Phono Preamp Tube Rush

@edwyun 

What tubes are you using in the V1, V2, and V5 positions?

@bigkidz

I have to disagree that the VTPH-2A is a poorly designed unit as it’s incredibly musical, especially at it’s price point. I really love what it has done for my vinyl experience. With that said I do wonder why Keith didn’t use the 6922/6DJ8 in his phonostage which is what he uses in his linestage. It seems noise would be much less of an issue because the EH 6922 is one of the quietest tubes there is for this purpose with ample gain.

I can certainly identify with this topic and the advice so far has been spot on consistent with my experience.  I too have a Herron VTPH-2A and noticed tube rush only a foot or so from the speaker when volume is up quite loud and BEFORE needle touches the vinyl.  I have found a bit of success (in my quest to lower the phono noise floor) by moving from a 0.3mV cart to a 0.5mV and by dialing gain and loading through a Zesto SUT.  I've had discussions with Roger Modjeski about possible noise reduction using his SNL tubes (at ~$100/ea) in the 1st gain stage of the Herron. He thought it might lower the noise floor a few dB but he said it's hard to say.  Haven't pulled the trigger on new tubes yet.

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. ;-)

@lewm 

I appreciate the detailed explanation!  I was unaware of the Manley hybrid design.

So curiosity got the best of me and I decided to try replacing the original EH 12AX7 1st gain stage tubes in my Herron VTPHA2A just to see if I could reduce the noise floor a tad.  I went with Gold Lion reissue ECC83/12AX7 tubes from Upscale Audio - ordering the quietest option they provide.  My expectations for improvement (over an already gorgeous sonic presentation in Keith's stock tubes) weren't particularly high but I was pleasantly surprised when I immediately realized a notable difference.  Tube rush, and still only at very high volumes, was reduced probably a few dB but even more surprisingly the sound character changed for the better as well - the Gold Lions delivering a very smooth, more richly dynamic presentation that's been improving further over the 10-12 hrs I have on them now.  Just thought I'd share the experience with anyone interested.

@dhcod   +1  I think that sums up my perspective as well.

@lewm

I completely agree that not everyone is going to recognize the same or even similar results as me as the change is certainly both system dependent and based on personal tastes. The stock tubes were only 7 months old so they had plenty of tread left. I just thought I’d offer a data point because in general I think you’re hard pressing to get a better sound than what Keith brings into the box from the get-go.

Ok, 24 hours later and I embarrassingly now need to confess that I'm not preferring the Gold Lions over stock EH's in the Herron.  At first I was smitten with the reduced noise, blacker background, silky smooth mids and extended bass.  I am now realizing that these sonic qualities came at a steep cost of losing the air and wide-open presentation.  Late last night during listening I became keenly aware that the highs were getting rolled off and the bass was actually bloated.  I immediately rolled Keith's stock EHs back in the pre and ahhhh.....everything was so much better.

Interesting lesson here in the psychology of perception.  I was initially seduced by the quiet and a "different" sound, and it took me a bit of time to realize different was far from better.  I have read many times that it's hard to improve on Keith's tube voicing and It'm seeing that now.  I'm still curious about rolling tubes in the Herron but I suspect you need to get into some nice NOS tubes like Tele or Mazda to move the needle any higher.

Agree completely with the several posts above this one.  I do find the science and psychology of my own perception interesting.  

@lewm   Agreed, that being honest with ourselves is not always the easy path.  I'd rather be happy than right.  Open-mindedness and honesty takes one far in this hobby I'm finding - or in life for that matter.