gene-pool said:
Frank (quote snipped) For Technics 1200's turntables do you suggest getting the Ortofon OM cartridges over the Concordes. I know you already explained the reasoning behind your contacts to me but, when you get a chance please elaborate more on the subject here. Also, could you explain what the best way of mounting an OM cartridge on a headshell is? Further back or forward and why? Thanks again. -Gene
OM (which btw stands f/ "optimum mass", due to the removable weight in the top plate) vs Concorde is really a matter of personal choice. The OM is less expensive because it lacks the integrated haedshell/finger lift. The CC is more convenient because there are no little wires to attach or adjustments within the headshell.
So, if you're heavy handed , the CC is the better choice.
Now factor in the "contacts" issue and we have another consideration. Because DJs take these on and off frequently, the contacts can oxidize due to finger contact and exposure to normal humidity, etc. (please no licking them, it's a temp solution that accelerates the oxidation). This is not so much a problem f/the Technics headshell because it is made to specfically fit /match the tonearm. However cart manufacturers have to compromise the spacing of the contacts slightly to fit all makes of TT, be it Numark, Gemini, Stanton, etc. In any event, there's no question that the mounting method (called SME mount) is a very weak link in a TT for DJ use. Contacts cutting in and out would not be an issue f/home use where once it's on, it's on.
Within the last year Ortofon has changed the shape of these contacts from flat to round, and changed the formulation of the gold plating, so it has helped the problem. (do you think
the Shure Whitelabel specs on there website " reliable electrical contacts" was aimed at us ?
)
To maintain good contact, the factory now recommends swabbing them w/ a q-tip lightly moistened w/ WD-40. Also apply to the 4 contacts within the tonearm and to the threads of the TA mounting collar. The last because mounting/removing carts on a regular basis creates aluminum oxide dust which gets inside the TA and RUSTS.
The inside of the OM and CC is the same and all the stylii are interchageable among all the models, Thus, sound/performance is not an issue in the choice. Orotofon Denmark does not always update the specs of the older models, but whenever there' s an improvement, it is appled to the entire model production.
Positioning an OM in the headshell (called "overhang") is done by using the round , plastic guage supplied w/ the TT. One end fits over the tonearm and the stylus should line up w/the tiny hole at the other end. Move forward or back until it does. If you've lost the guage I beleive subsiturtes are available at the Shack. (flat ones that fit over the center spindle)
Now to why : (gene, you got me writing an essay here, it was easier on the phone because I'm a hunt and peck typist) The only way a stylus tracks a record accurately over its entire surface is when you have a TT w/ a linear tracking tonearm (ie not pivoted) Thus the "angle" of the cart never changes. However w/a pivoted tonearm, the angle is constantly changing and is only 100% at two spots in it's sweep acroos the record. All other places are a slight compromise. (btw the guage adjustment is at one of those spots.) So the better you can adjust the OM within the headshell slots, the less of a tracking error. Again, less critical in DJ setups than hi-fi systems.
Tonearms w/ no "S" shape or angled headshell--ie completely straight, have the most error.
)
). i've always wondered why this type of info isn't included with the carts, especially dj carts since they are aimed at a specific group of consumers. - jeff h
Actually youre right , my force decriptions were backwards. Thanks f/pointing it out . I've gone back and edited the post so new readers won't be mis- led.