Cayin A88T break in and biasing??

No the 6550 is a close in design to the KT88, sorry that tube I do not think is gonna work for my orchestral. Back to KT90's. I wish some tube guru would post a comment on why the KT90 presents classical with the dimensions that other tubes fail at.
I think it has to do with the shape of the glass, its straight and narrow, so the musical energy doesn't get all sloshed around inside, as with the 'bulbier' 300 , KT88 and quite possibly with the 6550.
Thoughts?

I just want to clarify some biasing issue with A-88T. Its true that A-88T is not auto-biasing and if you want to re-bias then you would have to flip/open/bias and put it back together. However, it is my understanding that you do not really need to bias it. It will work just fine if you just swap the tubes (KT88&6550). Its probably not going make a very big difference in sound, and depending on your preference you may actually like it.

I have the A-88T too and wanted to try the 6550. I took it to the local dealer, in san jose CA, to help me bias so I can see how it it is done. The owner is very knowledgeable about tubes and build his own tube amps, so I assume he knows what he is talking about. He told me that it is not necessary to bias the Cayin and would sound fine as it is. His own demo model, is using the 6550 and never biased it. This also explains why many A-88T owners who are trying different tubes but never re-biased thinking its auto-biasing and have never had any issues.

I bought the tubes 6550 from him and asked him to show me how to bias it anyway, which he graciously agreed(it is exactly as it is stated above). In fact mine is biased at 30mV with the 6550 and the recommended number is 42mV. I was told by this dealer that the Cayin will actually sound better (more upper extension) if you bias it a little lower. When you lower the bias then you are essentially lowering the power output a little, but in some cases it sounds better.

This is my understanding based on my research and talking to the distributor and my local Cayin dealer.

And one last point, if you have A-88T, then you must try the Tung Sol 6550 reissues. They sound very good as compared to the stock KT88. KT88 sounded a little bloated in the lower frequency in my system.

I have a Cayin A-70T and this is NOT auto biasing. There is a section in the manual which details how to bias the tubes, complete with recommended voltage settings. It's really a very simple process and you don't have to move a thing to do it, other than lift the cage off.

I searched the net as well and found that the lower wattage models state that those are auto-biasing. Maybe there's something about the US Version (VAS) vs. the others.

Your manual has biasing info ?
Mine , A-88T , is completely devoid of any info !
It took repeated emails to the European distributor to eventually receive some very skimpy instructions ! The North American distributor completely ignored my 3 emails to them !!!
Maybe this is a side affect of outsourcing ???

My dealer said that VAS is very slow in responding to emails and that I should call if I had any questions. I only needed to call once but I had no problem getting an answer.