| Application | KT66/88/90, 6550, 6CA7 |
| Primary Impedance (Zaa) | 1885 ohm |
| Secondary Impedance (ZL) | 5 ohm |
| Turns Ratio Np/Ns (4 ohm secondary) | 19.42 |
| Ultra Linear Tap | 40 |
| -0.1 dB Frequency Range (flf) | 1.4 Hz - 96.5 kHz |
| -1 dB Frequency Range (fl1) | 0.6 Hz - 152.2 kHz |
| -3 dB Frequency Range (fl3) | 0.3 Hz - 217 kHz |
| Nominal Power, RMS (pn) (note 1) | 100 W |
| Full Power Bandwidth, -3dB, starting at (fu) | 20.7 Hz |
| Total Primary Inductance (Lp) (note 2) | 530 H |
| Primary Leakage Inductance to Secondary (lsp) | 1.8 mH |
| Effective Primary Capacitance (cip) | 585 pF |
| Total Primary Resistance (Rip) | 104 ohm |
| Total Secondary Resistance (Ris) | 0.18 ohm |
| Insertion Loss (Ilos) | 0.38 dB |
| Tube Plate Resistance (rp) | 1 kohm |
| Q-factor 2nd order HF roll-off (Q) (note 5) | 0.69 |
| HF roll-off Specific Frequency (Fo) (note 5) | 220.91 kHz |
| Quality Factor (Lp/Lsp) (QF) (note 5) | 294,410 |
| Quality Decade Factor (QDF) (note 5) | 5.47 |
| Tuning Factor (TF) (note 5) | 2.42 |
| Tuning Decade Factor (TDF) (note 5) | 0.38 |
| Frequency Decade Factor (FDF) (note 4, 5) | 5.85 |
