Brimar 12au7 in Sphinx v3
@decooney That is exactly what I intend to do. I may have 30 hours on the unit now. Running a computer as a server into it as I work on the new house. Will get to the 200 hour point within the next month. After that time I will consider all the suggestions acquired herein and purchase a pair of NOS tubes for trial. It's all fun & games with no one getting hurt :-) @paul_lindemann Thanks for the recommendation. @thecarpathian Please let me know if you put your tube up for sale. Thanks.
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@mesch if you can, try to take listening notes first 20hrs, 100hrs, 200hrs. Often times people don’t give it enough time with the stock tubes -or- internal caps before replacing them prematurely. Me included on a few occasions. Good lessons learned. While I’m over here making cool upgrades on mine, friends chose to "leave it alone" keeping the stock tubes and caps in their units for 200-300hrs. Their new vs. well burned in amps and stock tubes, caps, sounded better, given some patience and extra time. Then say at 200hrs if/when you still decide to swap in other vintage tubes, you’ll know what changes the changed tubes actually make. For your consideration. |
$200 is a very good budget. Brent is a good guy, so that is great if you buy from him.
I recommend the RCA 3 MICA Black plate 5814A tubes from the 1950's. Nice warmth and bloom - good transparency and dynamics...maybe $77 a pair. Also, the CBS 5814A - less warmth, better extension on top and bottom, great transparency. Raytheon is also excellent and similar to the CBSA.
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Not a Sphinx, but FWIW when I had a Rogue RP7 (driving a ST100 I still have), my favorite 12AU7 type in the primary position was the venerable Amperex 7316. It was the most dynamic, holographic, with just the right amount of "sparkle". The Amperex 7316 is difficult to find these days and commands quite the price. For a "fatter" sound, but still plenty of top end air and a wide bandwidth, RCA black plates did very well. These tubes were sourced from Brent Jesse. I tried many 12AU7 combinations and spent entirely too much money doing so, but I learned a lot and it was fun. Honorable mentions go to the Ken Rad 12AU7, which is a very unique and beautiful, almost chimey (in a good way) tube. I did not like, and TBH have never liked Mullards in my equipment. |
@thecarpathian Yes was an interesting read. Thanks. I spent some time on the Brent Jessee website. Read the review of the Pharaoh II. Been running my Sphinx Ii for several hours. Seems to be sounding better as hours go by. Going to let it break in. Get adjusted to how is sounds. Room is rather barren at the moment, still needs window shades and more furniture. Have yet not called Mark O'Brian of Rogue Audio. I intend to do so. I hope not to spend more than ~$200 on a pair of tubes. Thanks to all contributors! |
Why NOS tubes are better than new tubes - NOS vacuum tubeswww.nosvacuumtubes.net/customer-service/nos-tubes/
interesting read... |
decooney" I was noting the less expensive short plate 60's production @ Blackburn and Heerlen. I actually prefer them to my older (now super expensive) long plate versions. A modern 12au7 that interested me (reading between the lines of the reviews) was the JJ ECC802S, but having had problems with the undersized tube pins on their (JJ) 300B/2A3 tubes I never tried them (don't know if it's even a thing with their small signal tubes).
DeKay |
@mesch the article @juanmanuelfangioii shared from enjoythemusic makes an interesting comment. I also own some of the absolute best-of-best Blackburn plant Mullard 12au7 cure-tracer close matched triodes from Brent Jesse too, similar to what @dekay may have been referring to above. Sure, they are nice, expensive. and my other PSVANE 12au7 hold their own against them comparably, and I can run them all of the time with no worries. My amps came stock with JJs, and there are select au7s that sound much better, imo. Noting this comment in the recent Pharaoh_II article link above, quote:
When you call Rogue, maybe they can share more about why some of the more recent designs including the Pharaoh_II (reportedly) may sound better. See what they say, and why?
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@dekay A harmonically rich, liquid 3D sound is exactly what I am looking for. I will reach out to Brent Jessee. @decooney Yes, it true that rolling tubes in any tube product is not necessary, however should bring results. If not then one has to ask what are the tubes bringing to the design. I can't believe that tube rolling in this unit wouldn't alter the presentation in some fashion. I will call Rouge and see what they have to say regarding this.
