Utter the word “Bassman” in guitar circles, and most players’ minds rush to the tweed-covered 4×10″ combo of the late ’50s. Some, though, will reach for the cherished (and much more accessible) 50-watt head into which that combo evolved in the ’60s – a concerted effort by Fender to re-think the template and create a viable bass amplifier… one that resulted in yet another outstanding tone machine for guitar.
The blond Bassman of 1960-’64 and the blackface Bassman of ’64-’67 are somewhat different creatures, really, but perhaps have more in common than not. Part of the beauty of either version is that it’s such a pure template. Want to hear what a guitar sounds like through a pair of 6L6s without a whole lot of messing around? Plug into one of these.
Our feature amp this month is a transitional model between blond 6G6-B and black AA864 models, with a circuit that still relies largely on the former design. At first glance, it looks like a standard blackface Bassman (read on for the origins of its black cabinet, a slight red herring), but pretty quickly, you notice that extra knob at the right end of the panel. Hey, a Presence control! Then, just for fun – or perhaps to clean the rather cruddy control panel – you pop off one of the numbered black-skirted knobs to reveal the 1 to 10 control numbers beneath it that were standard on the brownface amps with blonde or tan Tolex (note: the present owner swapped to the cream knobs in the photo so these tell-tale numbers could be seen). The circuit, though, is the real giveaway; the presence of any original blue Mallory coupling caps will warm the heart of any fan of vintage Fenders, but those two enormous .25-uF caps in the Bass Instrument channel (to the left of the board) are real rarities, found only in the 6G6, 6G6-A, and 6G6-B amps. So, if Fender was tip-toeing toward a new cosmetic style in the black control panel and knobs on this one, it was still loading in that rather quirky, short-lived 6G6-B – and producing an amp that would become a secret weapon of several in-the-know guitarists as a result.
While the Normal channel on these amps is very much the preamp design that would become famous in the blackface amps, with the tone stack sandwiched between the first gain stage and a second gain make-up stage, the Bass Instrument is a real oddity. This channel opens with a cathode-follower that feeds the tone stack – well, the Bass control, at least – though one that’s somewhat different from the cathode-follower familiar from larger tweed amps (yes, other than in the fact that it comes before, rather than after, the primary gain stage). The Volume control follows this tone stack, then come two simultaneous gain stages, and finally the Treble control, which passes this channel’s signal onward to the phase inverter. An interesting preamp stage, to say the least, and one that was clearly devoted to the name in front of it – “Bass Instrument.” This channel sounds woofy and dark for six-string guitar, and each of our three noted 6G6 users are known to have plugged into the Normal channel, giving them essentially a blackface-style preamp.
Of course, there’s more to the early Bassman head than the preamp, and there’s plenty of goodness the rest of the way down the line, too. Compared to the AA864 Bassman that would follow in ’64, and the AA165 introduced shortly thereafter, the 6G6-B still used a 7025 (a rugged 12AX7 type) in the phase inverter, rather than the lower-gain 12AT7, and also had the Presence control within the negative-feedback loop, to dial in a little more high-end zing at the output stage. Together, these put a tad more sting in the 6G6-B’s tail, beautifully translated to a full-throated roar when you cranked those 5881 output tubes, which saw about 50 volts more on the plates than the 6L6s that the AA864 and AA165 would carry
For all these points, the post-’64 blackface Bassman is still a rugged, gutsy, and great-sounding amp. Scads of significant players swear by these humble workhorses, which remain among the more affordable of giggable vintage blackface Fenders, but guitarist and producer Steve Albini is one worth noting. The Bass channel on the AA8664/AA165 is still an unusual creation (hey, they really were trying to build a bass amp, after all), but the Normal channel is, once again, straight-up blackface goodness. A little less odd than the 6G6 Bass channel, though, the AA8664/AA165’s runs through one and a half dual-triode 7025s, with a fourth triode left unused. If you’re of a mind to mod the lesser of two channels on a vintage amp, this is a good place to stick a high-gain channel – or a big-tweed channel with two-knob cathode-follower tone stack – without touching the Normal channel.
The groovy 6G6-B here has an interesting history. Owned by Peter Kuttner, it was formerly – as the stenciled name on the bottom attests – one of the house amps belonging to John Neff, who co-owned a recording studio in Maui, in the ’80s and early ’90s with Steely Dan’s Walter Becker (at which the pair recorded Donald Fagan’s Kamakiriad album). “I had a ’65 Bassman head that needed work and did not sound too good,” says Neff. “Then I was working on the Big Island and found this ratty looking ’64 that sounded amazing, but someone had replaced the Tolex or painted it black – it looked like hell. Well, my ’65 had a great cabinet, so I swapped them.”