Vacuum Tubes

  • Black Diamond Series
  • Replacement Kits
  • Look Up by Amp
  • FAQ
  • Private New Old Stock

Black Diamond Series Vacuum Tubes

TELEFUNKEN vacuum tubes have been the benchmark of excellence in all audio applications, both production and reproduction, for many decades. This rich history continues with the introduction of new production tubes from TELEFUNKEN Elektroakustik, in partnership with JJ Tubes from the Carpathian Mountains of Cadca in Slovakia.

Each tube is meticulously measured for all critical parameters of performance including transconductance, gain, noise, and microphonics. All TELEFUNKEN branded tubes are hand picked to be the best examples of Eastern European construction in the proud tradition with which the name TELEFUNKEN Elektroakustik has become synonymous.

In addition to the rigorous testing procedure, all new production TELEFUNKEN tubes are cryogenically treated to ensure durability, and subjected to an extended burn-in period to ensure superior stability. The tubes are re-measured subsequent to burn-in in order to guarantee that only the best, lowest noise tubes are offered for purchase through your TELEFUNKEN Elektroakustik reseller.

ECC83-TK (12AX7)

Developed by RCA and released in September of 1947, the 12AX7 is a high gain / low noise tube that is the most popular tube used in input / inter-stage audio amplifiers. The dual triode design makes the 12AX7 compact, relatively inexpensive, and produces a high quality full frequency response....

Read More: ECC83-TK (12AX7)

E88CC-TK (6922)

Also known as the 6922, the E88CC was originally targeted for test equipment and radar. The E88CC has medium gain, low noise and is a favorite for tight sounding audio input stages. There are some that will argue that the E88CC is the best sounding input tube ever designed....

Read More: E88CC-TK (6922)


The 6L6 was developed more than 70 years ago as the first power tetrode. It produced 19 watts of power, and was the first "beam power tube". The 6L6 was first developed as an alternative to the high output pentode designs, which Phillips had under patent at the time....

Read More: 6L6GC-TK


Tung-Sol developed the 6550 in 1955 for use as a servo amplifier and in industrial applications. Based on the 6L6, the 6550 was designed to have more gain than the 6L6, and better stability....

Read More: 6550-TK


The EL-34 is smaller in diameter and taller than the 6L6, but it runs on a higher plate voltage, which gives the EL-34 its unique output stage properties. The EL-34 is a high output pentode tube as opposed to other output tubes like the 6L6 and the 6550, which are beam tetrode tubes....

Read More: EL34-TK


Originally designed for the output stages of audio frequency amplifiers, the EL-84 can deliver up to 17 watts. Commonly found in smaller guitar amps, this pentode tube can really deliver. In many ways it is similar to the EL-34 but without the output "horse power"....

Read More: EL84-TK


The GZ-34 isn't a very talked about tube, but it is one of the most common rectifier tubes found in audio, especially in guitar amps. Rectifier tubes were some of the very first tubes to be invented since their purpose is one of the first requirements in electronic and audio design....

Read More: GZ34-TK

Tube Replacement Kits


TKIT-001 includes: 3 ECC83-TK, 2 matched 6L6-TK
Ampeg GVT52, Bugera V55, Egnater Tweaker 40, Fender 57 Bandmaster RI, Fender 59 Bassman LTD, Fender Blues Deluxe, Fender Blues Deville, Fender Hot Rod Deluxe




TKIT-002 includes: 3 ECC83-TK, 2 matched EL84-TK
Bad Cat Cougar 15, Bugera V22, Fender Blues Junior, Laney Cub-Head, Laney Cub12, Laney Cub12R, Laney IRT-Studio, Laney IRT15H, Laney TI15-112, Laney VC15-110, Marshall 1974X 18W, Vox AC15 Custom




TKIT-003 includes: 3 ECC83-TK, 4 matched EL84-TK
Laney L20H, Laney L20T-112, Laney L20T-410, Peavey Classic 30, Peavey Delta Blue, Vox AC30 Custom




TKIT-004 includes: 3 ECC83-TK, 2 matched EL34-TK
Bad Cat 50H, Bad Cat Cougar 50, Marshall 1987X 50W, Orange OR50, Rivera Jazz Suprema




TKIT-005 includes: 3 ECC83-TK, 4 matched EL34-TK
Carvin X100B, Marshall 1959HW 100W, Marshall 1959SLP 100W, Marshall JCM800 2203X




TKIT-006 includes: 2 ECC83-TK, 2 matched EL84-TK for Orange Tiny Terror



What is the difference between Black Diamond Series vacuum tubes and the JJ-branded tubes?

