Jim Lesurf wrote:
In article , Serge Auckland
wrote:

I recently acquired a low output (0.2mV) moving coil cartridge (Sumiko
Talisman B), for which the manufacturers' recommend a load of 40-100
ohms. I am currently running it into a load of 47k as my standard RIAA
preamp has sufficient gain, albeit with a bit more noise than for the
earlier MM cartridge, but nevertheless, perfectly acceptable. My
question is:- as MC cartridges are voltage sources (and Sumiko's manual
also says) then why should the load matter once it is, say, 10x greater
than the source impedance of the generator, which in my case is 5.8
ohms. The sound I'm getting seems fine, so I would like to know what
change/improvement I should expect from a lower impedance load.

Any changes would depend on details you have not given (and presumably are
unknown to you).

A lower amplifier input impedance might also provide lower noise.

As the amplifier is seeing 5.8 ohms, would a lower inpedance make any
difference to the noise?


Since no source will be an ideal 'voltage source' a lower load may also
change the frequency response, or distortion, or some other parameter.
Perhaps even alter the compliance to a small extent.

At some point the coil inductance, etc, may cause a resonance. Probably
well above audio, but might make something like RF pickup more possible in
some circumstances.

But none of the above may apply in your specific case.

I am sure you are right that lowering the load impedance will make a
difference. My question was about what sort of difference, and would I
be able to hear it - many things make measurable differences, but are
they audible......

Given the high output you could check by simply putting 100 Ohm shunts
across the amp inputs and see if this has any noticable effect.

Slainte,

Jim


Yes, that's my next experiment. I'll start with 1k and work my way down,
and see what (if anything) I notice.

Thanks

S.