Shootout of Nos 6sn7 tubes
shkong... According to my research the early Melz tubes have the 1578 lettering. There were two factories producing Russian tubes and the holy grail tubes have multiple holes on the plates. https://www.ebay.com/itm/133366164135 |
Thanks for posting your results. I’ll start by saying all systems are different. I agree with your results of the KR VT-231, RCA 231. Also the Sylvania VT-231; very good tube but bass is light and not extended. RCA vt231 is kind of all around player. Compared with TS bgrp, its sound is slightly warmer with lush tone but with enough sparkle and air.Good description, I find the RCA to have great warmth and air. For a more neutral tube, RCA GTB has the same mids and great top-end. However, I must say the Tung-Sol BGRP is my favorite tube. I find it to have smooth extended highs, transparency, and solid bass. A very musical tube which presents realistic sonics. I paid close to $500/pair. Very expensive, it’s become difficult to find matched pairs with low noise and microphonics. Some of the Sylvanias would be a good substitute and they are very affordable. |
I’m loving my new 1578’s that shkong recommended (1980). They’re in the gain stage of my Atma-sphere S-30 and they sound as good if not better than TS Round Plates. The low-end is deep and tight with liquid mids, and the highs are extended yet extremely smooth. Clear and quiet, revealing the softest sounds in a deep and wide soundstage. Right out of the box (there is no box, they’re in rolls) music had the greatest sense of realism I’ve heard in my system. They’re so transparent and tonally accurate that the tube search for this amp is over. There are 6 input tubes in the amp; each channel uses two tubes in the gain stage plus the phase inverter (driver). The 2nd gain tube is a Sylvania GTB, the driver is a Sylvania GTA angled plate. Other 6SN7s I’ve tried in my amp or preamp are: Sylvania VT-231, which does everything well but is weak in the bass. Sylvania 1950s GT Staggered plates Sylvania 6SN7WGT KR VT-231 WWII RCA VT-231 & GT black glass RCA GTB 1950s Silver label T-S Black Oval Plates WWII T-S GTB 1950s Triangular plates Russian 1960s 6H8C black base I’m sure I’m forgetting some. |
So, 1950's tubes made in the same factory but with different plate construction. I read about these, but never found a review until now. I tried Syl 6SN7WGT brown base, but was too extended and thin in the highs for me. Would like to hear your review of the metal base, but they are expensive and hard to find. Now that I've spent some time with the 1578's, the TS Round plates sound sweeter and are more holographic. 1578 goes deeper with tighter bass. I'm so.pleased with my purchase, I ordered another pair of 1980 1578's. |
Ive been curious about the NU. I never ordered them since reviews say the bass is not extended. Can't wait to hear your thoughts. The NU tubes are both some of the smoothest 6SN7s I've heard. They aren't really lush so much as they are "liquid." RCAs are definitely sweeter. I prefer the gray glass for its tonality, but the black glass has better bass in my system” –Len ● “…the sound is very good. Wide soundstage, a little more forward presentation, very good bass, and treble, and a sweeter midrange than the Kenrad. I still like the way the Kenrad attacks better. but if your looking for a lusher sounding tube than the KenRad theses grey glass NU are good. They dont sacrifice the bass and little treble.” –tom hankins |
Big Greg and shkong, One of my 1578's started crackling and popping today. I cleaned the pins, no difference. Swapped channels and the noise follows. I let the amp idle for a while and then I smelled something cooking; it was the tube. I shut down and now will check the amp for any damage. I don't understand after full burnin and hours of playing that this tube problem presented. |
@testpilot Thanks for that info. I was wondering if there was a QC issue; first big Greg, then I lost a tube from the same batch (I think). When you refer to "closed in highs" do you mean less extension or less high-end energy than 1970s? The Melz followed by a Sylvania GTA in my amp have terrific highs. |
I'm using the 1980 1578 in the Atma-sphere gain stage with a Sylvania GTA in the 2nd stage. There's lots of high-end sparkle and air due to the GTA's excellent highs and mids. That's why I haven't noticed a lack of extension with the 1980's. @testpilot, there are no Melz 1970s to be found, but I'll continue to search. |
Thomas and big_greg, I'm not enjoying my second pair of 1578's at all. It's taking a long time to burn-in; they don't have the bass extension and impact of my first pair which sounded great from the start. It's a shame one of them crapped out. I have 35 hours on Melz #2 and pulled them out. I'll burn them in some other time. Early 1950s Tung Sol GTB are sounding better than the Melz. Luckily my replacement 1578's arrived today. |
@testpilot This subject was mentioned on another forum. All the best tubes went into service with the Russian Military and QC standards were high during the Cold War. The tubes in question are from 1980 and QC had slacked off by then. The Military still got the highest rated tubes, others were sold to the public. These do have the OTK inspection stamp. Sounds like a plausible explanation. |
I'm not enjoying my second pair of 1578's at all. It's taking a long time to burn-in; they don't have the bass extension and impact of my first pair which sounded great from the start. It's a shame one of them crapped out. My news of the day is very positive. The replacement 1578's sound incredible after 30 minutes warmup. A low noise floor is revealing subtle sounds from a deep 3D soundstage. Fingers crossed on these tubes. My first pair sounded great until 50 hours when they started to crackle and burn. Tracking shows my Melz 6N8S from Ukraine has passed through JFK customs. Something to look forward to. |
Another bad Melz 1578. I ordered 3 pairs and like the first set, one tube is crackling after 50 hours of burnin. It's also microphonic; in between crackles I can hear the tube echo thru the speakers when I tap on my amp. These are all from 1980 and the same dealer (who does accept returns), but I'm done gambling with this batch of tubes. Damn, they sound so good. I received my 6N8S 1950 pair from Ukraine, but will wait to try them until I've run-in my 1578's. |
I was pretty good at soldering, but over the years my vision has deteriorated. Plus this is not a task I would want to do. I think soldering would only make sense if doing pairs of tubes. I went back a few pages on the Head-Fi link and he was soldering all his Melz tubes. It would be great if somebody in our hobby who loves tubes was offering this service. I must say that my system sounds the best ever. I have a pair of 1578's in the front of my Atma-sphere gain stage, Sylvania oblique plate GTA's in the 2nd gain position, and Sylvania GTB's as the drivers. Music is transparent and realistic with high and low extension. And best of all is the 3D image which extends back into the wall and out in front of the speakers. I think this is possible due to having 2 different pairs of 6SN7's in the gain stage. |
Charles, I wanted to report back to you on adding Sylvania VT-231 to 1578 in the gain stage. What a great combination, thank you. To use your words, there's a spooky black background. Listening to some Blue Note, I heard the drummer breathing during his solo. The VT-231 is so quiet and refined, fantastic tube and perfect top-end for the Melz. |
@big_greg For now I have my Sylvania 1950s vintage 6SN7GTB chrome domes in. They are really nice sounding all around, but don’t have the bass of the 1578 and maybe a little less detail. They are very "neutral" sounding and do everything right, but I liked the way the 1578’s added more detail and texture to the bass.The Sylvania GTB is an underrated tube. I’m using them in the driver/phase inverter position. Excellent midrange, smooth highs with wide soundstaging. A laid-back sound which doesn’t have the typical Sylvania voicing. As good as it sounds in my system, I’m still auditioning other tubes. |
