Help with cartridge loading. . .

Hi Tom,

My Shelter 901 has a recommended load of 100 ohms, but the specs also seem to suggest a lower load if running through stepup transformers, which I am. It's very easy to change the load at the output of my transformers, and I'll experiment at some point, but I'm puzzled. Why would a cartridge want to see a different load depending on the presence or absence of a tranny. I can't get my head around that one and John Chapman couldn't either. Any ideas?

TIA,
Doug

Thanks, Tom. Maybe I can get a "butt-kicking" upgrade by swapping a pair of resistors, should take about 5 seconds per tranny.

Meriweth, sorry for threadjacking. Your question just inspired my (semi-related) one.

In theory, I agree with both Zaikesman and Pbb! :)

Start with the manufacturer's recommended setting and listen long enough to get a good understanding of how it sounds. Then experiment, listening critically to decide if the differences you hear are actually improvements. It's easy to get fooled into thinking something is better just because it's different. Having a second listener to give independent feedback reduces errors and is more fun.

Zaikesman's protocol is much better than the step-by-step chinese water torture method in Meriweth's owner's manual. Make a big move down from the starting point and get a handle on the sound there. Then make a big move up. This will help you hear and understand the differences quickly and easily. Make big enough moves so that you surround the sweet spot. Homing in on your one preferred setting can be done with more confidence if you've established your upper and lower tolerance limits first.

Zaikesman, thanks for the dope slap. My own ears tell me that I wrote it backwards.

Dan, thanks for the clear explanation of loading for tranny vs. phono stage. Brilliantly simple and helpful. Even an english major should understand that a tranny needs maximum current input while a phono stage needs maximum voltage input. The cart needs to be loaded to provide whichever is appropriate. TGIF!

Sean, you stated clearly what I was fumbling toward. A cartridge mediates between kinetic and electrical energy. Changing either side affects the result.

Can I go home now?

Sean, good post. According to my in-house scientist, raising the electrical impedance to a cartridge not only requires the cantilever to move more forcefully to generate a signal, it also makes the cartridge more resistant to such movement. Almost like you had the ability to stiffen the suspension. Reducing impedance has the opposite effect of course. Clearly this will effect transient response as well as tracking accuracy at different frequencies. Next time I have a vacation week to spare I'll look up that article by Moncrieff. He's good, but this whole forum combined couldn't outwrite him. :)

Pbb, near the end of an unwashed record the other day I noticed my cantilever had a big pile of fluff on top. Watching more closely, I saw the stylus shovelling stuff out of the groove at a prodigious rate. Most of it ended up on top of the cantilever somehow. When the pile got big enough some of it would actually topple off, only to be replaced by more junk being dug out by the stylus. Who needs TV? I can watch this for hours!

Happily for your "damn the washing, full speed ahead" philosopy, I couldn't hear any degradation of sound, even after I knew the grooves were full of junk. (My old cartridge would have sounded very scratchy in such circumstances, so YMMV. I'm sure stylus geometry controls how well it deals with dirt.)

Of course playing dirty vinyl will shorten the life of both stylus and record. That's just common sense. In my case, while I can apparently play through mounds of loose fluff, the slightest layer of anything is quite audible (mold release agents, inadequate rinse, smog from NJ, whatever). So I wash. That's also the only way to remove anything so stuck in the groove that the stylus won't dislodge it. That stuff causes those annoying pops and clicks, and can do real damage to a stylus.

OTOH, maybe you really should just enjoy the new table. The rest of us are pretty wacko anyway, as you well know!