Bass Block V803

800 Watts. Under 4 Pounds. Your Cab Has Never Had It This Good.
Bass Block V803
Bass Block V803
Bass Block V803
Bass Block V803
Bass Block V803
Bass Block V803
Bass Block V803
Bass Block V803

Bass Block V803

800 Watts · 3.78 lbs · Three Amps · One Head

800 watts of bass authority.
3.78 pounds.

Designed by Patrick Quilter — the "Q" in QSC Audio.

An 800-watt tube bass head doesn't exist. And if it did, it would weigh 90 lbs, cost $4,000, and need its own roadie. The Bass Block V803 puts 800 watts into 3.78 pounds for $699 — less than a Gallien-Krueger Legacy 800, a Darkglass Microtubes 900, or a Mesa Subway TT-800, and lighter than all three. No tubes. No bias. No excuses.

Three voices cover every gig you'll ever play: Modern delivers tight, controlled solid-state output with a bottomless limiter — 800 watts at 4 ohms, all day. Warm gives you tube-style output impedance with that same bottomless limiter — your low B stays planted while your overtones breathe. Q-Tube goes full vintage with real tube clipping behavior — the breakup, the sag, the grunt. Three amps in one box the size of a paperback.

800W Power
3.78lbs Weight
3 Voices
100–240V Universal power

The Quilter exclusive dual limiter is why this amp feels bottomless. It prevents your lowest strings from bottoming out — even with the BASS knob cranked — without choking or gagging the upper strings. Dynamic range stays intact, and you get a feeling of raw grunt and effort replacing the usual breakup at peak power. Push the amp and it pushes back musically instead of folding.

The 3-band active EQ is voiced specifically for bass: a 4th-order shelving filter on the lows, a semi-parametric midrange with a sweepable center frequency from 250Hz to 1kHz to find (or kill) the bark, and a treble shelf for snap and pluck. Dual inputs — Flat for uncolored response or Scoop for instant modern tone — plus an FX Loop for your pedalboard and a Mute/Active/Passive switch with a bright LED so you always know your status on a dark stage.

The XLR Line Out is pre-Master — your front-of-house feed stays consistent no matter where you set stage volume. Ground lift built in. Headphone output with automatic cab simulation — FRFR on Modern, cab sim on Warm and Q-Tube — so silent practice actually sounds like your real rig. Dual Speakon™ Combo connectors on the back work with any cable you own.

The FX Return doubles as a stealth input for backing tracks — insert your tracks, dial the mix with your external device, and control everything through the Master. Rehearsal just got simpler.

Universal voltage means it runs on any power grid on the planet. A variable-speed fan keeps it cool and quiet — you'll forget it's there. Fits in the Block Case 2.0 with room for your cables. Your entire amp rig weighs less than a set of bass strings and a six-pack.

What players are saying: "The tone mode switching is very cool — the smooth breakup with Q-Tube really does give you that vintage feel in such a small footprint. I'm amazed at how low-hiss it is, even at high volumes."
$699 or as low as $59/mo with Shop Pay

THREE WORLDS ONE SWITCH

This isn't a modeling amp. It's not switching between presets. When you flip the Voice switch on the V803, you're changing how the actual power section behaves at the circuit level.

Modern gives you solid-state output impedance with Quilter's bottomless limiter — tight, controlled, 800 watts into 4 ohms. The kind of clean headroom that makes your pedalboard sound exactly like it should.

Warm changes the power section to tube-type output impedance. Same bottomless limiter, but now your notes bloom. The speaker pushes back the way it does with a vintage tube head. Your fingers feel the difference before your ears hear it.

Q-Tube goes all the way — tube-type output impedance with real tube clipping. The sag. The grunt. The breakup that responds to how hard you dig in. The feel of a cranked SVT, from a box you can hold in one hand.

This is three whole dimensions of tone. One for every type of bass you want to play.

BOTTOMLESS

Every bass player knows the problem. You boost the lows, your B string flubs out and buries everything. You back off, and you lose the foundation. Traditional compression squashes the whole signal to fix it — your dynamics go flat and your tone turns into cardboard.

