This Article Was Originally Published On: June 3rd, 2015 #Issue 16.

The Ampeg brand needs no introduction, and stands as the most recognizable – and probably most referenced –bass amp brand on the planet. In fact, the venerable SVT may be the most commonly cited reference rig mentioned in our very own pages. In the context of medium-powered tube heads, though, the question invariable comes up, “How does it compare to a V-4B?” Needless to say, we were pretty happy to hear that Ampeg was going to reintroduce the V-4B and couldn’t wait to get one in our hands for review.

While history has shown that players still seem to find some magic in the older tube head designs, history has also witnessed significant progress in regards to the frequency range, efficiency, and power handling of loudspeakers. Embracing both of these trends, the fine engineers at Ampeg cooked up a couple of brand new designs – the SVT-112AV and SVT-212AV – to accompany their vintage inspired head. We chose the larger SVT-212AV as a dancing partner for this review.

Fender Rumble 600x200

Where It All Came From

Whereas the SVT was designed from the ground up as a bass head, the V-4B was born in 1971 as a result of the number of bass players who were using the V-4 tube guitar head (introduced in 1970). Basically, they just took out the reverb, and called it the V-4B. The power output from the four 7027A’s was rated at 120 watts. The original V-4B stayed in the lineup throughout the Magnavox era, and was eventually discontinued in 1980, at the start of the MTI years. Fast forward 15 years, and Ampeg was playing the “Updated Reissue” game, bringing back the Jet II and the V-4B. These new models were substantially different from the original designs, though the V-4B did land closer to the mark than the Jet II. The ’95 V-4B opted for 6L6GCs (as does the latest iteration), and was rated at 100 watts; the preamp layout was reworked a bit, with the biggest functional change being the switch from a 3-way rocker for selecting the midrange frequency to a 5-way rotary knob.

Where It’s Going

The layout of the new V-4B is clean, tidy, and very familiar to anyone acquainted with the older units. There are, however, several interesting twists. For inputs, we have two 1/4″ options, labeled “0 dB” and “-15 dB (compared to inputs “One” and “Two” on my ’75 V-4B). Next up, we have knobs for Gain, Bass, Midrange, Treble, and Master. The most obvious deviation from the original is the switch to separate Gain and Master volume controls, compared to the single-stage volume controls for the two inputs on the older amp. While Ampeg tells us that they were most definitely targeting the original V-4B’s in term of tone and function, it is worth noting that the 0 dB and -15 dB inputs, as well as the separate Gain and Master controls, were also found on the 1995 V-4BH.

Ampeg BassNot as obvious is the fact that the order of the tone controls has been reversed (on the ’70s V-4B, the stack is set up Treble, Midrange, Bass; the V-4BH, like the new unit, runs Bass, Middle, Treble). Similar to the vintage head, there are white rocker switches above each of the tone controls. There is an Ultra Lo 0/+ switch above the Bass control, and an Ultra Hi 0/+ switch above the Treble control. The Ultra Lo, when engaged, boosts the low frequency output by 2dB, centered at 40Hz, while cutting 500Hz by a sizable 11dB. The Ultra Hi switch boosts output by 7dB at 8kHz. The 3-way rocker above the Midrange control selects the center frequency for the boost or cut. On the classic V-4B, these frequency choices are 300Hz, 1kHz, and 3kHz. On the new model, the choices are very similar (and perhaps even a touch more useable), with centers at 220Hz, 800Hz, and 3kHz. Rounding out the front panel are “baseball bat” toggles for Standby and Power. My ’75 V-4B has white plastic switches for Standby and Power, but some classic V-4B’s used the baseball bat style switches. The esthetic treatment and design of the newer V-4B strongly follows that of the 1970’s models, but the new unit has shrunk a bit in width [hurray!], allowing it to sit properly atop an SVT-810 enclosure.

