Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot Tube Amps: Vacuum Tube Rolling Guide
New Posts  All Forums:Forum Nav:

Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 201

post #3001 of 7449
Quote:
Originally Posted by Iron58p View Post
 

Someone can please explain to me  what is the meaning of O-getters or D-getters ?

 

What part of tube i must to look ? For example, i'm referring to my TS 6AH6WA, but i have no idea where and what to look.

 

Thank's

 

Its physically the shape of the getter. The shape can be used to identify the the same tube make & model came from different factories or different dates.

 

A getter is a deposit of reactive material that is placed inside a vacuum system, for the purpose of completing and maintaining the vacuum. When gas molecules strike the getter material, they combine with it chemically or by adsorption. Thus the getter removes small amounts of gas from the evacuated space.

 

http://en.wikipedia.org/wiki/Getter

post #3002 of 7449
Quote:
Originally Posted by Audiofanboy View Post
 

"And now for something completely different."

 

OK, so I tried to ramp up the difficulty level a bit lol. Don't try to reproduce the experiment I'm about to show you at home, unless you really know what you're doing -I hardly am!

 

So, I'd been looking for 7-pin socket adapters -versatile adapters, not one-shot adapters that make a tube type into an other and nothing else- for a while, and finally bumped into a website that sold quality NOS adapters for cheap. Shipping across the world was cheap too, so I bought three pairs of adapters. They finally got here today.

 

Now, I'd had -and still have- a number of ideas in my head of new tube types to try on our LD amps, most of which would require some thorough pin reworking, but there was this one experiment I wanted to try first; ironically it was the most challenging one. Using one of those ubiquitous double triodes that everybody loves on my LD amp! It's a good thing I had an old mil spec Mullard M8162 lying around (it came with a box of very random tubes months ago, back in the EF91 days). So, I started working on adapting that single 12AT7 tube on my two-separate-pentode LD!

 

Here's a picture of the adapter/tester/savers I got. Brand name is Vector, and they seem to have been a reference back in the tube days.

 

 

The tube I adapted: Mullard M8162 / CV4024, mil spec 12AT7, Mitcham-made; barely legible when I took the picture 8 months ago, and even less now that I manhandled it into submission...

 

Just your basic 12V, center-tappable, high-mu double triode. I just realized that this a $30 tube on ebay, actually, so maybe not that basic.

 

 

 

I'll cut to the chase and just illustrate what I did with a picture (how's my "reach out to the gods" setup Mikelap lol?), just so you can see just how unpractical this whole setup is -and how crazy an attempt to adapt a tube it is!

 

Basically, I chopped up some old computer cables and stripped them on one end. The other end I used with its metal hole to squeeze onto the tube pins as DIY air socket holes (R) (with great difficulty and little fate that the contacts will last long). The stripped end of the wires I attached to the socket adapters' tester tabs in a non-destructive way (the adapters can be unscrewed and opened -which I had been hoping for since it was what I needed- so I squeezed the bare wiring underneath the tester tabs and screwed the adapters closed again).

 

Made each of the nine wires (9 pin double triode) go to the appropriate pins on the tube, and socket holes on the amp; using the heater center tap to power the tube (so pins 4+5 to one of the heater pins on one of the sockets, and pin 9 to the other heater pin on the same socket), and rerouting each triode pins to the appropriate pins on each socket. The pieces of paper below the tube aren't to make it pretty; they're there because I was very scared that the wires would touch each other, and they would have otherwise!

 

Interestingly, it only took me two attempts to make this mod work (I was expecting it to fail; I didn't even know if the tube was good). First time I had messed up some wires on the right side, so the heaters -fortunately- didn't power on, and I was spared the awful PPSHhhh noise, just got silence.

 

 

On my second attempt -a bit more thorough than the hasty first one- everything worked perfectly!! Filaments lighting up, music in both channels: success! I did get a bit of noise in one channel for half a second, but I know that's because the tube is barely attached to the wires and kind of hanging from nowhere, so I wasn't surprised. It worked flawlessly for 15 minutes after that.

