Tube rolling on the M1200

This morning I exchanged a bunch of new budget JAN GE 12AT7WCs and some used tubes for 5 pairs of tubes - a pair each of Mazda, Tronix, Belvu, and 2 pairs of the Miniwatt Dario. All of the tubes I acquired are used but were measured there and then, 4 pairs classfied as Grade A, a pair of the Darios graded B.

The Mazda kills the stock Psvane 12AU7-S.

Mid-range was fuller. Soundstage deeper and more precise. Bass is deeper and better defined. The tympani actually sounds like a tympani.

Prima facie, it looks like an unequal barter, but in reality it wasn’t. The JAN GEs I’ve tried to sell but no takers. The other tubes were well used so would be difficult to move on.

I’m happy with my trade. The M1200s sound like altogether a different amplifier, and a much better one too, at that.

I’ll tube roll through the other unlikely suspects and report back in due course.

On the basis of my trial with the used Mazdas, I’ll be confident to buy a couple of sets of NOS tubes.

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Do you know if your Mazda tubes were made in France or made in Germany?

Have no idea, sorry. I don’t even know if the Belvu’s are French or German either. I understand the Belvu’s are also Mazda.

All I know is the Mazdas are better than the Psvanes.


I have some Mazda 12au7 that were made by Telefunken, not Mazda, and they sounded very nice in M1200. Both NOS Mazda tubes are hard to find.

Mazda/Belvu tubes are French made I’m pretty sure.

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The Mazdas, one went kaput. Now using the Belvues. As good, if not better. Quiet. Nice.

Have some Ensemble Tubesox to try. Will report back.


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