I ran both in a prior system incarnation, albeit the original Ren Sig IIa, not SE. My IIa only had 8416's as the line stage tube, so I couldn't roll, and there is only one 8416, so no flavors to try (the 12AU7's are used as tube buffers for the tape monitor section, IIRC), Just by experience and reputation I would seek out some Telefunken NOS to try, as they typically excel at transparency and articulation (too much so for my tastes in some other gear, but it all depends on gear and system matching).
For the PHI 200 I ran most happily with the new Gold Lion KT88 "reissues". Now, I liked them because they had a fuller harmonic presentation, but I did not feel they did so with any lack of detail. I found that the VAC supplied tubes were too shrill in my system, so I may not be the best adviser, given the direction needs you have. My system at the time needed a wee bit of warming to hit the right overall balance.
I can't comment on the preamp, but for the power amp, shuguang WE-KT88 plus and their WE6SN7 red base fat bottles.
most open, organic sounding KT88 I have tried.
I also have a MkIIa SE preamp that is not an upgraded unit. Interestingly, there are no 12AU7 tubes in the power supply.
Currently I’m using a pair of Amperex 6922 PQ gold pins made in the US. They are transparent, detailed and tonally accurate. The soundstage, imaging and dispersion are incredible with these tubes. As jbrrp1 stated, the Telefunken’s may also be what you seek. I’ll most likely buy a pair of the white label, bottom diamond marked German made Telefunken’s to compare. Brent Jessee’s website has a lot of excellent info. http://www.audiotubes.com/6dj8.htm
I think you probably have the best 6SN7 tubes for your Phi 200, given your sonic preferences (I like a slightly richer sound, so I use NOS RCAs, but Andy Bouwman of Vintage Tube Services, who sold me the RCAs, recommended the Sylvanias if I wanted a cleaner, more transparent and detailed sound). I have had no problems (shrillness or otherwise) with the sound of the KT88s VAC sold me, using the RCAs.
I use NOS French 1956 12AU7'S and they are killers in the VAC system. You should contact upscaleaudio.com and discuss with them. They really make a difference in the quality of the sound, and this company can help you figure out what to do when it comes to tubes...they are EXPERTS.
I run all VAC equipment with dual PA8080'S, their DAC and their preamp all with upgraded tubes from upscale audio.
Interesting... I just got off the phone with Kevin at VAC, and he informed me that the 12AU7's are only used in the tape loop and are of secondary importance. He recommended that I focus on the 6922-family tubes on the preamp. He mentioned that if you don't use the tape loop, they have found that there is a SLIGHT sonic improvement by taking the tape loop out of the circuit altogether. In addition to the NOS 6922 variants, he mentioned that VAC is really impressed with the Electroharmonix current production 6922's.
They aren’t cheap at $200 each but you should consider the KR KT88s. Amazing tube. Open and airy. For current production, debatably the ultimate KT88.
for 6922s we use a NOS Philips with Art Audios that are outstanding and modestly priced.
Hi everyone. I just want to report that I finally installed the
WE-KT88's in my Phi 200's, and WOW! they surpassed the Genelex Gold Lion KT88's by a wide margin. Here is what I wrote to my friends:
"Changing the tubes was huge! Never before has my system sounded so natural, neutral, cohesive, enticing and involving. I'm no longer noticing congestion and loss of internal resolution. The micro-details are there, and yet it is fairly relaxed."
I am so impressed. Next I will try the WE-6SN7's. All of these are around $250 per quad at China-Hifi-Audio. Thanks @johnss for your excellent advise!
All the Best, Peter
Hi Peter S,
you are welcome.;
glad to hear you were able to get them. there are some shortages on these tubes now...due to China plants coming back on line after covid.
Agree with your comments, have 3 quad sets of GL 88s; they are nice, but they are really no competition for the WE KT88 Red base tubes.
if you opt for the red base WE 6SN7s, they wont be as big a change as the output valves, but still quite noticeable.
Right now, the Shuguang WE KT88 plus red base are the most organic natural, open and relaxed sounding K88 I have heard, bare none, and I have tried every current and past production KT88.
The PSVANE gray glass KTa88s are good, but the red base WE KT88s are better.
prior to the WE KZZT88 plus I was using the Shugang Nature sound KT88s in my 200. they are nice but a step down from the red base WE KT88s.
As a side note, I also have a VAC Auricle and use the WE 6CA7 plus fat bottles in it. Best sounding EL34/6CA7 I have tried. head and shoulders above anything else.
The boys at Shuguang have really done their homework on these.
I have been tube rolling on my VAC renaissance mk v line stage with 6922 variants. My favorites ordered:
1. Reflektor 6n23p 75
2. Amprex 6922 PQ pinched waist
3. Siemens cca 65