Pro Mode Guide

Pro mode exposes every parameter of the tube circuit. Over thirty knobs across seven sections. This guide tells you which one to turn for the sound you want.

Quick Recipes What to Change Knob Reference Tube Cheat Sheet
Quick Recipes

What sound do you want?

Start from one of these. Each combination produces a recognizable character. Every recipe matches a factory preset chip in the plugin's user-preset bar (tap it to load instantly), then fine-tune by ear. For a minimum-coloration starting point with no transformer, no aging, and a clean PSU, load the Super Clean chip.

Amp punch

Tube Amp Push

Snappy attack with audible sag on transients. The feel of a tube amp working hard. Best on drums, electric piano, bass, guitar bus.

  • Tube12BH7
  • Operating Point
  • Plate V220 V
  • Grid Bias−10.5 V
  • Drive
  • Input Gain0.70
  • Interstage0.34
  • Power Supply
  • Rectifier R180 Ω
  • Filter Cap50 µF
  • Recovery13
  • Transformer
  • Xfmr70
  • Tube Age
  • Drift1.2
Hi-Fi

Liquid Presence

Open and effortless. Wide-open NFB, big cathode bypass, generous Mu Scale for a forward presence band. Best on lead vocal, acoustic guitar, full-mix sweetening.

  • Tube6922
  • Operating Point
  • Plate V250 V
  • Plate R200 kΩ
  • Mu Scale2.5
  • Drive
  • Input Gain0.65
  • Interstage0.50
  • Circuit
  • NFB0
  • Coupling Cap0.068 µF
  • Cathode Bypass70%
  • Transformer
  • Xfmr100
Vintage warmth

Velvet Bloom

Slight veil over the top, woolly mids, gentle THD that grows with level. High plate voltage with a heavy rectifier for that "old console" texture. Vocals, strings, acoustic.

  • Tube12AX7
  • Operating Point
  • Plate V320 V
  • Mu Scale1.5
  • Power Supply
  • Rectifier R150 Ω
  • Filter Cap60 µF
  • Recovery10
  • Circuit
  • NFB0
  • Cathode Bypass55%
  • Transformer
  • Xfmr90
  • OT Bass Phase85 Hz
  • Tube Age
  • Drift1.0
  • Mu Loss1%
Lo-fi

Cassette Glue

Compressed top end, narrow stereo, tiny coupling cap rolls off lows for a tape-machine feel without the wow/flutter.

  • Tube12AU7
  • Drive
  • Input Gain0.60
  • Interstage0.45
  • Circuit
  • Coupling Cap0.005 µF
  • Cathode Bypass60%
  • Power Supply
  • Rectifier R80 Ω
  • Filter Cap30 µF
  • Recovery11
  • Character
  • Match18%
  • Imaging22%
Stereo wide

Crystal Air

Stereo expansion with deliberate L/R capacitance spread. Wide soundstage, airy top, and an extreme Mu Scale that lights up the harmonics.

  • Tube6SN7
  • Operating Point
  • Plate V200 V
  • Mu Scale5.0
  • Character
  • Match8%
  • Imaging35%
  • Crosstalk−60 dB
  • Transformer
  • Xfmr110
  • OT Bass Phase60 Hz
  • OT Phase3200 Hz
  • OT Ph Q1.2
Mix bus

Mix Bus Glue

Just enough to gel the mix. Small amount of even-order harmonics, transformer hysteresis on transients only, no audible coloration in quiet passages.

  • Tube6922
  • Operating Point
  • Plate V220 V
  • Drive
  • Input Gain0.40
  • Circuit
  • NFB0.06
  • Cathode Bypass25%
  • Power Supply
  • Rectifier R15 Ω
  • Filter Cap150 µF
  • Transformer
  • Xfmr30
  • Character
  • Match6%
Mastering polish

Master Polish

Even gentler than Mix Bus Glue. Very stiff PSU, tiny iron lift, no spread or artifacts. The "barely there" pass for final masters.

