6336 B Röhre entspricht CK6336 60Watt Oktal Leistungstriode

6336 / 6336A twin power triode for high-current audio amplifiers

The 6336 is an exceptional low-mu twin power triode with two independently accessible sections. Each section is rated for up to 30 W plate dissipation, giving a total of 60 W per valve. Approximately 200 Ω plate resistance and substantial current capability make it attractive for single-ended, parallel single-ended, push-pull and OTL amplifiers.

Its large straight-sided envelope is visually reminiscent of a KT88 or 6550, but the electrical design is completely different. The 6336 is a true low-mu twin triode with another pinout and heater demand of up to 5 A. Particularly ambitious projects may use both sections in parallel or employ two to four complete valves per channel.

The Luxman MQ80 and Luxkit KMQ80 provide a notable historical audio reference: one 6336A per channel operated as a cross-shunt push-pull output stage and delivered 40 W into 8 Ω.

Relevant audio applications

• Single-ended and parallel single-ended amplifiers with low primary impedance
• High-current PSE stages using two to four complete 6336 valves
• Push-pull and cross-shunt push-pull output stages
• OTL amplifiers, cathode followers and low-impedance outputs

Technical specifications

Valve construction

Two independent indirectly heated low-mu power triodes in one envelope

Base

Large-wafer octal K8A, 8-pin

Heater

Original 6336: typically 6.3 V at 4.75 A; 6336A: nominally 6.3 V at 5 A

Class-A1 reference characteristics per section

At 190 V supply and 200 Ω cathode resistance: amplification factor µ 2.7, plate resistance approximately 200 Ω and transconductance 13.5 mA/V

Maximum anode voltage

400 V per section

Maximum anode current

400 mA per section

Plate dissipation

Maximum 30 W per section and 60 W per valve

Heater-to-cathode voltage

Maximum 300 V in either polarity for each section

Minimum warm-up time

30 seconds

Dimensions

Maximum diameter approximately 52.6 mm and maximum overall height approximately 120.7 mm

Comparison with related power triodes

6AS7G and 6080

Classic low-mu twin triodes used in OTL, cathode-follower and regulator circuits. The 6336 provides substantially greater current and dissipation capability and can perform roughly the role of two parallel 6080 valves in a newly engineered circuit. Its much heavier heater demand prevents unchecked substitution.

6C33C-B / 6S33S-V

A similarly powerful 60 W high-current type with even lower plate resistance. The 6C33C presents one externally accessible triode, uses a different 7-pin base and requires another heater arrangement. The 6336 instead provides two independently controlled sections on an octal base.

6C41C / 6S41S

A single low-resistance power triode also suitable for SE, parallel and OTL concepts. The two independent sections of the 6336 provide additional freedom for balanced and push-pull circuits.

EC360 and ED8000

These also belong to the broader family of low-mu regulator and power triodes, but each contains one system and uses different heater, base and operating requirements. They are design alternatives for other power levels rather than direct substitutes.

KT88 and 6550

Large octal valves with a superficially similar outline, but electrically they are beam tetrodes with a different pinout, operating point and load requirement. A 6336 must never be plugged into an amplifier designed for a KT88 or 6550.

K8A base connections – bottom view

Section 1

Pin 4 control grid, pin 5 anode, pin 6 cathode

Section 2

Pin 1 control grid, pin 2 anode, pin 3 cathode

Heater

Pins 7 and 8

Notes for high-current amplifier projects

A single 6336A heater consumes 31.5 W. Two valves require 10 A and four require 20 A at 6.3 V, so the power transformer, wiring, socket, start-up arrangement and ventilation must all be generously rated.

The low amplification factor requires a large drive-voltage swing from a low-impedance source. A substantial cathode follower or comparable driver stage is often appropriate. RCA also recommends a 1 kΩ resistor directly at each control grid to suppress parasitic oscillation.

Parallel sections should be monitored individually and stabilised with separate cathode or balancing resistors. Closely performing valves are especially useful when two to four complete bottles operate in parallel or when the sections form a push-pull pair. The output transformer must provide a very low primary impedance and tolerate substantial DC current; BTB's transformer selection includes low-impedance SE configurations intended for one or two 6336 valves.

Safety notice: A 6336 amplifier combines high voltage, very high current and substantial heat. Construction and commissioning require suitable expertise together with reliable protection against electric shock, overcurrent and overheating.

Questions about selection and audio use

Is the 6336 suitable for powerful parallel SET and PSE amplifiers?

Yes, both internal triode sections can operate in parallel in a correctly designed single-ended stage. For still greater current capability, two to four complete valves per channel may be used in a parallel single-ended circuit. This requires a very low-impedance output transformer with substantial DC capability, a powerful supply and controlled current sharing between all sections.

Can one 6336 form a complete push-pull output stage?

Yes, its two independent sections can be driven as a push-pull pair. The Luxman MQ80 and Luxkit KMQ80 demonstrated this with one 6336A per channel and 40 W output. That result depended on a specialised cross-shunt push-pull circuit, a bifilar-wound output transformer and a powerful directly coupled driver rather than a conventional basic output stage.

Is the 6336 an attractive alternative to the 6AS7G, 6080, 6C33C-B, 6C41C, EC360 and ED8000?

Yes, as a purpose-designed alternative the 6336 combines two independent systems, 60 W total plate dissipation, low plate resistance and an octal base. It offers much greater reserves than a single 6AS7G or 6080 and more circuit flexibility than the externally single-system 6C33C-B. Heater demand, pinout, bias and transformer requirements differ between every type, so none should be treated as an unchecked plug-in replacement.