Shootout of Nos 6sn7 tubes

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.

@lowrider57

It is good to hear that you enjoy 1578 tube that I had recommend to you.

You also had gone through many 6n7 tubes.

1578 has the best bass, widest and deepest soundstage and sweet treble.

The only drawback of 1578 is that when I play lady vocal, I prefer Sylvania or TS vt231 due to more details

I know what you’re saying. The design of my amp with the extra tube stage allows me to add additional flavours. The Sylvania GTA Angled Plates have high-end energy that works well with female vocals. No sibilance, but crisp mids and highs.

@lowrider57 

i understand what you mean by mixing tubes.

Schitt Freya also use quad 6sn7 tubes, two for gain, two for buffer.

Kenrad  vt231 at gain and Syl vt231 at buffer work best for me.

https://www.ebay.com/itm/2-x-MELZ-6N8S-6SN7-Metal-Base-Tubes/264601117458?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


I got delivery of this 68ns Melz tube made in 1953 about 2 hours ago.

It took six weeks of wait from Ukraine.

But it is worth the wait.

This is the most exciting 6sn7 tube that I had tried in my Line Magnetic 508 amp.

it sounds very dynamic with excellent details, wide and deep soundstage.

Compared with famed 1578 Melz ( I have two pairs made in 80 and one pair made in 83), 1578 give slightly more bass slam, even wider and deeper soundstage.

While 1578 has clean treble, it sound rather closed in and bass heavy, but this 68ns Melz tube made in 1953 give more lively treble and details although its treble has slightly hard edge compared with 1578.

I am playing old rock. It seems that they are playing in front of me.

This is a steal at 65$ including shipping for pair which cost one quarter of 1578.

I place an order of two more pairs of this.

Thomas

It is going to be interesting if I can compare this 6n8s tube with Sylvania wgt metal base.

I have Sylvania wgt brown base which sounds similar to this 6n8s but 6sn8s give more dynamic sound.

But it is not easy to get Sylvania wgt metal base at reasonable price under 300$ per pair.

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.

 

@lowrider57 

I am quite impressed with 6n8s made in 53 with sparkle and air in addition to great bass.

Bohemian Rhapsody by Queen sounds so real through this tube.

I recommend you to get 6n8s metal base made in 1950 which cost less than 100$  per pair.

After 10 hours of listening to 6n8s made in 53, I am more impressed with it.

It sounds dynamic with nice air and details.

I am listening to "Hero" by Mariah Carey.

It sounds so delicious and nuanced through this tube that I am just happy.

It is kind of midway between 1578 and TS bgrp.

All Russian tubes that I had tried have better bass than even Kenrad vt231 which used to be called bass king of 6sn7.


The only drawback of this tube is it has some high frequency noise as well as 1578.

Some people had claimed to cure this through re soldering pins.

I had to try that someday.

That's very high praise for the
1953 6n8s.

I have not experienced any high frequency noise in my 1578's. They are so quiet and transparent I think I would have noticed.
Now I'll have to listen to the highs later today.

Do you hear any noise when music is not playing?

I keep hearing noise from 1578 made in 83 but not from two tubes made in  80.


68ns sounds lively but with some noise on an off.

After burning in, the noise may go off. Let us see.

@shkong78 Have you contacted the ebay seller about the noise in your 1578s? 

One of mine has noise with no music playing, some crackling.  I can hear it from my listening position about 9 1/2 feet away.  It's not noticeable while listening to music unless there's a quiet section.  I love the overall sound and tone of the 1578s but don't think I can live with the noise.  I've switched the tubes from one channel to the other and the noise follows.

I contacted them about it and they replied with a question, which I have answered.  Waiting to see if they'll offer a replacement.

@big_greg


I do not hear noise from the tube bought from Ebay dealer after playing it for 20 hours.

I recommend you to play it more and see what happens.

Some people claimed to have had cured the problem with re soldering pins.

They said most Russian tubes have problem with noise.

https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/page-120#post-15647922


But I am going to see what happens with more break in.


I like Russian tubes with excellent bass and nice value but some of them may need re soldering.

@shkong7One tube is as quiet as tubes get, the other is noisy.  

@big-greg

After playing 20 more hours, if you keep hearing noise, you can contact dealer about it.

Another choice is to do re soldering pins.

Some people in Headfi is of the opinion that it is better to do re soldering on Russian tubes.

I will also consider my options whether I will try to do re soldering myself or send my tubes to who can do better job than I.

I had gone through most of famous 6n7 except Telefuken and Sylvania wgt metal base ( I have Syl wgt brown base).

Now I am getting ideas of the pros and cons of each tube.

No tube is perfect.

1578 has rather closed in treble although its treble is pure and clean.

TS has no bass slam compared with Kenrad vr231 and Russian tubes.

So far my overall favorite is 6n8s made in 1953.

I do not claim that 6n8s sound better than 1578 or TS bgrp.


This 6n8s made in 53 goes midway between 1578 and TS.