 

What is even better is that it sounded great, which is not an easy feat considering that everything was wrong with this mod: wrong number of tubes, wrong tube type, wrong number of grids, extra 50 years old adapters, 15cm of crappy wiring without shielding, dubious tube...  But still, it sounded as good as my current fav' 6DT6 tubes, so top-tier. Very natural and musical sound, detailed and realistic but still toe-tapping; I guess double triodes are cool too huh?

 

It does kind of look like the amp is holding up a tube as an offering to the gods though lol. I'd imagined it would have looked even more rigged, so this isn't even that bad for a quick test.

 

 

Like I said earlier, the adapters unscrew, and the whole top part comes off with the pins and tester tabs, so you can squeeze stuff in there and not destroy an adapter by soldering wires for every new pinout you want to try.

 

 

Anyway, interesting experiment. Unpractical for sure, but my goal was just to prove that it worked, not to leave it there. Not only did it work but it sounded great! So, I'll be investigating this a bit longer. If a 12V center tapped double triode can be made to work on this amp, you can sure bet a 6V double triode like the 6DJ8 would too! And these are supposed to be very very nice tubes.

 

Notice how such a setup would use less power than our typical tubes: a single 0.3A heater instead of often two in our pentodes. Then again, the "prettier" solution using double triodes here would probably be to just use one per channel with a clean 9 to 7 pin adapter, and only use one triode out of the two in each tube. More expensive and a bit silly, but it would be the only way to not have a tube floating in the sky on top of your amp between sockets...

 

I had to open up my amp a few days ago and took the opportunity to take -non-destructive- pictures as best I could. You can't see much but it gives you a pretty good idea of what is in a MK IV SE, seen from the front. Pics can be enlarged if you actually want to see something.

 

 

Edit: See that wooden thing on the picture above? That's my solution for changing jumpers easily. Glued a match stick to an elongated jumper so that the wooden part pokes out by maybe 2 mm outside the amp, meaning that I can grab and change the jumpers by hand.

 


Edited by MIKELAP - 9/20/13 at 12:00pm
post #3003 of 7449
Quote:
Originally Posted by MIKELAP View Post
 

 

Like Arte Johnson ( 70's tv show Rowan and Martin Laughin) would say ¨ Very interesting¨  . I would call that Audiofanboy's REACH FOR THE STARS setup .Yup i like it !

 

 

post #3004 of 7449

Today i've put my TS JTL6AH6WA on my LDi+

 

Strapped on 2-7 pins.

 

Sound in different mode from Others tube listened before, bass are present well, very deep soundstage, vocal a little bit warm and "cottoned ", but i feel hights not very clean and detailed.

But i love this tube, after burn in can change something ; i can listen for hours without feel fatigue.

 

For my modest opinion, i prefer Sylavania 5915 strapped today for the first time to 1-7 pins.

Great soundstage, great hights and transparency.


Edited by Iron58p - 9/20/13 at 12:15pm
post #3005 of 7449

Received two pairs of GE 6HM5/6HA5 today. These tubes require no strapping of any kind. Simply set up the LD for EF95 tubes, plug them in and play. Both GEs indicate that they were made in Great Britain, but only one pair has Philips tube codes. The tube on the right was manufactured by Mullard while the one on the left has no markings of any kind. The internal construction of these tubes is also very different.

 

 

Comparing the construction of the RCA/Siemens and the GE/Mullard, with the exception of the glass envelope, they are quite similar. And since they were both manufactured by Philips, this is not all that surprising. If anything, I am a little surprised that they don't look identical. Hope to spend some time over the weekend with these tubes....

 


Edited by gibosi - 9/20/13 at 2:53pm
post #3006 of 7449

A quick update....  The RCA/Siemens 6HM5/6HA5  are not recommended. The soundstage is noticeably narrow, the bass is lacking and music sounds congested. They have more than 15 hours on them and I just don't think they are going to get significantly better. It is almost as if the short squat tube doesn't provide enough head room. lol  

 

Surprisingly, the GE/Mullard sounds entirely different, and much better, as does the other Great Britain made, but not by Mullard, GE. The two GEs need considerably more burning-in before I can say anything definitive, but straight out of the box, both sound pretty good to my ears.

post #3007 of 7449
Quote:

Quote:

Originally Posted by mordy View Post
 

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 View Post
 

 

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.

