Ohm Loads for cartridges

Mike Fremer thinks that low output moving coils sound best when "loaded", meaning a low impedance setting. I definitely agree. Generally, if your cartridge is high output, the best impedance will be over 1000 ohms, and usually around 50k ohms. I am using 384 ohms with my Benz Lo4 cartridge, and it's output is .85 millivolts (at 5 cm/sec, I believe). The Glider HO that I previously had, had an output of 2.8 millivolts, and sounded best with either the 50k ohm, or 100k ohm setting. My phono stage also has selectable capacitance loading (either 200 or 300 picofarads), and I've always used the 200, but need to try the 300. The amount of gain in the phono stage can also affect dynamic contrast. If there isn't enough gain, dynamics tend to sound soft, even though you may be able to play the music loud, if you turn the linestage's volume up far enough. Mine is set now, where I don't ever have to go above unity gain on the linestage, and is 55 dB of gain in the phono stage.....................Albert, it seems like the most pivotal area to replace with quality resistors would be in the section that determines gain, and not so much the impedance (since the gain is a pad circuit, where resistors are in both in series and parallel with the signal's path...and the impedance loading section is just different dip switches that select different resistors that are all in PARALLEL with the signal's path)...............ALSO, ALBERT, DOES YOUR AESTHETIX PHONO HAVE A SUBSONIC FILTER? I've decided that many records that have even slight warpage should use them....it'd be nice to be able to toggle between using a subsonic filter, or bypassing it, but I don't know of any phono stages that allow for that. Mine has no subsonic filter, and listening to speakers with cones allows one to see the subsonic noise....and also the load the power amp is being asked to drive...very close to direct current.

And Albert, I just listened to "Balalaika Favorites" and "Bartok: Concerto for Orchestra" ON 45 RPM....and sheesh, am I NOT interested in DVD-A, SACD, or anything digital for a while....I bet these would just make you die of delight on a "real table" with all those separate dedicated power supplies...heh heh.

In general, the preamp load setting should be 10x,or greater, the cartridge's internal load. This last number can be obtained from the cartridge manufacturer.

Hi Carl. I have experimented with cartridge load in the Aesthetix IO phono, and the hand trimmed resistor provided by Lloyd Walker (Walker audio) was an improvement over the standard one. As far as other places in the circuit, I agree that any resistor that parallels the signal path will effect the sound. On subsonic filters, the IO does not have one. My previous unit, the Elliott Magnum Opus Phono (previously the Counterpoint SA-9, less the Infinity caps and tweaks), did have a subsonic filter, and it was adjustable in two positions. I think it was 30 HZ and 10 HZ, but I may well be wrong on those numbers. My experience with the subsonic filter (either position) was negative in my system, but that could be due to the design of the filter in that particular preamp. I previously used a 28K Vishay for loading the Benz Ruby in my system, when it was my reference cartridge. The specifications had called for the Ruby to load at 49K. My Koetsu Rosewood Platinum Signature is running at 1K Ohms, and was determined by the (selectable) choices on the rear of the IO. After that load number was determined, I tried the hand trimmed resistor provided by Walker. The improvement was very nice, considering the little money and time spent for the change.

1000 ohms seems very high for such a low output mc like that Koetsu. According to the Guide, it's output is .2 millivolts at 5 cm/sec rms lateral velocity. My Lo4 is much higher at .85 millivolts, and seems to sound best at 384 ohms. Again, Fremer never sways from his experience, that very low output cartridges sound best when loaded (even well below 100 ohms). I don't doubt that you are getting excellent performance from your Platinum Signature, though. I also don't doubt that a subsonic filter would have a signature on the music, but feel that it'd still be nice to "switch one in", when needed, otherwise you're unnecessarily straining the power amplifier, asking it to reproduce a noise artifact that isn't part of the recording...and a very loud artifact it can be, even with slight warpage that's common in the pressing of brand new records.