December 29, 2017 chris

Acoustic Model 164 – the amp that should not be

In the run of their existence the Acoustic Control Corporation has manufactured several amps / cabinets which had a huge impact on the market. The astonishingly loud 360 / 361 bass amplifier / cabinet combination which was used on the stage of Woodstock for instance.
In the late 70s, 1978 to be precise, the Model 164 was released. This extremely powerful and versatile combo amp, along with the Model 160 (the head version) changed the course of the company itself and eventually led, at least in part, to its doom.
We’ve covered the history of the company to our best abilities in this article, so let’s focus on this very amplifier itself.

After Acoustic went straight solid state for more than a decade the major difference was switching to tubes.
Four 6L6s in the power amp and 12AX7s in the preamp made sure Model 164 can get extremely loud though it remains a pristine, crystal clear clean tone until about 50% of the preamp volume. After that it get’s bluesy.

When using the second channel, you’ll be able to reach the true tube distortion. Both channels work in a row, meaning the volume of the first will affect the output of the second. To this cascading gain circuit we’ll get back later as its results went way more far than just affecting the tone.

Speaking of it, the tone tends to get pretty bass-ladden when the amp is cranked up. But this is no issue the (+/- 18dB) EQ couldn’t handle. It really works on the sound in a profund way.


– brown tolex
– two channels, each with volume and master
– 3band EQ with bass-boost an bright setting
– adjustable presence
– reverb
– additional (+/- 18dB) 5 band Equalizer
– switch to select 100w or 60w
– switchable between tube and FET preamp
– Weight: 65lbs
– Switchable 4 ohm/8 ohm impedance
– Electro Voice EVM 12L 12″ Speaker
– 4x 6L6 power tubes & 12AX7 preamp tubes

Playing it clean it’s comparable to a Twin Reverb with a little more warmth, a little more bottom. Getting into distortion you’ll get the right amount of dirtiness (but not noise!) that only tubes a capable of. The late Kyuss / early Queens of the Stone Age come to mind instantly.



In 1971 former repair shop owner Randall Smith, who was famous for his Fender modifications founded a little company called Mesa Boogie (also known as Mesa Engineering). With popular early customers such as Carlos Santana and Keith Richards his amps, especially the Mark I became a success and approximately 3000 items were sold before the MARK II was introduced in 1978.

Why is that important at all?

When looking at the circuit of Model 164 Mr. Smith found some profund similarities to his just released MARK II. It must have been something within the cascading gain / mode switching structure getting a little bit too close to what his amp was about. Something that violated a patented concept he has just filed.
There is no evidence to be found that ACC ever got a call or letter from Mesa threatening a lawsuit but the abrupt reissuing of the brand new amps speak a pretty clear language. If this incidence played a part in Acoustics stepping out if business in 1983 is also uncertain.



The head version of the combo amp.

Technically identical to the 164 but the surface ist different. Instead of a brown tolex it comes in an oak / walnut finish and the grill cloth is different.

164 / 165 G100T 112
Here it get’s tricky. These amps have presumably (!) been produced in reaction to the Mesa Boogie / ACC incidence somewhere around 1982 and have a slight variation in the circuitry.
They have two inputs to serve channel one (low gain) and channel two (high gain). While the first has just a volume knob, channel two has an inside / outside knob for gain and volume just like the „original“ Model 164 / 165.

163 G60T 112
The small brother of the G100T with “just” 60 watts though it sounds like 100. Same inputs, same channel structure, same speaker, no 5 band EQ, 2x 6L6s and 3x ECC 83s tubes.

162 G60T
The head version of the 163 G60T 112.


An original Model 164 in very good condition apart from some scratches on the grill and a missing inside knob on channel one. An issue that’s going to be fixed asap. The amp has still the original EVM 12L speaker but has been given a set of new tubes, what (after more than 36 years) should be surprising.

From clean to bluesy to overdrive the tone is incredible warm and precise at the same time no matter how much use of volume you make. We have not dared to crank it up all the way though as it gets really loud.

Long story short: the amp sounds great, is a lot of fun, works well with electric and acoustic guitars likewise and is a more than welcome addition to our equipment pool.


Patent US 4211893 A “Dual mode music instrument amplifier”
Acoustic Model 160 schematic
Pirk’s guitars and amps – an Acoutic appreciation Blog
Our coverage of the history of the Acoustic Control Corporation

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Comment (1)

  1. Larry

    I have a 164 in near mint condition just has a creck in the leather handle that is it the rest is mint with all new tubes slovtech and castom cab under with ev matching speakers.

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