Preamps

Discussion in 'Preamps' started by sphinxvc, Sep 21, 2016.

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  1. fierce_freak

    fierce_freak Friend

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    Thanks everyone. I'd prefer the balanced but my current amp only has single ended in (suppose I could use an adapter).
     

  2. zerodeefex

    zerodeefex Unpaid LH Labs volunteer - Admin

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    I use this with a gungnir multibit. It's pretty good for $50.
     
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  3. sphinxvc

    sphinxvc Gear Master East

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    It's been a while since I did my SYS vs. Saga comparison, but I never got around to sharing my notes. I did comparisons at 3 different volume levels, low, medium, high. Used my phone's DB meter and test tones to roughly volume match. At low volume, it was tough to tell what the difference was, basically all you heard was a bit more decay, and maybe more engagement with the Saga. At medium volume, you started hearing more nuances out of Saga, timbral intonations were better, you heard the air around a mike more, and could picture the musicians and their instruments better. At high volumes, the Saga made you feel the power and energy behind crescendos, while the SYS made you think, "ow, turn that down!" Bad loud vs. good loud basically. It's like when brass comes off harsh and makes you wince on a poor system, but sounds startling and appropriately bright on a good one. With the tube buffer activated, the Z-axis opens up more, vocals sound a bit forward (maybe just part of tube-enabled holography, resolving the singers closer?)
     
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  4. zonto

    zonto Friend

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    @sphinxvc: Thanks for the write-up! Would you mind sharing roughly what dB level the low, medium, and high volumes were?
     
  5. neogeosnk

    neogeosnk Almost "Made"

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    Probably a stupid question but could I stack the Saga on top of the jotunheim? Or would it be too hot? I know the jotunheim doesn't really get too hot but just wondering if anyone has this setup.
     
  6. Cspirou

    Cspirou Friend

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    Official answer would be to keep them side by side. Real answer is that it might be fine. Does the Jotunheim feel warm when you touch it? If it's not too hot the gap between them might be enough.

    My answer is to keep them far apart. I mean why are they near each other in the first place? The Saga is a remote controlled device while the Jotunheim is a headphone amp that should be near you. I would keep the Saga on the equipment rack and run long cables to the Jotunheim in active mode. After all, why get an active preamp if you are not going to use it?
     
  7. sphinxvc

    sphinxvc Gear Master East

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  8. Cspirou

    Cspirou Friend

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    Just a list I made of volume controls. Not exhaustive or any comments on effect on audio

    Passive:
    log potentiometer
    fake log potentiometer
    double linear potentiometer
    rotary switch stepped attenuation
    relay based stepped attenuation
    chip based stepped attenuation
    Balanced shunt attenuation
    TKD ladder
    Auto-former or transformer based
    Light variable resistor

    Active:
    passive + active buffer (most active preamps)
    potentiometer after gain stage (the O2 amp arrangement)
    variable gain feedback (Peter Baxadall circuit)
    tube buffer

    Other:
    Digital volume control
     
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  9. kirayamato

    kirayamato Friend

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    Hi sorry if its already answered but are preamps good with headphones aswell ? as in if you add it to ur dac,amp chain does it help the sound or are they really for speakers.
     
  10. Yeskey

    Yeskey Friend

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    I use the jotun as a preamp for my Project Polaris and through uncritical listening, the Polaris sounds about the same to me. The only downside(?) is more knobs to turn. I suppose this can be tested by volume matching the amp and preamp + amp, then listening for any differences. I'll try this in the morning and will get back to you if I find any significant changes.

    I know that @atomicbob does something similar with the Val2 + jotun in the system synergy thread, so he can shed more light on this topic.
     
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  11. Yeskey

    Yeskey Friend

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    Alright, because of free time this late at night. I volume-matched my jotun+polaris and polaris itself within .2 dB and listened to kanye west. From a relatively short session, the polaris itself presents a larger, fatter bass presence and is subtly more treble-forward compared to the Jotun+polaris. My preference is with the Jotun+polaris because the bass sounds cleaner and blends more easily with the rest of the spectrum. (The bass on the Polaris-alone sticks out like a sore thumb)

    Takeaway is that preamps can affect sound sigs on headphones. For better or worse. (In this case, Jotun + polaris sounds good)
     
    Last edited: Dec 20, 2016
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  12. Cspirou

    Cspirou Friend

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    Usually I think it's best to avoid extra components in the signal path. Or in other words, the best preamp is no preamp. However in a headphone amp the volume is usually controlled by a potentiometer which can have problems with channel imbalance. In that case I do think using an external passive stepped attenuator(like the Saga) can be an improvement. If you do volume control with a preamp you should leave the headphone amp on MAX and do all the volume control with the preamp.

