Originally Posted by mordy
Hi Acapella 11,
Some time back you asked me if I had evaluated different power tubes that I had planned to do. I finally gathered up the mental energy to check out four different types that I have, all from the Novosibirsk factory. Driver tubes were the RCA DTox tubes in 1/7 strapping.
This task is akin to evaluating Coca Cola cans for taste from different bottling companies. Basically it is all very similar, but each bottling plant has a different water supply and ingredients from different places, and the soda tastes slightly different. In listening to these double triode tubes, I felt that it helped to have honed my ears on listening to heptodes, becoming aware of subtle differences.
The first power tube is a 6N6P from October 1975. The overall sound is pleasant, but the bass is soft and lacking in punch, slam and attack. The mid range tends towards the cool side. The highs are OK but too sharp. Details are good, but this tube is lacking in excitement and listening satisfaction, mainly because the macro dynamics are somewhat anemic.
The next power tube is the 6N6P with gold grid from October 1978. In comparison to the 6N6P above, it has much stronger and better defined bass with very good slam and attack. The mid range is sweet, and the upper range is very good. There is a coherent musical presentation and very good instrument separation. (BTW, GE invented the gold grid. It is found in their long life 5 star tubes. The amount of gold is minuscule, and I don't think that the price of the tube is effected by the changing price of gold - lol).
The next tube is the OEM 6N6Pi from June 1984 that came with the amp. Overall sweet and fairly detailed. Bass is good but lacking real heft and punch. The tube is lacking in treble detail and the treble is on the shrill side. Better than the 6N6P, but not the ultimate.
It has been said that the 6N6Pi is rated for 500 hours of service, and the other variants for 3000 hours. So far, none of these tubes have given up, and my guess is that those service hours are rated for a harsh environment in a MIG jet or military vehicle. Looking at the saucer getter, it is obvious that the tube was put together by a left handed person in their forties, and that you need to tilt your head towards the right to get the full listening experience.
Lastly, the mighty 6N6P-IR tube from May 1983 with smoked glass. These tubes are the best in this group, with real effortless punch, slam and attack in the bass, and top notch mid and upper ranges. These tubes bring additional clarity to the sound presentation with instruments standing out better in the sound stage.
In summary, the least desirable of the four types is the 6N6P and 6N6Pi. Then follows the 6N6P gold grid and the winner 6N6P-IR. The main easily noticeable difference between the tubes is how the bass is presented; the other differences described are there but more subtle.
The combination RCA 6DT6 (DTox) and 6N6P-IR is just plain intoxicating.....
Originally Posted by Audiofanboy
Mordy asked me if I could possibly add my impressions of the two types of power tubes I've tested, and it made me realize that I had never formally reviewed them; at least not in a nicely structured way with pics. So here goes nothing.
The Electro-Harmonix 6H30P-EB came stock on my MK IV SE. These are fine tubes: detailed, musical, balanced if slightly warm/colored; they make music sound very alive. You wouldn't notice anything is missing until you try a better tube really, and these complement the best but basic 6AK5 tubes very very well (the SE's stock tubes being these and the Mullard M8100 is no coincidence, it's an immediately satisfying mix).
Still, it took me a while to figure it out, but these definitely lack absolute transparency and detail, smear transients a bit, and above all, they add a color to the sound and keep the amp from being neutral -or at least controlled by the driver tubes, which is should be. So, excellent and musical tubes, but not the best; and for $60, probably not "better" than the best of the 6N6P family. These are just not that good of a deal at that price point imho.
The Reflektor factory 6N30P-DR are a totally different breed, even as an object. When you plug them in, you wouldn't notice an immediate and striking improvement but more of a "cold and neutral" signature (you can kind of picture Soviet workers making these in Siberia risking getting goulaged if they don't meet exact specs). So, at first, these definitely don't sound like $200+ power tubes; and there's no immediate "magic" -then again, power tubes are not supposed to sound magical, just neutral and transparent.