The back panel is laid out similar to other modern Ampeg tube heads, with an IEC power chord receptacle and a fuse holder on the left-hand side of the rear panel. Located approximately in the middle, we find 1/4″ jacks for Preamp Out, Power Amp In, and Slave Out, followed by a balanced XLR output (with ground lift). To the right, we find 1/4″ speaker output jacks for 2-ohm, 4-ohm, or 8-ohm operation. Intelligently, there is only one 8-ohm output jack, but two each for 4 ohms and 2 ohms. Another smart touch is the addition of language beneath these last two sets of speaker out jacks, which read, “use with one 4 ohm cabinet or two 8 ohm cabinets” (for the 4-ohm jacks) and “use with one 2 ohm cabinet or two 4 ohm cabinets” (for the 2-ohm jacks). It is very important for the proper operation of a tube head to connect the proper load to the proper tap, but not everyone fully understands these concepts, so spelling things out is a smart idea. That being said, I do prefer to see Speakon® outputs, or better yet, the combo Speakon & 1/4″ jacks. Now, I understand that Speakons are more important on higher output connections, and not all Speakon connectors are available with a shunt connection (which is important on a tube output section), but some Speakon connectors do allow for this function. Speakon connections have become very common, and a lot of bass enclosures (including the current SVT-810E/AV) come equipped with them. That being said, the SVT-212AV only offers 1/4″, so perhaps Ampeg is intentionally rolling “old school” with regard to speaker connections for this rig.

The Dawn of a New Era for the V-4B

When you are messing around with iconic designs, one must tread a careful path between preserving the “vintage vibe,” while trying to incorporate the benefits of technological and manufacturing advancements. So far, Loud Technologies, Inc. has done an amazing job with the Ampeg brand. They have brought back hand-built, USA production models, like the Heritage SVT-CL and B-15, and they have introduced brand new models, such as the SVT-7Pro and Portaflex line of heads and cabs. Across the board, they have shown that they know what they are doing, and – just as importantly – they know what the Ampeg player is after. I spoke with Senior Analog Design Engineer, Dawn Pfund, about their goals for the new V-4B:

“As far as design goals, it was pretty simple for us. We are Ampeg, so the amp has to sound amazing, be reliable, and be full of bassy goodness. Specific to the V-4B, there is a large following of bass and guitar players that were really looking forward to this reissue and our goal was to exceed all of their expectations and standards in regards to tone, distortion characteristics, functionality, and looks. We really had a great team effort on this design and it shows in the success of the product.  Rob Riggs and I headed up electrical, Zane Williams determined the key features and guided us to our end goal, Jon Bledsoe and Lu Yan handled the mechanical design and construction, and Kent Swendseid successfully merged vintage and modern looks together.”

As I mentioned, I have a vintage (Magnavox-era) V-4B, and a matching B-40 (4x10) cab. I’ve gigged this rig many times, and I actually know its previous two owners (one of them being the original purchaser) very well. This head has seen a lot of gigs, and that is where the V-4B really proves its worth. One of the reasons folks dig the V-4B over more powerful tube heads (like the SVT) is that you can push it to a very musical level of output tube breakup, and do so at more sane volume levels. But I always wondered if part of that magic came from the 7027A output tubes used in vintage V-4Bs. Knowing that the new unit has switched to 6L6’s (and made other changes reminiscent of the 1995 V-4BH), I was curious as to how their “modernization” of this classic design would impact its vintage appeal. Dawn explains:

“The main features we had to preserve were the tone and distortion characteristics, and this is where Rob and I obsessively tweaked the circuit over and over again, resulting in mild electrocution, cuts, burns, and other signs of a great time for electrical engineers. There are a lot of variations of the V-4B and all related models over time (V-4, VT-22, and more), but we heavily referenced a 1974 V-4B that we had around during development. The vintage tube count and complement were cost prohibitive, so that was one of the first areas we addressed. 6K11s are all NOS at this point, so they are difficult to source and really expensive. 12DW7s are in current production, but not very common. We decided to replace all of these preamp tubes with 12AX7s and 12AU7s to keep things as simple as possible. We built up prototypes with a long-tail pair and cathodyne phase splitter, with the cathodyne winning out for tone. For the output section, we wanted to use 6L6GCs as they are common, making long-term care easier for the customer, and we liked the way they sounded. Next were the transformers, which are so critical to the tone. We had no data on the original transformers, so we specified them to our needs, auditioning a variety of output transformer frequency ranges and primary impedances. The modern transformers sound amazing and were lighter than the vintage models, which was great, as we were really trying to reduce the weight of the head as much as possible. The remaining tone and distortion tweaks are too numerous to go through, but there were many late nights changing one resistor here and one capacitor there, running to our listening room between each change to evaluate the tone.

