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Amp Rx Part 2 - The Gibson GA-20RVT

by vaughn skow October 25, 2011 2 min read

Howdy do tone brothers and sisters.  This week has been really fun for me.  I recently acquired a Gibson GA20RVT amp.  Gibson has made amps with this model designation several times over the past 40 years or so; I’m talking about the latest incarnation ... from around 2001-2007.  These quality hand-built amps can be had cheap, so they qualify as a "sleeper" amp.  This model sports 12ax7’s in the pre amp and a pair of 6V6 tubes in the power section and is (very conservatively) rated at 20 watts.  She’s a real looker, and her beauty ain’t just skin-deep; when you look deep into her soul, you find even more to love.  She’s laid-out well, hand wired on a superb turret board, and has top-shelf components throughout. And the sound?  It’s thick, rich, complex, and, well, awfully dull on the top end. That’s the problem we’ve gotta fix!  Read on for the Rx.

So, first the gal got a ride to the amp shop where she received a couple of minor mods:  1. Reverb was enabled on both channels, and 2. the volume of channel 2 was brought up to the same level as channel 1.  I also hoped to make the weak tremolo rock, but alas, there just ain’t enough gain stages to be had in the available number of 12ax7’s!  I’m gonna just flat call this one a design flaw.  If really lush tremolo is your thing, get a pedal, or don’t consider this amp.  The verb, however, is straight-up good long-spring accutronics, very sweet. 

Next, I decided to address the suspected heart of the tone problem, the speaker.  This one left the Nashville Gibson factory with a Celestion "seventy-eighty"; most had Eminence Legends.  I got to choose, and I preferred the Celestion; the Legend only enhanced the amps overly-warm nature.

First, I tried the G12C.  I hoped this would bring out a nice fenderesque sparkle and chime.  It did, kinda, but I felt as though it lost too much of the sumptuous bottom:

Then came the Retro 30.  I feared this might take the amp too far in the Britt voiced direction, but my fears turned out to be unwarranted.  This combination actually gave me just what I wanted. I still had the big, beautiful bottom and complex mids, but now had all the sparkle I could ask for; wow, the treble control actually didn’t need to be on ten for the amp to sound good!

Last, I decided to give the Reaper 30 a shot.  This is a great all-around speaker, and it sounded great; but I felt that maybe it didn’t quite give me what I wanted in the sparkle and shimmer department.

So, last I decided to put the Retro 30 and the Reaper up against each other and see if I could be 100% sure that I had found this pretty gals speaker soul-mate.

That last little shoot-out confirmed that the Retro 30 was the speaker that amp had been waiting for all it’s life.

See ya next week fellow tone junkies!

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