ECC83

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ECC83 from the Slovak manufacturer JJ Electronic
ECC83 of Valvo and one as Marshall called
Anode current characteristic with grid voltage as a parameter

The ECC83 (American designation: 12AX7 ) is an electron tube (double triode ) that was primarily designed for low-frequency applications. It was developed by RCA in 1948 . The composite tube has two independent and electrically identical triode systems in a glass bulb.

Special features designed for use as audio amplifiers are their low noise, low microphony and high internal resistance of 60 to 80 kΩ. The ECC83 serves as a pre-phase and phase reversal stage in tube amplifiers . It is still produced today in larger numbers.

Meaning of the designation ECC83:

heater System type System type of the 2nd system Socket type Grid characteristic
E - 6.3V C - triode C - triode 8 - Noval socket 3 - serial number

(Designation scheme see also electron tube )

Technical specifications

The connection of the two filaments is brought out, so both triode systems can be operated either with a heating voltage of 6.3 V with a heating current of 300 mA or with a voltage of 12.6 V and a current of 150 mA.

Recommended static operating point (per system):

Anode voltage Anode current Steepness Grid prestress
250 V 1.2 mA 1.6 mA / V -2V

Different operating points can be found in the characteristic curves.

Limit values:

Anode voltage Anode power dissipation Cathode current Grid prestress Filament-cathode tension
300 V 1 w 8 mA -2V 150 V

useful information

Grid turns of an ECC82 (above) and ECC83 (below)

Some current versions, such as the J / J variant shown above, have a completely different mechanical structure than the original design: They are built with a tensioning grid and therefore look more like an E88CC / ​​PCC88 or other VHF double triodes with this technology.

The types ECC82 (12AU7) and ECC83 (12AX7), which appear visually similar to identical, can be distinguished in backlight by the mesh size of the grille through the peephole in the anode: the ECC83 has a much more closely wound grille coil. This leads to less penetration , a higher internal resistance and, with the same anode current, a higher slope.

Tetrodes and pentodes also have a high internal resistance and steepness, but are less suitable as preamplifiers due to the current distribution noise.

The ECC808 is a variant of the ECC83 with lower microphones and hum sensitivity and a different socket circuit.

The E83CC is a variant of the ECC83 with a long-life cathode (special cathode without an interlayer), it shows stronger flicker noise than the ECC83.

The ECC803S (Telefunken) or 6057 is the variant of the ECC83 for professional use (long-life cathode and narrower tolerances), it is designed using tensioning grid technology. However, this does not apply to the currently available ECC803S from manufacturer J / J.

A Russian / Soviet variant of the ECC83 is the 6Н2П (Latin 6N2P ), which only allows 6.3 V heating and has a shield plate between the systems.

Web links / individual references

  1. ↑ http://www.jj-electronic.com
  2. ↑ Archive link ( Memento from October 18, 2013 in the Internet Archive )
  3. ↑ http://frank.pocnet.net/sheets/030/e/ECC83.pdf
  4. ↑ Telefunken: Tubes and Semiconductors, 1959 edition, page 39f
  5. ↑ http://www.jogis-roehrenbude.de/Leserbriefe/Rabus-VV/rausch/rauschc.htm middle
  6. ↑ Archive link ( Memento from December 18, 2015 in the Internet Archive )
  7. ↑ Archive link ( Memento from December 25, 2004 in the Internet Archive ) Data sheet ECC803S / 6057 with example circuits and a lot of operating point data