Nelson Pass DIY H2 "injector" for loaner tour

Discussion in 'DIY' started by dBel84, Dec 8, 2019.

  1. skem

    skem Friend

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    I think the damage to staging damage was reduced with reverse polarity (i.e,. positive-phase distortion)—so I couldn’t say that stage degradation was a universal effect of H2.

    My experience with tube gear is limited (Dragon Inspire IHA-1, EC Zana Deux (heavily rolled), Woo WA3). It has always sounded nice, but a lot less detailed and more colored to me. Compared to op-amp or other lifeless solid-state gear, the advantages of tubes (or their simpler topologies) are obvious. But compared to good solid-state gear, like M22 or XA25, I haven't experienced any advantages of tubes beyond gentler listening and a warm glow. What would you say tube loyalists are after that cannot be had from top-quality solid-state, Marv?
     
    Last edited: Dec 29, 2019
  2. purr1n

    purr1n Desire for betterer is endless.

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    The IHA, WA3, and ZD you heard are warmpoo not reflective of what I would consider good sounding tube amps. The WA3 is truly awful. The ZD, depending upon generation and the tubes that most owners typically roll in them can sound like muffled rolled off AM radio, but at least with deep soundstage maybe. The IHA can't control the low end no matter what. An ant can generate more power. It's Cary a design and has their house warmpoo sound. You are truly picking the worst for examples of tube sound. These amps should be destroyed so as not to stain the reputation of good tube amps or what tube amps are truly capable of.

    You are also comparing miliwatt (tube) amps to 20W (solid state) amps. Not just that, but you are comparing to a legendary vintage solid state amp, and a modern $5-6k Pass amp.

    Better tube amps to use to compare in terms of equivalent price and quality to M22 or XA25 might be DNA Stellaris or EC Studio Jr.

    I will say nothing about what tube loyalists are after. It needs to be heard, but only with a proper comparison. Note that I use both solid-state and tube gear depending upon the transducer.
     
    Last edited: Dec 21, 2019
  3. skem

    skem Friend

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    Just to be clear, I was in no way making a suggestion that the tube amps I’ve heard were representative of good amps; quite the opposite. When I said my experience was “limited,” I meant it.

    What might be a Stellaris-grade speaker amp? Troels likes Glowmaster KT88 and EAR stuff.
     
    Last edited: Dec 21, 2019
  4. purr1n

    purr1n Desire for betterer is endless.

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    What speaker?

    I think of transducer and amp as a unit. In general, multi-driver skinny audiophile speakers are unsuitable for SET designs. Conversely, high power high gain solid state is dumb for high efficiency speakers in a home environment.

    I don't care for PP tube amps (more power than SET.) Maybe if fixed bias, but these designs do not lend themselves well to lazy or inattentive customers.

    I dislike the EAR speaker amps and feel that their amps are the weakest in their lineup. But again, it depends upon the speaker - speaker and amp are one unit.

    Asking what is a good tube amp without context is liking asking what is a good car with an old school OHV motor.
     
    Last edited: Dec 21, 2019
  5. dBel84

    dBel84 Friend

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    That is odd. The build is stock per NP and based on his article, the standard build should provide positive phase at the speakers.

    It doesn't matter in the end as this project is geared towards experiments with H2.

    There is something to be said for both good Class A as well as good tube (not to mention my favorite = hybrid class A)

    I need to get some decent measurement equipment, I only have a signal generator and oscilloscope but it would be good to be able to put some of the amps I have built through their paces.

    .. dB
     
  6. skem

    skem Friend

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    @dBel84. The initial confusion was mine. I keep forgetting my speakers are were wired up backwards w.r.t. color code (for a historical reason of spousal harmony). I’ve edited the posts above. At a prior point, there were even speaker cables with one color wire and another color connector; it was the cause of a lot of errors and bad initial impressions over the years. With this one, I’ve finally fixed it all completely.

    0F1E9CBD-020C-4A08-B0E6-8B5B52BF3597.jpeg

    But this does not explain why the phase-angle in the measurement shows almost 180 off. My test setup uses coaxial cables with BNC/RCA jacks, so I’m inclined to think polarity was hooked up properly, but I make no guarantees!!!
     
    Last edited: Dec 22, 2019
  7. penguins

    penguins Friend, formerly known as fp627

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    Received from @CEE TEE today. The unit will be sent to @purr1n after I'm done.
     