Some of the other vintage aspects we kept around are the fully passive RLC mid EQ, rocker switches, AV-style grilled cloth, and one of our favorites, the chassis suspension system. We really latched onto the floating chassis in the vintage 1974 unit we had around and it was decided early on that we would incorporate this into the modern design. We felt it was not only a cool feature, but that the floating suspension would isolate the tubes and other sensitive components from all of the vibration a bass head is exposed to, leading to longer tube and amp life. 

In regards to modernizing, we added a slave output, balanced XLR out with a ground lift, reduced the preamp to a single channel instead of the vintage dual channel, and added 0dB and -15dB input jacks for passive and active players. Our evaluation process included play testing through just about every cabinet we have in house, hundreds of hours of H.A.L.T. (Highly Accelerated Life Test), drop testing from the top of an 810, 24-hr. shake test, thermal testing, outdoor festival testing with the requisite beer spill, and much more.”

D'Angelico EX-Bass

Reading Dawn’s words, it’s easy to let your expectations start to run pretty high for the new V-4B. It sounds like Ampeg definitely brought their “A-game” to this task. Of course, the proof is in the pudding; more on that, below…

The New Kid vs The Old Dawg

I was super eager to A/B this new V-4B to my old one, but before I dive into the comparison, I want to point out some of the unavoidable factors which keep this from being a true apples-to-apples comparison. First off, it is always difficult to compare a single-gain amp to one with both a pre and post gain control – especially without any kind of signal monitoring (there are no level indicators, and no clipping lights, etc. on either unit). Secondly, we are dealing with two different (though admittedly, quite similar) types of power tubes, and a different mix of preamp tubes. So, I can’t even pull the tubes from one head to run in both, and try and level the playing field. That being said, getting both heads up to “gigging volume” through the same cab(s) while playing the same bass(es) still gives you some interesting feedback.

The newer V-4B was definitely more clear and articulate than the old one, and the vintage head was darker and beefier, and also smoother in the highs. However, the two heads were very similar in terms of overall fullness. I also noticed right away that the new head is just dead quiet in terms of noise, hiss and scratchiness (when turning knobs). Granted, my V-4B hasn’t been serviced in a couple of years, but it’s in very good working order. I guess when you play vintage tube heads, you kind of get used to a bit of extra noise (which you absolutely can’t hear once the gig starts). It’s only when you compare them directly to a unit that is so dead quiet that you notice the extra noise.

On the topic of noise, I observed that the new V-4B does not break up as quickly as you push it into overdrive. Of course, the two gain stages, versus one in the older unit, can make this a tricky comparison. And with those two knobs, I was definitely able to dial in a wider range of overdriven tones from the newer unit. But when I tried to get the new unit to yield a similar overdrive tone to my favorite out of the old V-4B, I found that I could get pretty close, but it required a lot more dialing in. Changes are much more subtle as things start to break up on the new head. Of course, once you dial it in to your liking, it should be relatively easy to recreate that same tone at a future point in time. Overall, these two heads are far, far more similar than different, and pretty much across the board, where I did hear differences, they actually favor the new kid.

D'Angelico EX-Bass

There’s a New Cab in Town

When I first heard the new SVT-112AV and SVT-212AV designs at the Winter NAMM Show, I was initially quite impressed by their tone, but the question which quickly formed in my mind was, “Are these sealed, or ported enclosures?” Then I noticed their deep extension and satisfying fullness down low and thought, “Ah, ported.” But then I started paying more attention to the overall tight response and good midrange detail, and I began second-guessing myself. When Dino Monoxelos starting cranking things up, though, I was starting to seriously consider shifting to the “sealed” camp. Once he was done demoing the new rig, Dino cleared the air and informed us that both cabs were ported enclosures, but that they were specifically designed to match up well with tube heads, like the V-4B and SVT. Mission accomplished on that front, Ampeg!

