so ive had about 48 ish hrs of burn in on these tubes and its quite a difference from stock… I just had one of those moments where you hear a song that you’ve heard many times before the best you’ve ever heard it… hd650 and gordon lightfoot read my mind the bass is really nice and smooth and apparent and the guitar in the right channel isn’t as dark as I remember and is very clear and sparkly and his vocals are always fantastic but yeah just really great on this little setup… there’s a hum in both channels but its become significantly less noticeable as more time passes and its not bothersome whatsoever… these tubes are staying
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gonna be selling my Darkvoice and a bunch of tubes as well, if anyone is interested pm me for more details
here is the AVexchange listing for anyone interested; https://www.reddit.com/r/AVexchange/comments/gai9i9/wts_ustn_h_darkvoice_336se_a_bunch_of_tubes_w/
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What are you replacing it with? I’m curious
already replaced it with a Hagerman Tuba also about to buy a LTA MicroZOTL mz2 soonish
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Very very nice! I just can’t seem to let mine go yet, eventually, just not yet. Both of those are very nice pieces! Give feedback and info whenever you can on either. 
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I do have some impressions over in the tuba thread if you want to take a look.
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lol Darkvoice already sold. Got bombarded with like 5 messages at once. If anyone is interested in the tubes they are still up.
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The Shuguang tube @ZeosPantera uses finally came in today.
Hum in left channel again, though less than I remembered from burning in the new Tung-Sol a few weeks ago. Of course, impressions to follow after burn in and listening.
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A quick note on this Shuguang tube… After about 2 hours sitting on the DV powered on, the buzz/hum in the left channel pretty much disappeared on my 6XX. That’s about 2 or 3 days faster than the Tung-Sol tube did so. I haven’t had a thorough listen yet as I also got my A3 today and am listening to that right now. First world problems…
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OK, I pulled myself away from the new A3 + Edition XX combo a couple of times over the past couple days to listen to this Shuguang tube (CV181-Z 6SN7). In @ZeosPantera’s review of the Schiit Lyr 3 he mentions that this is the tube he uses as the driver tube in his Darkvoice. In the Lyr 3 video he states how much he loves this tube. So, I thought I’d give it try. Spoiler: I don’t get it, Z. It’s hard for me to find a place for this tube. It’s a fine tube. It sounds really good. It just doesn’t do anything unique or special to my ears. Read on if you want to know why.
When I first turned this tube on for an actual listen, I put my DT880-600 on it, and when the music started my immediate thought was “sounds like solid state.” After a total of 3 days of burn in (which wasn’t necessary, the normal buzz really did vanish after 2 hours) and a few more hours of listening that impression hasn’t gone away. To add to that I now have a Schiit Asgard 3 sitting right next to my Darkvoice and TBH, that’s the most direct sound comparison I can make for the DV with this tube (and an RCA 7613 6AS7 power tube which the packaging I received it in claims was made in 1969). This Shuguang tube is super clean. There’s no hiss. There’s vanishingly little audible tubey distortion. It also narrows the soundstage noticeably in comparison to the A3. I did most of my comparison of this tube with the A3 trying to discern subtle differences. That’s how similar the DV with this tube sounded to solid state. I think that’s this tube in a nutshell right there. Within that slightly narrower sound stage there was still pretty solid imaging and separation. The Shuguang tube gave both the DT880 and HD6XX a little bit more bass punch than the A3, and maybe just a touch sweeter treble, but we’re really splitting hairs here.
Pulling out the Shuguang tube and putting back in a Sylvania JAN CHS 6SN7GT VT-231 from 1940-something, that “tube sound” came back. The soundstage widened out again, a bit more timbral and harmonic richness returned, and the dynamics were punchier and livelier. In exchange, yes a bit more hiss and a touch of upper-mid grain returned, but IMO the benefits hugely outweighed those negatives. These differences were noticeable on both the DT880 and the HD6XX, but moreso on the 6XX. Going back to the A3 to compare again, the A3’s sound was just as wide with similarly effective imaging and separation, but with the solid state cleanliness. The DV with Sylvania tube still gave both headphones more bass impact and extension though, again with the 6XX having the larger delta between tube and solid state.
So, I’m back to the basic question of ‘what does this Shuguang tube do for the sound that I’m not already getting from other gear?’ I can’t figure it out. I’m also puzzeled by Zeos here. To borrow his NSFW language, he often mentions “tube fuckery” - the tube is doing something to the sound to change it from neutral - as the point of a tube amp. To my ear, this Shuguang tube does little-to-no sonic “fuckery.” In fact, with the narrowing of the soundstage and reduction of some of the harmonic richness I get from the Sylvania tube, this Shuguang tube takes an OTL tube amp and essentially turns it into a solid-state-like amp. Why do that? IMO, if you have a Darkvoice you should skip this tube. If a DV is all you have and you want a solid state switch up, you’re probably better off going with one of the ~$100 SS amps floating around out there now.
What am I going to do with this Shuguang tube? For the time being I’ll probably store it away somewhere to see if I ever get a more expensive tube amp/pre-amp that takes 6SN7 tubes. Maybe there will be more magic there. If after some time I don’t do that, I’ll probably Ebay it away.
