12AX7 / ECC83 advice sought


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Nov 21, 2016
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I’m looking for tube recommendations.

Over the weekend I detected some distortion on one channel of my Jolida hybrid amplifier. It has two 12AX7 / ECC83 tubes.

I have replaced both tubes with Raytheon NOS (stamped made in Japan) that were kindly supplied by Tonetubes- who have many different tubes on offer. And from past experience have been a pleasure to buy from.

Now I want to seek opinions from anyone who “knows” 12AX7s. Which ones might sound good.

Here’s my humble experience.

The amp arrived with Sovtek LPS installed. I have no idea of the age. Good bass, slightly woolly mids and tops.

Amp also came with a recent pair of Mullards. Not NOS. Sort of okay, nice mids - but a few months later one started distorting. I donated these for use as guitar tubes (where distortion is desired). They were tested and one was dud.

Then had a potentiometer in the amp replaced as it was not possible to bias to specification (Jolida USA kindly sent me the bias process and circuit diagram for my amp). Albertronics did a fine repair on the pair of pots.

Then I installed Genalex Gold Lion 12AX7. Bass not quite as punchy as all other thus far tried. But mids and treble were very nice. These were enjoyed for nearly three years so I probably got close to 10,000 hours until one expired- no complaints.

So I have just re-installed the Raytheon tubes. And the bass is punching again. And thoroughly enjoying some music through them. But that Genalex sweetness is not quite there- particularly in the tops. So I want to know what you valve fundis recommend.

Please no weird suggestions for NOS unobtainiums at inflated prices. Been there, luckily I was warned by a kind forum member. That rascal didn’t get a cent from me. I’m tempted to try a new set of Sovtek LPS . But any other recommendations?