imaginary pace
but its faking, and not real
'musicality' disappears
it will sound more like a lifeless drum machine
but it may be difficult to hear at all
it's a bit like a live band where the drummer keeps speeding up the beat, and pushes the whole band to play too fast
will the audience hear it
I don't think so
even many musicans won't know the difference
it's a really difficult thing
a small thing, but exstremely important
could be like night and day
and the producer ... who knows what he will do ?
'slowish' means 'inaudible'
it should not be heard as 'slow'
but its where the music begins to breathe, and sound 'airy and liguid''
and in the same manner, 'faster' should not be audible as being too fast either
it does give the music imaginary pace
but its faking, and not real
'musicality' disappears
it will sound more like a lifeless drum machine
but it may be difficult to hear at all
it's a bit like a live band where the drummer keeps speeding up the beat, and pushes the whole band to play too fast
will the audience hear it
I don't think so
even many musicans won't know the difference
it's a really difficult thing
a small thing, but exstremely important
could be like night and day
and the producer ... who knows what he will do ?
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