Which B&K ST-140?

Thanks Unsound. Phase angle? The sales guy never said anything about that.

How do you calculate it?

Hi River251,
Phase angles are imperative to tube amplification, but don't effect ss amps so much, Phase angles tell us how far a apeaker dips or rises between resistive and capacitive loads, you can normally see it in an impedance chart, but some ss amps do not have enough ooomph in the power supply to properly handle a 4 ohm load.
I have an B&K EX 4420 in very good shape that I could sell cheap, it would do a good job on most any load. If interested, let me know and I can list it here on Agon, but there are several nice inexpensive amps that would do a good job for you.

How can one distinguish the year of the ST-140's? There is the brown/champagne colored one, the striped one and ?.

The Stereophile article doesn't really tip you off as to which is which.

And regarding durability, which one is the more sound choice? (no pun intended)

I used to own a B&K ST-140 as a backup amplifier. It ran 86dB Magnepan 1.6QRs without too much problem. It was a second generation one - 105WPC, torodial transformer, 2 output devices per channel.

The first generation has a standard frame transformer, while the third has a toroid with 4 output devices per channel.

My experience: much of the "tubiness" actually comes from the cheap electrolytic input capacitor. Once I replaced this with a film (and eventually a more space saving Elna Silmic), lots of the "warmth" went away, coming closer to my (now departed) Threshold S/500.

Timlub...
Resistive and capacitive load? I have to admit this is over my head.
When would a speaker see a resistive, or a capacitive, load?

Thanks much...took me a while to formulate this question in my mind...

Jim