Mesa/Boogie Mark IIa

This is a great amp, but it takes some tweaking of the controls to get the sound you want. Once you become familiar with the controls, you can get a wide range of tones.

I've primarily used this amp with two guitars. One is a Charvel strat outfitted with a Duncan JB and the other is an Explorer with some early eighties Dimarzio pickups. While the Charvel works good, I prefer the explorer. When using the Charvel I have to cut the treble a bit, otherwise it can be piercing. The older Dimarzio pickups (PAF and Super Distortion) give a really well rounded sound and not overly sharp. This amp can get almost any sound from crytal clear country picking to massive singing overdrive ala Santana and Nugent.

This amp has never broken down on me since I bought it in 1986. I've had it in the shop only once for a retube and general checkup. My tech said the amp was fine and he was amazed with it's power. He also said that my transformer "looked big" for the amp. I have the 60/100 watt amp, so maybe it has a bigger one than a normal 60 watt amp? ALl around Very Reliable amp. No problems.

I've never needed service from Boogie but I once asked them for a schematic and they seemed to blow me off. Never heard back from them.

My playing ranges from blues to hard rock. No problems when using this amp to achieve my tones. The thing I like about this amp is that it has most of the options that were available from boogie, including separate hardwood head and 1 x 12 cab, graphic EQ, and 60/100 watts. If this amp got lost or stolen I would probably try to find another one. If I couldn't find one, I would probably look for a Marshall, either JTM-45 or a plexi reissue.

The Mark IIa is a 60W Class B channel switching tube guitar amplifier made in the late 1970s. Combo amps with 12" EV speakers and standalone heads were built.

For a novice, it takes a little head scratching to figure out how to work a channel switching amp. The rhythm and the lead channels each have their own preamp volume and master volume control. Rhythm mode is just a single preamp channel, that's not too hard to use.

The fun start when you switch to Lead mode. The Lead channel mode cascades a 2nd preamp after the rhythm preamp for screaming leads. The trick here is that the Rhythm preamp setting affects the Lead preamp, you have to find a rhythm/lead balance that works for you.

Some of the controls have pull out switches. Rhythm and Lead preamp volume pull out for "bright", Treble pulls out for "Shift" (effective for more of a Fender-type rhythm), there's a "Boost" pull switch that sets all the tone controls to full and gives the signal a little more drive. And if you're missing the channel switching footswitch, there's a pull switch for channel switching.

The standard configuration is rounded out with treble, mid, and bass tone controls. These are passive, not active (like any amp of that era and before).

I got used to the interface, but a couple of my friends couldn't grasp the concept at all and didn't like the amp. It does take some getting used to.

There's an effects loop, but the jacks are weird. The effect return is on the rear panel, but the send jack is on the underside, it's very inconvenient to get to. Also on the underside is a footswitch jack for the "Boost" function. Seems the were in a hurry to get this amp done...

Mesa Boogie offered options for their amps. The most common one is the five-band graphic EQ on the front panel, which mine has. The EQ is very effective and is somewhat resonant at extreme settings, which is handy. Other options were reverb, 100watt, and Class A. Mesa Boogie can still add these upgrades at the factory.

The standard combo amp with no options is already a HEAVY beast, and I lifted a fully loaded MkIIa and it was VERY heavy.

It gets an 8 for not-so-intuitive interface.

A word of advice: tubes make a WORLD of difference in the tone of the amp. I took my amp down to my tech's shop and experimented with the variety of Groove Tubes he had in stock. I went through a whole set of preamp tubes and wasn't happy. Then I started going through power amp tubes, and they made a BIG difference. After I found a good set of power tubes, I found a set of preamp tubes that made me happy. The POWER AMP is where the *crunch* is, that's where the TONE is!

Mesa Boogie made three MkII amps; the a, b, and c series. I've had extensive experience with all three. My favorite is the "a" series. I had a "c" and found it better suited for metal and hard rock. The "b" I used to own was very similar to the "a" but it had this "rasp" I could never get rid of, so I sold it and kept the "a". In hindsight that may have been a tube issue.

