Some quick, immediate lessons from frequency/test records

[13hm13]

Recently, I acquired a few test LPs from local used record shops. One is from Shure (1981), the other from Command (1960).
These are not PROFESSIONAL test records, like CBS, which are filled with test tones, tracking tests, wave specific tones (like square or triangle) , and extended sweeps.
These "pro-sumer" LPs do contain basic tones and stereo balance tests.
Perhaps the most important learned lesson is that the high-freq tones (6khz and 10 khz) REALLY reveal surface noise and pops. No doubt all the high-freq groove angles capture dust and particles that are difficult to remove. The LPs LOOK clean and general record cleaner and carbon fiber brush does not seem to thoroughly remove the embedded contaminants.
The Shure LP has a slight warp, and a steady 1khz tone sways the channel balance on the warp hump.

 

[nopiano]

Perhaps the most important learned lesson is that the high-freq tones (6khz and 10 khz) REALLY reveal surface noise and pops

And when they are decades old, these grooves will be totally clapped out! Even at the time we were warned that using them with a mistracking cartridge could irreparably damage them, so I dread to think what they’re like today. I daresay even thorough cleaning with a wet machine can’t repair past damage.

However, a perfectly aligned cartridge will be much quieter, and lack the buzzing and whistling noises that is the harmonic distortion you are surely hearing.

 

[13hm13]

And when they are decades old, these grooves will be totally clapped out!

No!
Note what I said in the OP . The noise gets worse ONLY in the very-high-freq tones, So the grooves/tracks are mostly quiet ,
I haven't yet done ultrasonic or machine cleaning, so doing deep cleaning may very well help.

PVC records are not that fragile. Otherwise, their sales would've tanked early on. The scientists and engineers continuously worked on PVC chemistry and pressing techniques, and had most issues considering record wear licked early on. Of course there are exceptions, such as inexperienced kids handling records, etc.

 

[Al ears]

No!
Note what I said in the OP . The noise gets worse ONLY in the very-high-freq tones, So the grooves/tracks are mostly quiet ,
I haven't yet done ultrasonic or machine cleaning, so doing deep cleaning may very well help.

PVC records are not that fragile. Otherwise, their sales would've tanked early on. The scientists and engineers continuously worked on PVC chemistry and pressing techniques, and had most issues considering record wear licked early on. Of course there are exceptions, such as inexperienced kids handling records, etc.

If anything is going to get worn out with age it's exactly that, the high frequency grooves.
I would never use an old or pre -owned test record to set up my cartridges.

 

[nopiano]

Note what I said in the OP . The noise gets worse ONLY in the very-high-freq tones, So the grooves/tracks are mostly quiet ,

Yes, it always did, even when new. They are the most fragile - because they contain minutely fine high frequencies - and because they are the most played.

But good luck restoring them with your cleaning.

 

[13hm13]

Yes, it always did, even when new. They are the most fragile - because they contain minutely fine high frequencies - and because they are the most played.

The increase in noise during, say 10khz, is SIGNIFICANT. As if someone sprinkled sand on the grooves.
I'll have to look at the grooves with a microscope. Yes, all that heavy vibration (in those passages) with a diamond stylus can destroy the PVC quicker.