 

Appendix:

 

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.

 

Classical

Verdi.  Dies irae (http://www.youtube.com/watch?v=MeXR5blDTIk)

Mozart, Sleigh Rides (http://www.youtube.com/watch?v=EWHzu1FJaOk)

 

Jazz

Blues Company, Cold Rain (http://www.youtube.com/watch?v=nU8eBl2h8qg – This does not sound as clean as the original file.)

 

Singer/Songwriter

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)

 

Electronic

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
post #3008 of 7449

An udate on the Tung-Sol 6AV6: (And yes, I have been busy! lol )

 

 

In short, these tubes sound substantially identical to my 1958 GE 6AV6.

 

As others have pointed out, yes, most 6AV6/6AT6 tubes do sound quite similar to one another. However, if I roll through the GE, Mullard, Lorenz, Telefunken and then RCA, differences in warmth and forwardness are very easy to discern. 

 

Rolling through the GE, FIVRE, Toshiba and these Tung-Sols, I cannot hear anything substantially different. While I have to assume that these tubes do not sound perfectly identical, any differences that might exist would appear to be very subtle and will likely require extended critical listening and perhaps better ears than mine to parse. For now, I am quite content to say these all sound the same. :)

 

I have recently been using this track to help me distinguish between the the 6AV6:

 

Lana del Rey - Summertime Sadness (Asadinho Main Vocal Mix)

 

 

post #3009 of 7449
Quote:
Originally Posted by Acapella11 View Post
 

 

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.

 

Appendix:

 

Driver tube: Raytheon 6BE6W – 1/7 strap

Headphone: 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.

 

Classical

Verdi.  Dies irae (http://www.youtube.com/watch?v=MeXR5blDTIk)

Mozart, Sleigh Rides (http://www.youtube.com/watch?v=EWHzu1FJaOk)

 

Jazz

Blues Company, Cold Rain (http://www.youtube.com/watch?v=nU8eBl2h8qg – This does not sound as clean as the original file.)

 

Singer/Songwriter

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)

 

Electronic

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)

 

 

Finally a comparative review of the 6N6P-IR and 6N30P-DR! Great work Acapella!

 

Beyond being very useful, your review confirms a few of the things I'd been "speculating on" regarding the IR tubes. From everything I had read here, and my own impressions of DR tubes, I pretty much gathered that the 6N6P-IR were a better deal -higher "limits"- than the new production 6H30P tubes, and quite a leap from even the best 6N6P.

 

But it is interesting to have that fact put into perspective with the DR tubes. "Holographic" and "realistic" are the two words I would usually use to describe the 6N30P-DR; I know that they are musical and detailed as well, but those aren't the first things that come to mind as far as I'm concerned (the "musical" trait take a solid 100 hours to show up actually; it never leaves again though). So the fact the that you use "musical" to qualify the DR compared to other power tubes kind of confirms what I thought about them: that they let the amp breath like no other power tube, basically, and that makes the whole amp musical.

 

About treble on the DR tubes: I agree that they have very very detailed treble; probably so much so that it would be hard for me to downgrade at this point (you get used to quality lol). I also very much like the dry and perfectly controlled bass on those tubes.

 

Apparently the 6N6P-IR offer just slightly lower "limits" and an different flavor. It's good to have someone actually confirm that. I'd be curious to hear your impressions a few months down the road, between the DR and IR tubes though; you can really get addicted to the dynamic and ultra-detailed nature of those tubes imo!

 

I'd also love to hear the same review on a MK IV unit, just out of curiosity.


