I'm often asked the question that I dislike the most, which is what amp should I buy. I know, a peculiar opening but I really do hate that question simply because all players are different and my taste for tone will not be best for everyone. But, yes, there is a but. When I get the question accompanied by "I can't afford a Mesa or a 5150" then my answer is check out the B52. This is not to say that the B52 cannot hold it's own in the company of a Mesa or a 5150 but these things are simply the cheapest high for a real high gain amp that has a good build quality and pretty decent tone.
These amps get a very nice clean tone and if you take a look over on the customer review page http://www.eurotubes.com/eurotubes-customer-reviews.htm you will find several reviews on how the JJ 6L6GC's and ECC83S's pre's will really warm the amp up and smooth out the distortion tones.
Running in the tube rectifier mode using a good GZ34 (the stock russian 5AR4 is a bit sterol) these amps have a good dynamic response and this adds more warmth to the tone, especially nice for clean sounds or if you like a bit of breath or sag for solo's. If you're after a thick sharp response then switch to the solid state diode mode and it gets a pretty nice chug.
The bias is adjustable on these amps and for all you guys asking "Where's the trim pot?" here are a couple pic's. My recommendation is to use a bias probe to set the bias and anywhere between 36 to 40mA per tube is very nice. The reason I recommend a bias probe over the B52 method of measuring across the fuse holder, is because we have had calls from a number of B52 players who have used the fuse holder method and were not real careful and "slipped"! The issue here is that when the fuse is out of the circuit it cannot protect the amp and if you make contact at the wrong point you can do some component damage without the protection of the fuse! A bias probe is also a more accurate method.
We've recently received LOTS of calls asking for a "How To" video for the entire bias procedure on these amps. I wish I had time to make video's for all the amps we see but we don't! So I will refer you to what I call the "Generic bias video" over on the "How To" video page HERE. This video is #5 on the list and will show you the exact same procedure used to bias the B52.
To bias the B52 you must have a speaker plugged into the amp and it must be set to the "Solid State" mode on the back panel. This is the highest voltage setting with the amp running in the A/B mode which is where you want to be when adjusting the bias. These are cathode biased when in the "Class A" mode so with the proper grade of power tubes the bias will hold steady at between 60 to 70mA and you can turn the trim pot all day long and the bias will not adjust! this is why you need to be in the "Solid State" mode to adjust the bias to anywhere between 36 to 40mA per tube.