Quilter's exclusive dual limiter works differently. It controls the low frequencies independently — your lowest strings hit a wall before they bottom out, but your upper strings keep their full dynamic range. The overtones breathe. The D and G still cut. The low end stays massive and planted instead of flabby.

The result is an amp that feels like it has infinite power reserves. Push it hard and it pushes back musically — with grunt and effort instead of ugly breakup. Even with the BASS knob cranked, the lows stay controlled while the rest of your tone stays alive.

No other bass amp does this. Not at any price.

LIGHTER THAN...

Put the V803 next to everything in its class:

Same power. Less weight. Half the price. And none of those amps switch between three different power amp topologies.

This isn't a budget amp that cuts corners to hit a price point. This is Patrick Quilter — the "Q" in QSC Audio — applying 50 years of professional power amplifier design to a bass head. The same Q-Circuit technology that powers Quilter's guitar amps, purpose-built for bass. 3-band EQ with sweepable mids, dual inputs, effects loop, pre-Master XLR direct out, headphone output with automatic cab simulation, universal voltage, and a variable-speed fan that stays quiet under load.

3.78 pounds. Block Case 2.0. Walk to the gig. Be the bad ass you always knew you were.

$699 or as low as $59/mo with Shop Pay
What a comparable tube bass head costs you
All-tube bass head (300W, giggable)$2,500–$3,500
Power tube set — 6x 6550s (every 2–4 yrs)$200–$400
Bias adjustment (per retube)$75–$100
Weight penalty (65–85 lbs + road case)Priceless
Cab to handle 300W (matching 8x10 or 4x10)$800–$1,500
5-year cost of ownership$3,800–$5,500+
Bass Block V803 — 800W, 3.78 lbs, zero maintenance$699
In the 800-watt class
V803 $699 800W · 3.78 lbs · 3 voices
GK Legacy 800 $1,399 800W · ~5 lbs · 1 voice
Darkglass 900 $1,499 900W · 6.4 lbs · 2 drives
Designed by Patrick Quilter The "Q" in QSC Audio
What $699 gets you
XLR Line Out
Headphone + Cab Sim
Effects Loop
Dual Speakon™ Out
Universal Voltage
Dual Inputs (Flat / Scoop)
Zero maintenance. Forever.
No tubes to replace No bias adjustments No warm-up time No tech visits
The $699 is what you spend. Period.
Complete your rig Block Case 2.0 Your entire 800-watt bass rig — head, cables, and case — in one hand.

Three Power Amps.
One Switch.

Not presets. Not modeling. The Voice switch changes how the actual power section behaves at the circuit level — different output impedance, different clipping behavior, different feel under your fingers.

Modern Solid-state authority

Tight, controlled solid-state output with the bottomless limiter — 800 watts at 4 ohms, full headroom, zero flub. Your pedalboard sounds exactly like it should. The same power system as the Bass Block 800 and 802, refined.

Warm Tube impedance, modern control

Tube-type output impedance with the same bottomless limiter. Your notes bloom and sag — the speaker pushes back the way it does with a vintage tube head. Low B stays planted while your overtones breathe. The best of both worlds.

Q-Tube Full vintage clipping

Tube-type output impedance with real tube clipping behavior. The grunt. The sag. The breakup that responds to how hard you dig in. The feel of a cranked SVT — without the 85-pound road case or the $400 retube bill.

Controls
Gain Bass Mid Freq Treble Master
Voice Switch Input Switch XLR Ground Lift
Six knobs. Three switches. No screens. No menus. No firmware updates.
Quilter Labs

