Favorite 300B: Sophia vs KR

Murder of Crows- great flick!

Can anyone tell me if the Psvane and or Shuguang bTs are full WE spec compliant and if they can handle the high demands of the VAC Ren series amps?

Charles1dad- Pls send me an email [email protected], if you are interested in comparing the Takasukis and BTs to KR and/or AVVT We clones. I have a pair of each but my VAC takes 4 300bs, so they are "on the shelf" right now. With the need for 4 tubes, cost is an issue, so I'd love to hear how these compare. I understand that its likely to be system dependent, but what isn't. Anyways it would be a starting point.

Charles1dad- That be the beast (and I do mean beast...it made me recall the advice of one A'goner who said that the quality of a tube amp is very closely correlated to its weight, which, of course, correlates to the weight of its output xfrmrs.) Will be looking for your email.

OK, my vendor for the Shuguang BTs says he has 2 quads; one w plate current 48 mA, one w plate current 80 mA. Any thoughts on which might be best in terms of reliability/compatability w the Ren circuit. Kevin said he needed more info on measurement conditions which I am trying to obtain. Totally ignorant on any of this "ee" stuff so any help you can provide would be greatly appreciated.

My Ren 30 has the VAC branded 300bs so I'm pretty sure that I've got some untapped potential. From what I've read from VAC, I am concerned about the Sophia RPs in the Ren circuit. At $2K to retube, I've gotta be sure that they are not gonna go "poof" or worse yet, take out an OT if they fail. It really sucks that I only have a pair each of the KRs and the AVVTs (bought 'em when I have a Cary that used only a pair). Anyone got a pair or 2 of BTs they wanna swap?

Markus1299- Very interested in your results. I will tell you that I really liked the BT CV181s in place of the VAC branded 6SN7s.

Phaelon- Good idea, I should have thought of that. I do know that Kevin says that the tubes must be fully WE original spec compliant and I THINK he told me that mesh or carbon plates were not recommended.

Pdrehr- Got a response back from Kevin saying

We have one customer running the Treasure tubes in a pair of Signature 140's. If I remember correctly, the tubes labeled in the 70's will occasionally trip the 300B Sentry protection circuit. If that is correct, then perhaps the "48" tubes would be the better bet.

Comments anyone, before I order? Not trying to start a war, I am truly ignorant on these matters.

I will heed Kevin's advice, unless there is a strong reason not to, but Kevin was a little equivocal saying that the measurements needed to be put into context for him to be sure. The vendor has an impeccable reputation for honesty (even against his financial interests) and knows way more than I do about these matters. He said that in his experience w Shuguang and Psvane products:

cathode bias amps do well with the higher plate current tubes, and fixed (manual) bias amps generally like the lower plate current tubes. I've sold across those recommendations a ton of times, but if I saw any trend in regards to plate current, that was the one.

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So I thought I'd put it out there to get comments from people who understand the concepts behind this issue, which I most emphatically do not.

My VAC 300bs are marked 48 or 47, so that gives me SOME better confidence but not much if that can vary so much depending on the test conditions.