Audio quality and vinyl weight are not causally related, not that you would guess from the number of “180 gram audiophile pressings” in record shop shelves. However,the deeper groove cut facilitated by thicker heavier vinyl does have important audible benefits, as the music encoded on that deeper groove wall is better protected against damage to the vinyl surface, and heavier vinyl is more stable in the turntable platter.
Depth of vinyl groove is determined during the lacquer master cutting process, and produces the same groove depth whether pressed into wafer thin or jumbo-thick vinyl. That is why King Records in Japan could produce such great sounding Blue Note pressings on less than 120 gram vinyl.
Vinyl weight fell by over fifty percent in the decades between the rise of Bebop and the “demise” of mainstream vinyl as it became replaced by The Evil Silver Disk™. As a result, vinyl weight is a useful indicator of the probable date of manufacture, in addition to usual paraphernalia for establishing authenticity. I have a “Lexington” which has every mark of authenticity apart from its weight. You can stick a Lexington label on any piece of plastic, but you can’t disguise it comes out of a factory press at a time when 160 gram was the norm and not the 220 gram customary in 1956.
The availability of inexpensive accurate digital scales means it is easy enough to add this knowledge to your armoury of detective skills. As part of a housekeeping exercise my thousand-odd record jazz collection were put on the digital scales, allowing me bring some scientific rigour to my hypothesis about dating records.
An industry-wide overview of vinyl weight
First, an overview of vinyl weight distribution, as found in my 1,000 jazz records spanning from the early ’50s to the mid ’80s. All labels were weighed to establish “norms” for different labels and different times.
LJC Principles in dating Blue Note records
Label and catalogue number were used as a proxy for date of manufacture, allowing that some pressings out of chronological sequence. Records with mixed labels were assigned to the most modern one, hence a Lex/NY combination is an NY record. The change from Blue Note to Liberty is caught by the earless 1966 Liberty NYs, then the emergence of proper Division of Liberty. United Artists follows the same logic of approximate time periods which applied to label variations. Japanese and other non-US pressings are excluded throughout.
Blue Note originals and later reissues
Nine US-pressed Blue Note cohorts are found among Original Blue Note Liberty and United Artists, with characteristic average weight difference
The weight of vinyl biscuit and press settings in use varied between plants but reduced over time. Pressure to reduce the cost of manufacture lead to a realisation that a satisfactory fill could be achieved using less vinyl. Vinyl weight therefore remains a useful indicator of probable origin, particularly with records that appear from their labels to be early/original pressings.
Original Blue Note, 1956-66 (n=130)
There were significant changes in vinyl weight between the different label addresses during the original Blue note years. Whilst there are outliers which are untypically heavy or untypically light, none are found below 160 grams before a certain date
Lexington and 47W63rd label (1956-61)
There are many copies of Blue Note records found with earlier labels than their actual date of manufacture. I have 34 records I can confidently place in the 1956-61 date of manufacture – here is how they shape up on the scales, using catalogue number as a rough proxy for time.The first four monsters on the left are my Lexington. The trend is downwards over time.
New York New York
Next, sixty-four NY label pre-66 original Blue Notes of which I am confident, having assigned the earless ones into the later Liberty manufacture period, and letting in the mongrels with mixed labels of which one is NY (with ear, of course) A bigger sample, lots of individual variation, but nevertheless average of 165 gm weight, and a trend toward shrinking the vinyl biscuit over time. Makes sense to me, supported by physical measurements rather than opinion.
The Liberty and United Artists Years
As the cohort chart shows, the Liberty years 1966-70 Liberty-owned All Disc NJ pressed around a 145 grams, less for some West Coast variants. By the time United Artists and Transamerica accountants had their way, pressing fell to around 135 gram vinyl weight.
As noted at the outset, vinyl weight is not causally related to audio quality, however it is a useful shorthand indicator for a thousand other things detrimental to audio quality that came into play in those decades such as the shift from analogue to digital equipment
JAPANESE REISSUES TOSHIBA EMI (1983 – present day)
Japanese reissues each have a known date of release, hence the trends in weight can be stated definitively. With just the a couple of outliers, Toshiba vary between 110 and 155 grams vinyl weight. With the first wave of reissues 1983-5, vinyl weight was often typically 110-120 grams, very light. The second wave of reissues 1989-93 were actually heavier typically 120-140 gram. What is remarkable is the relative consistency compared with US manufacture, and the setting of minimum standards.