Ampeg V-4B Rør-basforstærker

Ampeg V-4B 100-Watt Tube Bass Head — Classic SVT Tone in a Portable Package

The Ampeg V-4B 100-Watt Tube Bass Head is a modern reissue of the legendary 1971 V-4B, packing the unmistakable Ampeg grind into a chassis that fits beside an SVT-head-sized cabinet. Riders on small and mid-size stages get genuine all-tube bass tone at roughly 18.6 kg, about half the weight and a third of the power of a traditional SVT stack. Built around an entirely vacuum-tube signal chain, the V-4B turns every bass — from passive four-strings to active five-strings and everything between — into the round, harmonic-rich, edge-of-breakup voice that defined Ampeg for decades.

What Sets the V-4B Apart From Other Tube Bass Heads

Two design choices set this model apart from competing tube bass heads in its tier. The floating chassis suspension system — rubber-mounted to isolate vibration reaching the tubes — carries over directly from the 1971 original and protects the glass during transport. Vintage rocker switches for ultra-high, ultra-low and three-position mid selection recall the cosmetic and tactile feel of classic Ampeg while giving the modern player genuine tone-shaping muscle, including the ability to nail that wide-open SVT grind at sane volumes.

Tube Topology — Why It Matters to Players

Tube count defines the voice of any valve bass amplifier, and the V-4B uses a fully analog, zero-modeling signal path. Every gain stage warmth, compression and sag is genuine — no digital circuits stand between the instrument and the speakers.

• Preamp Tubes: 2 x 12AX7 — delivers the punchy, harmonically rich front-end character that gives the V-4B its classic bite and sustain.
• The driver stage pairs 1 x 12AX7 + 1 x 12AU7 to handle phase inversion and feed the power section with the vintage Ampeg response curve.
• Power Amp Tubes: 4 x 6L6GC — articulates the deep low end and naturally compressed growl that defines the SVT family.

Tone Shaping & Connectivity — Built for Real Gigs

A —15 dB input, 3-band EQ with a switchable mid frequency (220, 800 or 3 kHz) and dedicated ultra-high / ultra-low boost switches put a wide tonal palette on the front panel. Around the back, five speaker outputs, a balanced XLR direct out and a slave output cover studio, stage and bi-amp setups without extra hardware.

• Front-panel EQ offers ±12 dB at 40 Hz on bass, ±17 dB at 4 kHz on treble, and a mid switch that selects 220, 800 or 3 kHz for surgical contouring.
• Speaker Outputs: 1 x 8 Ω, 2 x 4 Ω, 2 x 2 Ω — daisy-chain combinations to dial in any total load between 2 Ω and 8 Ω without rewiring.
• Direct Output: Balanced XLR with ground lift — feeds FOH or the recording interface with a full-range, amp-included signal.

Physical Specs & Cab Pairings — Fits Any Classic Rig

The chassis is cut to the same footprint as the rest of Ampeg's Classic SVT heads, so the V-4B sits cleanly on top of SVT-210AV, SVT-212AV, SVT-410HLF or SVT-810AV cabinets. Speaker-cabinet pairing, transport handling and rack space all work out of the box.

• Dimensions (W x H x D): 610 x 279 x 279 mm
• Weight: 18.6 kg
• Slave Output & Preamp Out / Power Amp In: Yes — chain into additional amps or run straight into a power section for silent-stage setups.

Who the V-4B Tube Bass Head Is Built For

The V-4B is the right choice for working bassists, studio players and weekend giggers who want genuine all-tube SVT-family character without the 300 watts, 36 kg chassis and back-breaking transport of a full SVT stack. Players running small-to-mid-size venues, recording sessions, rehearsal rooms and worship stages get the iconic grind and roundness at controllable volume. Bassists who want to push the front end into natural overdrive at reasonable SPLs — using a Ric 4003, Music Man Stingray, Fender Jazz or Precision — will find the tube breakup is musically rewarding. Anyone already owning an Ampeg 210AV, 212AV or 410HLF cabinet can drop the V-4B straight on top with a matching cover.

The V-4B Story — A 1971 Classic Returns

Launched in 1971, the original V-4B quickly became a cult favorite among bassists who prized Ampeg's grind at lower volumes than the 300-watt SVT could deliver. Players worldwide kept asking when the model would return — that long-running demand is exactly why the modern V-4B was brought back, retaining the floating chassis suspension, Vintage rocker switches and Black Line cosmetics of the original while adding modern essentials such as a balanced XLR direct out, a master/gain control pair and the —15 dB pad input. Today the reissue carries the unmistakable character of the 1971 design into clubs, studios and stages that do not need an arena-sized stack.