The TELEFUNKEN Black Diamond Series tubes are built in the JJ Electronic Factory in Eastern Europe based on their existing models. The Black Diamond Series tubes go through an extensive multi-tier testing and quality control process, as well as a cryogenic treatment in the USA to ensure they are the best representation of European made tubes. Each vacuum tube is burned in for 24 hours, tested for all critical parameters, cryogenically treated, and tested a final time. TELEFUNKEN Elektroakustik guarantees this by branding them with the legendary diamond logo.

What is the cryogenic treatment process?

After the initial 24-hour burn-in process, the Black Diamond Series tubes are placed into a cryogenic processor where a computerized system gradually cools them from ambient temperature to -300 F (-184 C), where it remains for 24 hours until slowly returning to room temperature.

What sonic differences will you notice with cryogenically treated vacuum tubes?

The cryogenic process is done for a number of benefits, both sonically and constructional. Cryogenically treated vacuum tubes have a lowered noise floor, less microphonics, expanded dynamic range with more tonal depth, and a more consistent tone for a longer lifespan. In guitar amps, Black Diamond Series vacuum tubes have more harmonic content and improved saturation, which results in a richer tonal quality and deeper overdrive character.

What effect does the cryogenic process have on improving the construction of Black Diamond Series tubes?

The cryogenic freeze process plays a key role in treating and strengthening the tube's internal metal construction. By bringing the tubes to these extremely low temperature conditions, the stresses of the internal metal structure from the high temperature manufacturing process are reduced and settled. This strengthens the construction as a whole. The cryogenic process also aligns the grain structure of the carbon in the metal to be more uniform, which yields a more efficient system with lower operating temperatures, longer life, and improved electron flow. The results are tubes with superior durability and stability. Preamp tubes offer expanded dynamics and a richer tone, while the power tubes are more stable and efficient.

What are the benefits of burning in vacuum tubes?

All Black Diamond Series vacuum tubes are burned in for a 24-hour period at real world voltages. One of the major benefits of burning in is to heat the cathode and remove any impurities or unevenness on the cathode coating. The cathode is the element in the tube that is heated and releases electrons. By burning the tube in, it reduces any popping, static sounds and erratic behavior. This is proven to benefit the vacuum tube's lifespan and durability.

What is the significance of the black ink on the new Black Diamond Series tubes?

TELEFUNKEN's Black Diamond Series tubes have been screen printed with black ink to clearly differentiate them from the original, white inked diamond-based TELEFUNKEN tubes, originally produced in Germany in the early and mid 20th century.

Can these Black Diamond Series tubes be used in TELEFUNKEN Elektroakustik microphones?

Black Diamond Series tubes have been developed for the Musical Instrument and Hi-Fi Audio markets and are excellent for use in applications like guitar amps, preamplifiers and power amplifiers. None of these tubes are currently used in TELEFUNKEN Elektroakustik microphone production.

Private New Old Stock

During the natural course of testing and development of TELEFUNKEN Elektroakustik microphones, no new model could be designed, tweaked, or manufactured to the exacting and consistent standards without a stable source of quality vacuum tubes.

Over the years the team at TELEFUNKEN Elektroakustik has tirelessly sought out large batches of the quality tubes necessary for a microphone and preamplifier manufacturing, and portions of these tubes are now being made available, in limited quantities, direct from the TELEFUNKEN Lab.

Each has been tested by the TELEFUNKEN Elektroakustik staff and will deliver the pinnacle of performance for whatever your application may be, from guitar amps to ultra serious audio reproduction amplifiers, the tubes from this private new old stock collection are sure to offer unparalleled performance.






General Electric
ECC81 / 6201

Originally made in the USA by General Electric, this tube shares the same EIA 9A type pin out as the 6201, 12AT7 and 6072a. Featuring gray wing style plates with copper grid posts and a halo getter, each tube has the original factory model of 6201 etched on the glass, with white ink featuring the GE logo and ECC81 model number. Originally intended to be an "industrial" equivalent of the US labeled 12AT7, the GE ECC81 sounds great in most pre-amplifier audio applications.


General Electric
JAN 12AT7WA / 6201

This early 1970s military spec General Electric [GE] 6201 [a.k.a JAN-12AT7WA] tube has gray wing plates with copper grid posts, extra support rods, and a large halo getter. The green label has the GE logo with "JAN-12AT7WA", designating that this tube was purchased by the US military. Overall, this American made tube is a step up from the standard 12AT7, and includes the original factory etched 6201 on the glass.


General Electric
JAN 5751

Based on the same pin out configuration of the 12AX7, the 5751 was designed with less gain in favor of lower noise and microphonics. Made in the late 1960's in the USA, the 5751 has a double mica and gray plates. Offering 30% less gain than the 12AX7, the 5751 can be used in the reverb driver and pre-amp stages of a guitar amp, allowing the amp to be pushed harder with a less aggressive, but balanced tone.


