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Best Tubes for VAC

Hi All,

I've got a VAC Signature iia SE linestage (upgraded from iia) and a pair of Phi 200 amps.  I'd like to optimize tubes for transparency and detail (of course I also want tonal accuracy, soundstage and imaging). I'm wondering if there are any folks out there who have optimized tubes in their similar VAC units?  The tube compliments are:

PREAMP:
2x 12AU7
2x 8416, 7308, 6922, E88CC, ECC88, 6DJ8, (or 12DJ8 twin triodes)

AMPS (each)
4x KT88
4x 6SN7 (in the best 2 positions, I've got a pair of NOS Sylvania 6SN7GT's)

What have people found to work best in these VAC units?  Thanks in advance, Peter
peter_s
kmmd's avatar
kmmd
73 posts
 
Hi Peter,

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

HTH.
Ken
rcprince
3,059 posts
 
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.  
preiter
2 posts
 
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.

Best,
Paul 
peter_s OP
1,313 posts
 
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.
verdantaudio's avatar
verdantaudio
1,463 posts
 
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.  
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