Any way to "improve" a Conrad Johnson MF 2500

I used to own a 2500, and I personally wouldn't advocate modding it - it was a great piece to begin with. Incidentally, that hum is probably a ground loop - CJ amps, especially the MF series, are highly susceptible. You can probably kill the hum by using a "cheater" plug to lift the ground. I used one on my amp and the hum disappeared completely - and I continued to use the amp for several years with no ill-effect.

Have an iec plug installed and use a better aftermarket power cord. It can also be upgraded to a 2500a by CJ with using better quality caps.

You can also install audiophile grade fuses for better sound.

Thanks for the replies. I read a review of the amp on Steroephile and the reviewer addressed the hum with a Shakti Stone. What the heck is that?

"........One note I should make here: when I first connected the amp, it did hum a little. I checked all of my connections and everything was tight. Instead of experimenting with cheater plugs, which I don’t like to use, I put a Shakti Stone on top of the amp, center towards the rear. The hum went right away and all of my listening was done without a trace of hum."

I have already contacted CJ and I am waiting for their response. Anyone have an idea of how much the upgrade to the "A" model costs? I wonder if it's worth it. Should it be given the "once over" by CJ without the "A" upgrade because it is ten years old?

Thanks for your advice.

Jeff

I put WBT RCA jacks and binding posts on my CJ 350. No A-B possible of course but I thought it gave a worthwhile improvement. I would change the RCAs at least; they are not CJs strong point. There are several RCAs cheaper than WBT which are still worthwhile upgrades. I second installing an iec plug.

Bad power supply caps cause a slight buzz with older amps thru the speakers. fYI