Favorite 300B: Sophia vs KR

Update: It's still early to judge, but I like what I'm hearing. I thought I would. Only one problem; there was a noise issue with one tube so Sophia generously replaced with a free upgrade to the ceramic base. And unfortunately to my astonishment that pair seems to have an issue also (one channel is louder then the other, or possibly the other is lower in volume). All I know is that the loudness is unbalanced between L&R channels and it follows the tube when switching between monoblocks. Sophia wants me to give it 100 hrs and hear if it changes. Otherwise, replacement #2.

I ordered a matched quad. Setting the bias of my amplifier to its minimum setting, I still can't achieve the amplifier's recommended bias. Sophia said they are willing to test for lower emission tubes to meet my amps specs, but that these tubes will actually be more satisfying. I'm trying to do a little research that will aid in my decision.

My amps have no manual bias control. Did you order the Black or Ceramic base?

I want to add that Sue at Sophia has been most gracious and accommodating. If this were KR or another I think the situation would be quite the opposite. ;-)

@Sakahara

I wouldn't judge KR bad so fast, unless you have had that experience already...

May I ask you which Sophia's did you buy? Thing is, at least with TJ's, where Sophia's are coming from, that the less expensive pairs aren't that good with keeping the bias and that's very well known problem with them, however Sophia's suppose to have much better quality control. I owned ceramic based Mesh plated, but the most expensive from their line with 1 year warranty and never had any issue with bias or unbalanced L&R.
I sold them and probably will never buy again, KR and AVVT's are my reference now. My next pair, probably, will be KR Balloon 300B, which seems to be better than reissue WE's and they are USD 525 a pair with 2 years of warranty http://www.kraudioproducts.com/Kr/ProductDetail.aspx?CatID=13&ProductID=3

Dont get me wrong guys, but most Chinese tubes are trash and the very small production line, which are also very expensive, are one to get, but than again, even Sophia's so called Mesh aren't really Mesh at all. I say, buy tubes from manufactures who developing and producing good quality tubes, support them instead of some who don't develop a single thing and just re-brand and re-sell.

Thanks for sharing and good luck.

Maxmad,
You raise an interesting point, there`s a big difference in quaility (sonically and built) between the lower/mid price chinese 300b and the premium models. This is why earlier in this threat I`d strongly recommended the Shuguang Treasure Series or the TJ Full Music SE 300b. Yes they`re more expensive but are far better sounding and also extremely reliable.
The KR tubes sound very good, but for a number of audiogon users(read previous threads on this topic) have been unreliable. My amp`s(Coincident) builder Israel Blume stopped using these tubes(he liked the sound)due to poor support by the company for replacing bad tubes, I hope your experience is different. Audiogon member Montejay formerly used both the TJ carbon plate(Sophia) and the KR balloon 300b and reported the Shugaung Treasure tube was an upgrade YMMV.