Sir Josepth2010,
I presume you are not from the Philippines? If you are from here, best if you bring in the until to us and we can inspect it for you. Or you can pm me the serial number so that we can verify the origin of the amp.
There are 2 version of A-100T; the EL-34/6CA7 equipped and KT-88/6550 equipped. The difference are as follows: 1) Latter has more rated power (100W vs 70W), this is basically due to the size of the tubes - KT-88/6550 being bigger tubes. 2) Sound characteristics. EL-34 sounds warmer and in general better for vocals. KT-88 is more dynamic and better for jazz. Both tubes are interchangeable (6CA7 and EL-34); (KT-88 and 6550). 6CA7 compared to EL-34 is fuller sounding. 6550 compared to KT-88 is faster sounding, livelier sounding. Other than the tubes, both versions are exactly the same quality wise. There is no best tube, its all subject to your personal preference. That is the beauty of tube amps, you can tailor your unit to your own listening preference - i.e. tube rolling.
The marantz 8 was actually a comment from a audio magazine review. Since the person is a well respected reviewer, the US distributor might have used it as a marketing tool. Personally I have not heard the marantz 8 as well but its supposedly a very good amp.
I am not too familiar with the US version. For our market we carry the German variant. I don't know if there are any differences between versions. What worries me is the modification in Jersey. We provide modification with full Cayin warranty since our technicians are trained by Cayin. However, these modifications are limited to upgrading of capacitors. On rare occasions we upgrade the wires to silver-gold mundorf wires but that it. We do not play with the design or schematics. Furthermore, the amp will be opened in front of our client and the replaced parts given to the client.
Hope I was able to help.