  • Tube6H30
  • Operating Point
  • Plate V250 V
  • Plate R33 kΩ
  • Drive
  • Input Gain0.24
  • Interstage0.20
  • Power Supply
  • Rectifier R8 Ω
  • Filter Cap200 µF
  • Reservoir560 µF
  • Circuit
  • NFB0.08
  • Transformer
  • Xfmr18
Guitar

British Chime

AC30-flavored chime. High plate resistor, tiny coupling cap, no NFB. Best on guitar tracks or as a DI stage before a cab IR.

  • Tube12AX7
  • Operating Point
  • Plate V275 V
  • Plate R220 kΩ
  • Mu Scale1.5
  • Drive
  • Input Gain0.40
  • Power Supply
  • Rectifier R120 Ω
  • Filter Cap70 µF
  • Circuit
  • NFB0
  • Coupling Cap0.01 µF
  • Transformer
  • Xfmr90
  • OT Reso12 kHz
  • OT Q1.3
Vocal lead

Vocal Silk

Midrange focus with soft presence and clean tails. Modest NFB tames sibilance, cathode bypass adds low-mid weight. Best on lead vocals, dialogue, expressive solo instruments.

  • Tube6SL7
  • Operating Point
  • Plate V250 V
  • Mu Scale1.15
  • Drive
  • Input Gain0.45
  • Interstage0.32
  • Circuit
  • NFB0.025
  • Coupling Cap0.047 µF
  • Cathode Bypass38%
  • Transformer
  • Xfmr65
  • OT Bass Phase70 Hz
  • OT Phase2600 Hz
Console warmth

Golden Glow

The classic 12AX7 console preamp. Stronger imaging spread and natural crosstalk give a "shared chassis" feel. Forward but never harsh.

  • Tube12AX7
  • Operating Point
  • Plate V265 V
  • Mu Scale1.5
  • Drive
  • Input Gain0.55
  • Circuit
  • NFB0.02
  • Coupling Cap0.01 µF
  • Cathode Bypass45%
  • Transformer
  • Xfmr70
  • Character
  • Match10%
  • Imaging22%
  • Crosstalk−55 dB
Bass weight

Low Iron

12BH7 current drive with controlled transformer low-phase rotation. Adds perceived weight without muddying the low end. For bass, kick, low toms.

  • Tube12BH7
  • Operating Point
  • Plate V280 V
  • Grid Bias−10.5 V
  • Drive
  • Input Gain0.50
  • Power Supply
  • Idle I85 mA
  • Reservoir330 µF
  • Circuit
  • Cathode Bypass35%
  • Transformer
  • Xfmr80
  • OT Reso7.5 kHz
  • OT Bass Phase105 Hz
Parallel saturation

Parallel Heat

Dense harmonic content with output trimmed −4 dB for blending. Drive hard and mix in parallel on drums, room mics, or vocal aux.

  • Tube12AX7
  • Operating Point
  • Plate V250 V
  • Mu Scale1.25
  • Drive
  • Input Gain0.85
  • Output−4 dB
  • Interstage0.52
  • Power Supply
  • Rectifier R90 Ω
  • Filter Cap80 µF
  • Circuit
  • NFB0
  • Cathode Bypass65%
  • Transformer
  • Xfmr115
Troubleshooting by Ear

What should I change if…

You don't need to know what every parameter does. You just need to know which knob fixes the problem you're hearing.

