6 Classic Amps Every Bassist Should Know

Here you are, perusing Reverb for a real, rump-shaking bass amplifier after looking forlornly at your 14-watt practice amp and realizing it has the same volume and tone as your iPhone on "speaker" mode. This is actually a beautiful time in a bassist's life, for your tone shall now only ever get louder, fatter, and punchier from here on out.

There are many tonal directions to explore. Before you get that red-hot credit card out and trade up to a new rig, you should be schooled on the classic tones that all bassists love, and the gear that got them there. I will place these amps in historical order. While guitar gear has tons of vintage options that come in and out of style, bass equipment, for the most part, just keeps getting better.

Ampeg B-15 Portaflex
Chief proponents: James Jamerson, David Hood, Carol Kaye

The Ampeg Company actually began making bass amps in 1946, when Everett Hull filed a patent for his “amplified peg” design for upright basses. Its initial amplifier models certainly broke ground in the industry throughout the 1950s, but the best was yet to come. In 1960, Ampeg released a bass amp that would shape pop music for a decade or more: the B-15 Portaflex “Flip-Top” head and cabinet.

Ampeg B-15 Portaflex

The B-15’s specifications seem quaint, outfitted with three 6SL7 preamp tubes and two 6L6GC power amp tubes that produced a mere 25 watts RMS through a single 15-inch speaker. It might sound like what you'd get from a practice amp today, but playing one is an entirely different experience. Grab your flatwound-strung P-Bass and start playing that opening line to “My Girl.” Or try some of Carol Kaye’s lines from the Beach Boys’ “Good Vibrations.” Next, cop the Staples Singers’ “I’ll Take You There.” Now it’s all clear, isn’t it? That’s the sound.

Compared with any amp of that era, the B-15 Portaflex has got booty, butter, and a sweet top-end courtesy of that glowing glass. It’s not powerful, per se, but it’s forgiving in the most musical way. Your notes sink into the power amp tubes like a luxury pillow top mattress, with clean lower-mids and punchy but not harsh upper-mids.

Acoustic 360/361
Chief proponents: Larry Graham, John Paul Jones, Jaco Pastorius

The volume of guitar amplifiers was on a hyperbolic curve throughout the entire decade that gave us The Boomers. If you start with the guitar volume of the Everly Brothers in 1960 and end with Jimi Hendrix in 1969, the volume differential is similar to the one between a sewing machine and a Saturn V rocket. The Ampeg B-15 was simply not designed to win a head-to-head collision with a Marshall stack set to “kill.” Something had to be done on behalf of bass players everywhere.

In 1967, enter the Acoustic 360, a 200-watt, solid state head designed to drive the 361 cabinet, a rear-firing 18” speaker enclosure modeled, I believe, after the Panzer tank. The 360/361 absolutely towered over the B-15, physically and sonically, and got the bass world ready for the Woodstocks, Altamonts and giant festival concerts to come.

Acoustic 360 Bass Head with 361 Powered 1x18" Cab

In December of 1967, the Acoustic 360 actually helped The Doors get arrested for noise violations and put them - and the amp - on the cover of Life magazine. This notoriety had a very predictable response, which is that it made the amp a must-have for serious rockers who would love to be arrested by The Man for bass notes alone.

Not that this was an easily accessible piece of gear. The suggested retail price of the 360/361 package back in 1967 was $1250.00, which in 2014 dollars comes to USD$8,850.00 Not. A. Typo. There is not, to my knowledge, another bass amp that costs nine grand, unless you’re cutting an SSL console in half and dragging that around, which is actually a pretty awesome idea.

Nevertheless, price be damned, the best bassists of the era knew that this was a killer amplifier. Larry Graham himself used these towering stacks for the thumb, the stank and the funk. Led Zeppelin’s virtuosic bassist John Paul Jones had to keep up with Jimmy Page, for the love of Pete, and with the Acoustic 360 (or, say, a wall of them) he could. And there was a young bassist from Florida who knew that if he was going to be The Best, he had to play The Best Amp. That’s when Jaco Pastorius saved all his money (legend has it, sleeping on the beach when his bandmates on the road slept in hotel beds) and eventually purchased an Acoustic 360, which gave Jaco’s fretless J-bass that instantly-recognizable bump in the upper-mids that provided him bassdom’s most enduring, original voice. Check out Bobby Vega’s paean to the Acoustic stack here, and dig his Zeppelin riffs.

Ampeg SVT
Chief proponents: Bill Wyman, Cliff Williams, Krist Novoselic, most every rocker

Get it straight - the Rolling Stones were not going to let anybody out rock them, on bass amps or anything else. As the guitar amps got turned up loud enough to knock the planet off its axis, Bill Wyman got ready for the Stones’ 1969 tour by setting up with an amplifier that was not even in full production at the time - the Ampeg SVT (Super Valve Technology.)

