Supratek or Don Sachs - which way to go?

I got my Cabernet a few weeks ago now, very happy with the quality of construction and the sound is very good, one thing I have noticed is that after a week or so I started noticing hiss from the woofer on my Graham Audio LS 6/9, I am sure it was not there before and I sounds like it is the woofers not tweeters, have not tried the 300b output again since trying it out the second day of ownership, for me the 6SN7 output sounded better and more resolving.
Could the tubes gone bad already ?
A family member did shot down the Hi-Fi the right way, but pre amp first, which gave a small thump from the speakers, but no damage to speakers, I have noticed that I have to wait 3-5 min after my Belles SA30 class A amp has been turned off before turning of my Cabernet, otherwise I hear a small thump and sucking noises from both speakers, if waiting a few minutes everything is fine. My speakers are 87db so I would thing the amp to be totally quiet.
Will investigate in the weekend, but if anyone has any input, I would be grateful.

The noise you are describing seems to be normal — same when turning on and sometimes iff my Chardonnay — and should cause no harm to your speakers no matter when you turn it on or off, but ask Mick if you want. I’d also ask about the hiss. Depending on the amount, that may or may not be normal. Jim Smith, the well known set-up guru in the U.S., says that in his experience systems with a touch of noise sound better than those that are dead silent. But of course, noise can be of different types and volumes, so it’s worth asking as well as checking all connections and making sure cables are well placed.

Hey gryphongryph, thanks for the input. My dedicated 2-channel system has always been tube based. Have SS in different HD family room setup (Anthem MRX 520, AE Aegis speakers/sub). Considered hybrid and Sutherland pre's for 2-channel but tubes seem more true and lifelike for vinyl. I ahve a 1500 LP collection. Sachs and Supratek are said to be well built and easy on tubes, don't expect the need to replace tubes often. 
Previous 2-channel system (15+ yr. setup) -
Jolida 202 (full upgrade last fall)
Antique Sounds ASUSA PP2 phono pre
Jolida JD 100 CD
ACI Force sub
Tyler Acoustics Ref. Monitors       

Thanks guys, the hiss does not bother me when music is playing although sometimes I think the blackness should be blacker so to speak, but maybe it’s my mind playing games with me after noticing the hiss, will try some things out, if no change, I will order me a new set of tubes to see if the hiss goes away.