NOS Tube Recommendation for Quicksilver Phono Pre Amp
I recently upgraded from the onboard phono stage in my Technics 1500SL to an all tube Quicksilver Phono Pre Amp. I’m about half way through the 30 hour recommended break-in period and so far, there is a lot to like about this piece of gear: Much thicker/more pronounced bottom end (I’ve had to readjust the gain on my subs quite a bit) and much wider/more defined sound stage. However, because I’m also running an all tube integrated amp (Raven Audio Osprey), there is now a very noticeable "warm" coloration to the music that wasn’t there before. I don’t want to give up on my new phono stage, but it’s like I’m listening to music with a wool blanket over my speakers. I’m thinking rolling the tubes to something a little cleaner/brighter could give me the best of all worlds. There are 3 tubes in the circuit topology: 2 12AX7s (one input, one gain) and 1 12AT7 (cathode follower). I’m currently considering a matched pair of Raytheon JRP black plate 12AX7s and either an RCA or Telefunken for the cathode follower (all NOS). Any and all suggestions/inputs are very much appreciated! P.S. my speakers are Raven Audio Corvus Reference Monitors and my current cart is the always amazing Nagaoka MP-500.
@onhwy61 gain (mu) is one of the differnces. there are more, and all are significant. 5751 is not a drop-in substitute for 12AX7. they are not interhangeable. any such substitutions are circuit dependent. check with the builder, manufacturer, designer to find out what substitutions are ok. |
The Quicksilver preamp tubes are curve traced at all frequencies. You will likely not do better than stock. Try a golden dragon in place of the JJ 12at7 however I have two of these units with stock tubes and they are the opposite of warm wet blanket. Check the input impedance of your one preamp. That can definitely give you a dark thick sound. Check with Mike on the speaks of your line stage. You can also change the input loading resistor to 1 k but that should not be necessary. |
