Cheap TT with speed control?

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rvb
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Cheap TT with speed control?

Post by rvb » 23 May 2019 20:08

My turntable runs 33.5 RPM and I can't adjust. I do not like. Should be perfect 33 1/3 RPM.

NewOldVinyl
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Re: Cheap TT with speed control?

Post by NewOldVinyl » 23 May 2019 20:55

How do you know it’s 33.5? Please don’t say it’s the RPM Pro smartphone app. ;)

Bob Dillon
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Re: Cheap TT with speed control?

Post by Bob Dillon » 23 May 2019 21:30

If it's a belt drive you can try another belt, or shifting around the motor slightly, if you can.

josephazannieri
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Re: Cheap TT with speed control?

Post by josephazannieri » 23 May 2019 22:02

Yo ryb:

Welcome to VE!

In my experience of over 50 years with many turntables, most healthy turntables will run about 1% fast, which will come in about 33.66 RPM. Your turntable is pretty accurate at 33.5 RPM. Are you checking it with a record being played when you check, or are you checking it just running free? I think that you should check it with a record on board and being played for the most accurate measurement. This might cure your problem. In general it is better for a turntable to run a little fast that to run slow.

What kind of turntable? Does it have vernier adjustment? How are you measuring the speed? There are strobe discs for both 50 and 60 Hz power if you click on "tools" at the top of the page. Looking at your country, I see that you are located in Europe, so I expect that you will need a 50 Hz strobe disc. Print one up and put it on the turntable and see how it measures.

I don't think you have a problem if your turntable is actually running at 33.5 RPM. My advice is not to mess with it.

And good luck from that easily satisfied old guy,

Joe Z.

rvb
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Re: Cheap TT with speed control?

Post by rvb » 24 May 2019 05:18

I measure the speed with a recording of a vinyl track against the cd track. That is were the dislike comes from. The tracks do not fit exact beneath each other in audacity for a 100% accurate inspection.

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Re: Cheap TT with speed control?

Post by josephazannieri » 24 May 2019 18:59

yo rvb:

You cannot be sure that the CD track is the exact correct speed, since it is not exactly the same as the master recording. You are just assuming that the CD track should be the same. If you are using Audacity, you should be able to expand or contract the vinyl track to make it match the CD track and lie right next to it. Audacity is remarkably flexible and allows time to be expanded or contracted and also pitch to be raised or lowered if you want. I make music for dancers, and, using Audacity, I can slow music or speed it up without changing pitch. In your case, you will want to expand or contract time and just leave the pitch alone so that time will match time. You then should be able to match track for track as you desire.

You are not going to find any turntable, even a direct drive with a vernier control, that will permit you to match up in the the exact way you apparently want the vinyl to match the tracks. I don't think there is anything wrong with your turntable, but, once again, you should use a 50 Hz strobe disc and measure the speed to be sure that there is no malfunction in the turntable. You should get a steady measurement that should not vary at all for periods of at least five minutes, or the period of the longest track that you wish to compare. If there is any variation in speed, you will have to have your turntable looked at. But, you may not be able to find a reasonably priced turntable that will supply the kind of precision you appear to be demanding. I believe the best way to achieve your objective is to expand or contract the tracks so that you can lay them exactly side by side.

And good luck from that Audacity-using but still easily satisfied old guy,

Joe Z.

chiz
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Re: Cheap TT with speed control?

Post by chiz » 24 May 2019 20:34

Easy way to check turntable speed with Audacity:
Record a few revolutions of the runout groove, then measure the length of the loop which should be (60/33.333=) 1.8 seconds for 33.333 rpm or (60/45=) 1.333 seconds for 45 rpm.

Bob Dillon
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Re: Cheap TT with speed control?

Post by Bob Dillon » 24 May 2019 20:50

rvb wrote:
24 May 2019 05:18
I measure the speed with a recording of a vinyl track against the cd track. That is were the dislike comes from. The tracks do not fit exact beneath each other in audacity for a 100% accurate inspection.
A digitally mastered LP from the same digital source as the CD might make this test valid, barring any speed deviation in the lathe used for the LP cutting. CD's and LP's sourced from analog tape are also subject to small speed deviations in the analog tape replay deck (s), unless they would have been mastered at the exact same time when the tape was played.

