AAW Black Amp impressions thread

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Erroneous, Feb 2, 2021.

  1. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Polite amps like Cavalli amps, still have transients come through.

    If you want to hear lack of dynamics, strap a limiter across the board. Some bad FM radio stations will have lack of dynamics.

    Strained amps or strained op amps will start to lose microdynamics. I never felt the Black Amp strained in anyway.
     
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  2. Armaegis

    Armaegis Friend

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    I'm going to disagree with these statements here as I feel you are oversimplifying an entire generation/culture's worth of music and sort of veering into uncomfortable racial overtones. Certainly with the development of digital recording and the ability to synthesize sounds, this had let to much more bass heavy and "slam" sounds being recorded, but you can't put this on the shoulders of hip-hop. Virtually all music from the past 3-4 decades will be mastered to have additional low end content. Blame some of that on the loudness wars if you need to. But hell, classical music can certainly slam and that stuff is centuries old. Broadly, percussion can be considered slam as well.

    All audio terms are tricky to define and slam is one of them, but I think you need to reevaluate your definition.



    Can you provide some references to the Long and Wickersham articles that you are referencing? I'm curious what type of work they produced.

    Have you explored outboard gear that musicians use to tweak their sounds? (also used in the production chain)
    For example: https://spl.audio/en/spl-produkt/stereo-vitalizer-mk2/
    But there are many other kinds that all do some kind of processing to the sound, some of which may fall under the "slam" ideology. Heck, even basic expanders do something akin to that as well.
     
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  3. BarryT

    BarryT MOT: Austin Audio Works

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    As who Ed and Ron were please see these and their ideas

    https://en.wikipedia.org/wiki/Ed_Long_(audio_engineer)

    Ron Wickersham - Alembic Guitars http://alembic.com/

    This website explains what they did and the patent I referred to

    https://bagend.com/the-company/e-m-long/

    Old friends and associates from the SF Bay Area audio explosion in the later half of the 1960s. They collaborated on a patent doing a unique expansion of low-end audio energy through an envelope modulation scheme for drivers below their open resonant frequency. It made SLAM.

    It was a wonderful time of audio discovery, experimentation, and codification of our art/science. We had unbelievable resources, energy and resolve.

    It is worth knowing the past, even better having been there and participated.

    But that was then and this is now and now my audio world is about things like sonic accuracy, detail, resolution, understanding and creating purity of process with the new parts we now have - and how man's past (anthropological) has caused us as a species to have propensities that are manifested as our interest in music and audio.

    In the end this all is an illusion in our heads, that illusion is based on our myths and the predispositions we have acquired over the last 350,000 years. Making a better illusion using the artifacts of our technologies and the way our 'brainware' was written is, in my consideration, a high-art. Thus am I.
     
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    Last edited: Aug 18, 2021
  4. Erroneous

    Erroneous Friend

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    Barry, it sounds like you are consciously diverging from what the people are telling you they want. If you're honestly asking for feedback regarding your amp, the people here are giving you honest feedback and I don't think they're listening to Hip-Hop while doing so.
    I personally have knowledge of your current-mode experimental speaker amp and I liked it, but you still need to figure out what slam is.
    I'd have purchased a Black Amp if I were in the market for such a thing.
    Regardless, listen to what @noisyscott says. He has our ears. We're only trying to help. We want you to succeed. We're pulling for you.
     
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  5. BarryT

    BarryT MOT: Austin Audio Works

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    Thank you. Graciously taken. Perhaps "Hip-Hop" should be a metaphor for the difference in the nature of content over the last 20 years and I have, as it my habit, intellectually attempted to disassemble a sensual/emotional with the physics I am immersed in.

    I am reluctant to add to the music we are trying to reproduce, while I don't mind building in a process that the user can control, it has to ancillary to the process, not the point of it.

    When I get one of the new Black AMP (PCB arrive on the 18th between 3:30 and 5 so UPS tells me) we shall all see if I figured it out better from the clues you have given me. This is afterall a process of trial and error driven by educated guessing and magic.

    In the epistemological process where data points aggregate into information which solidifies into knowledge then to evolve into wisdom to then is used to define new data point (OMG, it's a mandala) we are moving to figuring this out, what fun! Thanks for joining me in this trek.
     
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    Last edited: Aug 18, 2021
  6. Armaegis

    Armaegis Friend

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    You seem to be under the impression that we want you to add something to the circuit that will "create more" slam. I want to assure you that this is not the case. Reading over past posts though, I can see perhaps where you got that idea. Really though, I think this entire idea of slam has taken off in the wrong direction and you're trying to solve a problem that does not exist, at least not in the way you think.

