04 August, 2020

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

Official Link

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:

45 comments:

  1. cool! I guess I am somewhat of an expert on this unit! I actually think this is the least compromised product in schiit's portfolio, except maybe the Saga - and it is also the only all-tube one. they pursued the idea of a more upscale OTL amplifier but after several design iterations decided it would not work from an economical perspective, and I think sales of the Valhalla 2 are still very strong.

    I always used the stock tube set with mine - for better or worse. I tried RCA 6CG7 which greatly improved clarity at the expense of some holography and microdynamic shading (on headphones). also it made my unit run burning hot to the touch, not sure if yours is the same.

    Low gain means additional feedback, an option schiit adds to all their headphone amps for earphone users. but that also means reduced dynamics and a much less interesting sound.

    it's still my #1 recommendation for an affordable amplifier for high-impedance cans. I don't think I mentioned in my article but this was my first tube unit and a real eye opener to what was possible.

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    1. You did mention it. My unit is burning hot, WHATEVER tube I use! Not good in hot weather. For sure, 6CG7, a smaller 6SN7, should run hotter than 6DJ8 types. My view on Schiit more or less mirrors yours (the Mani is a bargain too). I am not impressed by the Vali 2, even the Magni 3 (my Micromega MyZic sounds distinctly different, especially after listening to the OTL Valhalla.

      BTW, your exotic headphone amp probably will be a very good preamp if it has a volume pot. I have tons of different 5687 and 7119 etc. Should you need them, give me a shout.

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  2. Nice review.

    How would you rate the Valhalla 2 as a preamp vs the Saga you used to have? I don't require a remote or multiple inputs/outputs. Just looking for an affordable solution that adds a 'tube' signature to the sound.

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    1. This is the easiest question I have been asked in a long time! :-)

      The Saga is a solid state device with a tube buffer that has only a very subtle effect. It is very good but definitely leans towards the neutral side. It certainly does NOT have that much of a tube flavor, nor is it so susceptible to tube rolling.

      The Valhalla is an all-tube device, and in comparison, much more affected by the tubes used. And tube rolling costs are low. Although I did not try the 5670, it can be had for $4 per tube on ebay (plus shipping):

      https://www.ebay.com/itm/5670-W-2C51-New-JAN-G-E-Tube-eq-Western-Electric-396A/382410760498?hash=item5909752132:g:Ty4AAMXQ8odRHC6e

      You have to be careful in getting the right tube adaptors. This one is the correct one:

      https://www.ebay.com/itm/1pc-5670-6N3-WE396A-instead-ECC88-6922-tube-converter-adapter/202978083111?hash=item2f426fc127:g:7oAAAOSwm9FbeiWj

      So for less than $30 you can upgrade it. As for the 7119, you can do it later, but it's not expensive either.

      I firmly believe if you only have one source the Valhalla is the top dog. I can't think of things that are even close. The Valhalla will do your desktop or big system well and give you the best serious headphone experience. And second-hand are easy to get should you want to save a little. No minus.

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    2. Awesome. Thanks for the quick reply.

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  3. Thanks for the review. For connecting to a receiver did you use the preamp out of the Valhalla into one of the RCA inputs on the receiver? Seems like the output would be low enough where that should be okay

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    1. The Akitika I connected it with is a power amp, not a reciever.

      If you want to connect to a receiver, first find out whether it has a set of preamp-out/amp in jumpers (like NAD). This is not uncommon in vintage integrateds and receivers. If it does, just remove the jumpers (don't lose them) and use the Amp In.

      If not, use any of the inputs and turn the reciever volume to around 12 o'clock and experiment with both volume knobs.

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    2. Thanks for the reply. Appreciate the information. I recently picked up a Marantz twenty six from Craigslist so I will see what it supports. Cheers

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  4. Just heard from that schiit company 😜that a line level input is fine on an old receiver like mine from the preamp out on the Valhalla 2. Cheers

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    1. Report back when you have time. Curious about progress! :-)

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    2. Okay sounds good. I just ordered a Valhalla 2 this afternoon.

