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KJF audio Introduce the MA-01 flexible amplifier

Discussion in 'audio' started by orangeart, Dec 12, 2018.

  1. Ian M

    Ian M pfm Member

    Yes, let’s hope this doesn’t turn into a certain DAC upgrade thread. ;)
  2. Ian M

    Ian M pfm Member

    I’m sure bleeding edge does not have an exact definition. You could say leading edge or cutting edge, does it matter?
  3. orangeart

    orangeart KJF Audio Ltd.

    Yes, I think that's maybe just an interpretation as I've always taken bleeding edge, cutting edge, leading edge etc to mean the same broad thing. Interesting how different sayings evolve. When I was a young lad involved in the 'rave' scene. We all referred to the razor's edge. Years later I had a conversation with a load of old ravers and we discussed what we though it meant. Some thought it referred to the physical activity of using a razor to 'cut' drugs, some thought it meant it meant that our scene was so small when it started we could fit on the proverbial razor's edge, some thought we were at the 'cutting edge' of music production and some thought it represented the razor thin line dividing our sub culture from mainstream society. Seemed so simple at the time!
  4. h.g.

    h.g. pfm Member

    This only matters if the distortion is above the threshold of audibility. As far as I am aware nobody reliable has reported this to be anything other than a transparent/audibly neutral amplifier (subject to usual caveats about load) and the measurements you cite seem to support that.

    @Stefan: Despite the current set of modules not being suitable for my current project (discussed elsewhere) I think the idea of a modular amplifier is a good one if it can be made flexible enough. One application for such a modular amplifier would be to drive active speakers and these would benefit from a DSP module. Don't know if Hypex themselves currently provide one but do you have thoughts along these lines if the project gets funded?
  5. orangeart

    orangeart KJF Audio Ltd.

    There is a current Hypex DSP Which was due to be replaced last year. There is no sign yet but hopefully next year will bring changes here.

    There is another design I am considering but that requires quite a large pool of user knowledge.

    In short, yes, if I can get this off the ground there will hopefully be a DSP box to follow in the mid term.

    You will see in my answer at the other forum that I still think this is the solution for you. I designed it for just your sort of application
  6. Shadders

    Shadders pfm Member

    The measurements are based on a measurement bandwidth of 22kHz. This means that from 11kHz to 20kHz, the reason the THD is the amplifier noise floor, is that they omit the THD.

    If people indicate subjectively that the amplifier is transparent, then the THD above 22kHz is not relevant to people ears, and maybe this is the proof required - those harmonics above 20kHz do not affect the subjective in band experience.

  7. h.g.

    h.g. pfm Member

    A separate DSP box rather than a DSP module inside the modular amplifier? That would be more flexible but a less neat package.

    The configuration is fine but the use of expensive top of the range amplifier modules for room control is not appropriate. I opted for a decent standard range home audio driver to make things quicker, easier and more flexible but for any revisions I will likely research using cheaper car audio drivers. When using lots of channels the cost of each channel needs to be minimised if the overall cost is to be acceptable for something that is more in the background like an accessory. In the foreground are things like the main speakers, amplifiers and other boxes in the hi-fi stack for which many audiophiles are comfortable spending thousands.

    I would like to repeat that I think the project is a good idea and would, for example, consider it for a future DIY active main speaker project hence the enquiry about DSP.
    orangeart likes this.
  8. James46

    James46 The Crystal Method

    Good luck with your venture, it's good to support new stuff. Personally, I have never found class D appealing at my home, but good wishes to you all who use it.
    orangeart likes this.
  9. Rodrat

    Rodrat pfm Member

    As a matter of interest, why have you used the power output to 4 ohms rather than the more normal 8 ohm figure. I am sure there is a good reason but a potential buyer may feel a bit short changed believing the headline figure is the latter.
  10. orangeart

    orangeart KJF Audio Ltd.

