Any old cheapie works I suspect. In our hospital wards they buy packs of 10 for the nurses to use, with each stethoscope costing only a couple of bucks. But actually they work pretty well, especially if you're not trying to hear some really quiet heart murmur. Rather like in the pro audio world there's a bit of a law of diminishing returns, except that as a patient you'd probably like to think that your doctor is using the best tools available. I just picked up this on on eBay. I think I might have got the idea of cutting off the tubing from an article in silicon chip magazine... it was commented that the less tubing the better as I recall. So you basically sacrifice most of the tubing and the earpieces. If I find the article in silicon chip I will post a reference but I don't think the actual article is in the public domain.