But, after a couple dozen hours, you can start to tell. Music just sounds right and better than you remembered: absolute transparency, realistic soundstage and detail retrieval (depends on your driver tubes, and the DR make finding good drivers difficult since they reveal faults very quickly), and as people have mentioned before, authority, absolute authority. Basically, after 100 hours with these, you can tell just how much of a bottleneck your previous power tubes were. The DR just remove that bottleneck entirely, and let you focus on driver tubes (a difficult search in and of itself).
Now, I can't recommend them to anyone without a few caveats. To me, they take away one the amp's limits and allow it to be worth twice its price -figuratively and not figuratively- and that let's me roll driver tubes knowing that I'm hearing the most they have to offer because the power tubes are just doing their job right. Compared to the $60 Electro-Harmonix or even $40+ Sovtek 6H30P-EV, the DR are vastly superior and in a different league altogether imo. They sound like a different tube type.
But compared to the best of best 6N6P, the 6N6P-IR, I'm not sure they're would be a seven-fold difference like the price would suggest. The 6N30 are most likely better than the 6N6, if just because they were made with even higher specs and are a stronger tube type in the first place (they were meant as an evolution of 6N6P tubes), but as far as sound quality goes, the 6N6P-IR are probably just as neutral and not limiting as the DR. Just different tubes, with a different sound, but that remove an absolute limit the amp has. That absolute limit just might be higher with the DR.
But, yeah, my choice of power tubes would still be between the best of the best Russians; and those would be the 6N6P-IR and 6N30P-DR, depending on budget and potential bottleneck concerns. I'd love to compare both, but I don't really wish to fork out another $40 to find out...
Thanks Mordy and Audiofanboy for your work describing the sound of your power tubes.
Long time back, I mentioned a surprise, I would come up with. And then nothing happened, lol. OK, now here it comes. I got myself a pair of Reflektor 6H30P-DR from 1983 and I considered a review since a while back but as you could tell from the frequency of postings, I haven't had time for it.
I thought, I put it all neatly together. Of course, this will give a huge post but it will prevent you with the need to go back in the thread.
Mostly, I focused on the differences between 6N6P-IR and 6H30P-DR but I also included my Sovtek 6H30P-EV and 6N6P gold grid tubes at least briefly.
6N6P Gold Grid, Novosibirsk - new (April 1995)
These power tubes provide a very pleasant signature. Gentle treble, sweet mid range but slightly mushy bass.
Sovtek 6H30P-EV (November 2011)
More transparency, more spacious than the 6N6P. In a classical concert the perception of room for example is better. There is more treble sparkle. The tube sounds overall more energetic. In a Verdi requiem Dies Irae, the kettle drum hits harder, punchier and reverb of the membrane is more apparent. This tube is definitely an upgrade over the 6N6P.
6N6P-IR, Novosibirsk - old (April 1974, side stamp says August)
6N6P-IR: Stage and ambience are the words peppered with lots of fine details. In the classical concert, the room now becomes more a hall in terms of depth. The signature is a bit warmer than the 6H30P-EV. The sound is not as energetic as the 6H30P-EV but more fine and detailed. The 6H30P-EV sounds “louder” but the 6N6P-IR more “real”.
6H30P-DR, Reflektor (March 1983) / 6N6P-IR
The king of the power tube price tag shows features of the 6H30P-EV sound: energetic, punchy and to some extend forward and on the brighter side. In comparison, the 6N6P-family has a warmer, “tubier” signature.
What do you get coming from a 6H30P-EV?
The DR sounds warmer, more natural than EV. The stage is particularly deeper and but also a bit wider. The ambience presentation is much better, i.e. the room around the performer has more presence. For example, a classical orchestra is more laid out in front of you. What about treble and bass? How are the mids? All these are more refined and natural. The signature acquires 6N6P-features but keeps the 6H30P framework. Now, many people would be satisfied and end the discussion but the greatest improvement is that you enter a more holographic music experience. The DR is definitely more musical and detailed. This may sound a bit stiff now, but I can imagine this as the transition from simple mid/treble/bass -based listening appreciation to the entry into high-end sound.