How Bass Block V803 Compares

800W Bass Head — $699
Quilter Labs BASS BLOCK V803 Gallien-Krueger LEGACY 800 Darkglass MICROTUBES 900 V2 Mesa/Boogie SUBWAY D-800+
Price $699 $1,049 $1,499 $999
Power 800W @ 4Ω 800W @ 4Ω 900W @ 2Ω 800W @ 4Ω
Weight 3.78 lbs 5.7 lbs 6.4 lbs ~5 lbs
Power Amp Topology Switching 3 modes
(Modern / Warm / Q-Tube)
Dual Limiter (Low-String Protection) Quilter exclusive
Drive / Overdrive Via Gain + Q-Tube Footswitchable
(G.I.V.E. circuit)
2 voicings
(B3K / VMT)
2 voicings
(Voice 1 / Voice 2)
EQ 3-band active
+ semi-parametric sweepable mid (250Hz–1kHz)
4-band active
+ Bump / Contour / Presence
6-band graphic 4-band
+ 2 semi-para mids
Compression Studio VCA
XLR Direct Out Pre-Master
(ground lift)
Pre/Post EQ Dual XLR
(Pre + Post w/ cab sim)
Pre/Post EQ
Headphone Out Auto cab sim With IR
IR / Cab Simulation Auto (per voice) 3 IR slots
Effects Loop
Dual Inputs (Flat / Scoop)
MIDI
USB / Software Editor Darkglass Suite
Universal Voltage 100–240V
(region-specific)
100–240V 100–240V
Safe Without Speaker Load
Aux / Backing Track Input Via FX Return 3.5mm Aux 3.5mm Aux Aux In
Fits Block Case 2.0
Patented Power Amp Technology Quilter Q-Circuit Class D
(G.I.V.E. preamp)
Class D
(Microtubes preamp)
Class D
(Subway preamp)
Quilter Labs

Bass Block V803 Settings Guide

Twenty genres. Twenty places to start. Then make it yours.

800W · 3.78 lbs · Three Voices
VoiceModern — tight, controlled solid-state  ·  Warm — tube-style output impedance  ·  Q-Tube — real tube clipping, sag and grunt
InputFlat — uncolored response  ·  Scoop — instant modern mid-cut
KnobsShown as clock positions. Mid Freq sweeps 250Hz to 1kHz. Master depends on your room — set it last.
Rock & Metal

Classic Rock

MODERNWARMQ-TUBE
Gain11:00
Bass1:00
Mid12:00
Mid Freq500Hz
Treble12:00
Input
FLATSCOOP
Master to taste

P-Bass and a pick. Warm adds the push without turning it into a fuzz box.

Hard Rock

MODERNWARMQ-TUBE
Gain1:00
Bass1:00
Mid1:00
Mid Freq700Hz
Treble1:00
Input
FLATSCOOP
Master to taste

Grind and growl. Dig in and Q-Tube sags back at you like a big tube head.

Modern Rock

MODERNWARMQ-TUBE
Gain12:00
Bass2:00
Mid11:00
Mid Freq800Hz
Treble1:00
Input
FLATSCOOP
Master to taste

Tight and controlled. Cuts through two guitars without getting brittle.

Punk

MODERNWARMQ-TUBE
Gain2:00
Bass2:00
Mid10:00
Mid Freq1kHz
Treble2:00
Input
FLATSCOOP
Master to taste

Pick attack up front, top end bright. Gain carries the aggression.

Modern Metal

MODERNWARMQ-TUBE
Gain1:00
Bass2:00
Mid9:00
Mid Freq800Hz
Treble2:00
Input
FLATSCOOP
Master to taste

Scooped and surgical. The dual limiter keeps your low B planted.

Doom & Sludge

MODERNWARMQ-TUBE
Gain3:00
Bass3:00
Mid1:00
Mid Freq400Hz
Treble11:00
Input
FLATSCOOP
Master to taste

Let it break up. Q-Tube wide open is the whole point — slow, thick, mean.

Funk, Soul & R&B

Fingerstyle Funk

MODERNWARMQ-TUBE
Gain11:00
Bass12:00
Mid1:00
Mid Freq700Hz
Treble1:00
Input
FLATSCOOP
Master to taste

The mid sweep is the magic here. Find the bark, then live in it.

Slap Funk

MODERNWARMQ-TUBE
Gain11:00
Bass2:00
Mid9:00
Mid Freq500Hz
Treble3:00
Input
FLATSCOOP
Master to taste

Scoop input plus a mid cut = instant slap. Thumb and pop, no thinking.