    I've been careful to always state that it's the 4 ohm figure and normally backed up by the 8 ohm as well. I'm not sure why but lots more amps are now stating the 4 ohm figure and especially the class-D ones. I suspect to demonstrate that they do double into 4 ohms. Hypex themselves publish the figures this way and I'm keen to not try and hide the fact the I am using thier modules, hence sticking to thier standard.
  11. orangeart

    orangeart KJF Audio Ltd.

    A week to go so if you are thinking about backing this project, you've not got long left!

    A couple of things I've been asked which are worth passing on.

    Can I have a black instead of silver front panel?

    Yes you can! I'll contact all the backers at the end to find out your preferences.

    Can I have a back panel with Neutrik speakon connectors instead of the binding posts?

    My original answer was yes but you will have to pay the extra costs involved. I've been back to my case supplier and actually I can do this alternative back panel at no extra cost. The answer is now an unequivocal YES! This is great news for those of you who keep your equipment in a rack or just prefer these great connectors. I'll contact all the backers at the end to find out your preferences.
    Ian M likes this.
  12. Adam N

    Adam N pfm Member

    Interesting project, but I'm struggling to find a differentiator from the Nord Acoustics or Apollon offerings? They also use the NC boards in stereo and mono configurations as well as offering 4 and 6ch options. Perhaps the key is maybe to also offer a half width option or move the case design further away from the others? Good luck with the Kickstarter though, I've done one (unsuccessfully) and they are a lot of work!!!
  13. orangeart

    orangeart KJF Audio Ltd.

    There are 2 big differences. Firstly it is very flexible, it allows a user to return to base to have modules added or swapped without having to completely rebuild the whole amplifier. The ability to cater for every configuration is built into both the case and the control board. This ability for the control board and the case to cater for this means that each build is not only a custom build but at the same time it is able to be built with production line ease. The problem with most 'custom' builds is that they end up looking a little DIY in their execution. I wanted to get away from that feeling while still being able to offer full customisation.

    The second major point of difference is the control board, it allows the amplifier modules to communicate to the user things like DC detection, temperature, clip, error shutdown etc. It controls start-up sequence to stop fuses blowing on power up and 12V triggers can be implemented as standard. It also provides for intelligent cooling which neither of the others do. Class D amps are obviously very efficient but pulling 6 x 500 Watts from the mains still potentially generates a lot of heat if those amps are being pushed to those limits. In this design a pair of large and essentially silent fans can be pressed into service should things get a little warm, under most domestic listening circumstances or course they don't. Even the very high end Ncore based offerings don't offer well thought out cooling.

    As you noticed Apollon and Nord also use the same off the shelf cases in an effort to keep the costs down so a similar look is inevitable as is the question you pose. I'm pretty happy that my version is much more flexible and offers greater functionality to the user at similar prices though.

    Adam N likes this.
  14. orangeart

    orangeart KJF Audio Ltd.

  15. orangeart

    orangeart KJF Audio Ltd.

    I'm one backer away from the project being a reality, roll up, roll up.
  16. G T Audio

    G T Audio Trade: Distributor and Manufacturer

    I assume the amp is fan cooled?
  17. orangeart

    orangeart KJF Audio Ltd.

    @G T Audio , Yes, although they are intelligently controlled by microprocessor so only come one when you are turning the wick up.

  18. orangeart

    orangeart KJF Audio Ltd.

    Wahoo! Fully funded There is still time if you'd like to get in on the action. Campaign closes today at 12:00 GMT
    Mintsauce likes this.
  19. Darren

    Darren All Business

    Brilliant news. I see someone has ordered the KW+ in each box option ... That should be fun!!
    orangeart likes this.
  20. orangeart

    orangeart KJF Audio Ltd.

    I'm so relieved, I've just been for a run to get my nerves back together and get some head space. I'm going to have the rest of the morning off now and watch a movie
    Darren, Ian M and pickwickpapers like this.

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