2. amps-preamps
  3. 161387-96791

Constant noisy tubes maybe go solid state?

I have a Quicksilver Line Stage Preamp (12AT7) mated to an Odyssey Khartago Stereo. Overall I like it. Way too much gain but I digress. Weeks after receiving it I rolled in a few different tubes, kinda fun to color the sound signature. I liked rhe RXA black plates I got and those stuck around for more than a year. They started going microphonic and making noises so I ordered another pair (noisy) then another different vendor (blasts of white noise) and another set that arrived today (one is noisy as holy hell and one seems fine).

So where does one order preamp quality tunes that are quiet? Is there something I’m not requesting when ordering? Maybe dump
snd go solid state? I’m trying to be humorous because I’m pissed. Ha.
gochurchgo
lowrider57's avatar
lowrider57
5,417 posts
 

And next, when we use the term quiet or noisy are we talking solely about the hiss in the speaker drivers ?

A noisy tube will be just that. It will raise the noise floor through your system. IOW, where your system once had a black background, there is now a layer of noise. In a worst case scenario you will hear some tube rush through the speakers.
Amps, preamps, phonostages with high gain will make the noise from a tube more audible. A phonostage with it’s high amount of gain should always use tubes that have been noise-tested.

Even true NOS tubes in original boxes can have a degree of noise.



audition__audio
1,536 posts
 
True NOS has little to do with test results. True NOS is a tube which has never been in a circuit other than a tester, which can be hard to discern at times. Most true NOS come with original boxes. Being NOS doesnt make the tube better it just means that the tube has never been used. Tests NOS is not true NOS. "NOS in white boxes" is rare and it is a misleading and some would say dishonest claim.

Further, I have seen up to a 20 to 25% variation in the test levels of true NOS tubes from the same family and manufacturer. Add to this the fact that each tester is idiosyncratic by tube type and you quickly understand that the average NOS reading listed of a particular tube is kind of a fiction. 
sounds_real_audio
1,019 posts
 
You hit the nail on the head. You have way too much gain for the amplifier. Check with Mike at quicksilver 
gochurchgo OP
923 posts
 
@sounds_real_audio  already asked him about it. He said his design is good and not to mess with it. I may add my Schiit Sys in between the QS and the Odyssey to pull gain down and quell the start up POP when the QS comes on (Odyssey recommends leaving the amplifier on 24/7). Not sure if the SYS will be any better than putting rothwell attenuators in after the QS which I have done and seemed to reduce the hiss but also the dynamics a little
bit.
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