Help with cartridge loading. . .


Hello,

I recently purchased a Pass X-Ono phono pre-amp, and both to my joy and horror I learned at once that there are over 500 different possible resistances I can choose to load my low output MC cartridge with. The manual gives the very helpful: "start with 100 ohms, then move up one setting; if it sounds better, then move up two. . .", which means of course I will be obsessing around in a circle forever.

Are there any rules of thumb that might help me zero in on an optimal loading more quickly? Better, is there a theory behind the settings, such that I could calculate the load given the output of the cartridge, etc.?

My analog front end: Orbe SE/SME IV/Ortofon MC3000.II. Any help would be much appreciated. Sad to say, I am a "fixed price" kind of guy.

Regards,
David Meriwether
meriweth

Showing 2 responses by sean

Pbb: cartridge loading has WAY more going on than just tonal balance. One of the most obvious changes in cartridge performance when varying terminating impedances are those of transient response and noise characteristics. While it is true that tonal balance can be altered to suit one's personal preferences, careful attention paid while experimenting will typically show that a cartridge will have a "sweet spot" where it works best at. This "best" is typically a compromise between tonal balance, transient response and noise floor. In my experience, most cartridges do NOT work best where the manufacturer recommends they be adjusted for. I don't know if this is because of production tolerances differing from unit to unit or if they had specific design objectives ( specific tonal / noise / transient characteristics ) that they thought were more important than how the cartridge performed on the whole.

Moncrieff touched on this in IAR a long time ago and gave some very specific recommendations with plenty of graphs to interpret. Even he comments that samples from the same batch of cartridges sent him by the manufacturer typically had measurable variances in them. In some instances, he even comments that three cartridges sent him measured much quite different from one another, so he typically gave the manufacturer the benefit of doubt and posted the test results and his observations for the "best of the bunch".

Like anything else, there is a certain amount of "science" involved in getting the best performance out of a component or system. One can strive to obtain that OR simply go for something that they think sounds "good" to their ears. Hopefully, the best performance and what sounds "good" to that person are one and the same : ) Sean
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Dan: Using a terminating impedance that is very near or lower than that of the cartridge itself will "load down" the cartridge. This typically results in muddy bass and severe high frequency sag. If one has a cartridge that has noticeable high frequency rise and very light bass, this can be put to use to some extent. Obviously, it is a matter of juggling the variables to arrive at something that you think is enjoyable and works well.

El: I agree that vinyl can be as simple or complex as you want to make it. Then again, it is not called "analog" for nothing. Some think you have to be "anal" to enjoy vinyl while others think it is "the shit" ( aka "log" ) compared to what other formats have to offer. Sorry for the bad pun, but i just hadta do it. If this type of stuff upsets some of you, send an audiophile woman over my way to "reprimand me" for "being bad" : )

Once you get things set up correctly though, it is relatively hassle free other than performing basic maintenance on the records and the stylus. That is, so long as you have good quality gear and your house isn't built over a fault line and gets shaken on a regular basis. I do have to admit that having test equipment and knowing how to use it can make things both simpler and "more accurate" rather than just twiddling, listening and guessing. Just having a scope, reference material and doing some experimentation can teach one GOBS in a very short period of time.

Doug: Since the phono cartridge is basically an "electrical generator" that interprets analogue data and spits out its' interpretation, it is sensitive to both the material that is fed into it AND the demands placed upon it by the load. Changing any of these variables ( quality and cleanliness of data presented to it, tracking angle, sidewall thrust, ability to transfer both electrical and mechanical energy, etc... ) may offer very different presentations.

As far as Moncrieff goes and phono cartridges, IAR Journal 5 ( the big thick one, NOT the "flyer sized" Hotline 5 ) covers quite a bit of info about phono cartridges. Most of it covers older products ( obviously ), but much of the knowledge learned then still applies today to much newer products. Sean