    Do what you think is best to reproduce the music faithfully. You've already mentioned reducing output impedance of the current cells (I'm not exactly certain what this "current cell" is though??) and increased current in the CCS which sound like positive steps. I'm curious what the modifications to the front end energy/time envelope have done. You mentioned adding a 3 position gain switch... might I suggest spacing them further apart (at least double), and would it be possible to make one of them 0 or even negative? That would allow greater usage of sensitive IEMs.
     
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  7. bilboda

    bilboda Florida boomer

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    Well, we all want something but we don't all want the same thing. Some strange responses, insinuations of racial overtones? Where da fauc did that come from? It's manipulative in it's nature and in my mind a bit of a disgrace. And woke.

    At the end of the day, there will still not be the one amp that rules all anywhere in existence. Tailoring an amp towards the many and myriad different definitions of the seemingly mythical "slam" is, in my mind, the wrong approach. Just use a more slamming headphone. It's what we do any way.

    When the music is dynamic, the amp produces dynamics, macro and micro just not with colorations that I get from the Zana Deux and SW51+ and these colorations can be quite nice but they are there as a byproduct of the design, maybe even sought after in the design. So, I have 3 amps + an ugly Crack (Bottlehead) that stays cause it has nowhere to go.

    Stop with the finger pointing, "you don't get it", "you are not understanding what we want" "you seem to be under the impression" and consider that it's likely a failure to convey your own thoughts. This sounds like kids and their parents. "But you don't understaaand That's not what I meant?" Can I borrow the car?

    For me, I wanna know what slam isssss, I want you to show mee, Only slam is real. Think foreigner.
     
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  8. Phantaminum

    Phantaminum Friend

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    Really, I personally like the amp the way it is but I'm not against any improvements. I paired it with a ZMF Verite Open which, in itself, is a pretty dynamic (has some nice slam) headphone. Paired with the ZMF Auteur, there are other amps than can push it a little bit harder when it comes to macro dynamics but I didn't care much as everything else (tonality, speed, openess, etc..) I enjoyed. Being an engineer and going down the rabbit hole to squeeze out as much performance is normal. I just hope the slam "rabbit" that's being chased won't lead us down a deep hole.
     
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  9. Beefy

    Beefy Almost "Made"

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    I mean, we're not talking Verum levels of horribleness. But if you can read the following paragraph in the context of this thread and not have your Spidey sense tingle even a tiny little bit? Well, then I'm not sure what I can say.

    "What I have discovered since is that SLAM seem to be a component of Hip-Hop music and is generally synthesized in such recordings. As Hip-Hop has strived to be sonicaly unique, SLAM became one of the effects developed to help the music style accomplish that, it is in effect a new (the last 20 years or so) and culturally acquired taste issue. Us 'white-head' hi-fi guys are generally not familiar with it because it did not exist in the music we enjoyed."

    I want you to do me a favor. Any time you feel like using 'woke' as an insult, substitute the following phrase/concept, and see if it still works as an insult:

    willing to acknowledge the human condition is a wide continuum, and willing to challenge damaging biases and preconceptions
     
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  10. dasman66

    dasman66 Self proclaimed lazy ass - friend

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    Unless we are dealing with Verum level issues, I think we need to refrain from even suggesting racism when all we are seeing are words on a screen. Words on a screen can be easily mis-interpreted... or things can be read into those words that were never intended.
    • I view "white-head hi-fi guys" is an age-reference.
    • Is equating hip-hop with SLAM in error? Yes... but I don't view that as a racist error (in fact, I could call racist on the person equating "hip-hop" to a racial group).
    • Heavy bass mixes are very much endemic to more modern/synthesized music. Yes heavy bass existed previously in certain pieces, but nothing like what is typical in much of today's music (intended to be a multi-genre statement).
    -------edit--------

    I also think it would be prudent if maybe the last couple days of this discussion were moved out of this thread
     
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    Last edited: Aug 19, 2021
  11. BarryT

    BarryT MOT: Austin Audio Works

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    Hello Folks,

    The Black AMP has returned home from the SBAF Tour alive and kicking; just a little shipping wear and tear.

    I want to thank all of you who participated in the tour for your thoughtfulness, patience, time, and comments. This has been a considerable learning experience for me and the AMP, and I have embodied many of your observations and comments into the rework of the unit for production.

    Changes embodied include but are not limited to:

    - Modified the incoming front end to pass greater low-end program material and thus altered the sub-sonic and low-end energy/time envelope of the amplifier. This is in the direction of SLAM but done without altering the AMP's extreme low-end resolution.

