Cayin A-300b vs Muzishare x9

@cb3489. Is your X9 came with Chinese or English manual? My came with Chinese manual. Do you read Chinese?

Are 300B and 274B fit not tightly compares to others? 6SL7 tubes very tight fitting and EL34 and 6550B snuggly fitted on the R8 but these large tub easily moved with slight  finger touching.

NFB 1 means -3db feedback and 2 means no negative feedback?

Thanks in advance.

@slowestrider congratulations. My came with Chinese as well :) nfb i liked up position. I don’t know the db difference. 300b and 274 are only 4 pin vs 8 pin kt88 or 6550 so I believe that is why we feel like they are not tight but actually they are and very good grip they have. I doubled checked when you messaged. 

Yes, tubes do have very tight grip and fully seated but it still wiggle slightly. I saw the youtube clip by China-hifi on the  Boyuurange A50 MKIII 300. Those tubes also wiggled as he demonstrate the correct way to install 300B tubes.

One of the 300B tube at V2 position has a ringing sound when I touch and release, not sure if it effects the sound. I still have not plug in and test it yet.

On the Pre-in/OFF toggle switch, is the up position/pre-in for use the X9 as amp and plug in a preamp? and the OFF position is for using the X9 as an intergraded amp? I made out some words in Chinese but not all. Thanks for you help cb3489.

cb3489. I finally plug it. No issue with the 300B with the ringing noise when I touch it. This amp is so quiet. No noise at all, even turn to 11 o'clock with my 102dB sensitive speakers. So I leave the hum balance at factory setting. Bias were a bit high on both tubes so I adjusted it back to 60mA. I leave NFB at 2 for zero feedback.

Stock tubes with no burn in, it doesn't have any harshness at all, noise floor so much quieter than the R8. High is more extended and bass is not over emphasis as the R8. Vocal and small jazz music gave me the wow even less than an hour burn-in.  It does loose some bogginess compares to the push pull R8 for it doesn't emphasis the upper and mid bass at all.

This will be my quiet morning amp and it will be much better when I start rolling the NOS MEL 6SL7.

Thank you for your help db3489.  

@charles1dad ​​​​@slowestrider 

i finally upgraded all tubes on X9 :) i got PSVANE Acme 300b and PSVANE 274B Tii. Using Tektons perfect set 15s.  The sound is really good. It improved amazingly. Huge bass sound level and more noticeable details. Every upgrade makes so much difference i wonder if there is any end to spend more money on hifi :)