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Cartridge loading question

O

oceanobsession

pfm Member
Can anyone advise me on loading a moving coil cartridge, in general what effect does more loading have on the sound, my system seems to have less
bass with more loading would this be the norm.
 
In general, an MC cartridge should be loaded by at least 10x it's DC resistance. Once the loading exceeds this resistance, the cartridge performs pretty much the same. I load my TSD15 cartridge with 47kohms.

Loading a cartridge with less than 10x its resistance will reduce output as well as possibly increasing distortion as the cartridge is being asked to provide more current.

I have no idea what effect loading will have on the frequency response, that I think will depend on the cartridge and how the magnetic circuit is arranged. I would expect, however, a small effect.

S.
 
Theory is fine, as is often the case, cartridges tend to have their own little loading quirks. I have a sut which allows lots of loading variations, essentially you get slight changes in volume (see above) and very slight changes in tonal balance.
As a simple rule of thumb, the higher the output the less fussy the cartridge will tend to be (because its resistance is usually higher). Above about 0.6mv, 47k is often fine; with very low impedance units you could go as low as 50 ohms.
If in doubt, and unable to experiment, 100ohms is a fair compromise.Rarely is this a matter to worry about very much.
 
By far the majority of modern carts follow the graphs rather than what yours, and my Benz LP does. Pick any MC from Lyra, Dynavector, most Benz carts, Linn, Denon's LO carts, Shelter, Koetsu, etc etc etc, they are all broadly similar.

I know the Shiraz and the EMT's are largely indifferent as is my Benz LP, I'm sure there will be others.
 
The cartridge in question is a cadenza bronze, Its got loads a body great with
classical, But somtimes a bit to fat, ive got it loaded at 150ohms which does
seem to tighten up the bass a bit, load it at 100ohms and the bass is more boomy, now i think this is the case thats the reason for the post, im using a nick gorham phono stage.
 
I'd ask Nick, there might be some loading on the circuit itself, or some effective limit, like the Naim 323's don't go above 3kr. Whatever sounds good is generally right.... ;-)
 
Should mention, this is about the only job that I think expensive resistors make any difference, I use Charcroft in my Prefix.
 
sergeauckland said:
I wonder what cartridge those graphs were taken from. None of my MC cartridges have shown that sort of FR change with loading.

In particular, my TSD15 has a flat response with 47k loading, as it does with a few hundred ohms.

S.
Click to expand...

None of mine either into active stages as opposed to SUTs.

The piece gives insufficient detail, and for starters we should be looking and the resistive loading in combination with the capacitance.
Certainly any MC with dc resistance down <10 Ohms should show only tiny changes at the very top for any load over 100 Ohms and the typically moderate levels of capacitance.
 
sq225917 said:
http://www.extremephono.com/Loading.htm

get it wrong and you can skew your FR by nearly 10db in the HF. Worth sorting out.
Click to expand...

I do not know who originally wrote this but chunks of it are identical to the material provided by FM Acoustics (for their phono preamp FM122 that I use).

I can certainly confirm that increasing loading on my FM122 pushes up the HF response. Altering the capacitance also seems to work as shown in the graph.
 
It's a pity IMO that "loading" is such a confusing term. AIUI, if you use no "loading" for your LOMC, then it sees the "normal" phono stage 47K. This is a high value. ;)

If you "load it" with load resisters, then you are in fact reducing this 47K to 100 ohms, 150 ohms ... 1K5 ohms or whatever load resistor you've used.

IME, the "right" loading resistor for your LOMC depends on:
* what you like to hear, in terms of bass "tightness" vs. the tone of the violins, and
* the circuit configuration of your phono stage. (What sounds best for one phono stage won't necessarily sound best for another.)

And don't forget that MMs/MIs can also benefit from being loaded < 47K. :)

BTW, SQ - to me, the optimum load for my Benz LP (with my phono stage) is 1K2. If I run it at 47K, the bass on my reggae LPs becomes too floppy. If I run it at 470 ohms, the violins don't sound right. :)

Regards,

Andy
 
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