Thus I enjoy this tube more than either 1578 or TS.


I placed just one more of 6sn7 tube.

Strong Matched Pair National Union 6SN7GT Black Glass Tubes Same 1951 Date
https://www.ebay.com/itm/Strong-Matched-Pair-National-Union-6SN7GT-Black-Glass-Tubes-Same-1951-Date/164063553459?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

It could be rebranded TS bgrp or maybe not.  

https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/

This will be my last order of 6sn7 (now I have around 100 6sn7 tubes).

I expect to get this tube this coming Friday.

I will finish shootout of 6sn7  tubes by this weekend.

I contacted them about it and they replied with a question, which I have answered. Waiting to see if they'll offer a replacement.

Who was the seller delax?
I purchased a pair from delax some time ago, one had the crackling noises, he was very helpful and refunded

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

The NU black glass is very similar to the KenRad, the bass is not quite as huge. A bit dark, beautiful sound.” –Robert H

@luisma31


It is good to hear good experience about Delax.

I ordered two more pair of 6n8s tubes from him.

https://www.amazon.com/Center-Stage-Lowell-Graham/dp/B0001XGOX8

I am playing Olympic Panfare.

6n8s give both sparkle and air on the top and also full bass slam out of it.

It sounds gorgeous through 6n8s made in 53.

Yes those are National Union tubes. The Gray glass NU tubes bass was a little soft. Those black glass have good bass and are liquid sounding. You should enjoy them. 

@luisma31 It was a different seller. 

@shkong78 It's been at least 20 hours. I'm not about to re-solder the tubes. 

@big_greg



It will be better to contact dealer explaining what happened, that is, one tube has no noise and the other one has noise even after 20-30 hours.

He may send you one replacement tube.

Please update the progress.

Yesterday I got delivery of quad Sylvania vt231 which I paid only 175$ for four tubes.

Both pairs sound nice with pretty good bass, but one pair give slightly more air and sparkle than the other pair.

I had experienced similar things with Raytheon vt231.

Three pairs of RT vt231 sound different from each other,

One sounds lively, the other one sounds neutral, the third one in the middle.

@shkong78 The seller of the tubes (the one in Russia that you recommended) has offered to replace the tubes and pay return shipping.  So far, so good.  I'll update once I receive the replacement tubes.

@big-greg



Nice to hear good news from you.

He seems to be a nice gentleman.

@shkong78 It's actually a she, someone named Olga.  It was a little odd that she asked me to send the tubes to an address in Delaware.  I'll wait and see how it all plays out.

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.

@lowrider57


Some people claimed to have had cured the problem with re soldering pins.

They said most Russian tubes have problem with noise.

https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/page-120#post-15647922


That is why I consider soldering myself or send them to someone who can do better job than I,

Even if you get a replacement tube, they can develop problem later.

I saw your earlier post about this. I'm pretty good at soldering, but have no clue how to work on a tube. Also, I wouldn't want to mess it up.

@lowrider57 

You can go through the Head fi thread that I gave you and then if you are comfortable, then you can try to re solder the pins.



Thomas

I'm going to contact the seller tonight. I received my second pair of 1980's, so I'll have a listen to them.

Did that high frequency noise go away? Which tube was it?

@lowrider57 

i remember hearing noise tube made in 83 ( that I got from Audiomart) but not from tubes made in 80( Russian and Ebay).

As I had played 6n8s tube for few days, I had not been playing 1578 for a while.

Melz quality controlled started to suffer in the 80’s.  If you want the best Melz 1578 look for a pair manufactured in the mid 70’s.  The hole plates construction is slightly different than tubes manufactured in the 80’s.  The 70’s 1578 do not have the slightly closed in high frequency extension like the 80’s tubes.  

If you have issues with the 1578's, your first course of action should be to contact the seller.  I'd avoid trying things like re-soldering unless you can't get satisfaction from the seller, or you don't care about taking a loss if you're unable to return them due to modifying them.

When you refer to "closed in highs" do you mean less extension or less high-end energy than 1970s?

The 70's 1578 have more high end extension which translates into a more balance sound. 

One person claimed that best 1578 that he had heard was made in 63.

There are many variations among the Nos tubes.

I have three pairs of Raytheon vt231 but they sound different from each other.

I also enjoy Russian 6n8s made in 53 with nice bass, air and sparkle.

Now I have around 100 tubes of 6sn7 variants.

I am listening to National Union black glass which will be the last one in the shootout.

I will summarize my findings this coming weekend.

I am listening to "Vision of Love " by Maria Carey through 1578 that I had bought from Russian dealer ( made in 80 same source as bought by big-greg and Lordcloud).

i do not notice any high frequency noise out of it.

Another interesting thing is that I had felt 1578 rather closed in with RCA 5691 (6sl7) in front of 1578 in Line Magnetic 508 amp.

But using Russian 6n9s made in 53 instead of 5691, this 1578 does not sound closed in but almost perfect neutral balance.