Even though I had seen this cab previously at the NAMM Show, when the SVT-212AV arrived, I was kind of surprised at its compactness. It is a nice form factor, and very easy to lug around. It also weighed less than I had expected, especially considering that it uses ceramic-based drivers. This is a 4-ohm enclosure, so it will present a near ideal load for most solid state heads. Of course, if you want to run two of them, you would need either a 2-channel amplifier, or a single channel capable of handling a 2-ohm load. Of course, the V-4B and many tube heads allow for running multiple impedances (the V-4B can handle 8, 4, or 2-ohm loads). The 3-way High Frequency Attenuator gives you the choice of either turning the tweeter off, running it wide open, or knocking the signal down 6dB. For some styles of music, turning it off is the way to go, but I found the tweeter to be smooth enough that I ran it unattenuated most of the time.

While the two new 12″ equipped cabs were designed with the V-4B in mind, I was also really interested to try the new V-4B with two of my SVT-210AV’s. Comparing the double 210AV rig to the 212AV, the two 2x10’s are a good bit louder, and definitely more full/warm/round. The SVT-212AV, however, is more clear and precise – even with the tweeter turned off. Either setup feels like a good match, and this just gives the player more options when putting together a rig based on the V-4B.

The more that I played around with the SVT-212AV, the more that I felt like it was a great all-around 2x12, and so I decided to put it up against two of my favorite 2x12’s, the TecAmp S212 Classic and the Bergantino HD212. Comparing it to the TecAmp, the first impression is that these two cabs are fairly similar, especially in the upper low end through the midrange. Additional listening reveals that the S212 is a little more full in the lowest notes, and the 212AV is a little more rounded off on the attack through the mids. While the two cabs have similar overall clarity, the TecAmp is more lush and smooth up high. Comparing the Ampeg to the Bergantino, the two cabs are equally full sounding, but the HD212 is more clear and precise throughout its range, and more airy up high, while the SVT-212AV is more warm and round. All in all, the 212AV held up quite well against two of the best 2x12’s on the planet. Oh, and it does so at a substantially lower price point, to boot.

D'Angelico EX-Bass

Real World Experiences

My past gigging experiences with my ’75 V-4B gave me a pretty good idea of what to expect, volume-wise, from the head. The unknown was going to be the SVT-212AV. I had concerns, initially, that it might not move enough air for a medium-sized hall my band was playing, and I heavily contemplated bringing my SVT-810E, instead. But when I did a brief side-by-side comparison of the two cabs with the V-4B, while the big 810E was definitely louder, it wasn’t so much louder as to inspire me to lug that beast around. So, the single SVT-212AV got the call, and it worked out just fine!

This particular gig was with a one-guitar band, so I end up filling a lot of space – especially when the guitarist solos. I had to push the Ampeg rig pretty hard to keep up with the stage volume (said guitarist was playing an Orange rig with a 2x12 on top of a 4x12!), but this had me in that great range of mild power tube breakup, where the added harmonics help make up for the lack of a rhythm guitar player, but the fundamental stays nice and tight and solid. By the end of the night, the typical scenario played out with everyone getting just a little bit louder every so many songs. For our last 4-5 songs, I was probably pushing this rig for all it was worth. But the beautiful thing is, even with some obvious overdrive going on, the V-4B/SVT-212AV still felt full and authoritative. No “running out of gas,” here! In an ideal scenario, I’d opt for a second 212AV and run off of the 2-ohm tap, just to push a little more air and have a bit more headroom. But I was amazed at how well that modest-sized bass rig held up against a much-bigger-than-necessary guitar stack.

The newer V-4B was definitely more clear and articulate than the old one…

The Bottom Line

If you understand what a 100-watt tube bass head can do (and what it can’t do!), and you are thinking about adding one to your stable, then I urge you to consider the new V-4B. Ampeg has really knocked this thing out of the park! The V-4B has all of the glorious tube complexity and texture we fell in love with “back in the day,” but it features modern conveniences, easy to find tubes (if they ever need replacing), lighter weight, a better form factor, greater gain control, and quality construction. The new V-4B is really everything that I had hoped it would be, with none of the shortcomings I feared.

I did not know what to expect from the SVT-212AV, but it has really won me over. The tone is full and much more balanced, from top to bottom, than I had expected. The ability to feel appropriate when dialing in “vintage” tones, but still offer all the clarity and articulation necessary for more modern material, is quite impressive. It’s also a surprisingly loud cab, in a very manageable package. Much like the V-4B, the SVT-212AV gives you lots to love, and very little to complain about. This is a great rig, and both components are worthy of consideration. Well done, Ampeg!