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Record clamp/level/45-adaptor/record weight devices? Are they entirely useless?

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#1
Okay so I basically need some kind of means to level my Sony PS-X800. I don't have a circular spirit level handy so I was going to purchase one. I saw this device. Yes, it is more expensive than just a bubble-level. However, I actually don't have 45 adaptor nor a record clamp of any kind so I thought this might be useful. Record clamps apparently help mitigate warp (though I have doubts that they are that effective as the record clamp only applies for in the middle and the warps are on the outside of the record). I am concerned about the mass though. The service manual for the PS-X800 states that loading is 0% up to 150g. Well this thing has a greater mass than that. I am not sure how it would affect the table.

It also has stroboscope markings. Seems handy, but I am worried the mass will be too great and it will be useless for actually checking the speed on lesser torque belt-drives (I occasionally do try and do some basic repair of cheap/found turntables). What is the best (i.e. cheap) light source that will reliably flash at 60Hz (aside from just a regular incandescent bulb).

It isn't hideously expensive, but it is pricey enough. I don't want to buy something that is completely useless. If you've got a recommendation for something better let me know. It isn't like I am super attached to the idea of fancy clamp thing. I mean this thing is $1,000. It just a "thing" with some half-decent machining (or so they claim). So at the $35 CAD it isn't the most hideously overpriced thing in its class.
 
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#2
Adding significant mass to a PLL DD is not a good idea. The entire drive system speed control loop is optimized for the platter, mat and typical record mass. Your wow and flutter could actually become considerably worse with the addition of a heavy record clamp.

According to a reviewer, the mass of the weight in question is 275grams, nearly double the 150g gam load for 0% deviation. Sure it would likely be fine once locked, but dynamic load variations with an additional 275g in the rotating system may compromise the otherwise excellent performance of the Sony's BSL PLL DD motor.

For speed testing on other TTs, you are better off to track down a test record and use a frequency counter on a cheap DMM for much greater accuracy.
 
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#3
Adding significant mass to a PLL DD is not a good idea. The entire drive system speed control loop is optimized for the platter, mat and typical record mass. Your wow and flutter could actually become considerably worse with the addition of a heavy record clamp.

According to a reviewer, the mass of the weight in question is 275grams, nearly double the 150g gam load for 0% deviation. Sure it would likely be fine once locked, but dynamic load variations with an additional 275g in the rotating system may compromise the otherwise excellent performance of the Sony's BSL PLL DD motor.

For speed testing on other TTs, you are better off to track down a test record and use a frequency counter on a cheap DMM for much greater accuracy.
Thanks for the info. I wasn't totally sure. I've never really bought into the whole "record clamp" thing, but the object wasn't super expensive so I was a little bit curious.

Do you have any specific recommendations with regards to test records and frequency counters? It isn't something I do a whole lot. There is local record/music store and I've had some luck selling my finds on consignment. I mean it does take like 4 months on average to sell a turntable, but everything I've put up for sale is (from an objective standpoint) significantly better than the AT turntables and whatever else they sell (though they do lack preamps).

I actually found a completely working Realistic R-8000 (Canadian version of the LAB-300). It also came with a free copy of the OST to Chariots of Fire. I was actually surprised by how decent it was. It has what I think is a novel anti-skate mechanism. I've included a picture
Realistic anti-skate.png


I tested it and it didn't sound "messed up". The rebadged Shure cartridge was surprisingly decent. In my purely subjective opinion it didn't sound "amazing", but it did sound "better" than the other random MM cartridges I had kicking around. I hope whoever owns it now is happy with it. I definitely think it is a lot better than my first table (Dual CS-515).

I thought it was a interesting table. No, it wasn't super "high-end". I don't know what it cost in 1970s, but it probably wasn't the cheapest table available. Presumably it was made for the consumer who was willing to spend a little more to get something that wasn't terrible, but was unwilling to shell out the cash for a "boutique" table (they were Radio Shack's house brand). A "mid-range" table. From what I can see such a thing doesn't exist anymore. There are only overpriced belt-drives that don't cost kilobucks and overpriced belt-drives that do cost kilobucks. Nothing much in the way of "value". Well I guess Technics has starting making tables at varying price points. Other than that I can't think of anything.
 
