Cayin A 300B

Thanks for your comment Pryso. 
I also own a Cayin - the MT 45 Mk2. It's also a push-pull using KT88 valves. 

Like you said, Cayin products are precious gems. Build quality, design, the small details and of course the sound. Everything excels!

I live in China, near by the place where they are made. Together with Line Magnetic, these are the greatest "bang for buck" I've ever seen. To get the same quality on other brands, one would have to pay much much more (especially here, where local products are so cheap).

I bought my amplifier one year ago and the choice was conditioned by my budget. In the same shop they sell all the Cayin line and also the Line Magnetic products. At that time I fell in love with the Single Ended from Line Magnetic, but money issues pushed me to my more modest Cayin. 

Now my situation changed and I'm planning to move to a SET (I really prefer the SET sound). I intend to go to the shop again to audition 3 amplifiers: the LM 518; the LM 219 and the Cayin A300B. 
There are many articles and opinions about both LM amplifiers, but only one review about the Cayin SET (from Stereophile).

The ride to the shop takes me one entire day, that's why I'm trying to get more opinions from people who have experienced this Cayin. 
But in the end it will be my ears deciding, with all the three amps lined up for an audition. 

Thanks once again!

I believe the same, Coolhunter, no need to reinvent the wheel. Cayin products prove that a classic approach works great if you put a lot of care and the best parts together. I'm very happy with the quality of my small Cayin and the sound is also great. But I do prefer single ended to a push-pull. I will happily move to another Cayin amp (the 300B) if it stands up against the Line Magnetic SETs. 

I totally forgot about this thread, but since Mozartfan revived it, here goes my follow up:
Some time after I started this thread, I went to audition the Cayin 300B. Didn't like it. Like all Cayin products, the amplifier was gorgeous and very well built, a work of art! But I found the sound to be lazy and too warm; sluggish. Was missing some spark, some crispiness - for my taste.
By the same time I also auditioned some amplifiers from Line Magnetic and my choice was clear, my favourite one was the LM 805 ia. I really like everything about this amplifier, especially the sound. And I was almost pulling the trigger when a fantastic deal came around: I got the bigger sibling, the LM 219ia for half the regular price. Even though this huge beast wasn't my favourite, I couldn't let it pass. So I bought it and I was very happy for some time. Until I discovered a very small, low powered push-pull amplifier developed by a friend of mine: the KA-101 from Kingko Audio. 
Kingko Audio is owned by King Ip, a good friend of mine from Hong Kong. He used to sell and repair amplifiers from  Line Magnetic and he knows everything about audio electronics and tubes. So after years of studying other brands, he developed a small and simple product, not expensive, that rivals in sound. It is a giant slayer! 
I bought one, together with his CD player (also using tubes) and it sounds as good as the best Cayin and Line Magnetic. Actually, is almost as good as an Audio Note, or a Shindo! We spent days comparing them, with a lot of different speakers. The little Kingko KA-101 surprised and amazed everybody.
Soon after I sold the LM219ia. And I don't feel the need to search anymore for a good SET, I'm happy with my Cayin MT45-Mk2 and this Kingko. For now... :)

T_ramey,
I never tried to bypass it because I don't have a decent preamplifier. My Kingko always worked as integrated. 
But according to King Ip, you will get better results if you use a good preamplifier; the preamp section of the KA-101 is not as good as the best preamps out there.
Regarding tube rolling, replacing the preamp section tubes (the small 12AU7 and 12AX7) will increase a bit of the sound quality, but the real improvement comes from the rectifier tube. Originally the amplifier comes with a chinese 5AR4 that is decent, but not spectacular. Once you replace this tube with a better one, it's an amazing improvement!
At his shop we tried many combinations and the one that really shines for me (and I was lucky enough to get a rare tube from King Ip) is the Westinghouse 5U4GB/5AS4A. Everything goes bigger, fuller, richer! Clarity, bass, soundstage... 
There is someone on another thread (maybe another forum, can't remember, but I'll search for it) that found another rectifier tube to be fantastic for the KA-101. Different flavours, so many possibilities...
Anyway, I advise you to contact King Ip regarding any question. His English is not perfect, but he's an amazing guy, always willing to share his expertise and knowledge. He will answer all your questions.

You're welcome. 
By the way, I found the comment from the user toro3, here in Audiogon, regarding tube rolling.

Looking at his KA-101 I saw a different rectifier tube. When I asked about it, this was his answer:
"...that’s the smooth black plate RCA 5U4G with round mica at top and lower d getter. I prefer the 5U4G over 5AR4 and 5U4GB due to sounding richer IMO".

This user, toro3, has a system similar to mine: Kingko amplifier and Omega speakers. You can find his system and comments here at "Virtual Systems".

I asked King Ip about that. His answer is Yes, you can use those tubes (274B and 5U4).