Published On: Thu, Mar 6th, 2014

Ampeg V-4B 100W Bass Amp & SVT-112AV 300W Cab Review

If you desire the Ampeg SVT sound with only half the payload, then the all-valve V-4B claims to cram the sound of 1971 into a modern, more adaptable, more portable package. Review by Gareth Morgan


Description: V4-B: single channel 100W valve amp with a suspension system steel chassis in a 15mm birch ply enclosure.
112AV: 300W 1×12″ plus horn cab with one Eminence Custom 12″ speaker and a HF horn (with three-position level switch) in a 15mm poplar ply cabinet with front porting, speaker out and through jack sockets. Both made in China

Price: £1290 & £535

Contact: Polar Audio – 01444 258258 –

Here at the G&B Mission Control, the advent of a new piece of high-spec Ampeg gear is always cause for celebration. Ampeg, of course, is one of the longest-standing manufacturers and purveyors of bass amps (and, to a lesser degree, basses). Established in 1946 by Everett Hull with Stanley Michaels as Michaels-Hull Electronic Labs – the named was changed to Ampeg in 1949 when Hull became sole proprietor – they produced their first bass amp, the Portaflex, in 1960.

The big stuff appeared in 1969 with the brutish 300W all-valve SVT (Super Vacuum Technology) which weighed in at a colossal 85lbs and actually carried the health warning ‘this amp is capable of delivering sound pressure levels that may cause permanent hearing damage’. You can get a Heritage reissue of this behemoth, the Heritage SVT-CL, which we reviewed in September 2010 (Vol 21 No 11). Now Ampeg has added another all-tube unit, the V-4B, a reissue of the 1971 original, plus a pair of cabinets, the SVT-212AV and SVT-112AV.


A threatening row of four 6L6 valves pump out 100W of power

Though Ampeg is very much part of the current trend towards smaller, lighter bass gear, the Chinese-made V-4B, the newest member of Ampeg’s Classic Series, comes in a 15mm birch ply box and weighs in at 18.6kg or 41lbs; that isn’t really too much, and anyway, it looks great with its silver control panel and cloth grille with chunky badge. At 267mm high, 606mm wide and 283mm deep, taking into account the chunky metal corner protectors and rubber feet, it’s certainly on the large side but this also means you get a much vaster expanse of mottled black Tolex overcoat to drool over.

The V-4B spits out 100W of all-tube power via two 12AX7 valves and four 6L6GC in the power amp section, with all the internal gubbins sitting in a suspended metal chassis. There’s a separate driver stage with one 12AX7 and one 12AU7 which is concerned with voicing and gain. Liberating this stage from the preamp enables the V-4B to run more cleanly at the front end and allows it to be nudged into distortion at low levels without working the preamp too hard, thus reducing the risk of excessive overheating.

The control panel has an uncomplicated look and is dominated by a line of five controls with knurled plastic sleeves and silver caps replete with black position marker. Gain adjusts the strength of your inputted signal while Master controls the overall volume. In between you get a three-band EQ of Bass (12dB of cut or 13dB boost @40Hz) and Treble(17dB cut or 14dB boost @4Hz), while the Midrange control works in conjunction with the middle of three cream switches located above the panel.


Two tone preset rocker switches and a switchable semi-parametric mids section and flexibility

You use this to select one of three frequency points – 220Hz, 800Hz or 3kHz – then the semi-parametric Mid control juices that up by 11dB or down by 21dB. The other two switches are Ultra Lo, which scoops the mids with a 2dB boost at 40Hz and an 11dB cut at 500Hz, and Ultra Hi, which offers a 7dB hike at 8kHz. The input jacks are labelled 0dB and -15dB for active/passive basses and, in true trad style, a pair of chrome switches are provided for power on and standby.

Screen shot 2014-03-06 at 10.16.30

The rear panel bears Preamp Out, Power Amp In, Slave Out and five Speaker Out jack sockets (two each for twin-cab 2- and 4 ohm operation, and one for single cab 8 ohm usage). You can also connect direct to PA or recording desk via a Balanced Out XLR with accompanying Ground/Lift switch.

We’ve running the V-4B through the smaller of the two cabs, the SVT-112AV. Constructed from 15mm poplar ply, it’s slightly heavier than the amp – 20kg/44lbs – but equally classy in its black Tolex attire with silver cloth grille. Taking into account the rubber feet and steel corner protectors, it’s getting close to the limit of acceptable size for a 1×12″, being 432mm high, 610mm wide and 406mm deep, and for carrying purposes you only get one, side-mounted recessed handle.

On the top are eight recessed plastic cups into which you plant the V-4B’s feet, thereby guaranteeing that the amp will not move around, even when the dial reaches ‘ear-splitting’. The 12″ driver is a custom Eminence unit joined by an HF horn. The presence of the horn perhaps doesn’t sit comfortably with the traditional intent of the rig as a whole but it does allow a better rendition of high frequencies, and there’s a three-position level switch on the back so you can turn it off, run it normally or at -6dB. Connectivity is of the traditional jack socket variety, two in number; plug the amp into one, and daisy chain a second cabinet with the other.


Plugging in with a flat EQ reproduces the sound of the bass without tonal bias but with a hint of valve warmness. It’s plenty fat enough at the bottom end, if not earth-shaking; the gunning growl of the E string is quite simply joy in a note, and thinner strings have plenty of weight and fatness. The midrange is solid and even with plenty of punchy impact for forward motion and definition. Highs are clean and snappy, producing cut and bite without brittleness. You can easily get faster, more aggressive spikey highs via the horn, with the expected trade-off of added finger- and fret-noise.


A controllable and defeatable HF horn joins the single “12 Eminence driver

Bringing in the EQ is a lot of fun and starts to put us in mind of Ampeg’s early health warning, especially when we set the Bass dial to full and the room’s fixtures and fittings started to rattle uncontrollably; you can really feel it in your gut when you hit a low note. As we mentioned, Ultra Lo is a scooped mids pre-shape, and this gives a smooth, warm tone with a lack of punch and definition which will work nicely for soul and blues. The Treble dial is fairly practical, although full boost is a bit nasty – synthetic, almost – and not as open as we’d like, even with the horn on; about half boost is a far as you want to go. Adding bass boost uncorks a fat, punchy sound with bags of snarl and stature, excellent for rockier gigs where you need to be heard as well as felt. If you want this as a default setting, leaving the Ultra Hi switch on pretty much gets you there.

Of the three midrange settings, boosting 220Hz produces a darker, punchy sound with a tightened bass end, while the other settings are a fraction brighter, with more snarl at 800Hz and a lighter, airier tone at 3kHz. These last two get you closest to a contemporary sound.


If you can cope with a fairly weighty amp and lust after an all-valve Ampeg rig but can’t afford the wonderful Heritage SVT, you’re going to buy one of these, no question. Ampeg has done a great job in putting the V-4B and SVT cabs together; they’re cool-looking and ruggedly constructed, and while the V-4B’s EQ is a bit limited, it’s powerful, and easy to use. A price of £1800 for a Chinese-made reproduction does throws up a few issues, but it looks and sounds like a classic Ampeg – and for many, many bassists out there, that will be more than good enough

Screen shot 2014-03-06 at 10.18.47



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