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Re: Cheap TT with speed control?

Post by Coffee Phil » 24 May 2019 22:01

Hi rvb,

You received a few answers on the importance or lack of matching your Lp to your CD of the same material.

If you want to know how close you are to 33 1/3 RPM put a small piece of tape on the edge of the platter and count the revolutions in 3 minutes. It should be precisely 100.

To figure if it is practical to "tweak" the speed of your machine we need to know what it is.

Phil
rvb wrote:
23 May 2019 20:08
My turntable runs 33.5 RPM and I can't adjust. I do not like. Should be perfect 33 1/3 RPM.

chiz
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Re: Cheap TT with speed control?

Post by chiz » 25 May 2019 00:27

chiz wrote:
24 May 2019 20:34
Easy way to check turntable speed with Audacity:
Record a few revolutions of the runout groove, then measure the length of the loop which should be (60/33.333=) 1.8 seconds for 33.333 rpm or (60/45=) 1.333 seconds for 45 rpm.
I just checked one of mine via this method and it is 1.800114 seconds at "33" so a touch slow but nothing I can't live with.

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Re: Cheap TT with speed control?

Post by Bob Dillon » 25 May 2019 01:07

Reminds me that a while back, I played my new Bert Jansch Live In Australia LP, lined up with the lossless digital stream of the album, because I'm pretty sure they were mastered from the same digital source (the gig was recorded to DAT). I wanted to see how they compared. The vinyl on my quartz lock DD 'table locked in time with the digital stream PERFECTLY, no drift in or out of time at all, at least for about the duration of 1/2 an LP side upon which time I took it off. :D

Like the thread starter, I'm also irritated by TT's that don't run perfectly on speed. I don't do this 1 % too fast or slow is perfectly normal stuff. Running right on speed is TT job # 1.

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Re: Cheap TT with speed control?

Post by AudioFeline » 25 May 2019 07:47

Laser digital tachometers can be bought cheaply from china/ebay for accurate measurements of turntable speed.

What is your turntable? Have you checked the library for a service manual, which may indicate how to set the speed?

If it's a non-quartz direct drive, you might be able to modify it to adjust the speed by putting a trim pot in the circuit that has the resistor which controls the speed. You may be able to identify this resistor from internet articles on how to change this resistor so the turntable will run at 78 rpm.

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Re: Cheap TT with speed control?

Post by aardvarkash10 » 25 May 2019 10:33

its out by 0.5%.

Good luck identifying that in any blind listening test.

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Re: Cheap TT with speed control?

Post by cats squirrel » 25 May 2019 12:24

why is it so important to have the record turning at exactly 33.33 rpm? I bet NO-ONE could tell it was 0.2rpm too fast, NO-ONE, just by listening, so what is the problem?

The instruments on a recording are not tuned to that accuracy and precision, and if they could be at the beginning of a tune/song, they wouldn't be at the end of it!

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Re: Cheap TT with speed control?

Post by rewfew » 25 May 2019 16:15

Having used belt turntables for years I'd been plagued with unsteady speed stability. Fast, slow, modulation with stylus drag, line voltage. During my modest income years I had a cheap Technics belt drive with strobe and servo speed pitch adjustment. Which allowed a capability to get back to stable speed, for awhile. Fast forward with more available green, I bought a Rega, which I though would upgrade to a higher level of quality. Other than an upgrade in tonearm quality. Playback was prone to speed variations with no ability to compensate for, and acoustic feedback, giving a false sense of dynamics, sometimes causing my amplifier to blow it's fuse.
Investing later into direct drive solved all these issues. If speed variation is as much a problem to record playback as was with me, and what the first post alludes to. Then how cheaply you can alleviate the problem are either searching for vintage direct drive or investing in current offerings. To me, it's worth it. No more piano or vocals changing tonal pitch. Heavily damped plinth, so no more feedback issues. Add in convenience with speed selection, VTA adjustment, headshell mounted cartridge change out with easy and accurate setup. What amount of money spent to get the accuracy of quartz locked frequency generator direct drive would be formidable with belt drive. It's not a problem to value the perception of pitch speed until it changes.

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