    I believe Doug at ECP Audio even makes headphone amps in a power amp configuration so you can use them with a preamp.
     
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  13. Priidik

    Priidik Friend

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    Very good hp amps make for great pres. Not necessarily the other way around.
     
  14. Cspirou

    Cspirou Friend

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    I t
    i think he was talking about adding a preamp to a headphone amp. Not using a preamp as a headphone amp
     
  15. msommers

    msommers Wow, I made it this far without being a friend?

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    Another preamp to keep an eye out for is from Modwright. Hard to find but excellent value
     
  16. Regular Petey

    Regular Petey Rando

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    I'm wondering what solution you decided to go with to address those issues, or are you still unplugging cables?

    I have a Bimby, Yggy, Valhalla 2 and Mjolnir 2. Additional sources will be SE from Mani/turntable and also from an FM tuner. I have a pair of passive speakers on order, so I'll need to get a preamp, or use the Mjolnir 2 as the preamp, plus get one or two Vidars when they come out. I'm not sure what the technical reason would be for it, but most mentions of using the Schiit headamps as two channel preamps, don't sound very positive, when compared to what people are saying about using Saga or Freya. The other downside of using Mjolnir 2 as my preamp is that it kind of forces me to buy a pair of Vidars or use the "gimped" SE output from Mjolnir 2.

    I was thinking that I would just buy a Saga and Vidar, feeding SE output from the Yggy to Saga, with Mjolnir 2 continuing to be fed from the Yggy balanced output. What you said in #3 above has me concerned whether that will work as I expect though.
     
  17. Aklegal

    Aklegal Acquaintance

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    I'm not sure what Garns did but when I got back into headphones about a year and a half ago I tried using both the Yggy's XLR and a RCA outs to a preamp and a headphone amp. It sucked. Less so for the xlr side but so much so for the rca side that I thought the headphone amp was broken because I couldn't get it to drive a pair of q701s to decent volume without distortion. Everything sounded great when I unplugged either the pre or the headphone amp. Needless to say I gave up on using more than one of the yggys outputs at a time and sold my preamp and headphone amp and bought my current headphone amp/pre combo.
     
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  18. Garns

    Garns Friend

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    Well... at the moment I am still unplugging cables!

    But thanks for reminding me. After communing further with my system I have discovered that all sorts of problems were being caused by ground loops. That's 50hz hum right? Nope. Not in my system. Ground loops were causing distortion all through the treble spectrum, most noticeably round 6khz and round 12-15khz. I've since fixed these by disconnecting pin 1 at one end of my XLR interconnects. I dunno, but it could be that this was also what was causing the distortion in #3 above rather than Yggy being unable to drive both outputs. I haven't tried re-testing #3 since I fixed the ground loops, so lemme have another go tonight and see what happens. I mean, what you suggest SHOULD work fine in any reasonable universe.

    Yep, this is very dependent on what you plug into Yggy's outputs. Some gear shorts its inputs when switched off. In that case if you leave it plugged into Yggy when switched off, it will present an impossible load and Yggy's output buffers will be exhausted trying to drive the switched-off equipment. So anything else that is plugged in simultaneously will sound like shit. Seem like that was the case with your preamp (same with my studio monitors). Long story short, check with the manufacturer of the downstream gear what its input impedance is when switched off. If the answer is 0 ohm or 100 ohm rather than 10kohm then you are stuffed and will either need to plug and unplug manually or get some kind of physical switch that in effect does the plugging/unplugging for you.
     
    Last edited: Jan 29, 2017
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  19. msommers

    msommers Wow, I made it this far without being a friend?

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    The other day I did some comparisons with my Hegel H360, Mjolnir 2 and Gumby in various combos. I re-visited those combos this evening, with help from my girlfriend who was enticed to be an additional set of ears via cinnamon bun.

    I need to preface this comparison for two reasons: (1) I'm very new and proper descriptors may not the best possible word choices and (2) Differences I detected were pretty subtle. There were NO things that I would say are night and day differences. So with that in mind lets move forward.

