Phono Preamp Tube Rush

I've just skimmed the thread and so may have  missed it, but nobody has mentioned low noise tubes.  I have found the NOS JAN-Phillips 7981's sold by The Tube Store to be substantially below stock tubes in my Brown Audio Lab headamp.  I also own a Counterpoint SA-2 headamp, and in that unit tubes are paralleled to achieve the same effect.

This is a topic I’ve been following for awhile. Although I’m not an EE, I do know I hear what I believe is tube rush from my Aesthetix Rhea eclipse phono pre. I’ve tried to ensure good connections from the cartridge all the way to the pre. I also found I had some RFI or EMI from a google mesh wireless extender that was positioned too close to my TT/cartridge.

But I can say unequivocally that going to ultra low noise 12AX7 NOS tubes (amperex) in V1 and switching from 6922 to 7308 ultra low noise amperex made a big difference. It did not eliminate but the rush but it is now very tolerable. And with the low-noise telefunkens in the other tube slots, a very very enjoyable sound. 

Harry, you did not read the thread carefully enough. I mentioned them way in the beginning.

Mike

I far prefer tube-based circuits to solid state, for sound quality, but all tubes do have a finite life span, and as the end draws near, they become noisier, until they reach a final common pathway of being noisy.  This malady will affect SLN tubes as well as non-select samples.  The variable is time from new to noisy, which is impossible to predict for a given sample of a new tube, but I would agree that for a tube that starts out SLN, perhaps (on average, but there are no guarantees) the time to its becoming noisy will be longer than for a non-select tube.  But the point I was trying to make earlier is that circuit design also has a lot to do with "noise" one perceives over the speaker.  For one example, ARC stuff was always known for driving tubes very hard, near their recommended limits for voltage and current.  In the old days, this led to short lifespan. Circuit layout also has an effect.  What tubes are chosen for a given task also has an effect.  Someone wondered why Herron(?) didn't choose to use a 6DJ8 instead of a 12AX7 in its phono stage; the simple reason is you could never get enough phono gain out of a 6DJ8, used as Herron uses the 12AX7.  The 12AX7 is a standard choice used in common cathode mode for the input of an MM phono stage; all the gain is done at the input before RIAA, as Hagtech mentioned.

I had brought up the question earlier in the thread about why not use a 6922 instead of the 12AX7.  You definitely could get enough phono gain with the 6922 and this is commonly used in the Manley phono pre's (for example).  Now would the overall sound quality be as good in the overall circuit design compared to what Herron achieves in the VTPH-2A?...I have no idea.  I use the Herron VTPH-2A and am happy with it.  I may try a coupe of Roger's SLN tubes in the 1st gain stage soon and see if it makes a notable difference but either way I'm perfectly good with the Herron. ;-)