Price paid: $ 999
Purchased from: Reverb.com
Features — 10
Rivera Knucklehead Reverb 55, I think it joined the market around '06? Give or take a few years. I know they don't make them any more so you usually have to find them used. Which is how I got mine. Like all Rivera's this thing is built like a tank, and it's heavy. Hand built in Burbank, California by Rivera (obviously). When they initially hit the market I know you could chose to either have them with 6L6's or EL-34's. Majority of retailers were stocked with EL-34's however. Which is the one I bought. Honestly, the EL-34's work extremely well with this amp. I also have a Knucklehead Tre with 6l6's in it, but the KR-55 has been my go to amp since I bought it. It features 3 channels and switching by either MIDI foot switch (comes with Rivera Headmaster MIDI switch) or a Rivera Foot switch.
The 55 watt version comes with 5 pre-amp tubes (12AX7's) and two Power tubes (EL-34 or 6l6). Channel one has its own EQ, master volume, and gain controls as well as push/pull tone enhancements and boost. Channels two and three both their have master volumes and gain controls but share the same EQ (which you'd think wouldn't work well but it actually works just fine) which also have push/pull tone enhancing, and individual boosts for each channels. Then you have a Sub volume control, which worked with the Rivera Los Lobottom Sub-woofer cabinet, which are now also out of production. Then you have Focus control, which gives you a tighter thicker bass end and a Presence knob, both focus/presence knobs are shared between all three channels. On the rear panel you have MIDI in and out inputs, foot switch input, effects loops send and return as well as volume controls for send/return, Sub output (for sub-woofer cabinet), recording out, an impedance selector, two speaker outputs, Vintage/modern power class switch, high/low output power switch, and the power cable input. The amp is seriously a monster in features. You could get any sound possible out of this model, I swear.
Sound — 10
Sound wise, you have so many options. Between the power soaking selections on the rear panel, the push/pull tone knobs in the EQ's and the Focus knob also takes it to different levels as well. With Each channel having a boost selection which takes the gain to insane levels. This boost alone on the clean channel gives you sweet breakup without using a tube-screamer. Both channels one and two have sufficient gain to satisfy most guitar players, but if you require more, select the boost. This takes you into levels beyond mesa boogie, marshal and on par with Uberschall and in my opinion even better, you also keep the note clarity. I play 7 string guitars and have even tuned as low as F# and still keep the clarity. In my opinion channel 3 has more gain in boost mode, and is more chunky, but channel 2 has more low end in the sound. I like this because again, you have two different sounds to play with, well technically four difference sound between two channels with regular gain, then both with boost options. And as with all Rivera's you get a sweet "Fender" like clean tones in channel one, with push/pull pot options to take the tone even further. I play music like Deftones, Tool, Korn, A Perfect Circle, Filter and Disturbed and can achieve any desired tone Needed for the sounds. Really I can't recommend this Amp enough.
Reliability & Durability — 10
I did by the head used, so it came with stock tubes. I used it heavily for about 3 weeks and blew a tube, mind you this amp is already almost 10 years old, so it didn't bother me one bit. I had my tech retube and bias with JJ EL34's and had him put in SOZO Caps inside the circuitry as well. if you aren't familiar with sozo caps, you need to check them out. those alone take your amps tone to a level well over 9,000. I've used the amp heavily since I returbed and have not had an issue yet. As most Rivera amps are built to handle world war destruction. construction alone gets this amp a 10. You'll have this amp and all other Rivera's for years to come, I promise.
Overall Impression — 10
I play several different styles of music, as well as sessions work. This amp has been with me through all of that. With a tweak of a knob and three channels to choose from, you could play anything from country to pop to metal. I've also found that Rivera amps REALLY love pedals played through them, whether in front or through the loop, you get a really sweet sound. Granted, like all amps, this isn't for everyone. But if you want a great boutique quality amp with fantastic sound and construction, I recommend giving this a shot.