Favorite 300B: Sophia vs KR

Hi Maxmad, I’m a happy owner of the Sophia Royals. I won’t disagree with your findings, which I couldn’t do anyway because you compared them to tubes I haven’t heard, but I’d like to say that 213 cobra’s points are very well stated. I’ve heard a variety of tubes demonstrate their sonic signatures very differently in different amps. I have a friend who is almost constantly modifying and tweaking his tubed components. After a modification, like cobra, he frequently winds up exploring his inventory of tubes and finding that a former reject now fills the bill.

A caution:
In a conversations with Sue from Sophia, she expressed great frustration with the number of Sophia counterfeits floating around.

Maxmad,

I can say that I would never recommend matching Sophia mesh (really, perforated) plate 300Bs with Cary amps. That's doubling down on the same basic sonic aberration. If someone likes that combination, one can't argue with that, but it would be a piling on of the same euphonic colorations that obscure what you value.

I have a pair of KR VV302 Blue glass that sound beautiful and bell-like in some amps, yet hard and overbearing in others. I also have the older KR Enterprises straight tube 300B with the AVVT-like interior structure. Those tubes have strong, vivid transient clarity, probably the firmest bass of any 300B I have, and good top and bottom extension. But in amps I've used them in, their spatial presentation is great in height and width but cmparatively limited in depth. I'm aware of the Takatsuki but haven't tried/heard them yet.

The Shuguang Treasure 300B has been unfailingly good in every amp I've heard them in, albeit a more modern sound than the typically vintage mesh plates. The current production KR AUdio balloon glass 300B nicely resolves a lot of the spikey differences between all these tubes. For me, a polar graph of its relevant sonic attributes is close to a circle in most amps. My mesh plates sound sensational in my re-capped Audion monoblocks, but I consider that a highly-specific match arrived at by chance since they didn't happen to be in the amp when the caps were chosen and installed.

I will say the Sophias were much less expensive when I bought them. But so were KRs. About $900/pr. now for the KR Audio 300B in the US. Partly a result of the dollar's slide and partly result of that company and its distribution chain realizing they had to own up to the true costs of running a business. In all this discussion, interesting that this decade's production of the WE 300B isn't in the mix.

Phil

Phil,
I must say I really agree with your observations. I `ve come to believe that ranking the performance of 300b tubes is not possible due to the many variables such as the ones you mentioned. Certain 300b tubes just seem to match better with different amplifiers based on circuit, passive parts,transformer, power supply design etc.

It can get expensive after a while trying numerous tubes in the higher quality range. If I come across a AVVT,EML or other highly regarded 300b for a reasonable cost I`ll give them a try. Otherwise the Shuguang Treasure is a wonderful mate with my Coincident Frankenstein, so I`ll leave well enough alone for now.
Best Regards,

I suppose the notion implied in my initial reply here, but left unsaid in a direct sense, should be expressed unequivocably:

The differences between power supply capacitors in an amplifier have, in my long experience making this change in push-pull tube and SET amps, been greater and more musically influential than the differences realized between any two alternative tubes. That's right, and I'll say this power supply cap difference is, further, much greater sonically in SET amps than in push-pull. Now, I'm not talking about mods that change the total power supply reserve in total capacitance. I'm citing changes in electrolytic capacitor construction between brands (or models in the same brand), that leave the total power supply reserve quantitatively unchanged from stock. I had the same experience with recapping my 845 SET amps.

It's not a convenient plug'n'play change like tube rolling, so not DIY accessible for most. But everyone should understand that recapping can introduce improvements (or if not chosen well, changes of the better OR worse kind) that can dwarf the results from changing tubes.

Another way to think about it: After my Audion Golden Dreams were recapped by Hovland, their performance with the cheapest, most prosaic $20 Chinese solid plate 300B everyone ships as stock, was better than their sound with my most exotic, scarce and expensive 300Bs prior to replacement of capacitors.

Bob also loaned me a simple Glow amp (5w, SE, EL84) that he recapped and made a few other small circuit changes to, as an experiment and to ask my opinion. I could get reasonable dynamics and SPLs from it on my 101db/w/m Zu Definition 2 speakers, and my Zu Druids. Within its clean dynamic range, the little Hovland-modified Glow wiped the floor with a number of $1500 - $5000 amps I put up against it, musically. And compared to a stock Glow, which is a well-liked tyke of an amp, the modded version was transformed, musically. No change in power tubes from among many I had on hand could remotely approach the difference.

Phil

Another example, numerous builders of 300b amplifiers say the type of driver tube chosen has as much if not more affect on the amp`s sound than the type of 300b output tube selected.