What is the 5639 vacuum tube?

The 5639 is a pentode vacuum tube designed for video / wideband (power) applications. Premium subminiature sharp-cutoff video power pentode (JAN / MIL-E-1) on the 8DL flexible-lead button base. Designed by Sylvania and Tung-Sol in the mid-1950s for broadband radar/airborne video service: high gm (9 mA/V), low Cgp (0.18 pF unshielded), and ruggedized against severe shock (450 G impact), vibration and altitude. Anchored on an identical tabulated typical point across both makers — Vp 150 V, Vg2 100 V, Rk 100 Ω, Ip 21 mA, Ig2 4 mA. Sylvania rates plate dissipation at 4.0 W and Tung-Sol at 3.5 W; conservative work uses 3.5 W. NO relationship to the European RO4404/RE604/D404 power triode family..

What is a 5639 substitute or equivalent?

Direct equivalents to the 5639 include 5639WA, CK5639, CK5639WA. 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 5639?

Transconductance gm ≈ 9 mA/V, plate resistance rp ≈ 50.0 kΩ, max plate voltage 165 V, max plate dissipation 4 W, heater 6.3 V / 0.45 A.

Is the 5639 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 5639 as Sought-after 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 5639 sound like?

Premium subminiature sharp-cutoff video power pentode (JAN / MIL-E-1) on the 8DL flexible-lead button base. Designed by Sylvania and Tung-Sol in the mid-1950s for broadband radar/airborne video service: high gm (9 mA/V), low Cgp (0.18 pF unshielded), and ruggedized against severe shock (450 G impact), vibration and altitude. Anchored on an identical tabulated typical point across both makers — Vp 150 V, Vg2 100 V, Rk 100 Ω, Ip 21 mA, Ig2 4 mA. Sylvania rates plate dissipation at 4.0 W and Tung-Sol at 3.5 W; conservative work uses 3.5 W. NO relationship to the European RO4404/RE604/D404 power triode family.. 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.

5639 (5639WA, CK5639) datasheet — pinout & specs

Characteristics

Datasheet values, once each. Every value cites its sheet.

Mode

HeaterIndirectly heated

Specifications of 5639 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.45 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 5639 — Limiting values
Plate voltageVa max	165 V
Screen voltageVg2 max	155 V
Plate dissipationPa max	4 W
Cathode currentIk max	40 mA
Peak plate voltageVao	330 V
Heater–cathode voltageVhk max	200 V

Mechanical

Specifications of 5639 — Mechanical
Base	8-lead subminiature (8DL)
Rarity	Sought-after
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 5639 — Small signal
Transconductance	9 mA/V
Plate resistance	50 kΩ

Capacitances

Specifications of 5639 — Capacitances
Input	9 pF
Grid–plate	0.18 pF
Output	8 pF

Charactereditorial reading, not a measurement

Specifications of 5639 — Character
Gain	0%
Power	10%
Drive	50%
Linearity	75%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Typical operation

Canonical operating pointModel

B+: 150 V
Load: 100 kΩ
Va: 90 V
Ia: 19.47 mA
Vg: -3 V
Pd: 1.75 W
Gain: 35 dB

At Q: Norman Koren
μ: 13.1
gm: 5.98 mA/V
rp: 2.2 kΩ

Design a stage →

Using this tube

Applications

Voltage amplifier

Generic pentode video / wideband (power) stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Sylvania Engineering Data Service 1957 · Tung-Sol Premium Tube 1955-1957 · Raytheon CK5639WA 1959 · Tung-Sol 5639WA 1960Active model : Norman Koren

Manufacturer datasheets

6 manufacturer datasheets cross-checked for 56396 verified

5639 Datasheet4 variants · pick below

Manufacturer datasheets (PDF downloads)

Sylvania Electric Products (Emporium, PA)

Sylvania Engineering Data Service, Feb 1957 · 11 pp · EN

Most complete US issue: typical point, full MIL-E-1 limits & acceptance band, pentode plate family, triode-connected plate family, gm/rp vs Vg1 graphs, 4.0 W plate dissipation.

Tung-Sol Electric Inc. (Bloomfield, NJ)

Tung-Sol Premium Tube, Oct 1955 / Jan 1957 · 6 pp · EN

Typical point confirmation, equipment-design range table, pentode + screen curves, 3.5 W plate dissipation.

Raytheon Manufacturing Co. (Newton, MA)

Raytheon CK5639WA, Mar 1959 (Tentative Data) · 9 pp · EN

Earliest WA issue. Confirms WA limits (Vp 250 V des.max, peak fwd 360 V). Carries the plotted gm/rp-vs-Vg1 transfer curve at Eb=Ec2=100 V used for SPICE-model validation, plus tabulated triode-connected curve on p.6.

