MC Load Resistance


I am using a Denon DL-S1 Moving Coil cartridge with a VPI Scout turntable. The spec for the cartridge recommends a Load Resistance of 100 ohms, but the test data sheet included with the cartridge showed that they tested it with Load Resistance of 47K ohms. Question is, do you think it is ok to set the phono amp at 47K ohms for this cartridge?
almandog
Allen, a peak past 'audibility' will have effects not unlike a tube without grid stoppers, exhibiting oscillation; IOW it can behave as if there is excessive ultrasonic energy. This can cause some preamps (not all) to exhibit excessive ticks and pops (in addition to brightness), due to the various instabilities introduced. The effect on the cartridge is easily measured, and without loading often there is more 'air' but when you examine it on the scope you will find that the 'air' is mostly just ringing (distortion).

This is why critical damping is such a nice value to achieve- you get out the the transducer just the signal, without additional 'commentary'. I suspect many cartridge distributors don't listen to any cartridge for very long so it might be that they don't bother, but they are simply missing bet, that's all.
Allenwright, Atmasphere, I do agree with Atmasphere (surprise...?). All (low-output) Moving Coils do need "some" dampening. And yes, - in my experience too that extra "air" is going in most (maybe all) cases along with "lack of body" and has a sense of being "artificial" and "somehow ringing".
Saying this I have to mention, taht back in the late 1980ies and early 1990ies I was a vivid frontman accepting nothing but high gain active phono stages and judging all step-up transformers as a waste of time and money.
In the following years however - mostly by using very low source impedance moving coil carts - I learned that there is more than just gain to a happy marriage between a top-flight mc and the matching transformer.
Knowing 3 cartridge designers personally, I do know that they do care about sound and the last jota of possible performance a lot less than I do.
Still the best "loading" and "dampening" for a low-output (= very often low source impedance) moving coil is in my ears and eyes a matching transformer.
Hi,
looks like we are back with the SUT business...
Let ME state categorically that the Dertonarm IS RIGHT with regards to a LOMC (>=0.3mV) producing more 'natural' sound with a correctly matched SUT.

Even with a pretty modern design cart like an Ortofon Windfeld that can pretty much work OK with loads from 500 - 47k ohm it sound *absolutely* better more natural with SUT.

In this case example: 4 ohm source impedance, ~ 20uH source inductance, and 0.3mV output.

Matched to an SUT of 30dB (1:31.6) i.e. 47ohm primary input impedance going into 47k phono-pre.
Primary DCR of SUT = 1.1 ohm)

Phono-pre is all SS, and in fact MORE quite! without SUT when set to 78dB. Using the cart with SUT gives more natural 'ambience' and depth information without perceivable loss of detail what so ever.

In comparison 1k resistive load gets to 'hot' in very dynamic passages, and already too 'sat-on' with ~500 ohm. Loading with 100 ohm sounds completely dead, or as Dertonarm pointed out by using the simile of far ‘too much feedback like’ sounding.

Now go figure...

Greetings,
Axel
It is a pity, that common Phono knowledge gets buried. Of course the user will find THE exception (SUT or high gain Phono) but may I add something important:
I listened to transformers from horrible-excellent, but honestly, horrible was majority. Colored, wrong in reproduction, channel separation and so on... I did that for 3 years with various units (EAR, Kondo, endless cheaper units) and at the end of the road I use now a top unit with 1.rate studio specs. No Hype, no miracles, just measured - and compared - datas.
And before I did that, I wasn't really mad for them.
Most manufacturers have no idea about the sense behind, they offer it - more or less - to make some money, top trannies are ALWAYS expensive, there is no way out and we know from former discussions, "expensive" is the most hated word in High End
(High End but lowest price, funny eh?)
But honestly, before some readers will say: "Great" after reading that and think, that is the - cheap - solution for everything: no, it's not.
It is just one more piece in the analog puzzle.
Axel, Can you or Dertonearm tell me how the quoted 20 uH inductance of the Windfield was taken into account in your choice of SUTs? You make no mention of the way in which you may have used that information, and Dertonearm did not really quite get there either, in responding to my earlier question. By my calculation, an inductance of 20uH will result in an impedance of 2.5 mohms at 20 Hz and 2.5 ohms at 20,000 Hz. In an MC cartridge, this suggests that the inductance has a negligible effect on the cartridge's internal impedance at low frequencies and only a modest effect at the top-most frequencies, not enough to affect dramatically the choice of an ideal load R, if no SUT was used, but obviously the impedance will increase with frequency ad infinitum.