    - Lowered the output impedance of the current cell to 5 ohms from 20 increasing available instantaneous current flow at lower frequencies.

    - Increased the current flows in several of the constant-current sources and current-gain cells in the AMP's infrastructure.

    - Added a 3-position Sensitivity switch offering +6, +12, or +18 dB levels.



    Revised printed circuit boards have arrived, revised metal work is out of the machine shop and to the powder coater and laser etchers.

    The first limited production run will be available at the end of the month (September).

    I am now taking pre-orders on the run so please let me know if you would like to book a unit for delivery.

    Thank you all. A more powerful version of the Black AMP at 100-Watts per channel is in prototype now for release by the end of the year.

    Again, let me say how educational this experience has been and how I am indebted to all of you for your help and concern. There are more chapters to write in our growing relationship but for now as I stuff and solder boards let me voice again my heartfelt thanks. Please feel free to address questions to me any time; I am just a keystroke or 10-digit number away.

    Oh, a final remark. The anthropologist in me has chewed on the question of why so few women in audio. I read comments, watched videos, listened to and read a lot of seriously misogynistic and childish experts and contributors give insulting explanations of why half our world's population is not into what we focus on. My assessment of the issue has resulted in a theory that I have been vetting on friends interested in the subject and I am writing a short paper, which I would to publish in the SBFA forum soon.

    Again, thank you all for this tour, your thoughts, convictions, and patience with me – a whitehead hi-fi antique.

    Warmest regards,
    Barry Thornton


    Warmest regards,
    Barry Thornton
    [email protected]
    512-912-6820
     
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    Last edited: Aug 28, 2021
  12. shotgunshane

    shotgunshane Floridian Falcon

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    @BarryT You’ve mentioned changes to both the Amp and Swan. Perhaps in the swan thread, could you please mention any changes you’re implementing to the production model?
     
  13. BarryT

    BarryT MOT: Austin Audio Works

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    Hello Folks,

    I have received several requests for more information about what I changed in The Black Swan and The Black AMP for my first production versions now in the Works part of AAW.

    My pleasure to ramble through your eyeballs and into your head for while,here I go -

    First a bit about capacitors - I altered and added some to each unit. No one would argue that capacitors have sonic qualities. Over the life of electronics they have evolved from glass plates separating thin pieces of copper to exotic metal foils separated with equally exotic dialectics (typically films), or very exotic pastes and polymers.
    Back in the 70’s and 80’s this became of interest to audio folks. Walt Jung and Dick Marsh published a seminal paper in Audio Magazine (Feb and Mar, 1980).

    <http://www.reliablecapacitors.com/oldRC/www.reliablecapacitors.com/pickcap.html>

    That set off the debate. They did excellent work. Go read it; it will be good for you.

    My designs have a propensity to avoid capacitors in the audio signal path. That means my circuits will pass DC, and is unacceptable when you apply gain. Exceptions to this are the passive RIAA equalizer in the Swan and the RF filters on the outputs (both of these are mitigated in use as they act as shunts and not in the direct signal path). RF and digital noise can leak into a product on it’s output lines; wires tend to be two-way (if I did icons there would now be a smiley face).

    I chose the DC Servo approach, which feeds some DC into the input to cancel out DC in the offset in a given stage’s output.

    The output gain of the Swan is very variable (0 to 40 dB) and beyond the useful range of servos without a lot of extra parts so I use a large cap there - 4 parallel Mylar capacitors to get 20 uF (microfarads) to block the DC gain. This also set the low-frequency cut off point and eliminated DC gain. I wanted to lower the cutoff point changing the general envelope of the lows altogether. I needed to raise the capacity but Mylar has an issue in that more capacity means a lot more physical size.

    The answer it to go to denser capacity devices, more uF per cubic inch and that means electrolytic caps which generally sucks in the audio stream for a specific reason. They are polar and as such change inside with the polarity of the voltage across them is reversed. AC without DC on it makes an electrolytic see reverse voltage for the negative half of a waveform. My solution was to combine Mylar with a non-polar capacitor which un-sucked the issue of large capacity and good performance. Thus I lowered the low-end response.

    I did the same for the AMP. Originally it had DC inputs, now a combination of a Mylar and in this case an organic polymer electrolyte changed it to AC only. This changed the SLAM effect of the amp without changing the frequency or quality.

    I want to comment here on this issue with the ultimate low-end frequency response. In a DC coupled circuit there is no lower limit, the response envelope is abruptly discontinuous at Zero Hz. In an AC coupling there is typically a 6 dB per octave slope so that the response fades to the Johnson-Nyquist noise floor (thank you Ludwig Boltzmann). Does how you get to Zero matter? It would appear that from the response of my listeners it does. I appreciate that this argument appears a bit arcane but isn’t this what Hi-Fi is all about?

