? cartridge should match vintage marantz reciever

The idea that it is the wrong gain could be. BUT: if you are turning the volume control about the same for the phono and the tuner, then that is NOT the problem. If the volume control is nearly all the way up, for comparable volume to the FM, then your PHONO section may have a problem. If the volume control is much less for the same volume, then you got a setup for MC in there and too much gain.
One other possibility, silly but: you MUST connect the phono RCA to the PHONO input. If you stick it in any other, the RIAA is not present, nor is the extra gain from the phono section, and your cart will sound dull and lifeless!! (I assume you KNOW that, but am telling it just in case.)
Finally, how LONG are the cables from the TT to the phono input? over 2 meters, and that may be your problem.

Having owned many vintage Marantz receivers in the past coupled with the Shure, Stanton, and Grace cartridges of the day I doubt there would be a mismatch with your 2325.

I spent a little time looking for specs on the phono stage for the 2325 but was unable to come up with any numbers, also I don't know which Shure you are using.

I do know that there are some really fantastic Marantz afficionados out there-- Ben Blish being one of them, here is a link to his website-- http://www.classic-audio.com/marantz/2325.html Maybe an E-mail to him will bring some answers.

As far as techs go Mike Zuccaro really knows vintage Marantz and does outstanding work. Perhaps a call to him would help. A google search for him will get you to his website. (He is based out of San Diego) Zuccaro did a great job on my Marantz 150!

Although I have moved to SET monoblocks, I guess it is easy to see that I have a real place in my heart for vintage Marantz!

Richard

Hello,

Your Shure should work just fine with the 2325 (I'm assuming it's in good shape). If you do not get better results by experimenting with the Height of the tone arm (VTA), or set up of the cartridge as your turntable allows...then I would suspect the phono stage of the Marantz..The 2325 is a great receiver but its well over 20 yrs. old and this phono stage has been known to have leaking transistors and capacitors. I have repaired several. Try cleaning connections too.. good luck