Now I am playing Miles and Coltrane "Straight No Chaser" track.

Trumpet sounds so clean with enough sparkle but not too hot.

I didn't feel like the 1578s had closed in highs and I didn't notice any noise in the upper registers, just the crackling out of one tube.  They definitely had more pronounced bass, perhaps that gives some the impression of "closed in 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.

@big_greg , did you return the defective tube?

@lowrider57 I returned they pair.  They said they'd send me another matched set.

Thanks, Greg. Sounds like a standup dealer, I'll contact him.

So far so good.  When I have a new pair of tubes that work properly, then I'll consider them a stand up dealer :)

Since I could not correct mis spelled words, I re posted.


  Third Shootout



1. National Union Black glass.



It was heard that National union did not make tube themselves but rebranded other tubes.



NU bg looks similar to either Kenrad bg or Tungsol bg.



its sounds similar to KR bg but with slightly less slam but slightly more treble extension.



i paid 120$ for this tube, It is not excellent value but worth its price overall.





2. Russian 6n8s metal base Melz made in 53



Most people talk about 1578 Melz.



But this one sounds nice with excellent bass, nice details, wide and deep soundstage.



Overall this give best performance for the cost (65$ per pair compared with 250$ per pair of 1578).



1578 sounds slightly more refined and dynamic while 6n8s made in 53 give slightly more detailed.



I had ordered four more pairs.





3. Amperex GTB



I had enjoyed Amperex 12Au7 tubes with neutral and round midrange.



Amperex may have house sound.



This Amperex gtb tube also sound round and refined midrange similar to RCA gray bottle.



It is a nice tube with Jazz.





4. CBS hytron gtb



This one sound lively with decent details and dynamics.



But compared with excellent vt231’s this tube is one notch below in details and refinement.



I would rather buy vt231’s or Russian tubes than this.





5. RCA clear bottle made in 56



I paid only 22$ for pair of this.



But it was very good value for the cost.



Sometimes you can get a hit from Ebay dealer.



It sounds similar to RCA gray bottle but with more transparency.



6. Russian 6n8s black base made in 78



I paid 46$ for quad.



But it was excellent with nice bass, details, dynamics, wide and deep soundstage.



It lacks refinement compared with 1578.



I like this tube overall.





Now I had gone through 16 different tubes.



My conclusion is all the Russian tubes give excellent bass, dynamics, wide and deep soundstage.



The best tube to me is 1578 Melz made in 1980 with explosive dynamics, widest and deepest soundstage,clean details.



TS bgrp has excellent transparency, details and speed but falls short of 1578 in dynamics and soundstage widtth.



TS bgrp sounds close to Sylvania vt 231 but more than three times of price.







My favorite is 1578 Melz, 6n8s metal base, Sylvania vt231, Kenrad vt 231, Raytheon Vt231.



RCA vt231 is also good with round and rush sound.



Pair of 6n8s metal base made in 50’s can be had under 100$ from Ebay, thus they are best value.








DetailsTransparenSpeedTonalityTreble ExTreble ClMi DynMac DynS. DepthS. widthNet costTotal Sc
TS bgrp9.59.51099.510989.5957593
RCA vt231998.59.59.598.598.5108990.5
KR vt231999108.59910998391.5
RT vt231999998.599.5996590
Syl vt10109.5810109.57.59910092.5
Bad boy87.58.597.58.58.598.5921584
15788.58.59989.59.510.51010.525094
S 181z88.5898.598.5898.512085
RCA gr87.5897.588.59.591010584.5
Syl Tall8.588.58888988.510882.5
Syl Wgt999998.5988.58.54587.5
Ts tall9998.5998.58.58.58.55487.5
Amperex8.588.59.58.598.59997688
Rca56999998.58.58892287
Cbshy989.58.5988.598.58.56586.5
6n8s(78)8.598.598.58.59999.52388.5
6n8s(53)99999.5991099.56592
NU bg9999.59998.58.5912089.5

https://www.head-fi.org/threads/shootout-of-nos-6sn7-tubes.932083/page-2

History of National Union...

https://www.radiomuseum.org/dsp_hersteller_detail.cfm?Company_id=2955

@lowrider57 



Thanks a lot for informative link.

Thank you for the helpful detailed notes Thomas.
I ordered on matched pair 1980 Melz 1578 from Olga. When they arrive will post my thoughts.
I own a pair of TS BPRP a pair of Sylvania metal base and Psvane Treasure CV181-TII. 
I find the coveted Tong Sol best it simply is more musical. Sylvania and Psvane a close second to each other. Sadly one Tong Sol recently died.

By the way I also live in the Seattle area. 

@mid40sguy 


Congratulation on getting 1578 tube.

Yesterday i had been back and forth between 1578 and TS bgrp.

Although, TS bgrp giive very sharp details, I prefer 1578 to it due to much better dynamics and wider soundstage.

But it will depend on system and personal taste.

After you get 1578, please leave your impression of it.

Thomas