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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.

crawfishdaddi

Showing 5 responses by larryi

larryi
4,280 posts
 

Is the cartridge loading the same for both the new and old phono stage/section?  That warm and "wet blanket" sound can be the product of incorrect loading.  If you have options, try a different setting for loading.  The right value for loading is somewhat dependent on the phono stage, so the optimal value may differ for the two stages so try all options available to you.

Yes, tube choice can make a difference.  You mentioned the options you are considering, but, you did not mention what tube brands/types you started with that you don't like.  This information will help others in offering suggestions on which way to go.

If you are looking for a clear, somewhat lean sound with a lot of "jump." I would suggest Telefunken, but some of those choices can be quite pricey.  

larryi
4,280 posts
 

The Telefunkens I run in my phono stage are the crazy expensive ECC 803S (equivalent of 12AX7).  I have heard others, but I don’t recall specifics.  

larryi
4,280 posts
 

New Teles are JJ (Slovakian).   Even supposedly vintage Teles could be Chinese fakes.  These days, the fakes look pretty authentic—they have the diamond molded into the glass like the real thing.  Anything good has fake copies.  I’ve seen fake Audio Note speaker wire that you can only tell is fake by peeling back the heat shrink cover at the spade or banana plug.  I saw a Western Electric preamp that cost $20k that was totally fake—rusty transformers and all.

larryi
4,280 posts
 

Yes, it has only 70% of the gain of a 12AX7.  Aside from reducing gain, if it is used as part of the equalizer circuit, that lower gain could screw up the equalization curve and mess up the sound that way.

larryi
4,280 posts
 

The sound issue you mention DOES sound like a loading issue which will have a much bigger impact on sound than would tube choice.  The VERY long cable to your phono stage would add a lot of capacitance.  The best thing is to find a way to locate the phono stage nearer to the table; a long run from the phono stage to line stage or the amp will be far less of an issue than a long run from the table to the phono stage.  If you must have a long run from the turntable, you should be looking for the lowest capacitance cables and you should make sure the phono stage is not set to add anything additional.

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