I had waxed lyrically about the Mazda 12AU7 tubes I tried. It is just the best tube I’ve tried so far, but I’ve only rolled a small number of tubes.
Well I found some Jan 6189W GE tubes for next to nothing (A$20 per tube would be conisdered cheap, surely). These were manufactured in July 1986. Reading about this tube, it would appear these were manufactured with reliability, robustness, and low microphony in mind.
Bung the tubes in. They will need to burn in, I guess.
Initial impressions compared against the Mazdas.
Smooth, but a slight hardness in the upper mid-range.
Sound stage L-R is truncated compared with the Mazdas.
Stage Depth appears to be the same as the Mazdas.
Treble is more muted than the Mazdas.
Bass is slightly bloated.
Deep bass is not as deep as the Mazdas.
Dynamics appear to be lesser.
Overall I would rank the JAN 6189W above the stock Psvane tubes supplied.
I understand these tubes are plentiful. My source in Melbourne has quite a stash. Peter is reliable too. He drove across town to drop the tubes off to me personally, he said he was in the area already!
I am tempted to buy a few more of the 6189W tubes as backup to the three sets of Mazda I already have. But alas Peter does not have any Telefunken 12AU7 tubes, or at least he hadn’t been able to find any yet in what I assume to be a fairly large hoard of tubes.
Message me if you would like Peter’s contact details. I may be slow to respond as I shall be away the front half of December. Sailing to NZ and back is fun!