  8. purr1n

    purr1n Desire for betterer is endless.

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    So I wanted to clarity, this device only generates H2 and at preamp levels? Would I have to sum the signals before the power amp / preamp?

    I read the linked Pass PDF. I'm super confused as ever with all this talk about getting absolute polarity on their speakers right therefore I have no idea how this hooks up.

    How do I change between phase with H2. Simply swapping the wires at the speakers would be an absolutely polarity change of both fundamental and H2 no?
     
    Last edited: Sep 8, 2020
  9. dBel84

    dBel84 Friend

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    I would assume that the fundamental follows the H2 when using the H2 generator as a pre. So yes, just switch the speaker connector. I also imagine that this is H2 dominant and not pure second harmonic. If the amp inverts phase (some amps do, you should not null but obviously absolute phase will be flipped)

    Hope that clears the mud and not only stirs it.
    .. dB
     
  10. penguins

    penguins Friend, formerly known as fp627

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    Did some initial listening this week. Using with arcam rhead as it's my only SS amp right now. I don't know how it measures, but based on other arcam stuff I've seen, it should be low enough for me to hear H2 distortion whereas I may hear tube distortion with my other amps.

    @dBel84 Played around with the pre-volume knob (and amp knob at same time) and have been using it mostly at 12'. If there is a "better" setting I'm supposed to use it at, please share.

    I don't have very good words to describe everything I'm hearing so my impressions and notes may not be very good. A lot of analogy and potential improperly used words, terms, or other I don't know what I'm doing ahead. Not to be taken very seriously.

    rHead (SS) experience: (reformatted and updated most of post 9/14 ~12:15AM)
    - Definitely hear a difference between none (no H2 pre plugged in), ~minimum, ~1%, and ~2% (per voltages from skem). I was originally going to try 1.5%, 0.5%, etc... I think this may be a bit much. Sweet spot on this thing for me I suspect is going to be between the minimum and 0.5%. Will do this part with both tube amps and rhead, update to come in another post later.

    -None to minimum: roughly akin to going from SS to tubes, IMO captures 30-50% of it, also wrong in some aspects of SS to tube. I think most people here already know this, but I've often heard elsewhere (not pointing at any one community or ASR in particular, just in general) that people like tubes because it adds harmonics and distortion. This device large shows that while this may be true to a degree, there's a lot more to tubes than some harmonics and distortion.
    Going to ~1%: A little like going from SS to tubes again but with some parts of the tube sound way amplified while other aspects aren't quite there - yes, roughly akin to what @purr1n was saying about orders of magnitude between 0.01 and 0.1% distortion vs 1% distortion.
    Going to 2% is a bit like drunk karaoke night or drunk mixing/mastering - a lot of the little audiophile and fine detail things aren't there, are messed up etc, but in some ways it's a lot of fun and some of the "fun" parts of music or audio recordings are way over emphasized and silly like when people drink too much. Especially annoying when say there is a single string pizzicato or guitar pluck that is supposed to ring out - it sounds messed up. I agree with skem that effects on staging and other subjective aspects of music will vary per song or recording, but generally speaking, most of this stuff goes away at 2%. Things like the relative wetness/dryness of the amps, transients, PRaT, don't change much, but as expected with the extra distortion and "noise" in the entire spectrum of sound, nothing will sound really dry, no transients will really sound that fast, etc.
    Going back to none after 2%: things sound normal again, but cymbals and metal instruments did sound a tiny bit tinny for the first 5 seconds.

    One somewhat curious thing I noticed - of the songs I like with more distortion, most of them are older songs (1950's - 1970's)... I wonder if this is related to available equipment of the era and how things were recorded/mastered/etc. or if it's coincidence so far. However, still ultimately per song. Roughly follows the Nelson Pass article linked in first post - busier music not as ideal, but not always. For example - listened to Elton John's Daniel at 2% is horrible and I had to stop after <5 seconds but Crocodile Rock on the same album is pretty fun at 2% (not super busy per se, but way more going on than in Daniel). Most rock / metal was not very good at 1 or 2% but this varied not only per song, but even per section of song. So on so forth.

