3Q4

3Q4 is also designated DL95. Completed sales put the typical price at $5.27 per tube.

General Description

The 3Q4 is an output pentode for battery receivers, intended as an audio-frequency output amplifier. It has direct heating by battery current, rectified AC or DC, with series or parallel supply.

Construction

The 3Q4 has two filament sections that can be connected in series or in parallel. The filament voltage is 2.8 V for series connection and 1.4 V for parallel connection. The filament current is 100 mA for parallel connection. The envelope is type A19-2, and the base is type 7C10. The tube can be mounted in any position.

Ratings

The maximum anode voltage is 90 V, and the maximum grid No. 2 voltage is 90 V. The maximum cathode current is 12 mA with filaments in parallel and 6 mA with filaments in series.

Capacitances

The input capacitance is 5.9 pF, and the output capacitance is 4.5 pF. The grid No. 1 to anode capacitance is 0.4 pF maximum.

Applications

The 3Q4 is intended as an audio-frequency output amplifier. The Mazda Belvu datasheet gives the 3Q4 as an audio-frequency output amplifier with filament supply in series or parallel.

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.

Per-tube prices from completed sales, 2026-06-20 to 2026-09-02. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 3Q4, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• MAZDA BELVU
• DL95 (filed under DL95)

1 further designation appears alongside 3Q4 in the literature but below the evidence threshold used here, so it is not listed as equivalent.