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#4
The anti-skate system you have shown was quite common on turntables and unlike some of the spring and magnetic designs, can often be 100% defeated by flipping it over and disengaging the two arms from one another.

In regard to speed testing, the Sony will likely be spot on and locked. You really don't have to worry about any Quartz PLL DDs in terms of absolute speed accuracy. It's rather difficult to get them "out of whack" due to the way they were designed. That said, you can never rule out some clown with a screwdriver hasn't poked around before you got to it...

Any test record that is well pressed will have a number of spot frequencies on it ranging from low frequencies to quite high. Most inexpensive DMMs these days <$40, will have a built in frequency counter function. Some will provide min/max and average, % variations etc. Depending on the gate time on the DMM and the spot frequency you use (1KHz min, maybe 5KHz max), you can get very accurate results from your turntables. There is no point measuring very high frequencies- the variation will be such that the frequency counter never stabilizes around a mean or average.

Your DMM can be directly connected to the tape-outs, preamp out, or even the speaker outs (at a low level only) for frequency counter measurements. You could also download VA (visual analyzer) or equivalent and use a PC/Laptop and a microphone to do the same job and save buying a DMM.
 
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#5
The anti-skate system you have shown was quite common on turntables and unlike some of the spring and magnetic designs, can often be 100% defeated by flipping it over and disengaging the two arms from one another.

In regard to speed testing, the Sony will likely be spot on and locked. You really don't have to worry about any Quartz PLL DDs in terms of absolute speed accuracy. It's rather difficult to get them "out of whack" due to the way they were designed. That said, you can never rule out some clown with a screwdriver hasn't poked around before you got to it...

Any test record that is well pressed will have a number of spot frequencies on it ranging from low frequencies to quite high. Most inexpensive DMMs these days <$40, will have a built in frequency counter function. Some will provide min/max and average, % variations etc. Depending on the gate time on the DMM and the spot frequency you use (1KHz min, maybe 5KHz max), you can get very accurate results from your turntables. There is no point measuring very high frequencies- the variation will be such that the frequency counter never stabilizes around a mean or average.

Your DMM can be directly connected to the tape-outs, preamp out, or even the speaker outs (at a low level only) for frequency counter measurements. You could also download VA (visual analyzer) or equivalent and use a PC/Laptop and a microphone to do the same job and save buying a DMM.
Is it common? I haven't seen it before, then again it isn't like I have a lot of turntables. I've only ever seen the spring and hanging weight variety.

It is mostly a concern with regards to belt-driven tables that lack any sort of speed control. Then again many of them aren't adjustable at all. The Duals that I've looked at usually have a means of adjusting the speed to a certain degree if you open them up. On top this they usually have a pitch control.
 
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#6
Is it common? I haven't seen it before, then again it isn't like I have a lot of turntables.
Here's a Sansui SR-838. Same basic design except they tie the string to the rotating pin on the arm collar:

1565741081062.png


And the SR-929:

1565741144507.png


Here's a vintage Akai:

1565741247101.png


An AP-003 Akai:

1565741347384.png


:)
 
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#7
Here's a Sansui SR-838. Same basic design except they tie the string to the rotating pin on the arm collar:

View attachment 31262

And the SR-929:

View attachment 31263

Here's a vintage Akai:

View attachment 31265

An AP-003 Akai:

View attachment 31266

:)
You'd have to look into the history of Japanese turntable manufacturing, but I don't even think it is impossible that they were all made by the same company acting as an OEM for one or more of those brands. How well does it actually work as an anti-skate mechanism. It seems like it would be better than just a weight on a string. I'm not exactly well versed in physics, but it seems like mechanism would at least vary the skating force somewhat over the course of the arm's travel (which is what you want as skating forces aren't constant as I understand it).
 

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