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    3. Just set it up this evening and sounds great. I tried 12 o’clock for both and used the aux input on the Marantz twenty six. Tried a variety of music: Dave Brubeck, Louis Armstrong, Tycho, Olafur Arnalds, and a couple songs from soundtracks Bladerunner 2049 and Tenet. Sounds amazing so far to my non expert ears. Will have to try more tomorrow also. Forgot to mention that I have Marantz Imperial II speakers also. Have a good evening. Cheers.

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    4. GREAT!

      I. You may play with the volume knobs of both the Valhalla 2 and Marantz 26. You should try 2 ways: a) Max the Valhalla and use the Marantz to control volume; b) Max the Marantz and use the Valhalla to control the volume. These 2 ways will sound different, and you will find out which one you'd prefer to have more dialed up.This is the difference between gain and volume, which many older preamps (like many famous ARCs and MFAs) have.

      II. You must try different input in the Marantz. Tape In and Aux will sound different. This is due to impedance and sensitivity differences. Try them both.

      III. I am intrigued that you have such a vintage Marantz system. I'd like to know more. Would you email me? Thx.

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  5. Thanks for the information and ideas. Sure I could email you sometime. Cheers.

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  6. Hello again, curious if you have had any issues with your Valhalla 2? I had to send mine back for warranty service (intermittent lower volume on one channel). They replaced transistor (both channels) and replace gain switch. Also, they're sending me another power cord that they forgot to send. Had to persist with their support because their communication was hit or miss. Glad to have it working again though. Cheers.

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    1. Oh my, sorry to hear about that. No, mine was perfect, and it was second-hand!

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  7. Just for fun, I hooked up my desktop Valhalla as a preamp to my main (solid state) speaker system. I was surprised at how good it was. Making me question if I’d have to go all the way up to a Freya in the line for better tube based sound.

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  8. Just for fun, I hooked up my desktop Valhalla 2 (headphones) into my solid state speaker system and was surprised at how good it was as a pre amp. It’s making me thing I’d have to upgrade to a Freya in the line to get any kind of improved tube sound. Saga seems like it may not cut it.

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    1. Great to bear feedback. Two comments. 1) should you have the time and small budget, you must try the tube rolling I suggested! ; 2) I don't think the Freya/Saga would add tube sound. They are rather transistor based with tube buffer, whereas the Valhalla is pure tube, and OTL at that. So I'd not "upgrade".

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    2. After trying the Freta+ in tube mode, I actually preferred the more ‘tube’ sound of the Valhalla in my system. This was a real surprise. Of course it doesn’t have the same features, but the euphoric quality of the Valhalla was present in a way the Freya didn’t seem to match.

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    3. Thank you so much for reporting back. Indeed, I think the Valhalla is hard to beat. Both mrgoodosund and I regard that as one of Schiit's very best products. A keeper and a classic really. The great thing is also tube rolling is not expensive. Salut and the best to you on your quest! Thx again.

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  9. I bought a Valhalla 2 specifically to use it as a preamp into my power amp after reading this article. I haven't done any rolling yet but it sounds great as is. I can instantly A-B between this and my SS preamp with all sources the same. No dramatic differences, but the Val is clearer warmer and sweeter on the high end.

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    1. Wow, I am perspiring, but am VERY happy that you're not disappointed! I hope this will jump start your journey to a little bit of tubedom, and the Val is a great medium. By all means, a little bit of tube rolling would be fun and not too costly, and I encourage you to do so. For a cheap start, I advise the 5670 with appropriate adaptors. Even if you move on, the tubes will likely be useful in future endeavors. But, as with all things, listen carefully, take your time. There's no hurry at all.

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  10. Very interesting info!! I have a Schiit Lyr 3… and thoughts on that as a preamp? With Dynaco MKIII’s? I’m looking seriously at the LTA MicroZOTL… or rather I was!!

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    1. Never had a Lyr, but I think chances are very good it should work very well. The Input part of the Lyr is very similar to the Saga, which I do have and is a good preamp. And you can go full tube mode too (an old stock 6SN7 makes a big difference). One thing, keep it on high gain, which sounds much better because of no feedback. Try it out and please report your findings! :-)

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  11. Thanks for the amazing article. I have a small question about running valhalla 2 as preamp. Can i run Val2 preout into another solid state amp RCA in (in my case schiit audio Jotunheim 2)? Reasoning being i also wanna experience tubeness on my low impedence cans. thanks!

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    1. Of course you can, and should. I always advocate trying everything out, and sometimes there are surprises and unexpected deliveries. Your idea is thinking out of the box, which I think is just marvelous! Things to consider and watch out for: 1) The Val2 is tube, and even if it has a relay (I don't remember), wait for at least half a minute before turning on your ss Jotunheim, because early DC offset at tube preamp turn on can damage ss amps and loudspeakers; 2) you have to juggle the volume knobs. At first, start with both around 12 o'clock. Maxing out the Jotunheim makes it serve as an amp for the Val2 to function as a full preamp. In reverse, maxing out the Val2 makes it serve as almost a Line Out and will make the Joutenheim control everything else. The difference in Gain structure will sound different; 3) Your Jotunheim is theoretically truly balanced, and gain will be very different with SE (RCA) inputs. Make sure you compensate volume when doing A/B. In any case, I'd personally love to hear the experiment. Report back if you can, and thank you.

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  12. Will this adapter on Amazon 5687 Replace 6N6 6N2 ECC88 6922 6DJ8 ECC85 6N11 Tube Socket Adapter HIFI Amplifier Valve Converter work with the Schiit Valhalla 2 and allow me to roll the E182CC ?

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    1. Yes. But to be save please post the link here and let me double check for you.

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    2. If you mean this Amazon item, then it's OK: https://www.amazon.com/Replace-Socket-Adapter-Amplifier-Converter/dp/B09HNSZLC1/ref=sr_1_1

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    3. Sorry was away from my computer for a few days, yes, that's the adapter I purchased and it works great. Based on you review and suggestions I rolled a pair of NOS E182CC 7119 Made in Holland matched pair and I'm glad I did, they sound great. Thank you, much appreciated.

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    4. Thx for reporting back. I'm delighted it all works out!

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  13. Hello! Thanks for this blog post on rolling the Vallhalla 2.

    I have rolled a great many tubes in my Valhalla 2 in the last year since purchasing. This blog contains the only recommendation I have been able to find for rolling the 6N6 output tubes. I tried it myself and the change I can hear is significant - my impressions of rolling the preamp tubes varies greatly with each type that I have tried (details below if interested).

    But being really new audio science and tube rolling, I’m wondering if I can try any other tubes in the 6N6 output position - considering that to use a 7119 type I need a 5687 pinout adapter, does that mean I can also run 5687 tubes like the 5687WB(A) JAN? Or even the 5687 GE 5 Star? Are there any other types you could recommend that I try next?

    In line with your recommendations here, I ordered a closely matched pair of NOS Amperex 7119s made in 1964 (they appear to be made in France for Amperex) from Brent Jessee Recording. I also ordered some pinout adapters similar to the ones you have mentioned here that I found on eBay (no trouble with inserting pins with these whatsoever).

    My setup:
    I have been using a BlueSound NODE for streaming and run both coaxial and USB outputs into a Schiit Bifrost 2, where I have found the coaxial out to be the obvious best choice after lots of listening. There’s a Schiit Lokius EQ between the DAC and the V2 that I usually employ for bass boosting on the two lowest bands - cuz I just love bass. I listen exclusively through Beyerdynamic DT 1990s (250 ohms) when I use my V2.

    Those 7119s really cleared things up and smoothed the sound out no matter what tubes I used for the preamp…differenc the difference was especially noticeable on the top end.

    The most airy and holographic preamp tubes I’ve tried so far were a pair of NOS BEL E88CC (bargain Amperex made in India to the exact same specs) - they really open up the treble and give a fairly decent 3D image. The bass is also nicely fleshed out. Great preamp tubes.

    I’ve tried the GE JAN USA 5670W (with adapters for preamp use like you said) and they are exciting tubes… though sometimes the low end is too punchy and not quite deep enough for what I prefer. The highs can also be fatiguing but the overall tone is very engaging.

    I’ve tried the RCA 6cg7/6fq7 Clear Tops with grey plates. They sound… kind of weird. Great bass and dynamics but they seem a bit sibilant and washy in certain areas of the treble range. I want to try out the US made Raytheon 3 plate version of this tube - I’ve heard they’re the best overall but are hard to find.