I find the "a" more versatile than the other three, and it has a nice round crunch for rhythm which I really like. My tastes run between blues and hard rock and I tend to set the amp to a moderate overdrive in rhythm. I play an Epiphone Genesis guitar through the amp, with the stock pickups replaced and it sounds really good. For a while I was using a Hamer Sunburst and went back to the Epiphone, it just plays and sounds better. The Epiphone is just a Les Paul reject with a 2nd cutaway. A real Les Paul sounds even better, but the Epiphone does what I need.

I have to say that the tone I go for is the vintage "Pearly Gates" of early ZZTop, that is a great guitar tone. I was also able to get some of Brian May's AC30 tones from this amp, it's all in the fingers.

In rhythm mode I can make it as clean and full as a Fender or overdrive it like a single channel Marshall. In lead mode, it can sustain a note forever. Beautiful. False harmonics really leap out at you.

Mesa Boogies are REALLY loud amps. A stock 60w combo with the master on "2" is LOUD. These can push 4x12s with no problem.

I don't use any effects with this amp, the guitar plugs straight into it. The only thing I use is a Hughes & Kettner Red Box (see the review in Harmony Central). Mesa Boogie sells a rack chassis for their Mark combo chassis; I got one of these, replaced the speaker with a 75W 8ohm power resistor (consult with a tech before doing this) and I put the Red Box between the amp and the resistor. The tube power amp section *has* to see a load or it will be damaged, that's why the resistor is necessary when removing the speaker. The Red Box is a speaker cabinet simulator with a balanced XLR output, so I can crank up the master volume past "2" for that lovely overdrive, plug straight into the board and hear my guitar through the monitor without the painful volume. No more lugging around speaker cabinets for my amp! The other plus: you can get feedback through the monitors with the Red Box, but it only does this if you take the signal out of the power amp, the speaker output. I tried plugging the Red Box into the preamp output of the amp and it didn't have near the balls as plugging into the speaker output.

I tried a lot of amps and I keep coming back to this one. Probably the only things that are superior is an old Marshall head or a Fender Bassman. Mark IIa amps sound really nice, and I have to add that I see very few IIa amps for sale in stores or on the net.

Mesa Boogies are built like a tank and they are one of the few companies that use conservatively rated transformers and other parts for long life. When I say conservative, that means for a amp that can deliver 60w, you should use parts rated for 1/2 higher wattage for reliability and long life. I'm an EE and that's standard design convention. Most amp manufacturers don't do that, that's where they cut corners. They'll just put a 60w transformer in a 60w amp, and the heat from the wattage dissipation will burn out the transformer.

If you've ever had to take a Marshall, Fender, Ampeg, or Peavey to have a $100 transformer replaced because it burned out, you won't have this problem with the Mesa Boogie. They *last*. I've had mine for over ten years and the only malfunction was a bad toggle switch for the EQ.

No problem. Got schematics and they were helpful, even giving me the model number by the serial number. That's when I learned of the three Mark II series.

It's hard to find a Mark IIa amp, and even harder to find them at good prices. These days a stock chassis will draw $800 and up, I feel lucky to have paid only $550 for mine. At the time I bought it, it was in a custom made cabinet the stock combo cabinet was long gone, but that didn't matter since ultimately the rack chassis/red box was a smarter way to go.

I play mostly 70s classic rock and blues/rock and this amp fits the bill very nicely. I definitely feel that the tube power amp plays a significant role in the sound of the amp, I have tried guitar preamps and always felt there was something missing. This amp is a combination of the clean vintage Fender tone in rhythm mode and almost a Marshall tone in lead mode. A vintage Marshall in overdrive seems to be the elusive tone, nothing sounds like them. But the Boogie gets a great guitar tone nonetheless, it is unique in the same way that a Marshall is. In fact, the Johnson Millenium has a Mesa Boogie modeled preamp; we put them side by side and there was no comparision. The Boogie sounded better. The Millenium is still an excellent amp, but again I keep coming back to this Boogie.

I hope I never lose it, 'cause it's hard to find another MkIIa amp. No one seems to get rid of them!