2009 Kasha Rockmod 50

Overview

This is one of my “secret weapon” amps due to it’s most unique feature: a switchable output tube section. You can load in a pair of power tubes, and switch between which pair is active by flipping the “OT” switch on the front panel. I’ve never seen another amp with this feature, at least with a traditional Class AB power section, and it’s one of my favorite tools to hear the difference between two given types of power tubes in a controlled environment (same speakers, preamp, guitar, etc).

Of course, this is more than a power amp, it’s a 3-channel amp with a clean, crunch, and lead or “burn” channel. The clean channel is extremely clean and a really great sound, and even with the gain control turned up it just adds compression and bass - not much grit or drive on that channel.

The crunch channel feels very British, with strong growling mids and a bright upper mid presence. It excels in mid-gain territory but can get saturated enough to do even classic metal, and adding a boost can push it over the edge.

Of course, you don’t need a boost, and the burn channel will go straight into modern metal all by itself. This channel has two gain controls for added tone shaping, labeled “gain” and “post.” I don’t have a schematic, but if I had to guess I’d wager that the primary gain control controls the gain after the input stage (like most gain controls) and the post-gain is between two stages further down in the chain - but I don’t know how many gain stages there are total in this design.

I should mention I do not have the original footswitch for this amp, and I’m not sure it’s even possible to acquire one anymore (the amp or the footswitch). The amp is still listed, with an updated faceplate, on the Kasha website but despite multiple emails I have never gotten a reply from them and can’t find any distributor or dealer for them, and it shows as out of stock on their website (and has for years). That’s really a shame because this is a great sounding amp that I’d rank very highly, even at its high price tag.

This amp originates from Kasha Rockmod preamps, but it’s hard to find a lot of information on them. There is a Rockmod 1, Rockmod 2, and a Rockmod 3 preamp which appears almost identical to this head (minus the power section). Dann Huff famously used the original Rockmod preamp in the 80s and I vaguely remember seeing a video of Brad Paisley using the heads in a live performance. My particular RM50 head has upgraded, red painted Mercury Magnetics transformers, further pointing to this amp’s top quality.

Also looking at the PCB, there is a small two-pin connector labeled “boost” with nothing connected, and several resistors on the PCB there are marked but not mounted (instead, just bare wire jumpers). I’m not sure what the details of the boost, whether it was for gain or volume - I assume it was an optional feature or perhaps something intended to be added in a later model that never came out.