    [​IMG]

    Music:

    Beck – Morning Phase (24-/96)

    Adele – Can’t Make You Love Me (Live from Bluray) (24/96)

    Band of Horses – Is There A Ghost (16/44)

    Coeur de Pirate – Ava (16/44)

    Eagles – Hotel California (24/196)

    Nils Lofgren – Keith Don’t Go (16/44)

    Gregory Porter – Holding On (24/96)

    Diana Krall – Case of You (24/96 LP rip)


    Squeezebox Touch --Coax--> Gumby --XLR-->Mjolnir 2 w/ Amperex 7308 --SE-->Hegel H360 HT input

    - This combo was my favourite for vocals – when Gregory Porter opens up on this song it moves you. ALL of the vocals sounded the best in terms of presence, weight, body and realism. From my limited experience, I can only attribute this entirely to the tubes. However for more complex layered songs like Hotel California, I did not like it best, I thought the Gumby->XLR->H360 faired the best here. Back to vocals, while I enjoyed listening to it the most, this setup did not extract as much detail as the latter mentioned setup due to a slight rolloff. Acoustic guitar did not sparkle as I had hoped on Keith Don’t Go. Certainly thicker than any other setup but I play acoustic and know roughly how it should sound. There is no setup that has yielded it yet without trying too hard and ending up with ear-piercing string plucking. A $15,000 Tannoy + H360 did well…may another lifetime.

    Squeezebox --Toslink-->H360

    - This combo was the least layered, felt a bit hollow in the mids by comparison and lacked in microdynamics, but felt it had the least amount of rolloff and also had the largest soundstage by a very noticeable margin. Beck’s Morning Phase illustrated this beautifully at a perceived 1’ further on either side than the Gumby.

    Squeezebox Touch --Coax--> Gumby --XLR--> H360

    - As an all-rounder setup this is the one for me as, to put it as amateur as possible, it just got my head and toe into the music the most. It highlights all the things I enjoy my Hegel but lifts the veil slightly increasing both macro- and even moreso, microdynamics. However as mentioned above, it also slightly constricts the soundstage.

    Squeezebox Touch --Coax--> Gumby --SE--> H360

    - I did not detect a big huge difference between the XLR and SE outputs of the Gumby. There was a slight increase in detail, layering and bass extension but I needed to flip back and forth to try and pick things out. Blindly comparing, I honestly don’t think I could do very well.

    All of this was prompted by my curiosity regarding obtaining a Freya. After going through this again, I can say I'm still not sure. The implementation Schiit uses in their dacs I would say overall I prefer it but the AKM AK4490EQ implementation that comes in the H360 is no slouch either.

    I'll be eagerly looking forward to Freya owners contributing their thoughts and hopefully someone out there has a Mjolnir 2 out there to do some A/Bing with.

    Best,
    Matthew
     
  20. Big D Design

    Big D Design I've got stereo junk in my trunk.

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    Freya and Mimby with Martin Logan ESL using the Freya 4 tube output produces guitar, piano, pedal steel, violin, banjo so far as realistic as I have yet heard thru my MLs. The Freya is not going to give you the high treble or bright sound with the tube output that some desire. I listened to the Freya without the Mimby for a few days at first. It shows no flaws, but you have to like a little bit of taming of the digital beast with the tubes. I personally find this sound closer to a real experience. Kind of like plasma Panasonic tv over LCD Samsungs. So when I got my Mimby and it warmed up for a couple of days, the sound from Mimby perfectly complimented what the Freya is doing to the music. Not a super wide soundstage that is kind of fake. Just perfect bass, midrange, and treble that won't make your ears hurt. My MLs don't like crap equipment or recordings. MLs reveal everything. It's like having your pants down, for all to see. Freya and Mimby have made me not want any more from my front end in my setup. Currently I'm using a ML Dynamo sub thru the SE outputs. Had to put an active gain adder unit in to boost gain just a hair for matching of a super strong balanced output of the 4 tube balanced 300 volt output of the Freya. This balanced output is spectacular. Peroid. Resistor volume control takes a little getting used to. But the reward of low volume listening with great sound is just better than I have ever heard. And this thing is only $700. Do yourself a favor and buy it. The worst the could happen is to return it. I sincerely doubt you will if you have one of the Schiit multi-bit DACs.

    PS: I have yet to test the JFET and Passive outputs on the Freya. Forget the Passive in my book. I imagine that some speakers could use the transparency of the JFET to their advantage to lift a film that their speakers may have. And that's a lot of them.
     
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