Audio Reviews
on ECC83 12AX7 Pre amp tubes.
Essentially there are only 3 major tube manufacturers
remaining in the world today. We decided to put the
3 most popular tubes manufactured by these plants to
the test. Audio tests were carried out firstly in a
Rivera 100W 212 combo and then in both driver and pre-amp
stages of a Leak 20/20 Hi Fi amplifier.
Electro Harmonix (Russia).
First up is the Russian ECC83 from Electro Harmonix.
We found these tubes, on average to have the highest
gain of the 3 types under test. Clean, the tube seemed
reasonably balanced with a tendency in High frequency
emphasis but not brittle in any way.
In our Hi Fi amp test we noticed the cymbals and stringed
instruments projected really clearly. When overdriven
in our guitar amp the tubes broke up nicely and relatively
easily compared to the other tubes under test. Driven
more and the tube sang with a sweet spot around the
upper mid frequencies. Definition was good but not the
best of the 3 tubes under test using severe overdrive.
These tubes produce a classic 'Marshall' sound.
JJ Tesla (Slovakia ~ Europe).
Second tube under test is the European JJ Tesla ECC83s.
This is a relatively modern design and has been recently
upgraded to include a humbucking heating element. The
idea of using a anti phase spiral heater is to reduce
the mains hum cross talking onto the valve plates hence
giving a much quieter tube at high gain. This tube was
warmer than the Electro Harmonix. The mid range was
amongst the smoothest we have heard to date when played
clean.
Driven into crunch the tube breaks up nicely. Driven
hard we found that instrument definition retention was
amongst the best. The tube did not display quite as
much bass as the other tubes under test but was really
refined in the mid range. This tube would work well
in taming down those harsh and brittle amplifiers offering
a classic warm tone. Fantastic clean and very quiet
in overdrive and high gain settings.
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