It sounds flat. Lifeless. No movement.
Lifelessness comes from a perfectly deterministic signal path. Turn up Tube Age → Drift (slow analog wandering) and Tube Age → Noise (subtle floor). Add Character → Match at 10–15% so L and R aren't perfect clones. Optionally bump Aging → Mu Loss to 1–2%.
Lacks punch. Transients feel limp.
Punch comes from PSU sag under load. Increase Power Supply → Recovery to 12+, lower Filter Cap to 40–60 µF, raise Rectifier R to 150–200 Ω. For more bite, also push Drive → Input Gain harder. Avoid stacking massive Match/Imaging values; those affect stereo, not punch.
Top end is brittle. Cymbals fatigue.
Brittleness usually means too much harmonic content above 6 kHz. Increase Circuit → NFB (negative feedback tames distortion). Bring Cathode Bypass up to ~40% so the lower mids carry more weight in proportion. If using a transformer, lower OT Reso below 6 kHz or reduce OT Q.
Bass lacks weight and authority.
Weight comes from output transformer bass phase rotation. Set Transformer → OT Bass Phase to 60–80 Hz. Increase Xfmr amount to 60–100. For added cohesion, use a larger Coupling Cap (0.1–0.22 µF) so low frequencies pass cleanly between stages.
Stereo image too narrow.
Widen via Character → Imaging (capacitive spread between L/R, 25–35%). Set Crosstalk to about −55 dB (HF capacitive bleed adds glue). Add Transformer → OT Phase dispersion around 2000–2500 Hz for subtle depth.
Too sterile. Too clean. Sounds like math.
Inject "analog imperfection" gradually: Aging → Drift at 1.5×, Aging → Mu Loss at 2%, Character → Hum set to AC (subtle 60 Hz adds psychoacoustic weight). Switch tubes: 6SN7 or ECC99 are warmer than 12AX7 or 12AU7.
Too saturated. Distorting unintentionally.
Lower Drive → Input Gain first; that's the master driver into the stages. If still hot, raise Plate V (more headroom before clipping) and increase Grid Bias magnitude (more negative, e.g. −1.8 V → −2.2 V) to bias deeper into the linear region.
Audible hum or buzz in quiet passages.
Set Character → Hum to Off. This disables both heater hum (60 / 120 Hz) and signal-correlated PSU mains ripple in one switch. Also set Tube Age → Noise to 0 for absolute silence between notes.
Vocal sibilance is harsh.
Sibilance lives in the 5–8 kHz region. Reduce OT Reso (push the transformer resonance below 5 kHz) and increase NFB to 0.06–0.08. A softer tube (12AU7, 6SL7) helps too.
Drums lose snap going through it.
Likely too slow a PSU. Drop Recovery to 5–6, raise Filter Cap to 120–180 µF, drop Rectifier R below 30 Ω. This is the "regulated supply" feel: tight transients, no sag bloom.
Knob Reference

What each parameter actually does

Sonic descriptions, not schematics. For every knob: what you hear when you turn it up vs. down, and a practical use tip.

Operating Point

Defines where the tube "sits" before any signal arrives. Affects headroom, distortion onset, and tonal balance.

Plate V100 – 500 V
Up: more headroom, cleaner, distortion arrives later. Down: earlier breakup, compressed, more "amp-like."
Match to the tube. 12AX7 likes 250–300 V, 6SN7 likes 200–250 V.
Plate R10 – 500 kΩ
Up: more gain, slower, higher impedance, brighter loading. Down: tighter, lower gain.
100 kΩ is the classic 12AX7 plate resistor. Try 47 kΩ for cleaner.
Grid Bias−15 to −0.2 V
More negative (left): deep cutoff bias, asymmetric clipping. Closer to zero (right): grid current onset, soft clipping on positive peaks.
Drop closer to zero for crunchy guitar tones. Keep deeper for clean hi-fi.
Mu Scale0.25× – 8×
Up: more gain, scales the tube's amplification factor. Down: cleaner, less colored.
Leave at 1.0 unless you want to push the tube outside its real characteristic.

Drive

How hard the signal hits the tube. The most direct character control.

Input Gain0.05 – 2.0
Up: deeper into clipping, more harmonics, audible compression. Down: cleaner, more linear.
Master driver. If unsure, this is the first knob to touch.
Output−48 to +12 dB
Compensates level after drive. No tonal change, just makeup gain.
Set last, after dialing the tone.
Interstage0.05 – 1.0
Up: stage 2 hits harder, cascaded distortion compounds. Down: only stage 1 colors, stage 2 stays clean.
High values give "stacked gain" guitar amp character.

Power Supply

Controls how the supply voltage moves under signal load. This is where punch and amp-feel live.

