PPI 2050 AM Amplifiers

[Rigs64]

I read on Ampguts.com that the 2050am amps were not adaptive mosfet...Is this true?

[ppia600]

The "am" means "adaptive mosfet". The 2050m's are the ones that aren't.

[Perry Babin]

What is adaptive mosfet and what's it supposed to do for the amp?

[Rigs64]

From what I hear...adaptive mosfet means that the power supply mosfets adapt themselves to the power supply demands.I could be wrong though.

[ppia600]

I believe it prevents too much current from destroying the output transistors and power supply but I'm not sure.(obviously doesn't always work :lol: ) The manuals for my art amps describe it almost like a power limiting design that prevents you from running too low of a load. The art amps actually reduce power output if you run lower than recommended loads. Something in the amp actually monitors current and adjusts as needed. I'm amazed it doesn't affect sound quality. I'm kind of curious how this is possible, and what the sampling rate of the monitoring circuits are. I'm not absolutely sure the finned am series does that though. I've had a few of the am series finned type and they are excellent sounding amps.

[Perry Babin]

It appears that the low impedance light came into the design about the same time that the AM series was introduced (going by the photos on the ampguts site). Maybe the low impedance circuit is triggering a rollback of the supply to help protect the amp. If that's the case, the monitoring would be continuous (no sampling rate) and there would be no effect on the output unless the low impedance circuit was triggered.

I think 'adaptive' and 'mosfet' are two different features (especially if M on the previous series stood for mosfet).