There are few groups of amps that are perpetually on my list to buy, with the end goal of eventually trying and comparing them all. One of those is the Rivera Knucklehead series, which started with a two channel amp which was more of a “Fender Clean + Slightly Gainier JCM800” kind of thing, back when that was a more novel idea. Next came the 3-channel Knucklehead Reverb, famously used on a handful of metal albums but most notably on Slipknot’s first few records, and sporadically since - this resulted in the KR7 Mick Thomson signature amp, which is the version that I own. Generally speaking I don’t like “signature” stuff, but I couldn’t refuse the price of the KR7 - but I’d have preferred a standard KR100.
While the 3-channel KR55 and KR100 amps were being produced, a new model called the “Knucklehead II” came out, which was a simpler design that was kind of a hybrd between the old and new Knuckleheads. The II had a fender-like clean channel, but instead of a crunch channel, the second channel of the II was an all out high gain monster. This amp seems to be pretty unpopular - someday I’ll find out for myself.
Then came this amp - the K-Tre. This is clearly based on the II, with the same headshell size and a nearly identical front panel. I didn’t realize quite how old these amps are - this one dates from 2006. The modern K-Tre Reverb is again another very similar amp, just adding a spring reverb single control for it, and that version is still available brand new today. In fact, according to the Rivera website at the time of writing, even this non-reverb K-Tre is still available, but I couldn’t actually find one for sale anywhere (whereas the K-Tre Reverb is readily available in stock at Sweetwater and other retailers).
Most chatter online is that the reverb and non-reverb K-Tre amps sound different from each other, with a few comments that the Reverb version is more aggressive and modern sounding. I have to wonder if this is a case where there were some circuit revisions along the way, so comparing a 2024 K-Tre vs a 2024 K-Tre Reverb would likely sound identical, but obviously comparing a 2006 K-Tre vs a 2024 K-Tre Reverb would sound quite a bit different because it has nearly 20 years of voicing, design, or part revisions since then.
I also think it is interesting that the Knucklehead II is considered one of the “bad ones.” It looks the same as the Tre, but the II has even more tonal shaping options - a master volume for the clean channel, and the gain channel has pull switches on all 3 EQ controls (Sweet, Scoop, and Bass Boost). The Tre’s (both my 2006 and current production) don’t have any pull controls on the gain channel. Not that more controls means better tone of course.
To make things even a bit more confusing, I’ve seen a Tre Reverb with a 1999 date code, but the earliest “II” I can find is from 2003. So I have to wonder if the “II” was designed to be an upgrade of sorts to the K-Tre models, but fell flat for whatever reason - voicing changes, or maybe the extra tweaking added by the pull controls just confused people. We guitar players are a fickle bunch, and plenty of amps have died unceremonious deaths due to “it’s complicated to dial in” perceptions even if the actual amp circuit and tone was identical to its predecessor (Peavey Butcher II comes to mind…).
So, convoluted history aside, this is a really awesome sounding amp. I find it unique sounding compared with the KR7, and definitely different than the Bonehead. The clean is no surprise - Rivera excellence - and the gain channel I’ve heard compared to a Mesa Rectifier which I can see, but the low end feels a lot different on the Rivera. It can get a little muddy if you aren’t careful with the Foundation control, but keep it in check and it tightens up nicely. Overdriven chords are extra chunky and it’s a little easier to play than the KR7, if that makes sense. It can do metal gain levels right out of the box, but a boost in front really helps keep that low end in check, so I wouldn’t pick this over say, a 6505 or Uberschall for the same basic type of sound. I’d actually put it in a very similar category to the Elmwood M90 I just picked up too, it’s an amp that has its own very unique voicing and sound, can do ultra high gain, but my favorite tones are somewhere in the “heavy crunch” territory, and I’d boost it for faster palm muted riffing. Now to try a II… and a Tre Reverb… and a K55…