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I thanks all for the great recommendations. I intend on leaving the JJs in place for a while I get acquainted with this amp. Then explore some of the options suggested herein. At the moment I have the amp in a system set up to supply music and augment TV in a living room which is on the bright side. As i move forward I will get the room tamed down some, however It will remain livelier than my dedicated room which is treated to my liking. |
My rogue set up is ST100 power amp with RP1 pre, so not sure if this is helpful. I've experimented with a handful of tubes in the 12au7 and 12ax7 spots and best combo for me without a doubt was Mazda 12au7 and Telefunken smooth plate 12ax7. I was actually surprised how much of a difference the 12ax7's made in the power amp. Brent Jesse tubes is a great resource btw, he responds to emails quickly, tubes descriptions on his website are very helpful, and he has a wide selection. Good luck! |
Brent Jessee has 1960's Amperex/Heerlen and Mullard/Blackburn short plate 12au7's starting @ $150-$160/matched pair (damaged printing/relabels). These are what I ended up with in the preamp that I have been using for 20 years now. I prefer a harmonically rich, liquid 3D sound. For around $100/MP he also has RCA 1950's RCA black plates. I used GE 5814's that I also liked, but I can't get to them now to see what type of construction/plates they have (they were smooth but lacked the mid-bass bloom of the others mentioned above). RCA clear top/side getter are not warm sounding tubes (you would want the 50's version with black plates and top flashing if you go that route). I've never purchased tubes from him (Brent Jessee), but he has a good rep (plus he has the goods and testing equipment). I purchased my various tube stock 20 years ago. I have not tried any of the new production 12au7's. .
DeKay |
Interesting point if this is true, and might be telling about this particular amplifier and it's design - - and how the tubes are incorporated in the circuit in this amp. If changing the tubes in this amps makes little difference, some might say "why have tubes in the circuit at all". Changing 12au7 input tubes in all of my amps and colleagues amps, we hear a notable difference with different tubes vintage or new.
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Mullards never worked for me- just did not care for the overall sound. FYI the JJs take a LONG time to burn in- they ship with McIntosh too and don't really smooth out until 700 hrs or so- no joke. In the mean time try amperex bugle boy, made by amperex philips or RCA 5963. clear tops are too bright IMHO. |
I upgraded with some GE 6189W tubes that I got from Upscale Audio. To be honest, I replaced the JJ's early on when I got the Rogue, so I can't take anything away from the JJ's. With that said, the Rogue is very smooth sounding with the GEs. I am using the Rogue with a pair of Zu Audio Omen bookshelf speakers. I am pleased with this pairing and enjoy it a lot. The speakers you use will most likely have more of an effect than the tubes. I was originally using Golden Ear BRX's with the Rogue and while I liked it and it sounded good, the Zu's are much more to my liking. Interestingly enough, I read somewhere (either a magazine review or Rogue literature) that tube rolling was not necessary. Rich
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Hey @mesch you can have fun messing with different 12au7s in that unit. Also seeing the lower version standard white MCaps used in yours stock. You can do better here too. I’d call Rogue first and ask them what upgrades (tubes and cap changes) they’ve tried or taken notes on from customers. Maybe they will share more. Not always. Most of the larger mfgs use basic JJs for low cost, availability, and reliability in new-production amps produced in volume. If it helps, my current mono tube amps use both 12au7 and 12at7s for input and drivers. Tried at least 20 different au7 pairs (mostly vintage), and while some of the best are my vintage "close triode matched" mid-60s Mullards, yes, was able to find a nice smooth tone with newer production Psvane au7s as an alternative.. If you want new production vs hunting matched triode pairs of vintage tubes, you could try the psvane 12AU7-S Art Series / ECC82. Viva and a few others sells them. They are fairly smooth and open up a little more after they are run in 75+hrs. Using psvane now in my current mono tube amps. Not too bad.
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