2. amps-preamps
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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

Showing 4 responses by lowrider57

lowrider57's avatar
lowrider57
5,391 posts
 
You can't assume one tube brand will have less noise than another, each tube must be individually tested.

Gochurchgo: noise testing is a must on any tube you order, especially since it's been established that your system gain is high.

I believe tubes from Upscale include testing for noise and microphonics. As far as "Kevin's Stash," I'd like to hear your impression of these tubes. His Platinum rated tubes have a triode balance of
10% or tighter, I wonder if the "Stash" will make an audible difference.



lowrider57's avatar
lowrider57
5,391 posts
 
Brent Jessee sells high quality tubes. The catch is you must request noise testing; it's $10 per pair I believe. 
Depending on the circuit in your component you may need to use low-noise tubes. I only buy noise tested NOS tubes.

Andy at Vintage Tube Services includes testing for noise and microphonics, Upscale does as well.
 
lowrider57's avatar
lowrider57
5,391 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.



lowrider57's avatar
lowrider57
5,391 posts
 
I don't understand how Mullard and RCA can sound like Solid state. These present warmth.
 It must have to do with the design of the circuit. What type of Mullard is it?
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