Favorite 300B: Sophia vs KR

Thanks to all of you for your participation in this valuable thread. I am enjoying all of the comments and posted some earlier and will only say the Takasuki's are still my favorite with my amp. thus this comment is a bit off course and adds nothing to the fact of any further sound re-inforcement of these tubes.

Since we are all talking so much about the high cost of these tubes (along with the great sound) I will share with
you that my amp. designer (Gary Dews from England) gave me a hint that in his experience (and some of his long-time customers) he has noted an "increased" life to any 300b tube if you have an adequate way to cool them......obviously this makes total sense.

He suggested I pick up a low voltage/low noise fan that is capable of moving some air from the back of the amplifier and blow onto the tubes. I thus have purchased a small computer tower type fan (4 X 4 X 1 inch) that is rated at very low noise and plan on configuring it (in an easily removeable way) on the back base of my amplifier to blow air across the tubes when in use to move air. My little fan is rated at 33DB noise and 56CFM so we will see. I also picked up a 72 inch power cord that has an variable speed control for the fan.

Everything I have read states you have to be 3-4 feet anyway to even hear it running so we will see. The key hear is to get one that moves some air yet is rated very low noise and they are out there and mine will be adjustable.

No offense but I paid $20 bucks for this experiment and what could it possibly hurt? The little fan is supposed to be here soon and if nothing else it will ease my guilt of trying to extend the life of the 300B tube which is a topic in itself.

Some of you might think I am lost in the wilderness but maybe some of you have already experimented and it would be nice to know if so.

Gwalt,
Your plan makes sense to me. The builder of my amp designed the circuit to be as he says "very easy" on the 300b tubes to greatly extend their lifespan. He alo used large over-speced transformers. Even when the amps are on 12-16 hours the transformers are warm but never hot to touch at all.
I hope the fans work out for you.

Jwm was you post aimed at mine? I never mentioned solid state? My equipment is all tube based.

Charles1dad:

Thanks for the reply. I forgot to mention I have no real detection of running the tubes hard in the circuit as I think both of our amps. qualify as over built.

My transformers do not even get warm to the touch after 12 hours but the base of the tubes are warm and I think the theory is if you keep the tubes cooler you tend to re-tard the damages that internal heat can do.

I run the tubes @ .68ma which is considered approximately 65%-70% of full output.

It's been noted that the participants of this thread have laudably avoided engaging each other in divisive battles of defensiveness. I think that’s due, in no small part, to Charles1dad’s leadership role. I’m saying this because I don't want anyone to think that this is a response to the consensus that Takatsuki is superior to the Royal Princess. I’ve never heard the Takatsuki’s so I can’t speak to that at all. But I’ve decided to share something that I wasn’t going to share because I thought it it might sound like some kind of sour grapes. That, and the fact that it just seems goofy to me. It’s simply this: The Royal Princesses have a very, very long break-in period and RP buyers will have to be extremely patient to hear these tubes at anywhere near their best. We’re not talking about the kind of break-in where you’re almost there after a 100 hours with only subtle improvements to follow. I bought these tubes in February 2011. I wish I had logged usage hours but I’m going to estimate fifteen hours a week. Last month there was a unexpected and startling improvement in my system’s performance - I did not jump to the conclusion that it was the tubes. I think we’ve all experienced those inexplicable “good music days”. But after a week of listening to CD after CD, the fact is, that there was an unmistakable and very significant improvement in detail, resolution, and coherence, particularly noticeable in the lower mid-range and upper base (sorry fellas, I can’t speak to real base because my speaker’s frequency response starts rolling off below 50Hz). I haven't changed or altered anything in my system or room since inplimenting the RPs. I reluctantly called Richard Wugang at Sophia - reluctantly because I thought it was nuts to think there might be a really significant improvement after all this time. I asked him if it was possible to have real break-in occur at 800-1000 hours. He said it was possible but very unlikely to take quite that long. But he elaborated that there are other influences, for instance, the duration of the listening sessions and the amplifier’s demand on the tubes. Richard went on about carbon plate vs. metal plate break-in. He said the RP carbon plate typically needs a minimum of 400-500 hundred hours in a SET application and considerably more in a push-pull (big "ah-ha!" moment since my amp is a push-pull). He admitted that it’s been a problem getting customers to demonstrate that kind of patience, but that when they do, he will put these tubes up against any 300b on the market including the Takatsuki which he claims benefits from a relatively short break-in period. That of course is where that subjective thing comes in. But the one thing that I can definitely verify about the Royal Princesses, is that after 13 months of nearly daily use, there’s been a startling improvement in all of the music I’m playing. Once again, the intention of this post is, in no way, meant to rebut the magnificent reports on the Takatsuki 300b - I believe every word of them. I just want to alert those, who more recently purchased the Royal Princess’s, that the best is yet to come.