Shootout of Nos 6sn7 tubes

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.