Schiit Valhalla 2 as Preamp Tube Rolling 6DJ8 6CG7 7119 Tube Adaptor

Click pic to enlarge. Valhalla 2 and LTA atop Genesis Digital Lens. Note the pair of Amperex USA 7119 seated in adaptors.

Review: Schiit Valhalla 2, as Preamp, Tube Rolling

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My interest in OTL has been long lasting (see my Overview), though it was mostly centered on their use with ESL or efficient loudspeakers. Understandably, it was a niche corner of the market and practitioners were few. UNTIL, that is, the advent of Personal Audio. Over the last decade and half, the varieties of headphone designs that have emerged are mind-boggling. Who would have thought high impedance cans would be so commonly embraced today (a paradox given that their power consumption is at total odds with portability). One reason is, given their small size, many people, if not most, own more than a pair of cans. No respectable Head-Fi person would think of showcasing himself without at least a pair of high impedance cans.

Hence, the renewed interest in OTL, as used in Headphone Amps. Most that people use now, including the Schiit, are really late comers. I still remember the first headphone amp I desired (when I didn't even own a decent pair of cans), the original German Ear-Max of 25 years ago, now in its nth iteration (here). I didn't get it because I thought it was way overpriced (it was, and still is) and the tubes used didn't seem that interesting.

When Schiit first came on the scene, I was instantly interested in the Valhalla 1 (I have to say, I love its looks), but I kept telling myself that I had no need for it (true). But, like fulfilling a past dream, when recently a fairly priced 2 became available (with added value) I decided to avail myself of it. Our own mrgoodsound once had used it, and wrote about it (and his exotic OTL Headphone amp) here.

In contrast to almost everyone, I was more interested in its use as a Preamp and Tube-Rolling. Of course, I briefly tested it with my Sennheiser HD-600 and Beyerdynamic DT-880 (300 ohm) and they sounded very good.

For the past few weeks, I have mostly been listening to the Schiit in my streaming station. A word on this station. I switched from LS3/5A for a larger image and a little more dynamics, which the under-rated Almarro provides. Although they are now defunct, Almarro SE amps are increasingly sought after, but their loudspeakers have fallen under the radar. That's too bad; the M1A is a gem, with a wonderfully pure treble (almost ESL like) and a surprisingly tuneful bass.

Bluetooth: Dayton BTR-01 Digital Out
DAC: Micromega MyDAC
CDP: Micromega Stage 2
Analog: Technics SL-1200ii/Denon DL-103
Phonoamp: Schiit Mani
Preamp: Schiit Valhalla 2
Amp: Akitika GT-102
Loudspeakers: Almarro M1A

Tube Rolling Some people say the Schiit Valhalla is not so responsive to tube rolling. Wrong; while the change in sound is not overtly dramatic, the improvements are critical. Rolling the 6N1 already is rewarding, but rolling the 6N6, which most people don't, is just as important.

• 6N1 to 6DJ8/6CG7 I used Amperex Bugle Boy (Holland) 6DJ8 and RCA Clear-Top 6CG7. Either is a significant improvement over the stock 6N1. The Amperex 6DJ8 smooths it out and brings about more air and details, but I ultimately prefer the more solidly grounded sound of the RCA 6CG7. With Adaptors, one can also roll in 5670/2C51/WE396A, which I'd be interested in. However, since I don't have these tubes in NYC, I'll pass for now.

