12AV6
12AV6 is also designated HBC91. Completed sales put the typical price at $11.66 per tube.
The 12AV6 is a double-diode triode miniature type tube, combining a high-mu triode and two independent diode units in a 7-pin miniature construction. It permits a single tube to function as detector, AVC rectifier, and audio amplifier. Coupling between the diode and triode sections is minimized by the use of internal shielding. The tube has a coated unipotential cathode, a glass bulb, and a miniature button 7-pin base. It can be used in any mounting position.
Ratings
The heater is rated at 12.6 volts ±10% at 0.15 ampere and can operate on AC or DC. Maximum heater-cathode voltage is 90 volts; maximum peak heater-cathode voltage is 200 volts with the heater either negative or positive with respect to the cathode. Maximum DC component of heater-cathode voltage is 100 volts. The maximum plate voltage is 300 volts, and maximum plate dissipation is 0.55 watt. Maximum diode current is 1.0 mA for each plate for continuous operation. Maximum positive DC grid #1 voltage is 0 volts.
Construction
The diode units are independent of the triode unit except for the common cathode sleeve. Diode biasing of the triode unit is not suitable for this tube.
Characteristics
At a plate voltage of 250 volts and a grid voltage of −2 volts, the triode section has a plate current of 1.2 mA, a plate resistance of 62,500 ohms, a transconductance of 1,600 µmhos, and an amplification factor of 100. At a plate voltage of 100 volts and a grid voltage of −1 volt, the plate current is 0.5 mA, plate resistance is 80,000 ohms, transconductance is 1,250 µmhos, and amplification factor is 100. The average diode current is 2.0 mA at 10 volts DC for each unit.
| Designation | Evidence | Confidence |
|---|---|---|
| HBC91 | 42 independent documents | confirmed |
Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.
Same design, different filament voltage. Not interchangeable with 12AV6: 6AV6.
| Measure | Per tube |
|---|---|
| Median | $11.66 |
| Typical range (25th–75th) | $8.54 – $22.83 |
| Most sales (10th–90th) | $3.99 – $32.54 |
| Extremes incl. outliers | $1.79 – $73.63 |
| Completed sales | 74 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| RCA | $11.50 | $8.99 – $18.00 | 18 |
| Sylvania | $15.13 | $7.60 – $16.00 | 6 |
| GE | $18.70 | $10.98 – $26.00 | 6 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $10.75 | 43 |
| used | $22.99 | 23 |
Per-tube prices from completed sales, 2026-02-02 to 2026-11-01. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for 12AV6, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Tung-Sol | 12AV6 | PDF (255 KB) |
| Brimar | 12AV6 | PDF (94 KB) |
| Mazda-Belvu | 12AV6 | PDF (32 KB) |
| Lorenz | HBC91 | PDF (86 KB) |
Documents held here and used to write this page.
- HBC91 (filed under HBC91)
- DOUBLE-DIODE TRIODE