All user reviews for the Hagerman Amplification 12AX7 Overdriver

NOTE: This review and video demo are for both the EF86 BOOSTER and the 12AX7 OVERDRIVER.

Hagerman Amplification knocked the ball out of the park on these two pedals, and for several reasons. First, the EF86 BOOSTER and the 12AX7 OVERDRIVER are tube-based (as per the names), which means rich overtones, superb dynamics and response to one’s playing, amp-like tone quality, and low mA requirements (215mA for the boost and 175mA for the overdrive). Below is a demo featuring these two pedals in isolation with clean and driven amps (both solid state and tube), but also with other gear and how they respond when stacked. I have the original beta models, if you will, which indicate EF86 BOOST and OVERDRIVE on their chassis, but are one in the same, but renamed, on the Hagerman site.



Boutique all the way, hand-built one at a time, the true bypass EF86 BOOSTER uses a pentode (5 electrodes), which means a warm and super clean gain for driving both amps and other pedals, which became obvious as tones blossom when matched with regular analog gear. And although the power requirements are modest, there still is high voltage (2V input and 140V tube supply) for optimal tube operation with a lot of headroom. With the Drive all the way down (and volume maxed), there is a noticeable boost, but start adding in the drive and it is LOUD, with 21dB maximum gain! The signal remains warm while still delivering ample second order (octave) harmonics. What really impresses me is how good the signal sounds when added to other gear, even if keeping the drive all the way down while pushing the volume… one of those always-on pedals.

The 12AX7 OVERDRIVER is a fantastic extension of one’s amp, as its gain can be described as a classic preamp-style overdrive, so that its tone accentuates a natural sounding fat crunch with lush tones. What makes this true bypass drive even more desirable is how it behaves with other gear – it responds incredibly well when stacked with other drive pedals or amps with moderate- to high-gain output (I also paired it with a Rockerverb-style preamp, and it rocks). Some drives tend to thin out a tone, but not this one, as it remains true to that thick, breaking-up quality guitarists want and strive to maintain within a signal chain. It also has huge headroom, with 36dB maximum gain and a 30mV input, onset of clipping. The grain is warm and generous, which becomes more aggressive as you push the drive, as experienced with real tube amps.

Now, it's part of a reviewer’s duty to discover elements that may be lacking, but these two pedals are so simple and deliver the goods so well, there’s not much to address. Some may want more of a Tone control range, but to my ears and with the various gear combined with these pedals, I never found that the case. In that regard, turning the Tone all the way left (more bass frequency) or right (more treble frequency) provides modest change to one’s original tone, which means dialing in your amp, then tweaking the boost and overdrive accordingly. For the most part, I never deviate between 10-o’clock and 2-o’clock, and often will keep it at 1-o’clock (flat), unless wanting a touch more bottom or top end (which really shapes those high-gain amps for thump or punch).

Both the EF86 BOOSTER and the 12AX7 OVERDRIVER retail for $342 USD, which is very much on par with today’s cost of gear, and is very reasonable when considering these are studio designed with engineered quality by an amplification company. Fantastic add-ons for tube amps, they literally help transform solid state amps and pedals amazingly well. https://www.hagamps.com/