Audio Technica AT150MLX finally gets some respect

why does the original poster state and I quote -

"If you want the best out of this cart, you *must* give it a capacitive load between 100 and 200 pF. In fact, my highly adjustable Jolida JD-9A phono stage indicates that the real sweet spot is right around 150 pF."

I don't have to do anything esoteric with my 150MLX on technics 1200mkII aside from proper alignment with Protractor and balance and weight.
Nothing else needs to be done in my case.
Why does this person suggest this?

Risking a guess at the OP's reasoning almost a year after his post, I would say he probably tried the cartridge with a range of different capacitive loadings and determined that he preferred it with 150 pF. This is not to say that you or anyone else would prefer it this way. Some may prefer wildly different loadings, and some may say that it makes no significant difference. It's also possible that your AT150 is loaded in that same range without knowing it. We audiophiles tend to see our own preferences as the only possible ones and, either explicitly or implicitly, decree differing viewpoints as more or less insane. :-)

-Bob

I have a Jolida phone amp as well and understand that one can adjust the gain and the capacitive loadings.

While I think that I understand gain, I do not understand capacitive loadings.

Can someone please explain this in simple laymen's terms?

Thanks!

Most moving magnet cartridges have a recommended load capacitance range specified by the manufacturer. For the AT150MLX the recommended range is 100 to 200 pf (picofarads), as can be seen here.

That figure represents the total load capacitance seen by the cartridge, which is the sum of the capacitances of all of the wiring between the cartridge and the input of the phono stage, plus the input capacitance of the phono stage.

If the amount of capacitive loading of a moving magnet cartridge is either too high or too low, frequency response flatness in the upper treble region, or possibly even in the lower treble and upper mid-range, may be adversely affected.

Phono cable capacitance is proportional to length, and is also highly dependent on the particular cable type. It may or may not be specified by the cable manufacturer. If it is specified, it would be specified in terms of pf per unit length (for example, pf/foot).

100 and 200 pf are relatively low values, and for typical setups the concern is more likely to be keeping the total capacitance low enough to be in that range, rather than having to increase it. So unless your phono cables are particularly short (for example, 3 feet or less) and are also of a type that has particularly low capacitance (for example, 15 pf per foot or less), I suspect that chances are you will get best results by adjusting the phono stage's load capacitance setting to its minimum possible value.

Ideally, though, you should try several different values, and it is certainly possible that the value which will sound best in your system, to you, will be different than what the OP found was best in his system, for him.

Regards,
-- Al

Hi. I'm the original poster, and Almarg explained it well. I have had this cartridge for four years and have used three phono stages with it--the phono stage in a pawnshop Amber 17, which had a series of capacitance DIP switches, a Cambridge 640P which has a fixed capacitance of zero, and my phono stage for nearly the last two years, a Jolida JD9A. The Jolida is very configurable, with MM capacitance settings of 0, 47, 100, and on up from there. My turntable's built-in phono cable has a capacitance of 100 pF. I think it's around 40 inches long.

Audio Technica's recommended total capacitive load for the AT150MLX is "between 100 and 200 pF." With both the Amber and Jolida phono stages I was able to experiment with various capacitances, and the most musical, relaxed sound definitely came in between 100 and 200 pF. The Jolida enabled me to try it at 147 pF and I liked that sound the best. Settings above 200 pF tended to sound bright and strident. You can also find testimony from other AT150MLX owners who warn that the AT150MLX can turn bright and sterile if the capacitance gets much above 200 pF total.

In fact, when I was in the market for a phono stage 2 yrs ago, I happened across an excellent deal for a demo Musical Surroundings Phonomena II for around $389. It was very tempting, but the P II's minimum capacitive input setting is 200 pF, which--combined with my turntable cable--would have created a total load of 300 pF. So I had to pass. The good news is that I really like the Jolida and it has so many gain, resistance, and capacitance settings that I'll probably be able to use it with any cartridge that strikes my fancy.

But these days I have even more reason to stick with my AT150MLX. Given that it's four years old and has at least 1,000 hours on it, I called my local LP-knowledgeable stereo store about whether I'm probably due for a stylus replacement or cartridge upgrade. He told me that the MicroLine stylus (which is what the "ML" stands for in AT150MLX) tends to last 4-5 times as long as a conventional elliptical stylus, and that mine should be good for another 3,000 hrs or so. Even though his store doesn't sell AT carts, he was very complimentary of this one and it reminds him fondly of the AT-sourced Signet cartridges from around 20 yrs ago. So I'm sticking with it. In fact, I recently changed my downstream electronics to a tube-based line stage and a transconductance MOSFET power amp, and my analog rig sounds better than ever.

In other words, any downstream changes I make serve to point up what a wonderfully musical, responsive, and great-tracking cartridge the AT150MLX is. It's ridiculously good for the money.