So I came up with this great idea to do an interlude between every chapter from now on in which I draw/write a tribute to a piece of gear that I like a lot and is relevant to the comic.  Unfortunately I came up with this idea after posting the first page of the new chapter last Thursday.  I was going to skip it this chapter, but then this picture came out too damn adorable not to post right away.  So I’ll post this today (Tuesday, April 15, 2014), and then swap it for last Thursday’s page when I post this Thursday’s page.  That way the archives stay pretty and nobody gets too confused in the process.

(EDIT: done!)

 

Marshall JCM 800 – 2204

You may remember seeing a JCM 800 earlier in this chapter (in this comic, to be precise).  It is Rachel’s (and my) favorite guitar amplifier of all time.  From the outside, the JCM800 looks a lot like its predecessor, the JMP Super Lead – the amp made famous in the 60’s and 70’s by Jimi Hendrix, The Who, and AC/DC to name a few.  They had the same number number of knobs, the same tubes, and the same power output.  Even most of the internal components were very similar.  However, their sounds were dramatically different.

The JMPs had two channels, each with its own input buffer gain stage made from one half of a 12AX7 (or ECC83) dual triode tube.  These channels fed into the same buffer stage made from a plate follower direct-coupled to a cathode-follower stage.  This buffer fed the same Fender Bassman TMB tone stack used in most of the big amps since the 50s.  After this came the phase inverter, power tubes, output transformer, feedback loop, presence control, and speaker.  This amp had a lot of gain, but the classic JMP didn’t have a master volume, which meant that to get the wonderful Marshall overdrive sound we all love, players had to turn the volume way up (to painful levels).

Fast-forward to 1981 – Marshall releases the JCM 800 series, including the 50W 2204 Lead Series (pictured) and it’s bigger brother, the 100W 2203, to name a few.  Much of the circuit of these amps was very similar to the JMP.  The power stage, feedback loop, presence control, phase inverter, TMB tone stack, and tone stack buffer were largely unchanged, save for the addition of the master volume control, which was added between the tone stack and the phase inverter).  That leaves only the input buffer stages, which were changed in a fairly small way that made a huge difference.

The 2204 and 2203 dropped the 2-channel approach, and adopted a single high-gain channel.  Gone were the two triodes in parallel as seen in the JCM.  Instead, these two triodes were cascaded in series, giving something in the neighborhood of 100x (40 dB) more gain.  Follow this massive gain with a master volume, and you get an amplifier that can create a huge, overdriven roar at any volume … but of course louder was always better.

 

Sources:  Knowledge and trivia absorbed from hours upon hours of poring over articles and schematics.  Also Wikipedia.  And the Line6 PodXT Live manual, which is actually a really great read if you’re a gear-head.