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October 25, 2009

Low wattage guitar amp - Mack GEM

The new Mack GEM is out, and I have played it quite a bit over the weekend. This low wattage tube amp is very cool. First of all, it looks killer! My friend asked if it had been built my smurfs. Well, it sure is small. Our daughter thought it was a lunch box. Keep the jokes coming if want, but it delivers plenty of grit and volume; even the smurfs might have to run for cover when you crank this baby.

Mack GEM

The Mack GEM is available as a head, or as a combo. I have the head version, and I also have a matching Mack 1x10 open back cabinet, which houses an Eminence Ragin Cajun. This cabinet is very well built, and super handy. I will likely use this little cabinet with other amps as well, since it's so portable and sounds really nice.

Mack Gem Specifications

 Gem Head

Gem Combo

The Gem has a power switching circuit that changes its single EL84's power output from 4 watts to 0.4 watt. You might be thinking, 4 watts must be too "weak" for most people. Well, I will tell you, this 4 watt tube amp can be LOUD, if you want it to. I can easily play smaller gigs with this amp.

I have so far played this amp with 3 guitars - my Squier Tele, my Michael Kelly Patriot Shadow and my Suhr Classic. I get classy tones with all three. I find that I can coax some big EL84 tones out this 4 watter, very similar to my Mack Heatseeker 18 watt amp, only at lower volume. The Mack GEM has big tones, even though it is small.

Another particularly interesting feature in this amp is the switchable pream gain selector. The Gem features a NOS 6AC10 preamp tube, which is a triple triode tube. The three tube sections in the Gem's 6AC10 provide some interesting preamp flexibility:

  1. Low gain mode. Two of the sections are paralled and cascaded into the third. This provides warmth and touch sensitivity with extra gain from the third stage.
  2. High gain mode. Flip the Preamp switch and the three triode sections are cascaded one into the other. This produces higher gain rock tones quite different from any other Mack amp.
  3. Power amp AND preamp distortion. As you turn up the gain control, adjust the volume control and you can dial in preamp distortion or power amp distortion or both at the same time. This is available at any volume level.


Enough talk, you probably want to hear what it sounds like? So, I recorded a video the same they day I received the amp, have a look. This is me playing the amp for the very first time. I wanted to capture the moment on video - I had no idea what to expect, and you can see how I'm turning knobs and finding tones as I go. I used my Suhr Classic, plugged straight into the GEM, without using any pedals or effects.

This video below features my Zonkin' Yellow Screamer MkII pedal, and a Boss DD-20 delay. This amp takes pedals well. I think this gain tone is really good. Realize that the volume is really low. You can hear me flicking the pickup selector switch as I holding a distorted note or chord. You can even hear the guitar strings acoustically sometimes, if you listen closely, while a good overdriven guitar tone is still being produced. Sweet!

In the next video below, I demonstrate how the sound doesn't change as you switch from 4 watts down to 0.4 watts. It just gets quieter, and the tone remains unchanged. Very cool. I am using my Squier Tele and Michael Kelly Patriot Shadow on this video.

By Robert Renman - www.dolphinstreet.com


Posted by Robert Renman on October 25, 2009

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