Schiit Freya Preamp Review (Episodic)

Discussion in 'Preamps' started by purr1n, Jan 14, 2017.

  1. purr1n

    purr1n Finding his inner redneck

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    Schiit Freya Preamp Review (Episodic)

    This will be a series of episodic articles covering the Freya. There’s too much to cover and I would like to evaluate the Freya under a wide range of circumstances with various systems. Doing it this way will also allow you guys to ask me questions or make special requests.

    1. Assessment in front of a headphone system with solid-state headamp: http://www.superbestaudiofriends.or...reya-preamp-review-episodic.3725/#post-111869
    2. Additional notes from a modest wide-range speaker system: http://www.superbestaudiofriends.or...reamp-review-episodic.3725/page-2#post-112470
    3. Sonic Comparison with Parasound Halo P5:http://www.superbestaudiofriends.org/index.php?threads/parasound-halo-p5-preamp-mini-review.3779/
    4. Freya Bitchisms: http://www.superbestaudiofriends.or...reamp-review-episodic.3725/page-4#post-116222
    5. On imaging precision: http://www.superbestaudiofriends.or...otunheim-impressions.2700/page-60#post-118996
    6. @Garns Impressions: http://www.superbestaudiofriends.or...eamp-review-episodic.3725/page-11#post-143840

    Let’s first start with the reasons for a preamp. For myself, I had an excellent reason. I have a Crest CA2 pro audio power amp which I knew had sounded pretty good in past systems. I was using the CA2 to power my Altec 511B horn / 12” woofer speakers. A Schiit Gungnir multibit DAC fed a Softone Model 5 passive preamp, which in turn fed the CA2. This setup sounded like shit. Muddy, dead, dull, and rolled. I kind of knew why, it was the Softone.

    It’s not that Softone makes a bad product. Not at all. It was an impedance mismatch. Like many other solid-state amps, the Crest CA2 has an input impedance of 10k ohms unbalanced. Looking up the specifications sheet of the Softone Model 5 passive preamp, we find that the input impedance can be anywhere from 34k to 10k ohms, and the output impedance can go anywhere from 20k ohms to 1k ohms. Ugh! This was a disaster in waiting. The only way this would have worked is if the power amp had an input impedance of at least 100k ohms. Only an active preamp which could act as a buffer between the DAC and the power amp would do in this situation.

    Let’s look at the feature set of the Freya. There are two balanced inputs, three unbalanced inputs. There is a balanced output and two SE outputs. The outputs can all be driven at the same time. The inputs are selected on the front panel with a button which switches the inputs up in order and cycles backs to the first. I would have preferred an actual switch with five positions or two buttons to switch inputs up and down so I didn't always have to cycle through all the inputs to get to the one before. But this is not a big deal.

    [​IMG]

    On the front panel, there is also a mute button,and a disturbing hole which is for receiving signals from the infrared remote. The small remote control replicates all controls on the the front panel. As with all other Schiit gear, the power switch is on the back.

    [​IMG]

    Now here is the real kicker: The relay-switched 128 step attenuator with discrete resistors. I've always hated steppers because it was impossible to find exactly that right volume level. You could have 24 steps. No way. 48 steps. Nope. 64. Well, maybe. But whoa! 128 steps at 0.5db increments? That is really nice! Wait, didn't the Ragnarok have 128 steps? Nope, only 64. I thought this was better! The volume knob on the Freya glides smoothly with a quiet series of clicks. The 0.5db steps provides me with more than enough granularity. Going back to other amps with potentiometers doesn’t feel as nice. In fact, they feel kind of shitty.

    If the fancy stepper isn’t enough, there are the three passive / active options available. Wait three? Yeah, there are three. The Freya can be used as a passive preamp, an active preamp with a JFET buffer, and a tube preamp. The tube preamp isn’t a straight buffer, it has a gain of 5 (14db), which could be useful for those running phonostages or tube monoblocks lacking sufficient gain. One thing that I did not like about this setup was that there was no option to cut off the power to the tube section when the passive or JFET sections were in use. The tubes are on all of the time. (I guess we could always remove the tubes).

    Just a tip on tube rolling: the first two tubes provide gain. Make sure those are quiet tubes. Your highest quality tubes go here. If your gain tubes are noisy, you will hear it. Match in pairs. One pair in the differential gain section. The other pair for the cathode follower. There is no need to match quads.

