Krank Amplification Rev Jr.

Active/passive effect loop
Channel switch (clean/overdrive)
Boost switch
3 band EQ
Sweep control
Gain (functions as volume on the clean channel)
Volume

2 Speaker outs

I am using a ESP Eclipse with EMGs with this amp. I have a Digitech Hardwire and MXR EVH Phase 90 I run in front of the amp and a Boss RC-2 looper which I run in the effects loop.

Clean channel
Very warm, well suited for Jazz styles, unfortunately the EMGs drive it too much and cause it to break up quickly. The boost switch makes the sound brighter but also a bit gainier - though not as much as you'd expect. The channel has no EQ but doesn't really need one, it sounds nice even with the "cold" EMGs.

Overdrive channel
Eventhough the amp doesn't look like it, there are lots of tweaking options here. First, the sweep button reconfigures the entire EQ. You could have all the EQs on 12 and just use the sweep button for your sound shaping. I have the EQ mostly on 12 and use the EQ to shape the sound. Over 12 the amp's character becomes more aggressive and definitely British, with tight bottom and quite piercing upper mid bite. The highs can quickly sound artificial on this amp so be careful with the dial. Set the sweep below 12 and things get very fat and bottomheavy, you can use the EQ to give a full Rectifier-style sound here, American in nature.
If it's too harsh on the other end, the activation of the effect loops makes the amp more mellow with even more tube feel to it.
With a bit of tinkering and setting you can get almost any type of sound out of this amp.

The amps biggest strength is clearly its blistering and roaring high gain sound, which belies the amp's size and price tag. Amazing, it rivals my 5150 in this respect. There is a slight Class A sag in feel, you get used to it quickly and only notice it when comparing it to other amps. The amp is also very responsive to touch and can be very dynamic, the difference to modelling amps like Line6 spiders and Vox Valvetronix (the amp I replaced with this one) is quite sobering.

Overall sound quality is good, high gain excellent. One gripe I have is that it could clear up a bit better when you dial down the volume on the guitar, but EMGs were never intended for this use really anyway so it's probably down to the individual guitar.

Home use only

This is great little metal machine, that can do so much more. The lack of a channel switch is a total pain in the arse, as the clean channel is not just a gimmick but a real nice channel in itself. I would feel absolutely comfortable using this for a gig for any blues/hardrock/metal band - it is perfectably loud enough and just delivers the goods.

My amp collection has been reduced to only this amp and a Peavey 5150. I used to own a Marshall JCM900, Vox Valvetronix, Roland Microcube and Fender Champ (just so you know what I am comparing it too).