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Thanks for being the guinea pig. Yeah, I learned long ago not to trust Zeos’s ears. Thankfully, my self-imposed budget for individual tubes prevented me from ordering the Black Treasures in the past and your experience cemented that moving forward. For my DV, I too like the gooey tubey-ness that comes from my Sylvania VT-231’s, early '50s Sylvania 6SN7GT chrome domes, '50s Sylvania 6SN7GTA’s, and RCA grey glass (both 6SN7 and 6F8G) compared to the more solid state sounding Tung-Sol 6SN7GTB’s for example. If I want a solid state sound, I have much better options than going through the tube amp route.
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Thanks for your comments. I do want to be clear I’m not trying to dump on @ZeosPantera here. I think his channel plays an important role in the hobby by informing us of the huge breadth of gear out there, and he goes into way more depth about functionality than other reviewers. But outside of that, yeah, I have several data points now that show he and I hear things differently. That’s OK. I do wish he would temper comments about “endgame” and the like, though.
My Sylvania VT-231 is not a chrome top. It’s all glass. I wonder if the all glass and chrome domes sound much different?
Likewise, my Sylvania VT-231’s do not feature a chrome top since their getters were flashed on their sides.
As for differences, I also hear the grain that you mentioned with my VT-231’s. Prior to reading your comment, I just thought that my VT-231’s were just getting old since I bought them used rather than NOS*. My chrome topped '49 Sylvania 6SN7GT does not have the grain of my VT-231, and is incredibly lush sounding. Probably one of my favorite tubes in my collection.
*As an aside, NOS is certainly no guarantee of a working tube. A surprisingly cheap NOS RCA '40s grey glass 6SN7GT that I purchased started to arc when I flipped the switch on, complete trash.
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OK. Interesting. I got my Sylvania VT-231 used as well. Maybe we can’t rule out the age-grain thing. I looked again. Mine has chrome around the barrel down near the black part:
and an all glass top:
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That looks right. I don’t think I’ve seen the getter flashed anywhere else on Sylvania VT-231’s other than the sides. I have two different Sylvania VT-231’s and they both have that side getter and, audibly IIRC, exhibit the grain that you mentioned, which why I limited my collection of that tube type to those two, haha. I’m going off memory because it has been months since I listened to those tubes, and I don’t have my DV with me right now while I’m away from my city.
Usually, my '54 Sylvania 6SN7GTA and '50s RCA 6AS7G are my good-enough, workhorse tubes in my DV. I’m not going to touch Tung-Sol VT-99 round-plates, Tung-Sol 5998’s, or Western Electric 421A’s. I just don’t feel like purchasing tubes that are approaching the price that I paid for my DV.
Fully agree on your last point. The VT-231 combined with an RCA 7613 6AS7 are a really good combo in this price range.
Hopefully this post will be my last report on new (to me) tubes I’ve been playing around with. I think I’ve found a tube combo I like. Furthermore, I have been falling into a rhythm of using my Asgard 3 + Edition XX for rock, metal, pop, hip-hop, and edm and using my Darkvoice + DT880-600 for classical/orchestral, jazz, and gaming.
Here’s a slightly more detailed report on the different power tubes I’ve been using. I’ve used the stock 6AS7 tube, an RCA 7613 GAS7G that the box claims was manufactured in 1969, and now a Sylvania 6AS7G ST about which I know very few extra details. I’ve settled on the Sylvania for most listening. That means I’m running a Sylvania VT-231 6SN7 tube and this Sylvania power tube. Most of this thread has been about the differences pre-tubes make in the Darkvoice. Here’s some more info about power tubes…
I will agree with those who have said the pre tubes make a bigger difference to the sound than the power tube. I noticed this too. But, the power tubes do still have a say.
The stock power tube really isn’t bad. Combined with the Sylvania VT-231 pre it is a mostly pleasurable listening experience. However, it has a brighter sound than either the RCA or Sylvania power tubes here. The treble initially comes across as bright and detailed, but does get sibilant. It also becomes hashy and breaks timbre when there is lots of rapid-fire treble in the recording (like riding crash cymbals while also foot-pedaling the hi-hat). This brightness also accentuates the VT-231 pre’s upper-mid grain. The RCA greatly reduces that sibilance but has a touch more high-frequency white noise ever-present in the background, though. This noise is not noticeable on most material, though. The Sylvania reduced sibilance yet more than the RCA. The Sylvania also did the best job with soundstaging and imaging. It really complements the VT-231 well by reducing its graininess and reducing the high-frequency white noise the RCA pushed a bit more forward.
Both the RCA and Sylvania sound warmer than the stock tube. They both have more bass extension and more bass quantity. The RCA has the most bass of the three. The RCA’s bass is also tighter and quicker than the stock tube’s, but the Sylvania has the tightest, quickest bass of the three.
To my ear, the Sylvania really separated itself in the mids. When a track got busy in the midrange, the Sylvania held up the best. It differentiated between individual instrument and vocal sounds better, had more overall resolution, and to put it crudely, didn’t turn into mush as quickly or easily. The RCA wasn’t bad here; just not as good as the Sylvania. The gap between the Sylvania and RCA was still much smaller than the gap between the RCA and the stock tube in this regard.
OK, I hope someone out there finds all my tube musings useful. Feel free to ask me questions if any of my tube comments are unclear. But for now, I’ll be running with this pair of Sylvania tubes. Cheers.
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Nice write up and really good insight. I commend people who put in the work like this and create a good resource 
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Hello everybody. I have a tung sol 6as7 and Im looking to upgrade. what do you guys recommend? I found these , are any a good deal? Any other recommendation is appreciated. Must ship to the Philippines