    There's also something that feels or sounds off, it may be the ~180deg out of phase in one channel that @skem mentioned - I'm not completely sure as I haven't played around with phase that much before. At most I'll flip the phase on my Yggdrasil from time to time but on most recordings this doesn't make a huge difference to me (on a few it will). This "off-ness" is more prominent at 1% and 2%, but I don't think it's the distortion itself (I've heard old equipment before that most likely had 1-2% distortion and did not get this same "off" sound). Also, not quite sure what it is, but there is an odd pressure or feeling in my ear canals / ears at 2% that I've only ever gotten with Massdrop CTH before that also develops within about 10-20 min but it's noticibly less than I got with CTH... Otherwise I've listened to music/movies/games/etc at similar or louder levels with HD6xx and rhead for 5+ hours before w/o this happening. Happened consistently across sessions.
     
    Last edited: Sep 14, 2020
  11. dBel84

    dBel84 Friend

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    The amount of preamplification is entirely dependent on what sounds best for you. I drove a power amp directly, so it was the only source for volume control.

    Glad you are able to easily hear the differences.

    .. dB
     
  12. penguins

    penguins Friend, formerly known as fp627

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    Tried this with Stellaris today.

    Results are pretty much the same as above at 1 and 2%. It's a little bit better overall - I attribute 75% of this to Stellaris can make most things sound good with most dynamics and 25% to slightly better synergy. I find myself listening a little louder than I normally would with Stellaris. I suspect I'm trying to hear/find the little details, etc. I'm accustomed to hearing with this amp.

    At ~0.5-0.6% (V-left = 16.00V, V-right = 14.99V, extrapolation of ~0.6% based on skem's measurements) - not bad, a bit much, all the fine details are still missing, things are still a bit muddy and not clearly separated, leading edge of cymbal strikes sound pretty muted (which makes sense if thinking of how that would look with a lot of harmonics added in). In short, nothing unexpected.

    ~0.25-0.3% to come later (will set V-left ~16.22V, V-right at 15.22V) -
    LATER: I like this better vs all other levels I've tried per my preferences. It's definitely going to impact the sound in the same ways described above and is still a bit much for me. However, if I'm going to purposely add harmonic distortion with this, I think somewhere around 0.2-0.3% on the Stellaris is the sweet spot for me. Best analogy would be like ordering your favorite frap at Starbucks or nacho cheese - it's too sweet, it's overdone, kind of fake, it's not true purist / aficionado coffee, and some people just won't like it no matter what. But the majority of people are going to enjoy this once in a while, a few people frequently, and even many coffee snobs will probably enjoy one occasionally too knowing in full acknowledgement of what it is.

    At minimum, it's still not close enough to "actual hi-fi", but it isn't quite there in terms of the extra enjoyment you will/may get out of the extra harmonics. Kind of like diet soda or a "diet frap" - it's still not the real thing, but it's still bad for you, tastes weird in it's own way, still fake to a snob, and is not nearly as enjoyable as just going all the way with a normal soda or frap. Actual traits are the same as I described above at minimum on rhead.

    I'm going to listen for a few more days with different gear/setups just for my own reference + knowledge + experience before sending to purrin. Thanks again for the loaner @dBel84 - it's been pretty insightful for me.

    Lastly, if someone has questions about what did I hear specifically and not with general subjective analogies, please ask. I have some actual listening notes, but they would have made the post too long and IMO the above and skem already describe this accurately enough.
     
    Last edited: Sep 15, 2020
  13. E_Schaaf

    E_Schaaf MOT: E.T.A Headphones

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    Late to the party and sorry for the necro. I think about this concept basically every day... I like a good color wheel. Is it still available for loan?
     
  14. purr1n

    purr1n Desire for betterer is endless.

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    Let me send this to you. Not enough time.
     
  15. skem

    skem Friend

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    It's too bad this didn't get more visibility; lots to learn here and a good balance to the Cult of ASR.
     
  16. dBel84

    dBel84 Friend

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    I am OK with more people signing up. Just post interest here and move it along when you have finished your exploration.
     
  17. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Asian tour please :rolleyes:
    (via US forwarder)
     
  18. dBel84

    dBel84 Friend

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    Sure, for trusted friends. I have had good experience with forwarding services thus far.
     
  19. CEE TEE

    CEE TEE MOT: NITSCH

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    This was very interesting, I should find my notes but I wonder if this could act as a pre-amp for people who want to put a tube pre-amp in front of a power amp.
     
  20. dBel84

    dBel84 Friend

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    Possible, but more distortion than you would likely want generally and a B1 would likely offer better audio performance while adding a little of the desired H2
     

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