OK to play 78s with elliptical stylus?

Plato...It's not the shape of the stylus but its size that will degrade the 78's. The stylus tip diameter was considerably larger for 78's, and a LP stylus will scrape along the bottom of the groove instead of riding on the two sides.

Shure makes pickups and stylus to suit the 78 groove dimension, at very reasonable cost. Check their website. (Other manufacturers may also make such pickups).

Thanks Eldartford, you are right. I found the following post: "What is the difference between LP and 78 needles?
The difference is size. the 78 stylus is 4 times larger than the LP stylus. This is because the groove dimensions of the 78 disc are larger. if you place a LP stylus into a 78 groove, the needle will be resting on the bottom of the groove instead of tracing the groove wall. The result is lots of surface noise and little sound. Over the years I have seen many collectors accept this poor sound as simply the fault of the record! Using the right size stylus is always important."

So I'll need to get a cartridge built for the wider groove width. I checked out the Shure website, but so far have been unable to find what I need. But I'll keep checking and see what I can come up with.

Doing a little more research, I see that I can get a Shure M78S for around $60 and I think that Grado might make a Prestige model with a 78 stylus for around the same price. I'm not sure if I want to spring for that since I only paid $30 for the turntable, but if I don't find a better deal in the next couple of weeks, then I guess I'll pay the $60 for a new one. Man, how cheap can I get! :)