MM Phono Input impedance change 47k to 100k ohms

Hi Erik,

I don't think it's possible to say without having a schematic and/or being familiar with the details of the design. There could very well be a 47K resistor between the input for each channel and ground, that could be changed to 100K. But even if that were the case, without knowing the details of the design I would not have confidence that the change would not result in unwanted side-effects.

Also, see my post here. Contrary to widespread belief, 47K could very possibly be a suitable load for the F9 cartridges.

Best regards,
-- Al

I agree with Al. I have sold, (I was a Grace dealer) and personally owned many various F9 cartridges and have found that in most cases, the 47K setting is perfect. I currently have several F9E's and have tried many different phono stages with them.

I have owned a couple different phono stages that allowed the 100k setting, but I always went back to 47K. IMHO, the 47K setting is just fine.

I've had a Grace F9E in my collection and system, non-stop for over 30 years now.

Thanks to both Al and Mofimadness, really appreciate the response and will stick with 47k ohms. Incidently the Grace F9Ruby seems to mate very well with the Herbies Most Excellent mat