    I don’t know why Schiit offered three preamp circuits, but I get the feeling that those guys did so as sort of a “fuck you” statement to the "audio industry". Allow me to explain. One of the tenets behind preamps is to not commit sins of omission. There is no such thing as a totally transparent circuit. Allowing the user to switch between three modes of operation, one of which is just a pair of resistors (this assuming the case where an active buffer isn't necessary) takes a lot of balls because it gives the user an opportunity to directly assess the performance of the active preamp circuits.

    In my next post, we’ll discuss more about transparency, sins of omission, sins of commission, and observations of the Freya’s performance in an odd application - in front of a headphone amp.
     
    Last edited: Jun 14, 2017
  2. purr1n

    purr1n Finding his inner redneck

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    So where do we go from here?

    I haven’t had time to finish the setup of my second speaker room, but I wanted to assess the performance of the Freya in the meantime. This is why I did this.
    DSC_1701.JPG


    I am using the Freya as a preamp for the Jotunheim. There had been some whispers of people using the Saga in front of the Jotunheim to cure its “ills”, in particular, the flat headstage and glary treble. Why not try Freya? In any event, it would at least give us insights into how the Freya might perform in a more appropriate two-channel speaker system. The Jotunheim is fairly resolving of low level information and super articulate with great transient response. Combined with an HD800 (Bill-P / Vader modification), this setup should be a good test that would equal if not exceed most speaker systems in resolution. (Keep mind what we get here are only insights. We really do need to evaluate under a speaker system - in time.)

    In my first post, we discussed the function of a preamp as a buffer. But there are also secondary reasons: to color the sound. Wut? Didn’t you just say something about transparency?

    Yes, but more precisely I said something about not committing sins of omission. By this, I mean the essence of music, the low level information, the small volume gradations, must not be lost. In real practice, there is almost always a balancing act between coloring the sound while not losing information. For example, some people use tube gear to color the sound of drier sounding solid state amps. I believe that there are people out there who use the Zana Deux as a preamp for big solid-state power amps feeding inefficient speakers. This example is on one end of the scale. (The other end is the pure transparency, the what goes in is what goes out philosophy). I wouldn't do this personally because for the kinds of systems that I run, I think the Zana Deux, while being a great headphone amp, is not sufficiently transparent: more precisely commits too strong sins of omission. Still, there is nothing wrong with using a preamp to color the sound, as long the loss of information or loss of musicality is ultimately not detectable at the transducers by ears.

    So let me cut to the chase - under the above described circumstances using the Freya as a preamp to the Jotunheim.

    The JFET buffer is incredibly transparent. Overall longer exposure, I started to be able to make out the difference between the JFET buffer and passive modes. But even now, I wouldn't bet any money on being able to consistently tell the difference. To put things in perspective, I’d bet anyone $5000 that I could tell the difference in a volume matched DBT between Schiit Modi and ODAC. If anything, the JFET buffer has more body and has a light layer on top of the pure passive circuit. This is actually impressive because the $1000 to $5000 preamps I've owned in previous lifetimes were not this transparent. (I have a Parasound P3 preamp in the house, so we’ll see how this compares later). I've heard that this JFET buffer the same as the buffer implemented on the Yggdrasil and Gungnir multibit DACs, but with evolutionary tweaks. A few months later: I'd have to say that I am able to identified the JFET buffer as having more "body" in terms of sound. Also the JFET seems to have more punch and dynamics in most instances over passive.

    The Freya tube stage is less transparent, I’ll just say this straight up. (I’m using vintage Sylvania GTB 6SN7 tubes.) I can’t quite decide if there is a veil covering up some low level information, or if low level information is being dropped. Most likely, it’s probably a combination of both. However, the tube stage does bring a lot of the table. The tubes add an amount of bloom. Not excessive. Not anywhere near the Elise headamp. Not anywhere near most 300B amps. But it’s there. I haven’t had a chance to directly compare to Saga, but my inclination (having heard Saga) is that the Saga is more transparent: less bloom, in fact barely any, and almost undetectable sins of omission. The Freya appears to lose a bit more information than Saga, and but what is lost in not significant (there's far less lost than using something like the Zana Deux as a preamp - we not that far toward that end of the scale).

    In conjunction with the Jotunheim, the Freya opens up the stage with more width, more sense of space, more depth and layering. The headstage is still rather upfront and close, maybe pushed slightly further in front. But the increased depth and three-dimensionality would be welcome to most. The glare is gone. The timbre of the treble is more realistic. The tips of transient attack are even faster and more incisive, there’s more bite to the sound, yet at the same time my ears hurt less! I love this. (Note: this is with the Sylvania tubes; other tubes may render a more rounded presentation). This doesn't really surprise me as I have had a similar experience with the Jotunheim when feeding it directly from my phonostage and TT.

