Carl Martin Ampster

I have worked with a number of pre-amps with on-board cab sims, few of which grabbed my attention. The pre-amp sections were fine, for the most part, but often their cab sims sounded boxy, honky or fizzy, thus making it difficult to dial into a usable tone. They were decent and did the job, but they did not find regular use in my home studio. The overall sound and quality of the fully-analog Ampster, which is 12AX7 valve-driven with zero latency, was a very pleasant surprise in both sound and its diversity, which I’ll get into shortly.



Being old-school, I like hardware, even when VST/plugins sound pretty amazing. The less I have to use computer-based digital stuff the better. The Ampster is small, rugged, sounds great, works like a regular amp and is a great pedal platform – overdrives and distortions sound astonishing! It operates via a 9V adapter (included), although any 1A power source will work.

Looking at the front, you have the usual controls, including a Master volume and a Gain. There is a significant amount of headroom with this pedal, and rarely did I have the Master past half-way. The Gain ranges from sparkling clean to modest dirt for slightly crunchy chords – and this is one reason why the Ampster is such a great pedal platform for one’s favorite ODs, fuzzes, etc. The EQ has a very good and usable range, and there’s a Presence knob, which I appreciate (particularly for clearing up heavier Metal riffing). The Mute footswitch works as per its name, and with zero popping in the signal. The Cabinet switch alternates between a 2x12 open-back cab (a crisper tone with more bite, indicated by a red LED) or a 4x12 closed-back cab (a heavier and fuller tone, indicated by a green LED).

The back of the Ampster holds a few surprises, besides the usual input and ground lift. There are different ways to output, including a balanced XLR that incorporates Ampster’s Cab sims. There’s also a Link output, which bypasses the Cab sims, so that you can go direct to an amp, to an interface/other Cab sim source, or you can run it with the XLR for double-tracking (direct to DAW vs. a mic’d amp/cab). Further, there is an FX Loop (send/receive) that works in the traditional manner, allowing you to run modulation and time-based effects; but there is a ‘normalizing’ switch of the Return socket, found under the hood of the Ampster, that reassigns the Send, to bypass the Cab sim of the pedal. You won’t be able to use the Loop in a traditional manner, but allows the Ampster to be used as a valve preamp in front of a physical guitar amp. The Remote socket can interface with both analogue and digital external footswitches, ideal for those mounting the Ampster under a pedalboard, if not in a convenient location for effective control or preferring a master control mechanism.

Next, a great feature of the Ampster is the three-way Voicing switch, which rolls off the lower-end mids, analogous to a mic’d cab position. One Voicing is similar to micing the outer edge of a speaker, another more toward the middle, and the third center of the cone. This is great if wanting a more robust sound with thin pickups, or to clean up darker and overly-rich pickups.

Overall, and particularly if you’re looking for a Marshall-style sound, this is a fantastic preamp. It works for live gigs as much as average players recording at home. It has a very good low-end response without any mud or muffle. The high end, even with the Presence and Treble up full, does not sound brittle, but maintains the tone’s composure and integrity. Similarly, its responsiveness is spot-on, cleaning up with soft picking, yet increasing in crispness and brightness with a harder picking attack. Best of all, this sounds like the real deal… its sound and responsiveness would sit perfectly in recordings, which tells you how far we’ve come with gear over the years.