Question about wpc on tube amps

Oddiofyl gave great advice as did others

@timintexas : I only speak from my own experience, so please take this with the appropriate grain of salt… Rated wpc doesn’t tell you much of an amplifier’s story. Someone else wrote that this one specification only describes the amplifier’s maximum output within the parameters of how the manufacturer tested it. This number can be “optimistic”. The power that an individual uses is typically (should be) much less than the maximum rated power of any amp. What you have to determine is how much power you actually “need” to play the music you like at the volume level you listen at. I’ve found that it is absolutely true that some amps with lower rated power sound more powerful than other amps with higher rated power. There are many factors that go into this. But it is not because “tube watts” are more than “solid state watts”. A couple of the big factors have also already been stated: 1) The fact that SS starts sounding strained earlier than a similarly powered tube amp, and 2) If the input sensitivity is lower on one of two amps being compared, the amp with the lower sensitivity will play louder at a lower position on the volume knob, which gives the perception that it is more powerful, when it is simply ramping up its power sooner… Another point; I have found that a tube amp has more of a “tube” influence on the sound of a system than a tube preamp - and I have nothing to say against trying a nice tube preamp.. I’ve owned many, but tube amplifiers are what really made me fall in love with the sound. Also: I have owned many different models of Magnepans over the past ~36 years, and I’ve used dozens of amplifiers of all (almost all) types, with a wide range of rated wpc, and I myself personally have usually preferred the sound of tube amps. They are definitely capable of driving Maggies very well “for Me” in “My systems”! You should be able to find a used tube amp for close to $1000… maybe more like $1300-$1500 as a lower cost starting point (I picked up a Music Reference RM-10 for about $1300 several years ago and it sounds amazing with my 3.7s). All that said, Bryston makes very good amps too, so there’s nothing wrong with trying a tube preamp with it. I think some experimentation is in order. Let us know how you make out. 

@timintexas

WPC is just an rough/partial measurement of capability to drive speakers by an amplifier.

There are multiple factor in really world how amplifier behave when driving a particular speaker.

e.g. Tube Amplifier most likely using output transformers which is an energy storage/converter, which helps boosting transitional burst energy when driving a speaker with linear impedances or speakers with capacitive load characteristics such as electrostatic speakers. Also tube amplifier tends to handle overload nicely. That is why people observed that tube amplifier seems be able to drive same speaker louder vs a solid state amp with same “WPC" ratings.

However, tube amplifier would suffer greatly when used to drive low impedance speaker or speakers with non-linear frequency-impedance responses, such as full range ribbon speakers.

The OP has made a decision to purchase a tube preamp to use with his Bryston amp. A wise decision I believe. One can be had for his 1K budget.

There’s a Jolida Fusion Tube preamp on the other free audio site. I would offer $600. Lots of bang for the buck.