Amperex 12ax7 Angled Foil getter Posted on November 28, 2020 by tubemaze (10 votes, average: 3.80 out of 5)Loading...No reviews found on the web. Read our reviews.Share this post:
This is one of the earliest European 12ax7 tubes. Produced by Amperex/Philips and predates Mullard  getter tubes. The tubes have been produced between 1951 and 1956 and come with date code that is printed between pins – I saw it with mP1 and mPC codes. There are a lot of unusual things about the tubes. First of all, the tubes has welded plates instead of riveted. This is more expensive, but at the same time reduces micro-vibrations. The getter is attached directly to the plate and angled at 45 degrees. Then the tube has a similar getter with foil strip as the later tubes.
The sound is a perfect example of Philips tubes of that era: Very delicate, a bit slow, highly euphoric. It is the most delicate sounding 12ax7 that I’ve experienced. This is definitely not a tube for all types of music – the best example would be vocal jazz to truly highlight the strengths of the tube. Rock wouldn’t be good as the tube is not dynamic enough for that genre.
Back in the days they really didn’t spare any costs and it’s evident by the noise floor of this tube – it’s measuring at practically impossible -90 dB level!!! Regular 12ax7 tubes measure -82-83 dB (remember the dB scale is exponential, so this would be around 2 times quieter than regular 12ax7).
Oh man, what an amazing tube! Honey sweet mid-range. Euphoric as all get out. A bit of a softened, yet oddly ultra realistic top end. Glorious bass. The little bugger just sings. I have a quad of rare Mullard made with Amperex labels. “Gt. Britain”. Faded Amperex globe. Date codes faded and all but unreadable. 1966 or 1968 production, maybe. A bit slow for some (though by no means all) rock music. Great for punchy R&B. Female vocals soar. (Sinead O’Connor’s “Last Day Of Our Acquaintance” plays as I type. Wow!) This may well be the most unique and satisfying sounding 12ax7 I’ve ever enjoyed. By the way, Matsushita made a decent (less than equal but still nice – not to mention more affordable) copy/clone.