Optimal Loading for Shelter 501 mk2

Shelter's specs call for a load of 100 ohms when running directly into a preamp. I'd start there.

http://www.eifl.co.jp/index/export/501.html

Enjoy!

David, You want guesses? I got guesses.

First
"Within" seems to me like typical translated Japanese, for who the hell knows what. ;)

Second
Whether the transformer is physically inside or outside a preamp is obviously irrelevant. If it's between the cartridge and the first gain stage then the cartridge is driving a current-sensitive transformer rather than a voltage-sensitive gain stage. I gather the basic idea is to optimize the output of the cartridge for whatever it's driving. That does not necessarily mean you should use the same load as outboard tranny users of course. That would only be true if the turns ratio of our trannies was the same and the load presented by the following gain stage was the same. The fact that your tranny is internally wired might also be a factor, since the wire is likely to have different impedance than an external cable.

Third
Since most outboard 20dB tranny users seem to prefer a load around 40 ohms with either the 501 or 901, I'm guessing the EIFL "specification" of 20 ohms isn't simply referring to the load seen by the cartridge. I don't know of anyone who likes that low a load. The operative word in the above was, "guessing".

Interesting that some of your records sound more "dynamic" with a much higher load. By changing loads we can affect changes in the dynamics of different frequencies, but never in overall dynamics. If I raise the load on my 901 from our normal 38 ohms to 42 my HFs start to get too dynamic and the LFs begin to lose weight. Dropping the load to 35 or below has the opposite effect. I'll admit I've never tried 300.

"My guess is that if you load at 100 ohm you will be thrilled in most all circumstances. Whether small changes will result in big improvements probably depends upon your ear and your equipment." Since Peter_s is not running through any kind of tranny, I agree!

I've tried the Buggtussel on several moldy-looking records. It helps, though I've yet to see it completely remove the spots on (in?) the vinyl. Definitely better than not using it, though it won't return a moldy record to shiny black either. Maybe a B+.

Williamdc,
Yes, my MM phono stage has the normal 47Kohm load. The resistor posts on the BentAudio stepups are wired across the secondary. The load is reflected back through the transformer, which in my case is wired for 20db of gain. We are currently using 4,078 ohm resistors, which the cartridge sees as a load of about 37.5. I think this is consistent with your revised calculations, but my partner is the math/science expert. I just do the talking! ;)

---
4yanx wrote,
"On certain LP's that have little bass info and not much in the way of complex mixing, say a female vocalist with an accompanying pirce or tow, things can sound a bit less "thin" using the 300 ohm setting. A slightly reduced soundstage but better front "presentation" of the vocals."

That sounds exactly like increased dynamics at HFs and reduced ones at LFs. The vocalists mid-hi freq's come forward and the LF soundstage info is recessed. I'd expect to hear the same thing on that kind of record. I think we're hearing the same thing.

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Spinitch, apparently the interpretation of the word "within" differs between Japanese and English. No surprise. If you can get a clarification from a local source we'd love to know!

If your female vocalists are accompanied by a purse or toe, you've got problems even a new Basis Reference wouldn't solve.

William,

Lowering the load seen by the cartridge *reduced* bass? That doesn't make sense to me at all. Should be the other way around.

Do you live in Australia? ;-)

When I first experimented with cartridge loads last year I was convinced that 22-25 ohms was best in my setup (901 >> BentAudio Mu >> c-j MM phono). I was wrong.

It turns out I was compensating for other setup errors. My arm was too high. That emphasizes HF's of course, so I was unknowingly loading the cartridge down to compensate.

Since January or February we've been setting VTA (SRA to be precise) for every record we play. There's only one ideal SRA for any given record, so it's essential to dial that in before trying to fine-tune your cartridge loading.

The following protocol seems sensible:

1. Start with a load value used by others with setups similar to yours;

2. Optimize SRA and VTF for several familiar records of complex music, the guidelines on Lloyd Walker's website are excellent;

3. Now fine tune your loading using the same records.

This seems like the logical order for making these mutually dependent adjustments. Comments?