[revelator]

What else is different between these two.  I've read that they both use the same number of output devices (2 pair /channel).  Are these different between the 550 and 350 models

I've also read that main power xformer on the 550 was upgraded recently .  Is this the same for the 350 EXR?

I've also read that both sound about the same except for at higher volumes / difficult loads (where the 550 excels better) .  Is this true? Is the 350 slightly better at lower listening levels?

Tnaks in advance

[avahifi]

Actually both the 350EXR and 550EXR use three pairs of power mos-fets per channel, not two pair.  Both are safe into very low impedance loads.

The 550 has a larger, higher current and higher voltage power transformer.  In addition, parts in the power supply and audio circuits are rated for higher power, higher voltage use with the bigger amplifier.  Otherwise the two amplifiers are identical in design and sonic performance, within the limits of the 350's power rating (about 200 watts per channel).

Frank Van Alstine

[Xi-Trum]

Hi Frank, what's the 350 and 550 power rating into 4 and 2 ohm?  Also, what's the gain of these amps?  I have the rm40 that dips to 3.8 ohm (I think).  Thanks a bunch.

[jackman]

Xi,
Are you in the Chicago area?  If so, I'd be glad to bring my newly upgraded Fetvalve R and T7 to see how they would work on the RM40's.  The upgrade is very impressive.  Sound is more transparent with better bass and more extended highs.  Retains all of the original Fetvalve smoothness however with more detail.  I can't imagine how great this stuff would sound with some RM's in a well set-up room.

J