Regarding the ST 140 and 4 ohm speakers. The early models with the gold lettering and silver handles used one pair of mosfets per side and do not handle 4 ohm loads very well. The later version with red & blue lettering is a completely different amp. The only similarity is the model number and power rating. It uses 2 pair of mosfets per side and will handle 4 ohm speakers just fine. It is also a better sounding amp. It has tighter bass, smoother highs, is more detailed and retains about 90% of the midrange magic of the earlier version. I have both versions and have compared them extensively. It is a major bargain at the normal selling price of $175-250. In fact it beats the pants off many more expensive amps. Here are a few I have compared it to with the ST 140 coming out ahead: Aragon 2004, Hafler 9300, Meitner STR 50, Nakamichi PA 5 & PA 7, Adcom GFA 555,
and several inexpensive tube amps. I have not heard the Forte 4A, but doesn't it use IGBT outputs which are no longer available?
and several inexpensive tube amps. I have not heard the Forte 4A, but doesn't it use IGBT outputs which are no longer available?