A Brief, and Incomplete History of Guitar Amplification

My recent purchase of a Quilter 101 amp head has made me think a lot about guitar tone and how it has “evolved” over the years.    One thing that sticks out to me is that MOST of the amps that have a “signature” tone, achieved that sound mostly by a happy accident.

quilter101I think the first recorded incident of a guitar amp being created with the idea that users would deliberately drive it into distortion was the Mesa Boogie in the late 60’s.   You can see Marshall advertisements in the 1960’s touting “distortion free sound”.

By the 50’s pickups and amplifiers evolved around each other, as did speakers, which in the early amps, were off the shelf items, rather than devices especially created for electric guitar.   None of these devices seemed to be designed with the idea of a “flat response” in mind.    Pickups, amps and speakers were all considerably “colored” and all evolved rather slowly: but everyone who designed a pickup designed it with the idea it might be plugged into some other manufacturer’s amplifier.

That said, the electric guitar never does seem to actually be an attempt to just make an acoustic guitar louder.    Right from the start, you can hear 1930’s and 40’s guitarists driving their amps into distortion and using that capability as a creative tool.      At the same time, the quest for a clear, undistorted rhythm sound lead to increasingly powerful amplifiers.   The Fender Blackface series of amplifiers hit the market just as baby boomers inspired by the Beatles exploded into garage bands, and needed amps.     These amps had a big dip in the midrange response which was a psycho-acoustic slight of hand designed to make the amps seem louder and more powerful.

Since most of the information in a guitar signal is concentrated in the 100 to 2,000 Hz range, “scooping” the mid range area had a HUGE impact on the perceived volume the amp was capable of.       A Fender “Dual Showman” with two D-130F speakers (you could see the bright aluminum cones through the grill cloth) was considered, (at least in my circle of friends) as the ultimate guitar amp.

As Fender was one of the leading amp manufacturers for professional musicians, this sound, however colored was taken as “just how an amp is supposed to sound” to most of us.   All we knew is that those “tweed” amps we saw in pawn shops got fuzzy at low volumes and sounded rather “dull” in comparison.

Looking at these photos generated by the “Tone Stack Calculator”  on the Seymour Duncan page it’s obvious how scooped the mids were on a Blackface amp.     If you look at the photos, you can see the response curves generated by various positions of the tone controls, which are shown to the lower left corner.  Look at the positions of the controls in the photo that shows a relatively “flat” response.  To this very day, Fender is still selling replicas of this series of amps (along with ones that feature “tweed tone”) by the thousands.   They’ve undoubtably sold more “re-issues” of both the black and Silver faced amps than they did back in the day.

Curve FenderThe above photo shows the response curve of a typical fender Blackface amp with all the tone controls set at “five”.  The “scoop” is quite severe, something around 12 dB in this case.

Below is a more typical tone control setting for a black face amp, in fact, this is my starting spot for my own Fender.

curve fender typicalThis one is what one would need to do to the tone controls to get a flat response out of  a Fender amp from this period.

curve fenderflatFinally, a graph showing a rather extreme setting with the treble control turned fully up.

curve fenderextreme

Most Baby Boomers will remember walking into a pawn shop and  discovering lots of old amplifiers sitting around and remember some that were actually painted or dyed black or maybe even covered with black vinyl in an attempt to make them more “modern”.    The period I’m speaking of was the early to mid 60’s and we all wanted to sound like Dick Dale or the Ventures.    When listening to amplifiers in music stores we determined that the ones that sounded the most like a Showman were naturally the best ones.

At this point in time it wasn’t common for rock & roll acts to show the actual guitar amps they were using.  (Also well before the “Guitar Hero” era)   I remember the first time seeing the Beatles on TV with these strange looking amps with a three letter name that I couldn’t quite make out on my parents B&W TV.   (A friend of mine thought they were VOC amplifiers)

Later on in the 60’s and early 70’s, most of the Guitar Heroes seemed to use Marshall amplification.  Most of us know the first Marshall amps were heavily based on the tweed Fender Bassman.     If you look at the control panel on an early Marshall it’s a dead ringer for what you’ll find on a Tweed Bassman.    The amps didn’t sound like the tweed amps, particularly when coupled with two 4 X 12” cabinets with British made speakers in them, but the sound was a lot closer to a tweed amp than a Blackface Fender. Below is a typical Marshall amp response curve.

curve MarshalThe mid bass dip is far less extreme than the Blackface ones.

Below is a typical curve out of a Vox amp.

curve voxVox amps fall somewhere in between and you also have the “Top Boost” option on the AC-30 to add it’s own personality.    The result of all of this is that people usually purchase a guitar amp with a particular “personality” in mind.    Mesa Boogie, Marshall, Blackface Fender, Vox AC series, Tweed Bassman all conjure up sonic signatures of one sort or another.   It’s not at all like purchasing a PA or Hi-Fi amplifier where the standard is fidelity to reproduction of the original signal.    A guitar amp is seen as a tool for the production of sound, as important as the guitar itself in determining the overall sound and many guitarists “play the amp” as much as they play the guitar.

The above is a huge oversimplification with all sorts of factors one can’t account for by frequency response alone.  We’re just isolating one factor.

Obviously, the above response curves are then added to the ones generated by the pickups and further on down the line by the speakers they run through, effects used and even the cable the guitarist is using to connect his guitar to the amp.  And on top of this, every guitarist has his own tone to add to the equation.   Plug Carlos Santana into Eddie Van Halen’s amp and he’s still going to sound like Carlos.

Introducing a new amp head in today’s market is a rather brave proposition as it has to sound like other guitar amps, particularly TUBE guitar amps in order to fit into the signal chain that’s been developed for use with those amps.    Indeed, Quilter has provided a “Voice” knob on the 101 to emulate the sonic signature of several common amp sounds: “Surf”, “Tweed” and “Jazz”.  They have accomplished this to a degree that would seem to be regarded as a breakthrough.

I’ve been using the Quilter for a while now and it is a veritable “swiss army knife” able to get most of the amp tones I regularly use and some I’ve not been able to make previously.

The Trunkslammers, (the band I play with) only do a couple of covers, so the Quilter works well for me, I only have to sound like me.    Once I convinced myself the amp sounded “tube like” I relaxed and started to explore the wide range of tones that ARE available.  The amp’s lack of a “sweet spot” that most tube amps have where they sound best and the fact that the distortion level is totally independent of the amp’s volume give one  a big advantage that the tube amps I’ve owned don’t have.

On the Quilter Facebook page, there have been posts from people who are not satisfied with some aspect of the 101’s performance.    I would be amazed if this was NOT the case, given the amazing variety of guitar amp sounds out there and all the possible combinations of guitar, pickups, speakers and cabinets, not to mention a range of tastes.   The odds of making all guitar players happy are not too great.

When someone purchases a Fender, Vox, Marshall, Mesa Boogie or Dr. Z amplifier, it’s often done (depending on amp model) with the idea of getting a few specific tones being paramount.    One doesn’t buy a Marshall stack with the idea that it also would be able to sound like a Fender Twin Reverb or a Vox AC30.   While some amps do have a reputation for being versatile, most brands do seem to have certain tones they are associated with.

Given all the attempts of manufacturers to make amplifiers without vacuum tubes sound “like a tube amp” over the last 40 or 50 years, it would seem at this point that arguably Quilter has managed this to an unprecedented  degree with several lines and models on sale.

Sounding “like a tube amp” is only the first stage, and we’ll discover if Quilter is “here to stay” when someone describes an amp as “Sounding like a Quilter”.