Tung-Sol Electric Inc. (Bloomfield, NJ)

Tung-Sol 5639WA, Jan 1960 (TENTATIVE DATA) · 9 pp · EN

WA limits (Vp 250 V des.max, peak fwd 360), Ec2=50 V + Ec2=100 V plate families, tabulated triode-connected curve grid steps Ec1=0..-16 V (used to fit 5639WA_TRIODE_CONNECTED).

Datasheet limits (full)

Va max

165 V

Pa max

3.5 W

Pg max

1 W

Ik max

40 mA

Rg max

0.5 MΩ

Vhk max

200 V (f−/k+) · 200 V (f+/k−)

Bulb temp

220 °C

5639 standard: Vp max 165 V (peak fwd 330 V). 5639WA rating raised: Vp design-max 250 V (peak fwd 360 V) — but both Raytheon and Tung-Sol WA issues are maker-marked TENTATIVE. Plate dissipation: Sylvania 4.0 W, Tung-Sol & both WA issues 3.5 W — use 3.5 W for conservative work. Max screen voltage 155 V, screen dissipation 1.0 W. Max grid-1 resistance 0.5 MΩ self-bias / 0.1 MΩ fixed (Sylvania); Tung-Sol publishes 0.5 MΩ unified. Heater-cathode symmetric ±200 V. Ruggedness: 450 G impact, 1000 G uniform, 2.5 G fatigue per MIL-E-1.

Per-section / per-manufacturer capacitances

Capacitance	sylvania5639	tungsol5639	tungsol5639WA	raytheon5639WA
Cgp_unshielded	0.18 pF	0.18 pF	0.13 pF	0.13 pF
Cgp_shielded	0.15 pF	0.15 pF	0.13 pF	0.13 pF
Cin	9 pF	9 pF	9 pF	9 pF
Cout	4.6 pF	4.6 pF	4.6 pF	4.6 pF

SPICE variants per manufacturer

Each card below is a named subcircuit inside the downloadable .subckt file. Same physical tube, different manufacturer / measurement convention. The Ampera loadline calculator uses the Philips/1953 family; copy the Koren line from any card into your own simulator to bias the engine the same way.

5639_PENTODE_SYLVANIA_1957

Sylvania 5639 (calc default; Pa 4.0 W)

Va150 V

Vg-2.5 V

Ia21 mA

μ35.97

gm9 mA/V

rp50 kΩ

Cag0.18 pF

Koren fit

MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886

Default Ampera engine for 5639. Typical-point reproduces Ip 20.7 mA / gm 9.27 mA/V vs sheet 21 mA / 9.0.

5639_PENTODE_TUNGSOL_1957

Tung-Sol 5639 (Pa 3.5 W)

Va150 V

Vg-2.5 V

Ia21 mA

μ35.97

gm9 mA/V

rp50 kΩ

Cag0.18 pF

Koren fit

MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886

Use when conservative 3.5 W plate ceiling applies.

5639WA_PENTODE_RAYTHEON_1959

Raytheon CK5639WA (earliest WA, tentative)

Va150 V

Vg-2.5 V

Ia21 mA

μ35.97

gm9 mA/V

rp50 kΩ

Cag0.13 pF

Koren fit

MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886

Earliest WA issue. Validated against Raytheon's plotted gm-vs-Vg1 transfer curve at Eb=Ec2=100 V (model 8718 µmho vs sheet ~9000 µmho at the typical bias).

5639WA_PENTODE_TUNGSOL_1960

Tung-Sol 5639WA (tentative; Vp 250 V des.max)

Va150 V

Vg-2.5 V

Ia21 mA

μ35.97

gm9 mA/V

rp50 kΩ

Cag0.13 pF

Koren fit

MU=35.97 EX=2.2 KG1=340.05361 KP=28.698 KVB=25.886

Use for WA-grade designs needing the raised Vp design-max of 250 V.

5639_TRIODE_CONNECTED

5639 triode-connected (refit, Sylvania 1957 p.9)

Va200 V

Vg-6 V

Ia41 mA

μ15

gm7 mA/V

rp2.1 kΩ

Cag0.18 pF

Koren fit

MU=32 EX=1.4 KG1=380 KP=35 KVB=250 VCT=0.5

G2 strapped to plate. Hand-fitted to Sylvania 1957 p.9 Ib/Va triode-connected plate family (Vg=0..-26 V). Mean ~16 % residual vs traced curves; over-predicts at Vg≈0 / low Va and under-predicts near cutoff — inherent Koren-shape limit for sharp-cutoff video pentodes triode-strapped. Used by the calculator's triode mode when the user toggles it.

