# TubeBias: Amp Bias Calc — Plate dissipation & OT match

> Plate dissipation & OT match (iPhone/iPad app by Yoshifumi Sato.)

- Source: https://appshunter.io/ios/app/tubebias-amp-bias-calc/id6795169914 (this page in markdown: same URL + `.md`)
- Developer: [Yoshifumi Sato](https://appshunter.io/developer/6780413827)
- Category: Utilities
- Price: $4.99
- Age rating: 4+
- Requires: iOS 17.0 · 11 MB
- Languages: American English, Japanese
- Released: 2026-08-05
- Data updated: 2026-08-07
- User reviews in markdown: https://appshunter.io/ios/app/tubebias-amp-bias-calc/id6795169914/reviews.md

## What is TubeBias?

TubeBias helps you bias a vacuum-tube amplifier and match its output transformer, with a clear safe-zone readout.

Enter plate voltage and idle current to get plate dissipation and its percentage of the tube's rating, with a green/amber/red safe-zone check. Solve the bias current for a target percentage, or work out cathode-resistor bias. On the impedance side, compute reflected primary impedance, turns ratio and per-tap loads for your speaker.

FEATURES
• Plate dissipation and bias % with safe-zone check
• Target-% bias current solver
• Cathode-resistor bias
• Reflected impedance, turns ratio, tap selection
• Common tube presets (EL84, 6V6, EL34, 6L6GC, KT88, 300B)
• Save your setups

No ads, no tracking, no account. A one-time purchase.

Safety: high voltage is dangerous. These calculations are a guide only; work at your own risk and have a qualified person verify.


## Version history (last 1 release)

### 1.0 — 2026-08-06

No release notes.

## More apps by Yoshifumi Sato

- [おけいこ月謝帳 教室の集金管理](https://appshunter.io/ios/app/id6787108752)
- [DualShot: Front & Back Cam](https://appshunter.io/ios/app/dualshot-front-and-back-cam/id6788761561)
- [Progressly – Body Progress](https://appshunter.io/ios/app/progressly-body-progress/id6789591055)
- [Holdly – Isometric Timer](https://appshunter.io/ios/app/holdly-isometric-timer/id6789790139)
- [かんじ1年生 小学1年の漢字ドリル](https://appshunter.io/ios/app/1-1/id6789917332)
- [かんじ3年生 小学3年の漢字ドリル](https://appshunter.io/ios/app/3-3/id6790055787)

All apps by Yoshifumi Sato: https://appshunter.io/developer/6780413827

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-07.*