General Electric
JAN 6072a

The 6072a is best known in audio as the engine for some of the world's most famous microphones, like the AKG C12 and TELEFUNKEN ELA M 251E. The tube is a dual triode with relatively low gain in relation to a 12AX7 (the most commonly employed dual triode that conforms to the EIA 9A pin configuration). The General Electric version of this tube is best known for its low noise and low microphonic character, as well as a very clear yet "and sweet" tone when used in critical amplifier applications.



National rebranded tubes, mainly from the Mullard and Raytheon factories. The "WA" designation means that this VHF [Very High Frequency] dual triode is a select version that is deemed acceptable for military applications [meaning it passed the strictest quality control standards for excellence]. Originally made in England and intended for use in Television and FM Tuners as an oscillator, the National 12AT7WA features the original red ink printing on the tube, and the original tube box.


Philips ECG

The JAN (Joint Army Navy) Philips 12AX7WA are the last of the U.S. made military tubes produced in the 1980s. In the overdrive stage of a guitar amp they offer a creamy sound. Built to last, these tubes are excellent examples of later era Philips production, offering a lower noise floor and good tolerance for microphonics. Excellent for hi-fi and guitar amp applications.


Phillips ECG

There were several grades of 12AT7 type tubes. The suffix letters that follow 12AT7 designated this grading process. "WA" was a military grade tube; "WC" indicated that the US Army as well as the US Navy purchased the tube jointly. The Phillips 12AT7WC was generally used as both a driver tube in the pre-amp stage of a multi-stage amplifier as well as phase inverter applications in Class B [push - pull] amplifier circuits. Originally produced in the mid 1980s, these Phillips ECG tubes are made in the USA and ship in their original factory boxes.


Philips Raytheon

Manufactured in the USA, these high-quality sub-miniature pentode tubes are well known for their extremely low noise and low microphonics. The 5840, also known as the EF732, is featured in TELEFUNKEN Elektroakustik's current production models of the AK-47mkII and ELA M 260 microphones. These tubes are also often utilized in Class A/B and Class A Design circuits, offering a balanced and rich tone.



Funkwerk/Neuhaus RFT tubes were made in East Germany throughout the "Cold War" era. These are an especially rugged version of the 12AT7 and sound wonderful in microphone, pre-amplifiers and guitar amplifier applications. Various resellers have relabeled these tubes over the years. It is not uncommon to find these tubes labeled as Orion, Tungsram, TELEFUNKEN (without the diamond stamp on the bottom), Haltron, and Glotron to name but a few. The R-F-T ECC81 is the tube currently issued in the TELEFUNKEN Elektroakustik ELA M 251E, C12, AR-51 and AR-70.



The TELEFUNKEN EF-95 (Mullard-Phillips designation number) is also known as the 6AK5 in the US, and was produced in the former Soviet Union under the 6Zh1P designation. This 7- pin pentode tube was originally designed for Radio Frequency Amplifier requirements up to 400MHz. Though its initial design was for radio frequency applications, the EF-95 found its way into audio applications, primarily in tube microphone amplifiers. The first use of this tube is found in the Lomo 19A9 microphones built in the former Soviet Union. The most prevalent use is in the modern TELEFUNKEN Elektroakustik CU-29 ("Copperhead") microphone.


(non diamond base)

These American made tubes were originally manufactured by General Electric and are not to be confused with the German made equivalent containing the diamond notch between the pins at the base. Made to the highest standards for military and navy applications, the German made ECC801S was made to the strictest tolerance and became the tube of choice for German / Austrian "Brown Book" broadcast standard microphone pre-amplifiers. These TELEFUNKEN ECC801S tubes are rebranded 6201 tubes. Originally made in the 1970s after the production of these tubes stopped in Germany, this version of the tube has been tested to the strictest tolerances and relabeled by the Micronetic company in Switzerland. While they are not as quiet as original German made ECC801s tubes, they offer a similar tone and are an excellent substitute for your ECC81 or 12AT7.



The EL-34 is a high output "pentode" tube which was designed to replace the "pre-war" era EL-12 (which was originally designed by TELEFUNKEN in 1938). Mullard, a subsidiary of Phillips, originally released the EL-34 in 1953. TELEFUNKEN also produced the tube under license from Mullard-Phillips, and their version has become a favorite in guitar amplifiers due to the "sweetness" of its tonal character. EL-34's are most commonly used in pairs in a Class AB1 "push-pull" configuration. This EL-34 is found in many amplifiers that offer the "British tone", where the 6L6 is more commonly found in American made amps like those from Fender and Mesa Boogie. The TELEFUNKEN EL-34 is being sold as a matched pair.


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