First Watt: current vs voltage

I have always seen voltage source attached to amplifiers that are capable of a high output in amps and can increasing their output into lower impedence loads. IE Krell is a voltage source amp, a Quad 405 isn't.At least this is the usage in England that I have seen in reading HF mags the last 40 years.

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Stan, sort of.

For a given input voltage an ideal voltage source will maintain a constant output voltage no matter what the load i.e. no matter how low the load impedance goes and no matter how much current the load draws. This requires the amp to have extremely low output impedance, ideally zero. Monstrous power amps like Krells are closer to these ideals than the Quad but they are both considered voltage sources.

Current sources are an entirely different beast.

For a given input voltage an ideal current source will maintain a constant output current no matter what the load. This requires the amp to have extremely high output impedance, ideally infinite. The First Watts are not that high with an output impedance around 80 ohms but that is 10 times most loads so they act more like current sources.

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Good discussion.
I've seen a particular modder design series crossovers for Magnepan panels.
Makes me wonder if this would be the way to go with higher powered tube gear, like the ARC stuff, which I sometimes seen mentioned as playing well with Maggies.
The old / original crossover for the MMG (maybe the SMG) was a series crossover.

What about just putting a couple ohms in series with my amps outputs? Would that work? Carver did it a couple years ago......

What Carver did was supposed to make the amp sound like a current source but it didn't actually make it one if I remember correctly. I don't believe adding resistance will do anything except possibly change your crossover and burn up more power driving the resistors.

I guess I was misled by the 405 output pattern, which was, according to a test in HIFI Choice no. 14: 115/90/32 on right channel and 115/81/28 on the left at one Kz at one percent distortion for 8/4/2 ohms. The Sansui 919 in the same issue did 145/217/288 and 164/210/264. The 8 ohm power is fairly close but the pattern is quite different. They commented " Steady state drive into low impedences was very well maintained, and on toneburst approched the theoretical 'voltage source' ideal. Since the 405 was so different I assumed it was not a voltage source amp.