Hitachi 12ax7 Long plates D-getter Triple Mica Posted on February 10, 2013 by tubemaze (12 votes, average: 3.58 out of 5)Loading...No reviews found on the web. Read our reviews.Share this post:
This is one of the rarest tubes out there. It’s a regular Hitachi tube with with a bonus, triple mica that separates getter and the grid rods completely. A lot of people believe that third mica is just for reduction in microphonics – that’s correct, but the benefits do not end there. One of the biggest benefits of third mica is that it protects grid rods, heater and second mica from the results of getter explosion. Because getter material contains metals like barium and strontium any deposits of this metals on mica changes chemical properties of mica and current (no mater how miniscule) can pass between elements of a tube. So if there is 3rd mica, 2nd mica is protected from the deposits and stays “perfectly” resistive to currents. So without going too deep into how and what, let’s focus on what – the result is that tubes with triple mica have much better transparency and amount of details.
Hitachi is not an exception – not only it is the only 12ax7 with triple mica, but it’s the only tube with long plates with 3 mica. Very cool tube. Sound wise, the tubes is very transparent and very airy, but somewhat analytical to my taste – this tube is quite similar to Telefunken in sound qualities. RECOMMENDED.