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Mono Reissues and the Conical Stylus

Hi Folks,

Recently I started buying mono reissues from Speakers Corner, Impex, and have recently ordered a few from Analogphonic. They're all of the 'long haired' variety. In the process, I've come to discovery threads where posters claim that the newer mono reissue grooves are cut in a V (stereo) shape rather than the vintage U (mono) shape.
My AT 33 mono cartridge comes with a conical stylus and from what I can tell, so do the better mono cartridges, i.e. the Miyajima Zero Mono. This of course would then create an issue where it pertains to using a conical stylus in a V shaped groove.

Around November, I plan to purchase a Jelco tonearm for my modified Thorens TD 160 and after that, will be looking to upgrade to a higher end mono cartridge. However, I don't see that they're would be a viable solution to the stylus dilemma given that I will only have one tonearm. I do by the way own a collection of early mono records but would like to find a cartridge that better crosses over between my vintage pressings and my reissues. Any help is greatly appreciated. Thanks!
128x128goofyfoot
intactaudio
302 posts
 
Can anyone provide a reference to the "U" shaped groove and how it is cut?

dave
lewm
13,242 posts
 
Hi Dave, Do you have any thoughts on the putative benefits of a "true mono" cartridge vs a mono cartridge created from a stereo cartridge by bridging the two channels internally?
I think someone originally must have used the upper case "U" to symbolize the shape of an early mono record groove, for want of a letter in the alphabet that better conforms to the actual shape of the groove, whatever that is. Now we all use it without thinking much about it.
intactaudio
302 posts
 
I think there is some general confusion about the bridging concept used to sum the stereo signal to add the lateral movement and null the vertical and a cartridge that only picks up information in the lateral plane.    My take is that if the coils remain oriented at a 45º angle to the record and then wired in series for mono then it is a stereo cartridge wired for mono and it doesn't matter if it if done internally or externally.  If however the same parts are used for a mono cartridge and the coil is oriented so there is only pickup in the lateral plane, then it is a mono cartridge.  In this case there would be only be windings for pickup in the lateral plane and the windings at 90º to that plane would not be used / wound.  

As for the "U" shape discussion I think it leads to a bunch of confusion.  I have yet to see a cutting stylus with anything other than a "V" shape with the angle of the v being slightly less than 90º.  Whether this cutting edge cuts with information in just the lateral plane (mono) or in both the lateral and vertical plane (stereo) does not matter and the groove cross section will always be a V.  The only way a groove with a rounded bottom to resemble a "U" could be done would be with a rounded point cutter and I have never seen anything like that and even if it existed, it would do a very poor job of cutting.

dave
goofyfoot's avatar
goofyfoot OP
1,380 posts
 
Dave, are you saying that late 1940's to late 1950's mono records are cut with the same V shaped groove as stereo records?
intactaudio
302 posts
 
That is my understanding.  I just looked at a 1955 London ffrr  (Ted Heath ant the London Palladium) and the groove is a V.  The bottom does have a slight radius.  A stereo cutting stylus specified by Ortophon has a 3-4µm radius which would explain that but that is still a fraction of the radius of even the smallest conical.  

dave
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