    I had a quick discussion with Ravi, and he seemed to imply that he slightly preferred the Jotunheim with the Freya to the Saga, although both were good. I did also mention in a profile post the Freya / Jotunheim combination as “Oh so sweet, a distinct sound that I haven’t quite heard” - referring to the combination of tube bloom from the Freya and the bass control, articulation, and neutral balance of the Jotunheim. Now I’m not suggesting that people go out and buy this combination, but it does work.

    Finally, I’d like to reiterate that these impressions are from this specific non-standard setup, and that performance in two-channel speaker setup could be different.
     
    Last edited: Jun 14, 2017
  3. jexby

    jexby Loves propane and propane accessories

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    gawd I've been waiting to hear about this exact Freya application since announcement day. in front my Jotunheim.... ooooh wow you just posted in #2.
    jinxy! Big Props @Marvey
    Thanks!
     
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  4. purr1n

    purr1n Finding his inner redneck

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    If the direct out experiment from the Gumby/Yggy DA chips to Freya works, this could be goosebumps scary good. I'm sure @MisterRogers could help out with the soldering. Of course warranty = void on the DAC.
     
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  5. Vansen

    Vansen Gear Master 2.0

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    I want to see Jason throw this combo together at canjam for shits and giggles.
     
  6. FallingObjects

    FallingObjects Pay It Forward

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    Would you (or anybody else who has their hands on a Freya) be willing to measure the distance between the tubes and the end of the board? On the longer side. I can sorta eyeball the Jotun on the second set of photos and see that it'd probably fit, but firsthand perspective is definitely gonna be more accurate to see of well the Jotunheim would sit ontop of a Freya (and whether it'd just end up looking plain silly).
     
  7. schiit

    schiit SchiitHead

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    I am almost afraid to know the results.
     
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  8. jexby

    jexby Loves propane and propane accessories

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    any chance for a DAC donation in the Name of Science? :)
    or hell, just the boards and power supplies, let's skip the fancy aluminum casings.
    @MisterRogers and I could jointly perform the lobotomy and rejigger connection hocus pocus over night while fueled on Chartreuse and various Belgian Beer.

    between the two of us, we've got a stash of 6SN7 to tube roll into Freya also, and the balanced Utopia and HE1Kv1/v2 just waiting with baited breathe....
     
  9. drfindley

    drfindley Secretly lives in the Analog Room - Friend

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    Are you talking hard-wiring it into the Freya? Or just a direct pass?

    As in, if I can plug this into any pre, I might just plug this into my EAR 912, as long as it won't blow it up.
     
  10. EraserXIV

    EraserXIV Friend

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    Freya into Jotun, what are you using for volume control? If you're controlling volume with the Freya, what are you keeping the Jotun pot at?
     
  11. purr1n

    purr1n Finding his inner redneck

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    Jotun: between 12 and 3 on high gain. The Freya tube out already has sizeable gain.

    If you have balanced in with high enough input impedance. Might need to build in analog low pass. Without it, it could sound like crap or cause strange things like oscillation depending upon bandwidth of components. Not responsible if diamond tweeters shatter. Do at your own risk.
     
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  12. jexby

    jexby Loves propane and propane accessories

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    is the "first two" above interpreted as:
    the front two tubes provide (differential) gain?
    and
    the other/rear tubes are the cathode follower?

    Note to self: RTFM.
     
    Last edited: Jan 16, 2017
  13. sphinxvc

    sphinxvc Gear Master East

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    I was wondering the same. Found this in the manual:

    upload_2017-1-16_11-14-13.png
     
  14. jexby

    jexby Loves propane and propane accessories

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    Many thanks for RTFM.
    i downloaded the PDF manual after posting the question and should have edited/answered.
    time to find Freya money someday.....
     
  15. Cspirou

    Cspirou They call me Sparky

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    Any reason why you wouldn't just put the Jotunheim on max and bypass the pot completely? Would this be only if you run the Freya in passive mode?
     
  16. purr1n

    purr1n Finding his inner redneck

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    I dialed it back before because I had some noisy tubes. Now I have it turned to max without an issues. I backed off to the 3 o'clock position because pots tends to have better L+R matching away from the extremes.
     
  17. hifi01170

    hifi01170 Facebook Friend

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    is it a headphone out on the freya front panel??
     
  18. t3hwx9

    t3hwx9 Acquaintance

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  19. Kattefjaes

    Kattefjaes Mostly Harmless

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  20. Cspirou

    Cspirou They call me Sparky

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    If you have high impedance headphones (~600 ohms) wired with dual XLR connectors, you could probably use the XLR outputs in back.
     
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