TELEFUNKEN 6L6GC-TK Vacuum Tube Matched Quad

Product overview

The TELEFUNKEN 6L6GC-TK Vacuum Tube Matched Quad is the Black Diamond Series 6L6GC, an octal power tube with tight lows and a shimmering high end, supplied here as a matched quad of 6L6GC-TK tubes.

The TELEFUNKEN 6L6GC-TK has tight and defined lows, transparent mids and a shimmering high end. Installed in an amplifier, these octal power tubes offer a focused bite with well-defined articulation.

Octal power tube	6L6GC
6L6 introduced	1936
Tubes in this product	4
Treated, tested and burned‑in	Cryogenic

Key features

• 6L6GC octal power tube (power tetrode)
• Tight, defined lows, transparent mids and a shimmering high end
• Focused bite with well-defined articulation
• Top-end sparkle and clean headroom
• Breaks up later than the EL34 and EL84
• Black Diamond Series: rigorously tested, cryogenically treated and extensively burned-in

The 6L6GC-TK sound

Introduced in 1936 as the first power tetrode, the 6L6 is most associated with American sounding amplifiers, and its modern version, the 6L6GC, dominates the guitar amplifier market. In comparison with the EL34 and EL84, the 6L6 tends not to break up as quickly.

A long-running design

With its top-end sparkle and clean headroom, there is a reason the 6L6 has had one of the longest active lifetimes of any electronic component. The Black Diamond Series 6L6GC-TK carries that character in a newly produced, cryogenically treated tube.

Applications

• Two-tube guitar amplifier: guitar amplifiers with a pair of 6L6GC power tubes, for clean headroom
• Four-tube guitar amplifier: larger guitar amplifiers with four 6L6GC power tubes
• Clean stage tone: players who want sparkle and clean headroom on stage
• Studio backline: studios keeping their 6L6GC amplifiers session-ready
• Live sound and touring spares: backline techs carrying replacement power tubes
• Rental inventory: rental stores retubing amplifiers between bookings

Black Diamond Series

TELEFUNKEN Elektroakustik Black Diamond Series vacuum tubes are new production tubes, manufactured in partnership with a specialist vacuum tube factory in Slovakia and designed to be harmonically rich and tonally balanced. Each tube is rigorously tested, cryogenically treated and extensively burned-in before it carries the Black Diamond name, so the 6L6GC-TK arrives ready for the most demanding applications.

This configuration: Matched Quad

This product is a Matched Quad: four 6L6GC-TK tubes matched by TELEFUNKEN and supplied together as one set. Keep a matched set together in the four positions of the same circuit.

Fitting and care

Always switch the equipment off, unplug it from the mains and let the tubes cool completely before removing or fitting a tube. Fit the 6L6GC-TK only in a socket specified for the 6L6GC, keep each tube in the position of the one it replaces, and press it straight and fully into the socket. Power sections hold high voltages, so leave any work inside the chassis, including any bias adjustment the amplifier requires, to a qualified technician. After fitting, let the equipment warm up and listen at low volume first. Store spare tubes in their packaging, protected from knocks and moisture.

What's included

Included	Four TELEFUNKEN 6L6GC‑TK vacuum tubes (matched quad)
Not included	Amplifier or equipment, sockets and installation, bias adjustment

In the box

• Four TELEFUNKEN 6L6GC-TK vacuum tubes (matched quad)

Vacuum tubes are glass components: handle them by the glass envelope, avoid knocks and keep them in their packaging until fitting.

TELEFUNKEN 6L6GC-TK Vacuum Tube Matched Quad: frequently asked questions

How does the 6L6GC-TK sound?

TELEFUNKEN describes tight and defined lows, transparent mids and a shimmering high end, with a focused bite and well-defined articulation.

How does it compare with an EL34?

TELEFUNKEN notes that the 6L6 tends not to break up as quickly as the EL34 and EL84, with top-end sparkle and clean headroom.

What does Black Diamond Series mean?

It is TELEFUNKEN Elektroakustik's range of new production vacuum tubes, designed to be harmonically rich and tonally balanced; each tube is rigorously tested, cryogenically treated and extensively burned-in.

Do I need a technician to fit it?

Fitting is a straight swap in the socket, but power sections and rectifier circuits hold high voltages. Where an amplifier has adjustable bias, have a qualified technician check it after fitting new power tubes, following the amplifier maker's instructions.

How many tubes are included?

Four tubes, matched by TELEFUNKEN and supplied as one set (Matched Quad).

Where can I buy the TELEFUNKEN 6L6GC-TK Vacuum Tube Matched Quad in India?

The TELEFUNKEN 6L6GC-TK Vacuum Tube Matched Quad is available from Shivansh Electronics, Kolkata, West Bengal, India, with delivery across India.

Workflow 1: Two-tube guitar amplifier

Guitar amplifiers with a pair of 6L6GC power tubes, for clean headroom.

Connections

Connect	To
6L6GC‑TK	The two 6L6GC power tube sockets

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.

Tip: Keep the matched quad together in the same circuit.

Workflow 2: Four-tube guitar amplifier

Larger guitar amplifiers with four 6L6GC power tubes.

Connections

Connect	To
6L6GC‑TK	The four 6L6GC power tube sockets

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.

Workflow 3: Clean stage tone

Players who want sparkle and clean headroom on stage.

Connections

Connect	To
6L6GC‑TK	6L6GC power tube sockets of the stage amplifier

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.

Workflow 4: Studio backline

Studios keeping their 6L6GC amplifiers session-ready.

Connections

Connect	To
6L6GC‑TK	6L6GC sockets of the studio amplifier

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.

Workflow 5: Live sound and touring spares

Backline techs carrying replacement power tubes.

Connections

Connect	To
6L6GC‑TK	Spares case, then the 6L6GC sockets of the touring amplifier

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.

Workflow 6: Rental inventory

Rental stores retubing amplifiers between bookings.

Connections

Connect	To
6L6GC‑TK	6L6GC sockets of the rental amplifier

Setup

1. Switch the amplifier off, unplug it from the mains and let the tubes cool completely; power sections hold high voltages, so leave work inside the chassis to a qualified technician.
2. Note each position, then gently rock the old 6L6GC tubes straight out of their sockets.
3. Fit the 6L6GC-TK tubes with the pins or key aligned, pressing each fully home, and refit any retainers.
4. Power up and let the amplifier warm up; have the bias checked by a qualified technician where the amplifier requires it, then check the sound at low volume.