6L6GC-STR Tung-Sol Powertube Röhren BTB matched Pair
€66.50
Delivery time: ca. 1 - 5 days
Two output valves matched by BTB at a practical 450 V test point
For compatible hi-fi and guitar push-pull stages using 6L6GCs
Verify bias, screen loading, heater supply and physical clearance
Tung-Sol 6L6GC-STR – BTB-matched pair for hi-fi and guitar amplifiers
This set contains two current-production Tung-Sol 6L6GC-STR beam power tetrodes. The valve uses an eight-pin octal base, a nominal 6.3 V heater and carries a maximum plate-dissipation rating of 30 W.
BTB matches both output valves at a practical plate voltage of 450 V. The manufacturer describes the STR version as a rugged 6L6GC intended for audio and particularly musical-instrument amplifier applications.
Suitable applications
- Guitar amplifiers using a total of two 6L6GC output valves
- Hi-fi push-pull stages using one 6L6GC pair
- Stereo single-ended amplifiers using one 6L6GC per channel
- Complete replacement of an existing two-valve 6L6GC set
- New builds using a suitable output transformer and screen-grid circuit
- Equipment explicitly designed for 6L6GC operating ratings
BTB matching and package contents
- Package contents
- Two Tung-Sol 6L6GC-STR valves
- Selection type
- BTB-matched pair
- Matching plate voltage
- A practical 450 V unless the specific product states otherwise
- Test system
- Roetest V11, current as of 2026
- Parameters considered
- Plate current, transconductance, grid currents, plate resistance and acoustic checks
Technical data
- Valve type
- Beam power tetrode
- Type designation
- 6L6GC-STR Tung-Sol
- Base
- Eight-pin octal K8A
- Nominal heater voltage
- 6.3 V
- Heater current
- 0.845 to 1.06 A per valve
- Data-sheet test point
- 350 V plate voltage, 250 V screen-grid voltage and -18 V control-grid voltage
- Plate current at the test point
- 42 to 72 mA
- Screen-grid current at the test point
- 6 mA maximum
- Transconductance at the test point
- 4 to 7 mA/V
- Single-ended output example
- At least 8 W into a 4.2 kΩ plate load under the stated conditions
- Maximum plate voltage
- 500 V
- Maximum screen-grid voltage
- 450 V
- Maximum plate dissipation
- 30 W
- Maximum screen-grid dissipation
- 5 W
- Maximum cathode current
- 100 mA
- Dimensions
- Approximately 97 ±2 mm overall height and 38 mm maximum envelope diameter
- Country of origin
- Russia according to current BTB and manufacturer information
Pinout
- Pins 1 and 6
- No internal electrode connection according to the current data sheet
- Pins 2 and 7
- Heater
- Pin 3
- Plate
- Pin 4
- Screen grid g2
- Pin 5
- Control grid g1
- Pin 8
- Cathode and beam-forming plates
Comparison with 5881 and KT66
- 6L6GC-STR
- 30 W version using 6L6GC ratings
- 5881
- Related output valve with potentially lower voltage and dissipation limits
- KT66
- Larger related beam tetrode with greater heater demand and different characteristics
Selection and application notes
Matching does not replace bias adjustment. Check the quiescent current, plate dissipation and screen-grid loading of each valve after installation.
The 500 V, 30 W and 100 mA limits must not be exploited simultaneously without a complete load-line and dissipation calculation.
High transconductance and long wiring can encourage parasitic oscillation. Suitable control-grid and screen-grid stoppers and effective supply decoupling are important.
Power valves operate with lethal voltages and become very hot. Installation and bias work require suitable technical expertise.
Questions about selection and use
Is the Tung-Sol 6L6GC-STR BTB-matched pair suitable for a push-pull stage using two 6L6GC valves?
Yes, the Tung-Sol 6L6GC-STR BTB-matched pair is suitable for compatible push-pull output stages using a total of two 6L6GC valves. The heater supply, bias, plate and screen-grid voltages, output transformer and cooling must suit the circuit.
Can the 6L6GC-STR pair replace an existing two-valve 6L6GC set?
Yes, the 6L6GC-STR pair can replace an existing two-valve 6L6GC set when the socket wiring, bias range, heater demand and mechanical clearance match. A 5881 or KT66 is not electrically identical in every circuit.
Should the bias be checked after installing the matched 6L6GC-STR pair?
Yes, the bias or quiescent current must be checked after installation and correctly adjusted where the amplifier provides that facility. BTB matching does not replace adjustment for the actual operating voltage.
Note: All brand names mentioned, such as Marshall, Fender, etc., are registered trademarks of their respective owners and are used here for descriptive and compatibility purposes only.
BTB Elektronik Vertriebs GmbH Kepler Strasse 6
DE-90766 Fürth
Email: info@btb-elektronik.de
The EU Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (2011/65/EU = "RoHS 2") aims to exclude certain hazardous substances from electrical and electronic equipment or to restrict the use of certain substances in electrical and electronic equipment. These include substances such as lead, mercury, cadmium, and chromium, as well as certain brominated flame retardants and plasticizers. These substances may only be used in electrical and electronic equipment up to a maximum concentration limit, unless exemptions in the annexes to the directive permit their use under certain conditions. This can reduce and eliminate harmful substances and improve the recycling of waste electrical and electronic equipment. To find out whether the component you purchased from us is permitted in your device, please refer to the current directive or the current law applicable to your country. If you are a manufacturer, please feel free to contact us to find out whether the component you require can be tested and approved according to the current directives. We would be happy to assist you.
Fact sheet on EU Directive 2011/65/EURestriction of the use of hazardous substances in electrical and electronic equipment (PDF, not accessible, 2 MB)
Source: IHK Mittelfranken
Tariff Number: 85408100
Country of Origin: RU