The Ampeg SVT is a 97-pound amplifier head designed to work with two 104-pound cabinet enclosure, each with eight baffled ten-inch speakers. Its 300-watt amplifier section was powered by fourteen tubes which required iron transformers that came from fallen asteroids. It will, by design, instantly produce a hernia in every single human who touches one with intention of loading it in a car or truck. It could possibly move enough air to rip your pants off, and its sounds as heavy and aggressive as a bowling ball going through a wood chipper. As such, the Ampeg SVT is as necessary to rock music as Marshalls, groupies, and teary-but-they-end-OK Behind the Music specials. You hear it everywhere and on everything - the Allman Brothers, AC/DC, Nirvana, the list goes on.

SWR Redhead 2x10
Chief proponent: Marcus Miller

Everything got very Hi-Fi and neon in the 1980s. The warm and tubey sounds of the 60s and 70s gave way to a bright, solid-state, cathode-ray, excitable, possibly-cocaine-related verve that began in earnest around 1982. And don’t get me wrong - some of this sounded very, very cool - at least for the time period. The Yamaha DX-7 synth was the state of the art and was spread across all sorts of tracks. Mullet-coiffed producers were using new “drum machines” to make grooves. And back in the day, it was cool and refreshing to “slap” your bass in a funky manner. For bassists, it was time for round wound strings, time to grow a luxurious mullet, and time for a new bass amp.

SWR Redhead 2x10" Bass Combo Amplifier

Back in the late 1970s, a tone guru by the name of Steve W. Rabe became enamored of the idea of giving bass players an amp that would fulfill the new, dreamlike age of Atari, Ronald Reagan, and parachute pants. The SWR Amplification company site describes his research and development thusly:

“[Steve W. Rabe] visited studios, asking the pros working in Los Angeles what they thought. They all just pointed their fingers at the studio monitors and said, ‘Make a bass amp sound like that, ‘cause that’s what a bass is supposed to sound like. So that meant hi-fi, clean, full range. With that ideology, SWR was born.”

Early products hinted at a design that would emerge in 1987 to light up the creativity of players such as the inimitable Marcus Miller - the Redhead 2x10. The combo amp featured 400 solid-state watts, two ten-inch speakers, a horn, and handy little wheels to transport the rig easily. True to the original vision, the Redhead produced super high-fidelity sound, and had a host of features to make it like a Swiss army knife for the studio: onboard EQ, compression, “aural enhancer,” an effects blend knob, and controls for the Tube DI were all on the front panel. There’s not much more to ad - the things sounded unbelievable.

David Eden World Tour 800
Chief proponents: Oteil Burbridge, Gary Willis

The modern era of bass tone may have coalesced with the introduction of the David Eden World Tour 800, a heavy-duty, reliable, gorgeous amplifier for nearly any situation. Its sound can be described as clean and warm with enormous headroom, good for nearly any purpose. Getting a good tone through the amp was not especially complex:

  • Step 1: Plug the amplifier into a wall socket.

  • Step 2: Plug your bass into the amplifier.

  • Step 3: Make sure the amplifier is connected to the speaker.

  • Step 4: Have a nice gig.

The amp was reassuringly expensive and heavy, just like the cabinets. For a while there in the late 1990s, you would roll into a festival gig, see that the back line provided included an Eden World Tour 800 and its machined 4x10 cabinet, and you could breathe a sigh of relief. Reliability and great tone were married up happily with crushing weight and professional price tags, and much music ensued.

Though there still remained an area for R&D exploration - weight.

MarkBass (MiniMark, Mini CMD 121, etc)
Chief proponents: Alain Caron, Jeff Berlin, Tom Kennedy, me (not that anybody cares)

Perhaps other bassists would criticize me for declaring MarkBass a classic amp, but for many other pro players those ultra-light rigs made by clever Italians have been a game changer of the best kind. Let’s take the MiniCMD 121, which I play. At 500 watts of Class D power through a 1 x 12 speaker weighing in at a ludicrous 27 pounds, MarkBass managed to defy the fundamental conflict between physical size and sufficient sound production. Before this amp, it was either 1) herniate a disk in your spine loading and unloading your gear or 2) sound like a weenie. And then, as if by divine decree, all of the sudden you could get 500 watts of ripping tone in a package the same weight as a reasonably hefty sandwich.

The CMD121 is inexplicable: a single 12-inch speaker can fill everything but outdoor amphitheaters (which you can do easily by adding an extension cabinet), and yet you can swing it around with one hand. In addition to a very musical EQ, It has two knobs on it - a Jaco knob (VLE) and a Marcus knob (VFP). It has enormous headroom and clarity, and you can load in and out without a single herniated disk.

Before, there were other ultra-light amps before MarkBass that either cost $2000 (Walter Woods) or others which just didn’t sound very good. Today, there are plenty of ultra-light options that have finally joined the party with their own sound. But Marco di Virgiliis and company really made a classic that I imagine shall endure.


So, what are you going to get?

As a bassist, you have several decades of very cool options. Which will you choose? If you’re in a Motown tribute band, you might be extremely happy with a B-15, or something trying to cop its vibe. If you’re young, with a strong back, good health insurance, and a van, perhaps the SVT lifestyle is right for you. Or maybe some other piece of gear strikes your fancy. The important thing is that you know the history of bass tone and the best way to get that sound that returns you, the bassist, to your rightful position as the musical leader of the band.

Happy hunting!


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