    OK, capacitors and leaving the DC world were the key elements.

    Next, for the Swan. The MC input on the Swan is a true differential instrumentation amplifier; the two inputs (+ and - signals) are buffered to absolutely match the input impedance so that the differential stage gets 120dB plus common mode rejection. Thus it has a DC Servo and is DC in from the cartridge.

    By the way, cartridges are a special case; their low end rolls off smoothly and by definition cannot produce DC signals. No blocking capacitors are needed. I changed the way the floating input system works by adding some resistance to the chassis ground for each input, housekeeping as I see it for stability when there is nothing plugged into them.

    For the Swan I got rid of the pilot light intensity control. I added RF shunting capacitors on both the power-input connector and in the power plug. This made for better RF and line digital noise (had a remark about very low house wiring noise of Ethernet for streaming audio). I improved the inter-tracking level accuracy of the Gain Control by paralleling multiple potentiometers.

    And for the AMP I added a three-position “gain” switch on the front panel that doesn’t change the gain but does change the sensitivity to simulate a gain change. This way, I effectively changed the gain for different headphones without screwing with the individual current-mode gain cells performance.

    Changing the DC decoupling on the input of the AMP gain cells had me change the amount of the Servo control for each channel and I increased the current in the Cells themselves to move into a more linear part of the transistors current-gain transfer curves.

    I lowered the output impedance to 5 Ohms per signal output (10 ohms bridged) for better natural damping of headphones and more power output. I also made some improvements in the Safety System that protects the headphone from a output transistor failure or DC on the output lines.

    Finally I added more capacitors on the power supply feeds to individual circuit areas for better stage de-coupling.

    OK again, that’s pretty much it.

    Naturally all this required new boards and chassis for all, which have arrived and are now being ‘worked’ to becoming bright and shiny little specialized audio analog signal processors ready for you. If you are interested please contact me and get on the list. If not, please remember what you learned here, keep a warm spot in your heart for me, and ponder your decision to move up to my hardware, my BlackDAC is in the mill along with a 100-watt version of the Black AMP.

    Thank you for your questions and interest and please fee; free to ask anything else audio on you mind.

    Here a gem I ran across the other day you might find useful.

    audio descriptor.jpeg


    Thanks, Barry
    [email protected]
    512.912.6820
     
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  14. dasman66

    dasman66 Self proclaimed lazy ass - friend

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    Do you have prototype photos of the new casework and did the size/aspect ratio of the case change at all?

    Also, all the revisions make me wonder if the new version is going to sound significantly different than what was on loaner. You may have people on the fence until some trusted ears listen to the new edition...
     
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  15. BarryT

    BarryT MOT: Austin Audio Works

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    Thank you for the questions. The chassis is the same with the exception of an additional knob (Gain) next to the Input Selector. This will have the same small knob as the input. On the back the sensitivity control has been removed (it was added for the Tour and is not in any photos). I will have photos in two weeks and will post them.

    My ear team which included one of the Tour listeners has heard the modifications in the test platform and the sonic change is more bass response and an improvement in 'SLAM', nothing in the midrange or high end is different. I would suggest we wait until the AMPs are finished to confirm the improvements.

    Is there anything else I can help with?

    Thanks for your caring and interest. I will pass on more as I discover it. Barry
     
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  16. Erroneous

    Erroneous Friend

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    @BarryT Might I suggest a finished amp tour for anyone considering buying one (or also anyone interested in what changes came about) once you get production units in hand?

    Might be cool to see the effect the SBAF tour had on the amp and maybe finalize some folks who could be on the fence?
     
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  17. loadexfa

    loadexfa Friend

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    I would definitely be interested in hearing the changes, good suggestion. :)
     
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  18. BarryT

    BarryT MOT: Austin Audio Works

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    A minor-retour would definitely be a good idea. Am building BlackAMPs now.

    Barry
     
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  19. loadexfa

    loadexfa Friend

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    Thanks Barry, the extra generosity is appreciated.:cool:
     
  20. BarryT

    BarryT MOT: Austin Audio Works

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    I appreciate your input on this amp very much In a strong way you guys have offered up insights and you comments have condensed years of thinking into a short but intense learning curve with dynamic reality checking.

    Inside the shelter of a lab and shop it becomes harder and harder to hear the outside world and the truth. You have gifted me your most valuable possession, you attention and thoughts. I am thankful and acknowledge the debt.

    Again, onward into the fog -
     
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