What is the 35LR6 vacuum tube?

The 35LR6 is a pentode vacuum tube designed for sweep / power applications. High-power sweep tube. 35V heater chain..

What is a 35LR6 substitute or equivalent?

Direct equivalents to the 35LR6 include 6LR6 (35V heater). These share the same pinout and operating envelope, so they can usually be swapped without circuit changes — though batch-to-batch variations between manufacturers (NOS vs current production) may shift the sonic character noticeably.

What are the key specifications of the 35LR6?

Transconductance gm ≈ 16 mA/V, max plate voltage 900 V, max plate dissipation 30 W, heater 35 V / 0.6 A.

Is the 35LR6 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 35LR6 as Moderate availability. NOS (new-old-stock) examples from RCA, Mullard, Tung-Sol, GE, Sylvania and Telefunken trade among collectors; modern production where it exists comes mostly from JJ Electronic, Electro-Harmonix, Tung-Sol (New Sensor), Genalex, and a handful of small-batch makers.

What does the 35LR6 sound like?

High-power sweep tube. 35V heater chain.. Sonic character also depends heavily on the circuit operating point, the surrounding tubes in the stage, and the output transformer when present — use the interactive loadline calculator on this page to explore the trade-offs.

By Jean-Michel Falligan Devergne

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35LR6 Pentode Vacuum Tube

Pentode35V / 0.6A12-pin Compactron

SourceSylvania·RCAReviewed—StatusDataModelCalcModelunder reviewPDF

Power pentode delivering up to 30W in pentode, UL, or triode mode

Datasheet ↗

35LR6 — Sylvania·RCA — pentode vacuum tube — (1968)

16.0mA/V

17.0pF

1.0pF

12.00pF

GAIN0%

POWER75%

DRIVE50%

LINEARITY75%

SPECIFICATIONS

Heater35 V · 0.6 A

Max Plate Voltage900 V

Pa max30 W

Gain Factor—

gm16 mA/V

rp—

Inter-electrode capacitances

Cgk17 pF

Cgp1 pF

Cpk12 pF

Pinout12-pin Compactron

Era1968

RarityModerate

HEATER35V / 0.6A

MAX PLATE900V / 30W

BASEcompactron

EXECUTIVE SUMMARY

The 35LR6 is a indirectly-heated pentode from Sylvania·RCA, introduced around 1968. Commonly used in sweep / power applications. High-power sweep tube. 35V heater chain.

APPLICATIONS

Power output

Generic pentode sweep / power stage

• PA/public address

HISTORY

Introduced1968ManufacturerSylvania·RCA

Late Production

35LR6 Datasheet

Frank's Electron Tube Pages · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

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