CHECKING OUT THE SOVTEK 6L6WXT+ TUBE
I don’t know how long this tube has been around but it’s new to me. I saw it first in the
most recent Parts Express catalog, #24. (www.partsexpress.com) I was intrigued by the
claims being made for it.
“Modeled after the vintage RCA 6L6GC “blackplate,” the Sovtek 6L6WXT+ features
larger plate dimensions and improved grid structure for increased power handling
capabilities. The 6L6WXT+ also features mica spacers with metal springs to eliminate
tube rattle and microphonics. The Sovtek 6L6 WXT+ yields a 20% higher output than
the Sovtek 5881WXT and offers superior tone and overall performance to any 6L6 or
KT66.”
I have quoted selectively from the catalog description but the same information is found
on the Sovtek web site from which I assume PartsExpress got it. (www.sovtek.com)
It has been a while since I put new tubes in the VTL 50-50. The 5881WXTs in it are
hardly worn out but I thought that it certainly wouldn’t hurt to try something new,
especially something potentially better. A matched quad from Parts Express is only
$55.60 so I got out the credit card and ordered a set.
As you can see in the photo, neither the 6L6WXT+ nor 5881WXT is a visually exciting
tube. You may be able to see that the interior structure differs (to my untrained eye)
quite a bit between them, though. Click here for the photo.
I should mention that in going through my tube stash this summer, I found that I had a
new set of four Philips JAN NOS 12AT7s. I went ahead and put these in the VTL several
weeks before I installed the 6L6WXT+s. I heard no change in the sound with the new
Philips tubes. The tubes that were in there, also Philips, weren’t very old but it seemed
like a good time to replace them since I was changing the output tubes.
Prior to switching from the 5881WXTs to the 6L6WXT+s, I did some test tone
measurements using the Stereophile Test Disc 1 and my Radio Shack meter at my
listening position. I retested with the 6L6WXT+s in place and there was no measurable
difference in the VTL’s output.
I biased the 6L6WXT+s at 27 milliamps, a DC voltage of 280mv. This is pretty much the
same setting I had been using for the 5881s. It’s at the low end of the bias range.
Diana Krall's The Look of Love CD was in my transport. When she started to sing, with
no warm up and zero time on the new tubes, her voice was immediately wonderful. As
the system warmed up, it got even better. The overall sound of this CD, except for her
voice, isn’t exceptional. The string sound, to my ear, sounds like it could have been
lifted from any Sinatra album of the 1960s. But that voice.
I subsequently listened to a lot of vocal music, especially female; these tubes improved
all of it.
It’s tempting to describe the improvement that I was hearing as providing substantially
better focus, which is correct but doesn’t adequately describe the extent to which the
vocals were more realistic. To carry the photographic analogy further, it wasn’t so much
that voices were better focused, but that there was a significant improvement in the
depth of field. Front to back it conveyed a greater sense of a whole person where
previously there had been, by comparison, only a voice. Clearly the 6L6WXT+s were
letting me hear more of what was coming to the VTL via the Perpetual Technologies pair
and the preamp. More information seemed to be available than had been there before.
And this wasn’t unique to this CD.
Eva Cassidy’s Live at Blues Alley was improved atmospherically as well as emotionally.
As a trade-off though, the tape hiss on the recording seemed more prominent than I
remember. Except that it didn’t matter. Her voice was enough more real that I could not
have cared less about the tape hiss.
My favorite Frank Sinatra album, and the best sounding in my experience, is Francis
Albert Sinatra & Antonio Carlos Jobim (Reprise 9 46948-2). Even though it is somewhat
disconcerting how Antonio sort of pops up just inside the left speaker to sing from time
to time, Frank has never sounded so emotionally connected. You sense he is putting
everything he’s got into every song. “Quiet Nights of Quiet Stars, Meditation, and How
Insensitive,” are some of the best Sinatra song interpretations that I have heard.
