@crawfishdaddi
Thanks for the information. The model I have calls for all AX7 tubes. I use both 5751 and AX7 type tubes!!
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.
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@larryi , I'm embarrassed that I didn't know this (I only upgraded from a vintage console ~1 year ago, so I'm still steep on the learning curve). The worst part is, my TT is only ~2 ft from the phono stage on the same rack! I was using that ridiculously long cable (originally bought for my R2R which is across the room) because the cable I ordered specifically for my new QS phono stage hasn't arrived yet (it should be here tomorrow according to USPS tracking). Last night, I took that long cable out and swapped in the 1M Raven Audio Soniquil RCA interconnect cable I was using for my Cassette deck. The sound INSTANTLY improved. A LOT. The invisible wool blanket over my speakers is gone. I'm still interested in rolling the tubes at some point, but the urgency is gone. I think I'm going to start with switching the input tube to a Raytheon/RCA 5751 with windmill getter or the GE 5751 triple mica. When I finally pull the trigger, I'll update this thread with the results, but for now, I think the problem has been resolved. Thanks again for all the help P.S. kudos for identifying the correct issue early in this thread... you had the right idea all along!! |
@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. |
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