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
Lewm, - a further add-on to my earlier statement and more direct in answer to your questions.

- the mismatch between the source impedance and inductance of the moving coil cartridge with the following amplification-stage does result in a NOT optimum performance. This may and will mean the frequency response, as well as dynamics, timbre, most likely soundstage reproduction (= low level resolution).

- the matching inductance is only correctly obtained with a matching coil as following stage.

- I would not try to simulate the inductance with a wire-wound resistor.
Nor would I add an inductor in series.
Depending on the circuit and principle, your phono input stage may not like the idea at all.

I like looking at technical aspects in the most straightforward and "natural" way. The concept of a moving coil cartridge does longing for -and ask for - a matching first amplification stage in the form of a matching coil - a step-up transformer.
Here - and only here - he find the natural corresponding partner with exact the technical periphery and resulting inductance and impedance needed to ALLOW the moving coil cartridge to perform at its optimum.

Give it a try.
There are good reason why - even given today's high gain phono stages - there are still a lot of step-up transformers around.
Just get a good one which does match the requirements of your given moving coil.
It may open up ears and eyes.
Thanks.
Dertonarm, the use of the word 'feedback' in your posts above either has a new meaning for the term or else the term is misapplied (language issue). My theory is the latter right now.

There is an ideal loading for any inductive audio device wherein the device does not exhibit either ringing/overshoot (under-damped) or excessive rounding (overdamped).

This can be accomplished with or without a stepup transformer.

Loading can be used as a sort of tone control but is ill-advised, but sometimes very difficult to set up otherwise if the right equipment is not available (which is a 'scope and a squarewave generator). With the test equipment, the inductive device (cartridge) can be 'rung' by the square wave and the resulting waveform displayed on the scope. Without loading ringing will be observed. A load in parallel with the output of the device will cause the ringing to decrease- there will be some point where the ringing will cease altogether.

If loaded excessively, the corners of the square wave will be rounded. The debate about where critical damping lies centers around whether or not any overshoot is allowed (I tend to go for a slight amount). At this point the loading value will be only slightly higher- often the difference of only a few ohms.

A transformer can complicate the matter as the transformer can ring also. In addition, the load on the secondary will be 'transformed' by the transformer to a load on the cartridge, so if you are loading the secondary this must be taken into account. Jensen transformers has published a chart of how this is done with their transformers (they make some excellent SUTs BTW).
http://www.jensen-transformers.com/design/MC_Table.zip

Atmasphere, I took the term "feedback" for good reason.
It illustrates nicely what happens when the MC cartridges gets "loaded down" into the 10 - 30 Ohms region and gives a nice idea too about the sound you may expect to get.

The point of inductance matching in moving coil cartridge and the following step-up transformers was throughout explained and discussed when you and I weren't even born yet.

I can only recommend to every audiophile really interested to get the most out of his moving coil cartridge to give it a try with a high-class (Jensen Transformers is indeed a very good address...) step-up transformer with a suitable step-up ratio (not too high...).
The resulting sound will proof that there is more than just correct resistance loading to get the full and real sound of a high-class low output moving coil........
Dertonarm, I'm not familiar with any MC unit that actually loads correctly at 10 ohms! I imagine that the results might sound like the application of excessive negative feedback, but it is *not* in fact feedback.

Even though the Jensen transformers are some of the best (we offer then as an option), I've yet to hear a situation where they actually sound *better* in all regards. Usually, they help a lot with noise, but the best I've heard over the years, time and time again, they rob the signal of detail and 'air', as well as bass impact.

The exception to that is if the MC signal by itself is too low for the phono stage, then the transformer is a benefit; actually *adding* impact, reducing noise (and thus revealing detail). So from your posts above, is it simply that the phono section you are using falls into that category?
Atmasphere, apparently you totally miss my point - your initial two sentences in your last post seems to imply that...
Anyway - I have built, bought, had and still have active phono stages with gain up to 78 dB. Suitable for almost everything the cartridge industry has ever produced.
Tube based and J-Fet based.
Hybrids too.
All very quiet - you would be happy (and surprised...) with any of them.
Lets further assume, that my playback system is the sonic equal of anything - for any price tag - the industry has (or had) to offer ;-)...
Lets assume further, that I am not deaf.
Lets assume even further that I do have a very precise idea about live-like sound and what REALLY is possible in analog-playback and have (big surprise....) the tools and (even bigger surprise...) the skill to get what I want.
Based on all those assumptions I am favoring a GOOD (wide range...) and WELL-CHOOSEN (skill-depending...) step-up transformer not out of despair or lack of gain.
I favor it because I know and have heard often enough its benefits vs an active gain stage.

That your experience is different is fine with me.
Everybody has and had his own.
Whatever assumption you may have from my posts is - again -fine with me.
And not my problem - nor the problem of others.
Whether anybody wants to follow my suggestion regarding a step-up (and seeing moving coil cartridge and corresponding primary .... and secondary if you want ..... of a step-up transformer as a "team") or not is (...you guess it...) fine with me too.