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Sofia Electric Blue 6SN7

Just received a pair of these this morning and to say I'm delighted is an understatement.At $99 per tube I was so hoping it wouldn't turn out to be a mistake.Big sigh of relief and a bigger smile.After fooling around with various tubes,footers,and cables trying to clear up what I was hearing as a congested midrange when there were multiple instruments,this tube has done it.

I replaced the Sylvania 'bad boy' driver tube in my Aric Audio Transcend amp just to get a feel for the sound before removing the bazillion tiny screws in the LTA MZ2 to try them there.Well it's staying right where it is in the amp.The mids cleaned up immediately and the entire presentation seems faster and even more dynamic.The vocals retain their sweetness with no excess sibilance.I recently tried a new EH in that position and also in the MZ2 which gave me the clarity but they were relentlessly hyper detailed.
I have read some cautionary tales about Sofia tube's reliability but they mostly involved power tubes, so fingers crossed.I'll update if any problems surface.So far my perfect tube compliment is one Sofia blue 6SN7,two Sylvania 6SN7,four (new)Tung Sol KT150 power tubes in the amp.The pre has two 12AT7 Sylvanias and two (new)Tung Sol 6SN7.
128x128jtcf
brownsfan
1,508 posts
 
@jtcf, I may well find the same thing when I pick up another pair.  It takes some patience in finding an optimal mixture of 6SN7s in my M-60s.  I'm going to leave everything as is for a couple of weeks to permit burn in before I make a final decision on buying more tubes.  
jmolsberg's avatar
jmolsberg
467 posts
 
very nice! 
jtcf's avatar
jtcf OP
1,589 posts
 
Best of luck brownsfan.You have quite a few tubes to mix and match before hitting on the ideal combo.
brownsfan
1,508 posts
 
@jtcf  Thanks.  I've been through the drill before with the M-60s, and yes, it takes a bit of time, but I have a pretty good feel for what the amps like in terms of 6SN7 attributes at each of the 4 positions, so its not quite as bad as trying to work my way through all of the 256 possible variations.  In actual fact, this comes down to a yes/no on two of the 4 positions, with the new Sophias potentially replacing the RCA grey glass tubes.  Those two positions have the greatest impact on sonics.  The third position (back, center, one the MK 3.3s) really seems to benefit from the bad boys.  Assuming I like what I hear with Sophias in the two most impactful position, it really comes down to getting a quick A/B  on the bad boys vs. two other Sylvanias that I have on hand.  Tube rolling in the 4th position (front tube), which requires GTA or GTBs, has less impact on sonics.  I always roll that position after I have the other 3 established.  I can probably get this done in 3 or 4 listening sessions, so it is really not all that laborious.  
jtcf's avatar
jtcf OP
1,589 posts
 
An update about these tubes after almost a year of daily use:They seem to have lost the beautiful tone I was so thrilled with initially.The vocals especially became increasingly harsh.Of course I didn't suspect the Sofias and began switching out other tubes with no luck.Yesterday I swapped in a Sylvania in the amp and it was instant relief.Dang.Next were the two in the pre.
So it seems they were good for about nine months/-500 hrs and began to decline slowly.
The Sylvanias are ok but a little congested in the midrange.I've got three pairs of different NOS tubes on the way to try now.
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