300b vs 845

Artg,

Thanks for you comments. Those Nagra VPA's are great amps, which I'd really love some day to put head-to-head with mine. It wouldn't surprise me if the Nagras would win.

You're right about the KR tube. It is a peculiar beast and in fact I have elected to shun it in my own amps for sustained use. Audion does offer it as an extra-cost upgrade and the factory speaks highly of the tube. I have had zero trouble with the very affordable Shuguang tubes, and the new metal plate is so desirable, even at 25% less power, that I haven't felt any need to spring for hyper-cost tubes, current or NOS. I think the 845M is a breakthrough and I'm really eager to buy a pair of the further upgraded metal plate version that appears imminent from superTNT.

The 845 requires a challenging high-voltage circuit to build which I think explains why some of the entry-level amps sound unmusical when built to a price point. You have the opposite - amps built to a quality point, and I am sure you enjoy them every minute they have glow in their tubes.

Phil

Thanks for the very kind words, Phil. I am enjoying the VPA's very much these days. In fact, i will be receiving dsome NOS 12AX7's and E182CC's to drop into these puppies today! I cant wait. Thanks also for the tip on the upcoming SuperTNT 845M. I will be buying them also.

Have any of you folks tried Pearl tube coolers on the 845s?

I concur, thanks to Phil for an excellent summary of his vastly greater valve experience than mine. i have just as it happens, installed the 845B valves in my Solista and am very impressed. I don't know if I would describe it as darker, but the base was the first thing I noticed. The amp audibly goes deeper and I believe the treble is better defined too and with better imaging too. i am tempted by the 845M valves, but I'm told they shine like searchlights and my wife is already muttering darkly about the heat from the Solista. I think anyone taking the plunge needs to take the greater heat with 845 based amps, into consideration, it really makes Summer use problematic.
Excuse me if I bang on about the Viva amps, but they are not as well known as they deserve to be. I believe a review by Art Dudley in Stereophile is imminent.

I meant to make it clearer that the Chinese graphite plate 845s, both the A and B, are darker sounding than the vintage NOS, KR and metal plate variants, which are in turn quite different from each other. If you've never heard anything other than the contemporary Chinese graphite plate 845s, then the 845B sounds as you describe, David. The 845M does light up a room, but I don't experience any more heat output than the 845B. It's just that the glow is more shrouded by the graphite plate configuration. They both get hot but if you've dealt with the heat issues for the B tube, the M will be no worse.

By all accounts the Viva 845 is excellent. I haven't heard it.

Phil