Motown & Vintage Soul

MODERNWARMQ-TUBE
Gain10:00
Bass2:00
Mid1:00
Mid Freq400Hz
Treble9:00
Input
FLATSCOOP
Master to taste

Flatwounds, thumb over the neck pickup, treble rolled off. Pure thud.

Neo-Soul & Modern R&B

MODERNWARMQ-TUBE
Gain11:00
Bass2:00
Mid12:00
Mid Freq350Hz
Treble11:00
Input
FLATSCOOP
Master to taste

Round, fat, content to sit under the keys. Warmth without mud.

Gospel & Worship

MODERNWARMQ-TUBE
Gain11:00
Bass1:00
Mid12:00
Mid Freq600Hz
Treble1:00
Input
FLATSCOOP
Master to taste

Clean headroom for miles. Whisper-to-roar dynamics stay intact.

Jazz & Blues

Upright Jazz

MODERNWARMQ-TUBE
Gain9:00
Bass1:00
Mid1:00
Mid Freq250Hz
Treble10:00
Input
FLATSCOOP
Master to taste

Woody, not clicky. Mind the Active/Passive switch with a piezo pickup.

Electric Jazz

MODERNWARMQ-TUBE
Gain10:00
Bass1:00
Mid12:00
Mid Freq300Hz
Treble10:00
Input
FLATSCOOP
Master to taste

Neck pickup, tone rolled back. Let the note bloom instead of snapping.

Fusion

MODERNWARMQ-TUBE
Gain12:00
Bass12:00
Mid1:00
Mid Freq800Hz
Treble2:00
Input
FLATSCOOP
Master to taste

Every note defined, top to bottom. Articulation over weight.

Blues

MODERNWARMQ-TUBE
Gain11:00
Bass1:00
Mid12:00
Mid Freq500Hz
Treble11:00
Input
FLATSCOOP
Master to taste

Vocal and dynamic. Play soft, it cleans up. Dig in, it leans forward.

Roots & Americana

Country

MODERNWARMQ-TUBE
Gain10:00
Bass1:00
Mid11:00
Mid Freq600Hz
Treble1:00
Input
FLATSCOOP
Master to taste

Clean, tight, fast decay. Stay out of the vocal and hold the floor.

Rockabilly

MODERNWARMQ-TUBE
Gain12:00
Bass2:00
Mid1:00
Mid Freq500Hz
Treble12:00
Input
FLATSCOOP
Master to taste

Thump plus click. Q-Tube gives the slap its snarl.

Reggae & Dub

MODERNWARMQ-TUBE
Gain10:00
Bass3:00
Mid10:00
Mid Freq800Hz
Treble8:00
Input
FLATSCOOP
Master to taste

Bass cranked, treble gone. Where the dual limiter earns its keep.

Pop & Indie

Pop / Top 40

MODERNWARMQ-TUBE
Gain11:00
Bass1:00
Mid12:00
Mid Freq700Hz
Treble1:00
Input
FLATSCOOP
Master to taste

Even and mix-ready. Send the pre-Master XLR and let FOH stay happy.

Indie & Alternative

MODERNWARMQ-TUBE
Gain12:00
Bass1:00
Mid1:00
Mid Freq600Hz
Treble12:00
Input
FLATSCOOP
Master to taste

Mid-forward with a little hair on it. Bass as a melodic instrument.

These are starting points, not rules. Your bass, your strings, your hands and your room all get a vote. Dial one in, play for five minutes, then move the mid sweep until it sounds like you. Found a setting you love? Post it in the Community — we might just steal it.
User Guide & Specsquilterlabs.com/products/bass-block-v803

You may also like

Don't take our word for it

★★★★★

This small amp really packs a punch! I’ve put it up against my Orange and Marshall amps and it really holds its own. Such a great size for traveling and amazing saturation for a great gained out tone.

Chris C.
★★★★★

Love it’s lightweight and it is just as good as the tube amp I was using but more practical for travelling!

Ryan F.