I also listened to the new Jackson Browne album, Solo Acoustic Vol. 1, which I totally
loved. This album locates Jackson close enough to fill the listening room with a living
person but far enough back that it doesn’t distract with fingering noises, breathing, and
so on. I certainly hope that titling this album Vol. 1 indicates that there are other
volumes in the works. www.jacksonbrowne.com
I also spent some time with James Taylor’s October Road, which seemed appropriate at
this time of year. I had only given this album a quick, cursory listen when I first got it and
never got back to it. This is a really fine album. It rewards repeated listening. It also
offers some excellent soundstage depth. The snare drum that fades out at the end of
“Belfast to Boston” was crisp and extremely snare-like as it faded out from the left rear of
the stage. The background singers are absolutely intelligible and sound like they are
really standing behind James and not just recorded at a lower level. As with the Jackson
Browne album the perspective seems ideal to my ear.
And the sound improvement didn’t just apply to vocals although it was more evident
there. I listened to all three Sounds of Wood & Steel albums from Windham Hill and
some lute music from Paul O’Dette as well as a bunch of other stuff. Everything I
listened to was better sounding through the 6L6WXT+s and, as a result, more musically
credible. And I think they are still breaking in.
Everything else that I value from my system is still there; there have been no trade-offs
that I can hear. The bass is great, the soundstaging is just as good as it has been, and
the subjective noise, measured by ear at the speaker, is actually noticeably lower.
Now it’s true that the 5881s I replaced had some mileage on them but there were hardly
worn out. Some of this improvement is undoubtedly due to the fact that the 6L6WXT+s
are new. Still, I have had several sets of 5881s in the VTL during the years I have
owned it and no replacement set ever made anything remotely like the difference in the
sound quality these tubes have. If they had, I know I would have remembered it. It’s that
obvious. I think it’s likely that the construction of these tubes does result in lower
microphonics and less smearing, producing a more realistic result.
If you have an amp running 6L6s or 5881s these tubes are worth trying. They’re cheap;
they cost no more than a matched quad of 5881WXTs. Given that the primary market
for these tubes is a guitar amp, I would expect them to be completely reliable.
Try a set of them. If they aren’t every bit as good as I say they are, give them to me. I’ll
be glad to have them.
Kent Johnson
October 20, 2005
I don’t know how long this tube has been around but it’s new to me. I saw it first in the
most recent Parts Express catalog, #24. (www.partsexpress.com) I was intrigued by the
claims being made for it.
“Modeled after the vintage RCA 6L6GC “blackplate,” the Sovtek 6L6WXT+ features
larger plate dimensions and improved grid structure for increased power handling
capabilities. The 6L6WXT+ also features mica spacers with metal springs to eliminate
tube rattle and microphonics. The Sovtek 6L6 WXT+ yields a 20% higher output than
the Sovtek 5881WXT and offers superior tone and overall performance to any 6L6 or
KT66.”
I have quoted selectively from the catalog description but the same information is found
on the Sovtek web site from which I assume PartsExpress got it. (www.sovtek.com)
It has been a while since I put new tubes in the VTL 50-50. The 5881WXTs in it are
hardly worn out but I thought that it certainly wouldn’t hurt to try something new,
especially something potentially better. A matched quad from Parts Express is only
$55.60 so I got out the credit card and ordered a set.
As you can see in the photo, neither the 6L6WXT+ nor 5881WXT is a visually exciting
tube. You may be able to see that the interior structure differs (to my untrained eye)
quite a bit between them, though. Click here for the photo.
I should mention that in going through my tube stash this summer, I found that I had a
new set of four Philips JAN NOS 12AT7s. I went ahead and put these in the VTL several
weeks before I installed the 6L6WXT+s. I heard no change in the sound with the new
Philips tubes. The tubes that were in there, also Philips, weren’t very old but it seemed
like a good time to replace them since I was changing the output tubes.
Prior to switching from the 5881WXTs to the 6L6WXT+s, I did some test tone
measurements using the Stereophile Test Disc 1 and my Radio Shack meter at my
listening position. I retested with the 6L6WXT+s in place and there was no measurable
difference in the VTL’s output.
I biased the 6L6WXT+s at 27 milliamps, a DC voltage of 280mv. This is pretty much the
same setting I had been using for the 5881s. It’s at the low end of the bias range.