Rectifier5 – 300 Ω
Up: more voltage drop under current, sag, compression on loud transients. Down: solid-state tight, no sag.
Solid-state: 5–20 Ω. Tube rectifier: 100–250 Ω.
Filter Cap20 – 200 µF
Down: larger Vps wobble under load, "spongy" feel. Up: stiffer supply, cleaner transients.
30–50 µF for vintage amp character. 150+ µF for hi-fi tightness.
Recovery5 – 15
Up: slower PSU recovery after transients, sag lingers, sustain blooms. Down: snap-back fast, drum-tight.
12+ for tube amp feel. 5–6 for studio compressor-like response.
Idle I3 – 150 mA
Up: higher quiescent current, hotter tube, more class-A character. Down: cooler bias, more headroom.
Preamp: 5–10 mA. Driver: 20–40 mA. Output stage: 80–150 mA.
Reservoir60 – 560 µF
Main PSU storage cap. Up: stiffer global supply, less channel-to-channel modulation. Down: stereo channels couple via shared sag.
Lower = more "vintage glue" between L/R.
Decoupling20 – 1000 Ω
Up: strong inter-channel coupling via the shared rail. Down: nearly isolated channels, hi-fi separation.
200–700 Ω for "integrated amp" feel. Below 50 Ω for clean separation.

Circuit

Inter-stage coupling and feedback. Defines the tube's gain structure and frequency response.

NFB0.0 – 0.2
Up: less distortion, flatter response, controlled top end. Down: open, more harmonics, dynamic.
0.04–0.08 for hi-fi. 0.0 for vintage / guitar amp.
Coupling0.005 – 1.0 µF
Up: more low end passes between stages. Down: HP at higher Hz, thinner, lo-fi character.
0.022 µF is standard for hi-fi. Down to 0.005 for "small radio" sound.
Bypass0 – 100 %
Cathode bypass cap depth. Up: more gain and weight in low-mids. Down: flatter, more present.
40–60% adds "vocal warmth" without muddiness.
Stg2 Cath0 – 100 %
How much of the cathode bypass shaping happens in stage 2 vs. stage 1. Up: more affected by signal level.
25–40% gives natural envelope-following.
Cap Rate0.001 – 0.050
How fast the coupling cap charges from grid current. Up: faster recovery from grid-current peaks. Down: more "blocking distortion", slow ducking after loud notes.
Higher values = cleaner. Lower = more vintage compression-on-attacks.
Grid Leak0.1 – 5 MΩ
Discharge resistance after the coupling cap. Lower: faster recovery. Higher: longer attack-ducking.
1 MΩ is textbook. 470 kΩ for tighter behavior.

Transformer

Output transformer hysteresis and parasitics. Adds saturation on large signals and resonant character.

Xfmr0 – 250
Output transformer amount. Up: more flux saturation on bass and large signals, characteristic "iron" warmth. Zero: no transformer, preamp-only path.
30–80 for subtle. 100+ for amp-like saturation.
OT Reso0 – 20 kHz
Resonance frequency of leakage-L × inter-winding-C. Position it to boost or de-emphasize a specific HF band.
Vintage: 4–8 kHz adds "bite". Hi-fi: 12+ kHz for openness.
OT Q0.1 – 3.0
Sharpness of the resonance. Up: peaky, more pronounced. Down: broad gentle bump.
0.5–1.0 typical. 1.5+ for vintage colored character.
OT Bass0 – 200 Hz
Primary-inductance phase rotation in the bass. Adds perceived weight and bloom below this frequency.
60–80 Hz for that "big iron" feel.
OT Phase0 – 5 kHz
Allpass phase shift center in mid-band. Subtle depth and space without changing frequency response.
1800–2400 Hz adds soundstage depth.
OT Ph Q0.3 – 3.0
Phase dispersion width. Up: tighter focused rotation. Down: spread across more frequencies.
1.0 is balanced.

Character

Channel-pair variation and global hum/buzz. The "feel" knobs.