• 6N6 to 7119 This requires an adaptor (pictured), but somehow nobody does it, perhaps because the 7119 (E182CC; same pin-out as 5687) is too exotic. Since I have the Artemis LA-1 which can use this tube (here) I was keen. A Note on the Adaptors The adaptors arrived in about 2 weeks from HK, not bad. There is something one needs to watch out for this type of adaptors. The design is ingenious, a small tube socket clamped and soldered to a small circular circuit board fitted with gold pins. It is solidly made, BUT the socket itself has very tight spring clips. The Tube has to have absolutely straight pins to go into it; otherwise, some of the pins won't go in and will be deformed further (don't force). Since old-stock tubes more often than not don't have straight pins, one should use a pin-straightener. The socket in the Schiit is another common type that is bigger, with a well designed shallow central depression that facilitates to a certain extent tube pins sliding/going in. So, what I did was to insert the 7119 into the Schiit first, then take them out and insert them into the adaptors. Sound While the Russian 6N6 is a well made tube, it does have an edge. The 7119 smooths it out. The Amperex Holland is the most refined, but the Amperex USA has a bit more punch and gravitas. I alternate between them and am very satisfied. Thus tubed, there is no edge to this fine piece of kit. Again, the 7119 is a very fine tube.

High vs Low Gain In my loudspeaker system, in terms of volume setting, Low Gain works about as well as High Gain (I don't feel challenged). However, there is absolutely no question that the High Gain is more detailed and better (I also find this to be the case with my other Schiit Headphone Amps, the Magni 3 and Vali 2). The low gain is meant for low impedance cans.

Comparisons The comparison with the LTA MicroZOTL is almost shocking to me. My LTA is also tubed with all old-stock (Tung-Sol 12AT7 and Sylvania smoked glass 6SN7). The LTA is just a little quicker; otherwise there is no difference to the sound. Of course, the Schiit runs much hotter than the LTA. For reality check, I also compared the Valhalla 2 with both the Magni 3 and Vali 2 Preamp Out: a joke, not even close.

Headphone vs Loudspeakers These days I am also doing a bit of headphone listening in my bedroom. With the Magni 3 and Vali 2, my impressions are the same as on my loudspeakers. Both of these are more closed in, less airy and, simply, less exciting. But, despite its sonic advantage, I am not going to use the Valhalla 2 in the bedroom - just too much heat.

Conclusions

• Desktop For those who also use a Headphone Amp as a Desktop Preamp, the Valhalla is a far cry from the rest of the pack, which just has the Preamp Out as a value added feature. This is a serious Preamp in its own right. Its tube rolling potential is icing on the cake. Its OTL topology confers the utmost clarity one otherwise would not obtain at this price. For budget people, rather than building your system around your headphone, build it around the Valhalla 2. Serious!

• As Preamp in Your Big System Aside from Streaming, I have also listened to my CDP and Analog, and the Valhalla 2 just sailed with it. I can imagine a big "real" preamp having even more gain or monstrous power supply; I can imagine certain high-value vintage preamps (such as the old Naim's and NAD 1020/3020 that I wrote about) doing a great job, but I am also certain, for the very modest outlay of the Valhalla 2, it can go head-to-head with many Preamps many times its cost. Despite my pontifications, I doubt anyone is going to buy the Valhalla 2 only as a Preamp in their main system. BUT, if you have it already, you really should try it out in your main system. Like a really good preamp, you can listen at very low volume and still hear plenty of microdynamics. You'll be surprised. Caveat Big one. There is only one input, so there, you either plug and unplug (like I) or add a device (maybe the Saga?)

The Schiit Valhalla is already a Classic. No doubt Schiit will continue to refine it or evolve another OTL model. It is a screaming bargain, but do budget for some tube rolling.

Now that I have heard the LTA and Schiit, I hope one day to hear use of 6AS7 OTL as preamp. Of course, what I really want to hear is the Western Electric 421A.

Basic Repertoire Classical Music has an endless array of short pieces that can serve well as openers or encores, much like hors d'oeuvres or dessert. One subset comes from the vast world of Operas. Many forgotten operas, like those by Offenbach, Auber, Suppe and Rossini, live on via their Overtures (played before the curtain rises), Preludes (at the start of an Act) and Intermezzi (usually a moment of repose within an act). Some are achingly beautiful, like this Intermezzo from Mascagni's warhorse one-acter, Cavalleria Rusticana: