The Mjolnir 2 thread

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by maxedfx, Oct 11, 2015.

  1. Mithrandir41

    Mithrandir41 Friend

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    Good on ya, man
     
  2. klyrish

    klyrish Almost "Made"

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    Thanks man, I appreciate it. Just responded to you at HF.
     
  3. RobS

    RobS treboR (Psalmanazar Groupie)

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    Got a heck of a used deal on this amplifier yesterday. Excited to have the Convert-2 hooked up to it with the HD650/600 balanced. Although I'll probably stick with the Gungnir Multibit.

    Can I get an opinion from one of the tube rollers here please? I'm not sure what I should try after reading the various posts in this thread. I'm looking for a tube that can give a deeper soundstage, more lively and slightly wetter mids, but I don't want anything bright. The bass isn't a priority for me with the Sennheisers, I would like to get a tube that can take advantage of its wonderful midrange. Perhaps a tube that is the most euphonic and provides the most plankton with HD650. I tend to like a touch of syrupiness. Any budget for tubes works but not looking to spend hundreds.

    Any suggestions would be helpful. I'll try to give the stock tubes a try. I don't need to use tube risers correct? The seller is including them in the package.
     
  4. BenjaminBore

    BenjaminBore Friend

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    WE396a was the consensus here for the Mj2, and most closely fits your requirements from the few I have tried. You won’t need risers, but the WE396a do require adapters. Do a back search for impressions, and there’s an old write up in my sig for the Mjolnir 2.

    Be advised. Using the WE396a in this way will make @purr1n cry milky man tears. ;)
     
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  5. RobS

    RobS treboR (Psalmanazar Groupie)

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    Thanks, holy smokes those are expensive. Got any recommendations in the $200 range and below? I'll take a look at your write-up now.
     
  6. BenjaminBore

    BenjaminBore Friend

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    Prices must have risen considerably since I got mine. I believe the GE JAN 5670 were the affordable goto, but I’ve not heard them.
     
  7. RobS

    RobS treboR (Psalmanazar Groupie)

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    Oops I may have made a mistake, I got linked to some ebay auction that had the tube set at $1500. But then there's some of them for 100-200. Is this another tube where there are specific differences that account for the difference in cost?

    EDIT: I haven't checked any other Tube sites. All I'm familiar with is Brent Jessee's
     
    Last edited: Dec 13, 2019
  8. KaiserTK

    KaiserTK Acquaintance

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    Usually the tubes vary in pricing due to how well they test and what date code they’re marked as.

    From my experience the 50’s or earlier WE396A tubes sound slightly better, and you can find a decent testing pair from a reputable seller on eBay for about $100. Worthwhile upgrade imo, but don’t forget a pair of 6922 -> 396a adapter as well.
     
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  9. Sonorus

    Sonorus Almost "Made"

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    The GE JAN 5670 is a great tube and it is so dirt cheap that you should absolutely
    give it a try.
    You have to spent a lot lot more to get greater sound , you have to go to CV Mullards
    This was my first choice for more relaxed and warm sessions and the Genalex Gold Lions
    were the most linear , dynamic , slamming and not rolled off.
     
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  10. BillOhio

    BillOhio Friend

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    Edit: Sold

    I have two matched pairs of WE396a's and a set of 6NB to ECC88 adapters, all bought through SBAF and most of the boxes have Brent Jesse stickers on them. I paid $100 per set for the tubes and $20 for the adapters. I'd be happy to sell these on at the same price.
     
    Last edited: Dec 13, 2019
  11. lagadu

    lagadu Acquaintance

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    Not common but my favourite tube ended up being the Ericsson 2C51 (they require the 5670 adapter) exactly for the reasons you described. I've read that they're supposed to be the same as the western electrics but the pair I had definitely didn't sound the same.
     
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  12. RobS

    RobS treboR (Psalmanazar Groupie)

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    Quick impressions with WE396A tubes. For me it's an upgrade over the stock tubes but it does the Convert-2 no favors as a DAC in this chain.

    From a scale of 1 to 10 on impact (1 being hit with cotton candy and 10 having prime Mike Tyson sucker punch you in the gut), with the Convert-2 and stock tubes...it's maybe around a 7.5. With the WE396A it's down to 6...maybe a 5.5. They definitely scale back considerably the aggressive attack, to where the presentation is much more softer and more rounded.

    So the good traits of the Convert-2: thunderous, surgical incendiary snare pops/cracks and power chords are smoothed over a bit, they aren't as sharp and well defined. It's like there is a tiny bit of Vaseline on some of the strings. The Convert-2 no longer has this explosive hard-hitting sound to it. And worse it accentuates its flaws. One of the things I've noticed over time with the Convert-2 is the lack of reverb around certain instruments that should be there. It also cannot do layering like the Gungnir Multibit A1 can, Convert-2 is one-dimensional in comparison. While the tonality is fantastic, there's something off about how the highs are rendered. The Gungnir is much more liquid in the highs and in the overall audio band, there's more cohesion. And how the Gungnir can extract the tiniest bits of information is impressive, where on the Convert-2 they are missing. Also the center image on the Convert-2 doesn't stay stable in the center, it can sometimes shift even during a track.

    Probably the most noticeable feature with the tube change is the bass quality takes a hit, it's a lot more floaty and loose. With the Convert-2, the bass is too lean, eventhough in other systems I've had it hooked up to arguably has the best bass I've ever heard from a DAC. But with the Mjolnir 2 and these WE396A tubes, it definitely needs the fatter bass from the Gungnir Multibit to make up for it.

    Overall there is much better synergy with the Gungnir Multibit in this chain with the tubes. It mitigates some of the weaknesses while playing more towards the strengths of the tube, which is able to retrieve a lot of the finer textual nuances that the stock tubes couldn't do. The harshness with the stock tubes in the upper-mids and sibiliance in vocals has disappeared with the new tubes. These tubes provide a thoroughly engrossing presentation with just the right amount of syurpiness to my preference. The stock tubes were clinical and colder. They serve as a better point for neutrality with the HD600, but the WE396A win out for how musical they sound with the HD650. Very satisfied with rolling the tubes.
     
    Last edited: Dec 19, 2019
  13. Thomas Seok Hwan Kong

    Thomas Seok Hwan Kong Rando

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    Hello!

    This is my first post here.

    I had been driving Raal Sr1a by Jot R for the last three months.

    I found the sound to open and exciting but close to hot.

    Thus I consider adding tube amp in the chain in front of Jot R.

    I consider either Schitt Freya or MJ2.

    Freya will be better as preamplifier but it uses 4 tubes that make tube rolling harder.

    MJ2 may not be as good as Freya as preamplifier but using 2 tubes, it is easier to do tube rolling and it could drive HD 800s well (maybe marginally Abyss 1266 TC as a starting point).

    I do not have good collection of 6DJ tube but nice colldtion of Nos 12Ax7. 12 Au7 and Sn7 tubes.

    Had anybody tried either 12Ax7. 12 Au7 and Sn7 tube on MJ2?

    Thanks in advance

    Thomas
     
  14. RatSalad

    RatSalad Friend

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  15. Phantaminum

    Phantaminum Friend

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    You can’t run SN7 tubes off the MJ2 as amps being pulled are too high and may/will fry the amp. I’m not sure about the 12AX7s but with the right adapter that feed the 12AU7s = 6v you can run those and still be in spec.
     
  16. Thomas Seok Hwan Kong

    Thomas Seok Hwan Kong Rando

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    Thanks a lot for your quick and clear answer.

    How good pre amplifier section of MJ2 compared with Rogue Audio Rh5?
     
  17. famish99

    famish99 Friend

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    MJ2 is a crappy preamp imo, it's a little noisy for the task. Quite frankly I think throwing a pre in front of the Jot R sounds like a bad idea; if you're driving it from a DAC, you're going to have way too much gain and pick up things like microphonics all day long.

    If you want to fix the sound, change the amp, just because the Jot R is good amp, doesn't mean you have to like it.
     
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  18. Thomas Seok Hwan Kong

    Thomas Seok Hwan Kong Rando

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    I am using Deva pre output with -20db not to saturate Jot R.

    But it still sound close to hot compared with 009s driven by Kgsshv Carbon or HD 800s.

    Thus I consider using some tube pre in front of Jot R to make its sound more natual.
     
  19. lagadu

    lagadu Acquaintance

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    Have you considered replacing the jot R with the regular interface box and a gentler sounding power amp? Getting something whose sound you like right from the start might be a better option than adding extra stuff to work around a piece of equipment you dislike.
     
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  20. purr1n

    purr1n Finding his inner redneck

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    Don't do MJ2 because it's not meant to be a preamp - you will lose too much. Freya maybe. Saga maybe. Freya tube rolling can be made a little less neurotic by concentrating on the voltage gain tubes first, which will have the most effect. What are you using as a source? If the highs are too hot, try software EQ, or can you try digital EQ too (Behringer DEQ2496). I run the SR1a with EQ regardless of amp.
     
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