5639WA_TRIODE_CONNECTED

5639WA triode-connected (same fit; WA-grade Cgp 0.13 pF)

Va200 V

Vg-6 V

Ia41 mA

μ15

gm7 mA/V

rp2.1 kΩ

Cag0.13 pF

Koren fit

MU=32 EX=1.4 KG1=380 KP=35 KVB=250 VCT=0.5

Same fit as 5639_TRIODE_CONNECTED — Tung-Sol 5639WA p.8 and Raytheon CK5639WA p.6 tabulated triode curves converge on the Sylvania p.9 graph within reading tolerance. Use this subckt when the WA-grade tighter Cgp (0.13 pF) matters for HF / Miller analysis.

Transfer curve comparison

Ia vs Vg at Va = 250 V — each manufacturer Koren fit overlaid. The de-rated French families (μ=30) read lower than the Philips/1966 high-gm family (μ=32) at the same grid voltage.

Sylvania 5639 (calc default; Pa 4.0 W)5639 triode-connected (refit, Sylvania 1957 p.9)

Original descriptive texts

Verbatim excerpts from the four manufacturer datasheets. Expand each section to read the original text — the Philips technical article carries the richest application content.

SPICE models

Revision and verification status

Source: Sylvania Engineering Data Service 1957 · Tung-Sol Premium Tube 1955-1957 · Raytheon CK5639WA 1959 · Tung-Sol 5639WA 1960
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Norman Koren

7 Koren fits

Context

The 5639 is a premium (JAN / MIL-E-1) subminiature sharp-cutoff video power pentode built in 8-lead flexible-lead button construction (8DL), produced by Sylvania and Tung-Sol in the mid-1950s for broadband radar, airborne and industrial video service under severe shock (450 G impact), vibration, high temperature and high altitude. It uses a 6.3 V / 0.45 A indirectly-heated coated unipotential cathode. The two original-issue manufacturer datasheets (Sylvania Feb 1957, Tung-Sol Oct 1955 / Jan 1957) are electrically the same tube and share an identical tabulated typical point: Vp = 150 V, Vg2 = 100 V, Rk = 100 Ω giving Ip = 21 mA, Ig2 = 4 mA, gm = 9000 µmho, rp = 50 kΩ. They differ only in stated limits — Sylvania rates plate dissipation at 4.0 W, Tung-Sol at 3.5 W — and in minor curve reference conditions; conservative work uses the 3.5 W ceiling and the 1.0 W screen ceiling. The Cgp = 0.18 pF unshielded (0.13 pF on the ruggedized 5639WA) makes it attractive as a low-Miller video / pulse stage even by modern standards. Triode-strapped operation (G2 to plate) is possible: μ ≈ 18, rp ≈ 1.6 kΩ from the 5639WA tabulated curve, μ ≈ 20, rp ≈ 2.5 kΩ from the indicative Sylvania p.9 graph. The 5639WA is the JAN/MIL ruggedized variant (Raytheon Mar 1959 earliest, Tung-Sol Jan 1960) with raised Vp design-max of 250 V (peak 360 V) but is maker-marked TENTATIVE on both issues. Note: the 5639 has NO relationship to the European RO4404 / RE604 / D404 family (which is a 1930 4 V directly-heated audio triode).

History

Introduced: 1955
Manufacturer: Sylvania·Tung-Sol
Era: Golden Age

METRIX TESTER

5639 Pentode Vacuum Tube

Characteristics

HeaterIndirectly heated

Limiting valuesDatasheet maximum ratings — not to be exceeded

Mechanical

Small signalDatasheet parameters at the reference operating point — not limits

Capacitances

Charactereditorial reading, not a measurement

Typical operation

Using this tube

Applications

Replace or compare

Sources

Manufacturer datasheets

SPICE models

Context

History

Test this tube on a Metrix

Characteristics

HeaterIndirectly heated

Limiting valuesDatasheet maximum ratings — not to be exceeded

Mechanical

Small signalDatasheet parameters at the reference operating point — not limits

Capacitances

Charactereditorial reading, not a measurement?

Typical operation

Using this tube

Applications

Replace or compare

Versus 12SJ7

Similar tubes

Sources

Manufacturer datasheets

SPICE models

Context

History

Test this tube on a Metrix

Charactereditorial reading, not a measurement