Now comes the 6N6P-IR: The stage becomes greater, who would have thought that? An amazing space is laid out in front of you. But the 6N6P-IR plays more with the 6N6P traits only on a totally different level as compared to the 6N6P (I have). Compared to the 6N30P-DR, the signature is warmer, the treble is more refined – the music comes across gentler. The DR throws more treble presence and overall a greater dynamic experience at you. This is particularly good for the harder kind of sounds, for example electric guitar riffs, which appear crunchy as crisps. The DR just eats power.
Let me picture you an example of how the stage is rendered differently between EV, DR and IR: In the Verdi Requiem Dias irae, trumpets play in the front and back of this huge venue in my recording. With the 6H30-EVs, you think the back trumpets sound further away, with the DRs you get a much better spatial resolution, the impression of the room is more apparent and the trumpets sound actually like they are further away. With the 6N6P-IRs, the trumpets sound not as metallic as with the 6N30P-family, but, they now actually do sound properly placed in the back. You can feel them pushed back as compared to other instruments and the room is most delicately resolved.
How come the IR renders more space? This is probably due to the fact that it sounds wetter as compared to the DRs. In Cold Rain, you can hear the high hats echoing more in the room and having a longer decay than with any of the other tubes.
In terms of bass, the DR and IR are very articulate, the IR is more biased towards deep bass and plays it of course wetter as well, which gives bass drum strokes more volume. The DR plays more the punchy and crisp mid bass, powerful - again. Mind you, these are relative differences. Both have slightly different styles.
The DR treble is really immediate, extended and on the brighter side, more refined than the EV though and feels well balanced. As mentioned, guitars sound very crisp with either but more natural and real with the DR. The IR plays it a different way, not as pronounced but delicate, still well balanced.
The DR has a very appealing and direct transparency, the IR plays (even) more holographic but gentler and more seductive with female voices for example. You could almost say that the IR is the “heptode of the power tubes” and the DR resembles rather a TS 6485 (6AH6). The 6H30P-DR brings the 6H30P sound in perfection. The 6N6P-IR follows the traits of the 6N6P but is really a whole world better. Now, the IR is enormous value for the money and although the EV is an upgrade from the classic 6N6P, the IR beats it easily. The big ranking question: Is the DR the ultimate choice? Maybe . Its power and detail richness are great. If this is your main focus, please tempt yourself in buying a pair. If you want to feel even more stage finely created before you, then the IR will make you very happy and (even) the DR won’t give you that in the same quality. There is a trade off you cannot avoid.
Driver tube: Raytheon 6BE6W – 1/7 strap
Headphones: Sennheiser HD800
I have FLAC files or PCMs from the original discs from files I have listened to during the review. In order to give you the option to listen to the tracks, I have linked youtube files for initial impressions.
Verdi. Dies irae (http://www.youtube.com/watch?v=MeXR5blDTIk)
Mozart, Sleigh Rides (http://www.youtube.com/watch?v=EWHzu1FJaOk)
Blues Company, Cold Rain (http://www.youtube.com/watch?v=nU8eBl2h8qg – This does not sound as clean as the original file.)
Mim Grey, Purple Sky (found no good link)
Rock / Hard Rock
Brice Springsteen, My Hometown (http://www.youtube.com/watch?v=S4F2VeHQe0Y)
Manowar, King (http://www.youtube.com/watch?v=m49tmKxq8gg – The interesting bit is at the beginning until 1:40)
Lindsey Stirling, Stars Align (http://www.youtube.com/watch?v=zKSs41Hv2AM)
Blank & Jones / Where You Belong - Poolside House Mix (http://www.youtube.com/watch?v=kRJsDStHZA8)
Edited by Acapella11 - 9/21/13 at 1:02pm