Where do classical vinyl records get their rumble from?

@richardbrand Yes, some mono cartridges are compatible with stereo pressings and others will chew it to pieces. Why this is the case, I haven't yet been able to figure out. Some folks will claim that a true mono cartridge will ruin a stereo pressing but a strapped stereo cartridge for mono will play fine on a stereo record, or vise versa. Neither of these to my knowledge is true, it just requires a little online research.  But I will say that I'm truly a lover of mono vinyl, so if there's ever a reason to consider buying a mono cartridge, I'd recommend it. The Hana SL MK II seems to be a great value and an excellent place to start.

Now as far as using a computer-based analysis program, I don't know of anything but that's not saying much. There may be a way to trace sound waves and then make determinations visually by interfacing your turntable to a computer with professional software but that sounds very expensive and complicated.

Anyway, given that your noise and rumble issue seems to to be imperceptible, it was just a curiosity on my part. However, if you did purchase a quality mono cartridge that was stereo compliant, then you'd also have a reason to collect recordings that were made between the 1920's and the 1960's.

@goofyfoot 

Yes, some mono cartridges are compatible with stereo pressings and others will chew it to pieces. Why this is the case, I haven’t yet been able to figure out. Some folks will claim that a true mono cartridge will ruin a stereo pressing

It is because before stereo, there was no vertical component in recordings, so mono cartridges did not need to track vertical modulations.  Consequently they had no need for vertical compliance - which you can think of as springy suspension in the vertical plane.

Stereo records are cut so left and right channel are at 45-degrees.  Each stereo channel has both horizontal and vertical components.  If a stereo record is played with a pure mono cartridge (one without vertical compliance) it will tend to plow through the vertical components, pretty much destroying the record.

I only have one mono LP record which I guess was a purchase mistake on my part.  I do have most of Elgar’s pioneering electrical records, which have been transcribed to CD.  I recently bought a 1934 recording of Walter conducting Mahler 9 and was rather stupidly surprised to find it was transcribed to CD from 78-rpm records.  Somehow I thought the Germans would have been using magnetic tape by then.

I’ll just note that DS Audio has recently released mono versions of all its optical cartridges, for those like you who are really into mono!

@richardbrand I'm referring to mono cartridges made today. You said,'If a stereo record is played with a pure mono cartridge (one without vertical compliance) it will tend to plow through the vertical components, pretty much destroying the record.'

This is not the case. I have a true mono cartridge (individual mono coils in the left and right) and it will play fine on stereo pressings with no damage to the record. A strapped mono cartridge may or may not hurt a record. Same goes for a true mono cartridge.

Anyway, the reasoning behind playing those troubled stereo records with a mono cartridge is deductive. If you play those records with a mono cartridge and you don't experience rumble or noise, than the problem is coming from the vertical walls of the groove.

@cleeds No there are true mono designs made today that play in both right in left channels. Those cartridges have four pins on the back. These make up the large majority of cartridges on the market today. You can buy mono cartridges that play in only one channel and they will have two pins on the back, Most of those cartridges are specially ordered, i.e. Miyajma. The distinction between true mono cartridges and those that are not, pertains to whether a stereo cartridge was strapped. This has been discussed in past Audiogon posts to great detail.