Diana Krall's The Look of Love CD was in my transport. When she started to sing, with
no warm up and zero time on the new tubes, her voice was immediately wonderful. As
the system warmed up, it got even better. The overall sound of this CD, except for her
voice, isn’t exceptional. The string sound, to my ear, sounds like it could have been
lifted from any Sinatra album of the 1960s. But that voice.
I subsequently listened to a lot of vocal music, especially female; these tubes improved
all of it.
It’s tempting to describe the improvement that I was hearing as providing substantially
better focus, which is correct but doesn’t adequately describe the extent to which the
vocals were more realistic. To carry the photographic analogy further, it wasn’t so much
that voices were better focused, but that there was a significant improvement in the
depth of field. Front to back it conveyed a greater sense of a whole person where
previously there had been, by comparison, only a voice. Clearly the 6L6WXT+s were
letting me hear more of what was coming to the VTL via the Perpetual Technologies pair
and the preamp. More information seemed to be available than had been there before.
And this wasn’t unique to this CD.
Eva Cassidy’s Live at Blues Alley was improved atmospherically as well as emotionally.
As a trade-off though, the tape hiss on the recording seemed more prominent than I
remember. Except that it didn’t matter. Her voice was enough more real that I could not
have cared less about the tape hiss.
My favorite Frank Sinatra album, and the best sounding in my experience, is Francis
Albert Sinatra & Antonio Carlos Jobim (Reprise 9 46948-2). Even though it is somewhat
disconcerting how Antonio sort of pops up just inside the left speaker to sing from time
to time, Frank has never sounded so emotionally connected. You sense he is putting
everything he’s got into every song. “Quiet Nights of Quiet Stars, Meditation, and How
Insensitive,” are some of the best Sinatra song interpretations that I have heard.
I also listened to the new Jackson Browne album, Solo Acoustic Vol. 1, which I totally
loved. This album locates Jackson close enough to fill the listening room with a living
person but far enough back that it doesn’t distract with fingering noises, breathing, and
so on. I certainly hope that titling this album Vol. 1 indicates that there are other
volumes in the works. www.jacksonbrowne.com
I also spent some time with James Taylor’s October Road, which seemed appropriate at
this time of year. I had only given this album a quick, cursory listen when I first got it and
never got back to it. This is a really fine album. It rewards repeated listening. It also
offers some excellent soundstage depth. The snare drum that fades out at the end of
“Belfast to Boston” was crisp and extremely snare-like as it faded out from the left rear of
the stage. The background singers are absolutely intelligible and sound like they are
really standing behind James and not just recorded at a lower level. As with the Jackson
Browne album the perspective seems ideal to my ear.
And the sound improvement didn’t just apply to vocals although it was more evident
there. I listened to all three Sounds of Wood & Steel albums from Windham Hill and
some lute music from Paul O’Dette as well as a bunch of other stuff. Everything I
listened to was better sounding through the 6L6WXT+s and, as a result, more musically
credible. And I think they are still breaking in.
Everything else that I value from my system is still there; there have been no trade-offs
that I can hear. The bass is great, the soundstaging is just as good as it has been, and
the subjective noise, measured by ear at the speaker, is actually noticeably lower.
Now it’s true that the 5881s I replaced had some mileage on them but there were hardly
worn out. Some of this improvement is undoubtedly due to the fact that the 6L6WXT+s
are new. Still, I have had several sets of 5881s in the VTL during the years I have
owned it and no replacement set ever made anything remotely like the difference in the
sound quality these tubes have. If they had, I know I would have remembered it. It’s that
obvious. I think it’s likely that the construction of these tubes does result in lower
microphonics and less smearing, producing a more realistic result.
If you have an amp running 6L6s or 5881s these tubes are worth trying. They’re cheap;
they cost no more than a matched quad of 5881WXTs. Given that the primary market
for these tubes is a guitar amp, I would expect them to be completely reliable.
Try a set of them. If they aren’t every bit as good as I say they are, give them to me. I’ll
be glad to have them.
Kent Johnson
October 20, 2005
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