Comparison

ThermVoltTube vs spool.

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

ThermVoltTube

Features
Read full description

ThermVoltTube is an asymmetric triode distortion processor for iPhone and iPad. Use it as a standalone audio app or insert the included AUv3 effect in a compatible host such as GarageBand. Its nonlinear core models a tube preamplifier with selectable 12AX7 and 12AT7 behavior. Asymmetric plate transfer, grid conduction, Miller capacitance, plate impedance, operating temperature, tube bias, and selectable plate-supply behavior create a response with prominent even-order harmonic content. FEATURES - Selectable 12AX7 and 12AT7 tube behavior - Asymmetric triode transfer and grid-conduction modeling - Temperature and tube-bias controls - Selectable 200 V / 300 V plate-supply behavior and sag - Instrument and line input modes - Boost stage - Adjustable gain, high-pass filter, tone, drive, and output - 2x and 4x oversampling modes - Standalone iOS/iPadOS app - AUv3 audio effect for compatible hosts TRY BEFORE UNLOCKING The app provides 10 minutes of full-featured active use. Demo time advances only while the standalone app or AUv3 effect is actively being used. After the allowance is used, audio processing is disabled for 24 hours. A one-time, non-consumable In-App Purchase unlocks unlimited use in both the standalone app and AUv3 extension. Restore Purchases is available in the standalone app. ThermVoltTube is designed for guitar, bass, synthesizers, keyboards, and other sources that benefit from asymmetric tube-style saturation.

About

spool.

Create full songs on your phone with this pocket music studio. It offers a variety of sound engines, sampling capabilities, step sequencing, and a 4-track tape recorder for recording and mixing your music. Effects and MIDI controller support enhance the creative process.

Highlights
  • Multiple sound engines
  • Sampling and sequencing
  • 4-track tape recording
  • Extensive effects rack
  • MIDI controller support
  • Step sequencer
Features
Read full description

Make a whole song on your phone. Spool is a pocket music studio inspired by the joy of hardware grooveboxes — play, sample, sequence, and record to tape, all in one playful instrument. Fourteen sound engines. From punchy FM and fat subtractive Pulse to shimmering Cluster, plucked String, granular Cloud, the TALK vocoder, the WIDE stereo engine, THUMP bass, a Sampler, and two drum machines — each with its own animated, touchable visualizer and four hands-on controls. Sample anything. Record straight from the mic into the sampler or drum kits, trim it, and play it across the keyboard. Drums & beats. Build kits, chop a sample into a playable kit, and lock in grooves with the step sequencer. Playful sequencers. Pattern and arpeggiator to start; unlock Stream, Taps, and the bouncing-ball Gumball machine for happy accidents. Six minutes of 4-track tape. Record, overdub, varispeed (including reverse), scrub, and bounce your jam to a finished mixdown — export to WAV. Your tape is saved with your project. Effects & mixer. A deep rack — delay, spring reverb, drive, compressor, chorus, multimode filter, phaser, tremolo/auto-pan, beat-repeat stutter, and a pitch-shifter/harmonizer — many tempo-syncable. Plus a master EQ and brickwall limiter so it always sounds finished. Plays with your gear. Connect a USB or Bluetooth MIDI controller and play Spool like hardware. AUv3 plugin support is planned for a future update. Free to download and make music with a starter set of engines and sequencers. A single one-time Spool Pro purchase unlocks the full instrument — all engines, sampling, every effect and sequencer, unlimited projects, export, and MIDI. No subscription. Spool is an original, independent work by a solo developer — affiliated with no hardware maker.

Screenshots

ThermVoltTube2 screens
spool.4 screens

Verdict

The call

ThermVoltTube and spool. are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. ThermVoltTube sells 1 one-off in-app purchase and spool. sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ScorecardNo meaningful differences
ThermVoltTube versus spool.: the parameters behind the verdict, then further details
ParameterThermVoltTubespool.
PriceFreeFree
Rating—5.0 (7 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—7 — better
AdsNoNo
In-app purchasesYesYes
Monetization—Free with in-app purchases
DevicesiPhone, iPadiPhone, iPad
Requires iOS16.0 — better17.0
Further details — not scored
Size27 MB2 MB
Age rating4+4+
DeveloperShoma KondoKristopher Yang

In-app purchases

1 purchases

ThermVoltTube

One-time1
  • ThermVoltTube Full Version$4.99
1 purchases

spool.

One-time1
  • Spool Pro$9.99

Questions

Is ThermVoltTube free?
ThermVoltTube is free to download, with in-app purchases available.
Is spool. free?
spool. is free to download, with in-app purchases available.
Do ThermVoltTube or spool. have ads?
Neither ThermVoltTube nor spool. shows ads.

Other comparisons