Edited by Audiofanboy - 9/21/13 at 1:18pm
post #3010 of 7449
I can't work out what happened but I bought the Hytron tubes and thought they were amazing straight away with no burn in times. But after about 10-15 hours they have gone from being detailed and a great soundstage with deep bass. To veiled and to be honest my least favourite tube ??? Burn in has changed them for the worse. From my initial impression of them I thought these are awesome to now meh! Has anyone else had this happen to them.
Edited by foreign - 9/21/13 at 3:08pm
post #3011 of 7449
Quote:
Originally Posted by foreign View Post

I can't work out what happened but I bought the Hytron tubes and thought they were amazing straight away with no burn in times. But after about 10-15 hours they have gone from being detailed and a great soundstage with deep bass. To veiled and to be honest my least favourite tube ??? Burn in has changed them for the worse. From my initial impression of them I thought these are awesome to now meh! Has anyone else had this happen to them.

 

Which Hytron tubes do you have? But yes, while tubes usually improve after burning in, sometimes they get worse. And in fact, I seem to remember that not that long ago, some members of this forum observed that the Voskhod 6J1P-EV improved after burning in, but then, after 100 or more hours, they changed for the worse. So while not all that common, your experience is not unheard of.

post #3012 of 7449
Quote:
Originally Posted by foreign View Post

I can't work out what happened but I bought the Hytron tubes and thought they were amazing straight away with no burn in times. But after about 10-15 hours they have gone from being detailed and a great soundstage with deep bass. To veiled and to be honest my least favourite tube ??? Burn in has changed them for the worse. From my initial impression of them I thought these are awesome to now meh! Has anyone else had this happen to them.

 

 

Quote:
Originally Posted by gibosi View Post
 

 

Which Hytron tubes do you have? But yes, while tubes usually improve after burning in, sometimes they get worse. And in fact, I seem to remember that not that long ago, some members of this forum observed that the Voskhod 6J1P-EV improved after burning in, but then, after 100 or more hours, they changed for the worse. So while not all that common, your experience is not unheard of.

 

Indeed... Some tubes -often not that top tier all in all- just sound better a bit raw just out of the box, and end up too thin, mellow or just bad after 10~120 hours...

 

Of course, despite the realness of burn-in -especially as far as tubes are concerned- brain burn-in also plays a large part in the process of liking a tube (the new best thing turning into the new standard, you know).

 

My recent "new best tubes", while still my best native tubes, are pretty much already getting superseded by my freak experiment with a flying 12AT7 tube (true story). So, nothing surprises me at this point...

post #3013 of 7449
Quote:
Originally Posted by Audiofanboy View Post



Indeed... Some tubes -often not that top tier all in all- just sound better a bit raw just out of the box, and end up too thin, mellow or just bad after 10~120 hours...

Of course, despite the realness of burn-in -especially as far as tubes are concerned- brain burn-in also plays a large part in the process of liking a tube (the new best thing turning into the new standard, you know).

My recent "new best tubes", while still my best native tubes, are pretty much already getting superseded by my freak experiment with a flying 12AT7 tube (true story). So, nothing surprises me at this point...
Actually that is really true I initially didn't like the voskod tubes but after changing the Hytron jhy 6ak5 yesterday to the voskod the sound only after about 6-8hrs burn in is great. I kept reading where people gave good reviews of the voskod and I just couldn't understand why. But now they really have opened up and impact and detail has improved and now the good reviews given match sonically to what I am hearing.
post #3014 of 7449
I initially didn't think that burning in tubes would make a huge difference maybe a slight change but boy was I wrong. With the senns hd650 any change is picked up quite quickly and very noticeable.
post #3015 of 7449
Quote:
Originally Posted by foreign View Post


Actually that is really true I initially didn't like the voskod tubes but after changing the Hytron jhy 6ak5 yesterday to the voskod the sound only after about 6-8hrs burn in is great. I kept reading where people gave good reviews of the voskod and I just couldn't understand why. But now they really have opened up and impact and detail has improved and now the good reviews given match sonically to what I am hearing.

 

I still haven't got to the point of liking the Voskhods very much yet, but they have fallen very far behind the tube rotation and I haven't heard them recently.  I just popped in RCA 6DT6As last night - very impressed out of the box - but I want to live with these for a week or so.  I still have IBM heptodes I haven't gotten to yet! :D

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot Tube Amps: Vacuum Tube Rolling Guide