I decided to conduct a blind tube test with my AKG 701's.
I randomized all my 6sn7's in a drawer, grabbed them blind, and inserted into the DV without looking. All tests were conducted with a Sylvania 6080WC JAN tube in the back. I had previously found this was the 6as7 I seem to enjoy the most.
Below are my comments. After I finished listening to each tube I layed them in order so I could match up with the tubes when I was done my listening tests. Comments are somewhat random as I just jotted down thoughts as I had them and didn't necessarily try to compare individual passages of music.
There may be contradictory statements about each tube as on some songs my impressions were different. I listened to the same 10 songs with each tube. Testing occurred over several days.
Tube1: (GE 6sn7gta flat Grey plates, side halo getter and flashing, red print)
Bad Hum Initially, and throughout. Distracting on quiet passages.
Good bass
Full Sound
Detailed
Something missing?
Soundstage a bit compressed.
Very full sounding.
Soundstage fine.
Seems detail a bit missing on some tracks.
Nothing offensive with this tube.
Well balanced.
Tube 2: (Sylvania 6sn7gta Short bottle, black triangular plates, heavy flashing, green print)
Significant Hum, that went almost completey away.
Good bass
Soundstage a bit compressed
Balanced.
Very good male vocals.
NOthing offensive with this tube.
More open and detailed.
A bit bright.
Tight bass
Better than Tube1
Very good detail
Soundstage great
Far better than Tube1 for detail
Great low end
Great with female vocals.
Tube 3: (Sylvania 6sn7gtb - Black triangular plates, red print, date AJR)
Significant hum initially, that remained
Good detail and impact
Something missing in bass detail.
Soundstage and detail better than 2, but something missing from top end.
Good female vocals
Soundstage very good.
No issues with this tube.
Very nice.
Not noticing the same brightness as 2.
Tube 4: (Emerson 6sn7gt Grey T-plates, circular mica supports at top actually a rebranded Tung-Sol Mouse Ear)
Very mild hum
Decent impact
Something not right, soundstage somewhat limited. Some songs seem to lack detail, others are fine.
A pretty good tube. Quite good on some songs.
A little harsh and fatiguing.
Tube 5 (Brown base Sylvania 6sn7WGTA, black triangular plates, halo getter)
Decent impact
Soundstage significantly better
Good detail
Balanced
Smooth
Great detail
Just a little bright
Good female vocals
Good male vocals
Significantly better than tube 4, no harsh sound.
Tube 6: (Sylvania 6sn7GTB Grey parallel plates, made in England, strange saucer getter at bottom)
Bad hum
Good impact and detail
Good soundstage
Good balance
Good female vocals
A bit bright
Nice tube except for hum, and fatigue from brightness.
Tube 7: (Original tube from amp)
No hum
Impact not quite up to snuff
Detail seems to be a bit lacking
Soundstage a bit limited
Not bad
Female vocals good
Quite good with some songs.
Tube 8: (RCA 6sn7GTB, flat Black Plates)
No Hum
Impact a little lacking
Laid back
Soundstage a bit lacking
Highs seem recessed
Neutral
Detail ok on some tracks, lacking on others.
A little harsh on some tracks.
Tube 9: (Sylvania 6sn7GTB, black triangular plates, green print)
Significant Hum
Fairly detailed
Pretty good impact, a little less than some of the other tubes.
Soundstage seems slight less than some of the other tubes.
Balanced.
Female vocals missing some detail
Detail good on some tracks, seems to lack on others.
NOthing offensive other than hum.
Tube 10: (Motorola 6sn7GT, made in USA, Grey prallel plates, circular mica supports, actually a rebraded TungSol
Mouse Ear).
No hum
Good impact
Good soundstage
Good detail.
Very nice.
Good female vocals
Nice balance.
Musical
Great sound, developed a hum in left side.
Tube 11: (Sylvania JAN 6SN7WGTA, Brown base, black parallel plates, halo geter)
No hum
Good Impact
Balanecd
Good detail
Good soundstage
Good female vocals
Good male vocals
Musical
NIce.
Good low end.
Tube 12: (Sylvania 6sn7GTB, red print, halo getter, black triangular plates)
No Hum
Good Impact
Missing some detail on some tracks, but good on others.
Soundstage not full on some tracks.
Good male vocals.
Good female vocals
Overall Tube 11 is my favorite and now resides in my DV.
I've tried this tube with RCA, Sylvania, and Westinghouse in the back but always go back to a Sylvania 6080WC. This combination just sound right to me. How I expect live music to sound. Detailed but not harsh.
After the blind comparison I have compared Tube 11 with a VT-231 Sylvania with parallel black plates, with the flashing on the bottom, but still slightly prefer Tube 11 although they were sonically very similar.
I have not tried to go back and relisten to the some of these tubes for further comparison, but I plan to review the two Tung-Sol mouse ears as I'm suprised I found the Motorola much better than the Emerson considering they look virtually identical.
