Music Reference RM-4 Input-Loading and Gain-Select plugs


I have been using Music Reference RM-4 pre-preamp with MCC cartridge Denon DL103R for quite some time. This cartridge has an output voltage of 0.25mV and output impedance of 14 ohms. I am aware that the Music Reference RM-4 has some switchable Input-Loading and Gain-Select plugs. Unfortunately, I have purchased RM-4 with no user manual. And I was not able to locate one on Internet. I wonder what those Input-Loading and Gain-Select plugs are and how they could be used to match RM-4 to Denon DL103R cartridge "better". I would also appreciate any help in getting a copy of the user manual (regardless if it is PDF of just the mobile phone photos of the manual pages).
esputnix

Showing 3 responses by imhififan

I beleive you need to take off the top cover of your Music Reference RM-4 pre-preamp and look inside if the gain plug is 30dB, if it is 30dB then you should connect the RM-4 outputs to phono stage MM input, because most MM input of a phono stage will provide about 40dB of gain and give your Denon DL103R a total of 70dB gain!
Usually the MC input of a phono stage provide about 60dB of gain and give you total gain of 90dB! It will hurt the overload margins of your setup.
With RM-4 adding a 30db of gain, how much its output voltage will be if the incoming voltage is 0.25mV the MCC cartridge outputs?
= 7.9mV
http://www.sengpielaudio.com/calculator-amplification.htm


@hjak 

I am posting this to help anybody now who gets one of these units with no documentation.

Great! it definitely help, thanks!

I can’t seem to be able to upload an image of his note to my response.

You can upload those image to your system page, and provide a link to it in your post.