    The best value I’ve found so far are the Russian NOS Reflector 6n23p-ev (OTK military). These were made by the same Russian factory that made the tubes that come with Schiit products like the V2 or Folkvangr. You definitely want to go for the more durable military version of this tube as the regular version can be quite finicky, microphonic and brittle sounding in comparison.

    I’ve even tried adapters to use various 6SN7 tubes in the V2 preamp section. So far the amp really seems to like Sylvania GTBs with the black triangular plates and top silver flashing. GREAT BASS and the treble and mids flow nicely as well. A lot of the GE GTBs sound just as good.

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    1. Oh man! What a feedback! Many thanks! I'm indeed glad a few people end up rolling the 6N6 - the difference is indeed significant. 5687 is electrically similar - yes, you can plug it in and there should be sound, but I know it doesn't deliver the same output, smaller for sure. So, it's not recommended - even if u get sound the life will be very short. In the worse case, u may get popping sound, so stay away. Many thx again.

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  14. Doctorjohn? I found some Holland made Amprex for my Valhalla 2 changed the sound completely so much base I am trying to deal with it Have some tubes comfroming Hereford UK. I am almost 90 and having the time of my life!!

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    1. Great! I'm a firm believer in music as medium to improve our well being, and you are a great example!

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  15. I got the Valhalla 2 base on your recommendation as I was looking for a OTL tube amp for my headphones. I love it so far. I did tube roll the 6n6 with 7119. For the 6n1, i tube roll it with Amperex 7308 and I like it alot. Just wonder have you tried it before and compare to the Amperex 6DJ8 or RCA Clear-Top 6CG7?

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    1. No, I actually don't have the Amperex 7308, which is now a very expensive tube! I'm pretty sure it sounds excellent.

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    2. Try looking for the Indian version of that tube made by BEL, a subsidiary that made the same tubes to Amperex specs, look exactly the same. I found a pair and I like them quite well. Matched pairs go between $90-120.

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  16. Wayne SikorskiJuly 12, 2023

    Found this blog whilst searching for tube rolling ideas for my Valhalla 2. On the input section I've settled into the JAN 5670 I like the sound. I've been using a good matched pair of 6N6P for the output was pretty happy with them. I read your info on the using the Amperex 7119 and had to give it a try. They have worked out much better than expected. they've just opened up this amp. Thanks for putting this info up.

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    1. Thx for your comments. I should try 5670 myself!

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  17. Hi Dr John , Can I add the Vahall2 in this setup : Sony TT DD with Nagaoka MP 110 ( MM cartridge ) , phono Stage : Schiit Man2 or ifi Zen Phono preamp connected to Marantz receiver . Will like to get 1. Tubesy sound with greater holographic sound stage and clarity . 2. To Do tube rolling 3.
    The output of the phono preamp to be connected to input of Val 2 and then to Marantz reciever CD or DVD input . or what is the best approach to introduce the Val 2 in the above setup. Thank you in advance

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    1. Yes, that is OK, but you'd have to work 2 volume knobs (Valhalla and Sony) to obtain appropriate volume and quality. Start with both at mid point first.

      Don't know if your receiver is new or old. Many an old receiver in the back has Pre-Out - Amp-In sockets linked by metal jumpers. In that case just pull out the jumper and plug the Valhalla into the Amp-In. This bypasses the receiver's Preamp stage,

      One thing to be careful of. To avoid DC, Always switch on the tube preamp first, wait for 1 minute before switching on the Receiver. For turning off, turn off amp first, then preamp.

      have fun!

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    2. Thank you Doctor John , its a Marantz SR 7010 . a 9.2 receiver with analog inputs ( RCA) and dedicated pre- outs ( RCA) for 7.2 surround.
      The L and R Pre outs are connected to a Yamaha AS 501 with- Speakers A : KEF Q900s pair and Speakers B : KEF LS50 pair.
      The remaining preouts for surround are fed into an Outlaw 7x 140 W RMS power amp.

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    3. Ah, so it looks you will have to use one of the Line Inputs. No problem. Start with the Marantz volume at 12 o'clock and adjust Valhalla volume. Adjusting TWO volume knobs is actually fun. It teaches you about the difference between gain and loudness

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