Conrad Johnson MF2250A / MF2500A vs CJ MF2275SE / MF2550SE

The biggest difference is that the SE indicates it has the Teflon Caps. I had a 2500A but haven't heard the newer amps

Also, the resistors in the SE models are supposed to be superior & more costly VISHAY brand.  But I wish I knew if it would be a change that was apparent.

The MF 2250 and 2500 were basically the same amps but with different power. 25 years ago they were good amps but not the last word in detail. But musical with good control. The 2275 and 2550 SE are far superior in sound and build. The circuit and power supplies were changed and all the parts upgraded. The MF 2550SE was probably the best ss amp CJ ever made, possibly one of the best ss amps out there. The 2275 has a hair less headroom and bass but if you have efficient speakers will be just as good. The MF2550E is one amp I wish kept. Read the reviews, they are spot on. Call Jeff at CJ and he can walk you through with more details. 

Consider posting the same question on the CJ owners group forum. I find it much more helpful than Agon when it comes to specific CJ questions. No offense to members of this group. The CJ forum is brand specific. 

Thanks to all

47ghibli--

I provide concierge service for CJ. To add a little more to my earlier post. The main difference between the MF2500 and 2500A was internal wiring and binding posts. The 2275SE and 2550SE are an entirely new generation of circuitry and parts.  They use Teflon caps throughout and Vishay resistors in the audio circuit. Sonically they are the same except for the added power of the 2550. If you are looking at the 2275 for sale now, it is a great price for a great amp.  CJ can go over it if you want it checked out. Hope this helps.  Happy New Year to all.

For years, I have known the differences in build, but has anyone done any detailed listening comparisons?

47ghibli--

I have shared some thoughts on these amps. To answer your question more directly. Yes, I have owned and used them both, as well as the Premier 350 and CA 200 (ss amps, plus 4 other CJ tube amps). Have I listened to the 2500 and 2550 side by side? No, as that was never possible due to the age gap between the two amps and I simply never kept the 2500. I do not think many have been able to doing that comparison. As I wrote, the reviews on the MF 2550SE are accurate and describe the sound in detail. But in simple terms: the MF 2500/2500A are musical with good detail and sound stage. The MF2550SE is in another class and is far superior in sound, detail, control, and musicality. You hear more with the 2550SE and its is more pleasing to the ear. With the 2500 you are somewhere in the audience. With the 2550SE you are on stage hearing the music as the musician do. You hear detail and harmonics with wonderful placement. You are engulfed by the music and able to hear what the 2500/2500A did not deliver. If you want a SS amp that you can keep, then the 2550SE is that amp.  If you do not need to extra power then the 2275SE will deliver the same results. Both amps are identical except for their power.

Thanks again for your detailed response.  Sounds like I may like to upgrade to the later amp from my MF2250A.  I am reluctant to do so because it has had little use and is perfect cosmetically.  I bought it from the original owner that lived near CJ.

He took it to the factory and they made sure it was to spec, upgraded it to "A" and shipped it directly to me.

It hasn't seen a lot of use having been in rotation with my VTL Stereo 70 and Manley Retro 100 monos.