To preface, this might sound like a sales pitch because I love this thing so much, but I have no stake in this business whatsoever, I just want to express how well this device addresses so many common complaints about guitar amps, and yet I rarely if ever see it come up in conversation. I've went through a handful of passive attenuators to get the goods out of my non master amps, and even though they're not supposed to be safe to use, I had a power tube burn out with a '59 Bassman reissue after relatively little use. The fact that the power tubes burnt up makes me thing the Webber attenuator was reflecting too much voltage. I was just happy the transformer survived. So I decided to stop screwing around and spend real money on an active attenuator, and got the Fryette Power Station. I wanted to remark about how amazing this thing is, it basically lets you take any guitar amp with speaker 1/4" speaker outputs, and run them into any speaker with 1/4" inputs, regardless of impedance on either side, since it has impedance selections on the back, and it has an independent volume, so you can crank the amp itself to any output level, and the Fryette Power Station's volume smoothly regulates the actual SPL you end up with in the room. Passive attenuators do this too, but it's usually not smooth, neither to the touch, nor in terms of linearity. Turning the knobs on my high wattage Webbers feels like operating a manual coffee grinder, and it's hard to get "just right", this unit is like butter. But there's more, the presence and depth controls offer a second dimension of EQ that most amps dont come with, most have B/M/T, or a single tone dial. Some guitarists resort to rack mount graphic EQs to trim the lows and highs, but these two knobs have been all I've needed to make room for the bass guitar, or compensate for the lack of a bass guitar, or to trim off some brightness from single coils. And when you want to make an adjustment mid-song, one knob to one problem is ideal, you can't being doing a graphic EQ soundcheck on the fly. A problem with passive attenuators is that they tend to knock down the bass or the treble. The Webber units have seperate bass and treble attenuations to address this, but it's like performing surgery with a butter knife. The presence and depth controls address the same underlying issue, but do it 1000% better by focusing more on where those losses occur. One way to run this is in between the amp and the speaker, but what I'm doing at the present is pairing it on a permanent basis with a Marshall 1960 4x12, and having it divide work load with two out amps. It can even handle Fender Blackface amps that usually don't play nice with extension cabs due to the low output impedance. Then I have the choice: a) push the Fender Blackface hard and let the Fryette eat up some of the power, or b) run the amp low and have the Fryette provide clean power, for a sparkly pedal platform. And in either case, I have the Marshall 4x12 and the Blackface's speakers all running in tandem, so there's a wall of sound filling the room. I agree with the sentiment that Blackfaces sound best around "4", with this thing, you can live around "4" and are afforded a whole lot of other tonal options to boot. The only downside is that I feel weird using so much power between the two amps in exchange for moderately loud jamming volume, but the tone is so awesome that I forget about it quick enough. There is a lot of talk about the pros and cons of attenuators, the fact of this being a powered unit and having selectable impedance pretty much eliminates all of the common the downsides, only adding the inconvenience of having another active unit that requires power. I do weekly jam sessions in a set location, so I don't have to lug it around, but if I were gigging, I'd probably pass on this luxury since I don't have a rack mount setup. They sell a rack mount kit for this unit, though. This thing isn't just great for non-master amps though, I personally believe that attenuation gives better results than master volume attenuation. Attenuation creates the sort of distortion that sounds like a monster is in the speakers and it's trying to get out, where as master volume attenuation still sounds rather tame, unless you really turn the amp up loud, which is why we wanted the master volume in the first place.