HumOff / AC / DC
Off: silent, disables both heater hum and signal-correlated PSU mains ripple. AC: 60 Hz heater hum + ripple punch on transients. DC: 120 Hz hum + ripple punch.
"Off" is the cleanest. AC gives the "tube amp under load" feel (see "Tube Amp Push" recipe).
Match0 – 50 %
Spread of tube electrical parameters (gain, plate R, bias) between L and R channels. Up: less matched pair, more channel-to-channel character difference.
10–15% sounds natural. 25%+ is "mismatched old tubes".
Imaging0 – 50 %
Spread of capacitances between L and R. Affects HF phase relationship, widens soundstage.
20–35% for dimensional sound. Subtle effect; listen on speakers.
Crosstalk−80 to −30 dB
HF capacitive bleed L↔R. −80 = perfect isolation. Higher: natural stereo glue, like a real shared-chassis amp.
−55 to −60 dB sounds like a real high-end preamp.

Tube Age

Long-term drift and broadband shot noise. Adds "alive" feeling without going lo-fi.

Spread0.5× – 4×
Global multiplier on tube-to-tube variation. Up: old/cheap tube set, parameters wander more. Down: fresh matched pair.
1.5–2× for vintage character.
Drift0.0 – 5×
Sub-Hz wandering of bias and gain. Up: subtle breathing, alive. Down: perfectly stable, "DSP-flat".
1.0–1.5× for tasteful "movement". 0 for mastering use.
Noise0.0 – 5×
Shot-noise floor. Up: audible analog hiss texture. Zero: absolute silence.
0.5–1.0 sounds natural. 0 for clinical mixing.
Mod0 – 100 %
Shot-noise modulation. 0%: constant noise amplitude, classic character. 100%: noise scales with plate current, more energetic on transients.
0% for a steady tape-hiss floor. Higher values make the noise breathe with the signal.
Mu Loss0 – 15 %
Permanent reduction in tube's gain factor, simulates worn cathode. Up: softer, lower-gain, vintage. Zero: fresh tube.
1–3% feels broken-in. 5%+ feels actually old.
Tube Type Cheat Sheet

Which tube for which job

Nine tube types, each with a different character. Pick by what you want: clean preamp, driver, output, smooth or aggressive. Switching a tube also resets Plate V, Plate R, and Grid Bias to that tube's textbook operating point.

12AX7 / ECC83
High gain, bright

The most-used preamp tube ever made. High mu (~100), lots of gain per stage, slightly bright. The "guitar amp" tube.

Good for: guitar dist, lead vocals, anything that needs to cut.
12AU7 / ECC82
Clean, mellow

Low gain (mu ~20), high headroom, gentle harmonics. Classic "audiophile preamp" character, never aggressive.

Good for: hi-fi color, mastering bus, line buffering, smooth vocals.
12AT7 / ECC81
Medium, punchy

Higher current capability than 12AX7, less gain. Originally a phase splitter / driver tube. Snappy attack, full mids.

Good for: drum bus, electric piano, anything punchy.
12BH7
High current, headroom

Made for driving low impedances. Big rugged sound, lots of headroom, fast transients. The "driver stage" tube.

Good for: mix bus glue, bass guitar, kick drum, anything that needs authority.
6SL7
High gain, smooth

Octal tube from the 1940s. Similar gain to 12AX7 but mellower, with the characteristic "warm haze" of older tubes.

Good for: vintage vocal, jazz horns, brushed snare.
6SN7
Medium, vintage glow

Beloved by Western Electric and McIntosh era hi-fi. Lower gain than 6SL7, very linear, classic "warm" sound.

Good for: mastering glue, strings, classical, acoustic.
6922 / E88CC
Studio quality, detailed

Premium tube for precision audio. Low noise, high transconductance, very detailed top end. Modern hi-fi staple.

Good for: mix bus, mastering, vocal chain, anything that demands clarity.
6H30 (6H30Pi)
Russian, robust

Modern Russian "super tube". Very high current, ultra-low distortion, designed for high-end audio. Punchy and authoritative.

Good for: rock mix bus, drums, anything that needs both clarity and weight.
ECC99
High power, bold

JJ's high-current twin. More like a small power tube than a preamp. Loose bass, big midrange, three-dimensional.

Good for: stereo widening, depth, "amp-like" character.

Got a sound you can't reach?

Recipes here came from real user questions. Send yours.

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