1. Things you need to know about the new ‘Conversations’ PM system:

    a) DO NOT REPLY TO THE NOTIFICATION EMAIL! I get them, not the intended recipient. I get a lot of them and I do not want them! It is just a notification, log into the site and reply from there.

    b) To delete old conversations use the ‘Leave conversation’ option. This is just delete by another name.
    Dismiss Notice

KJF audio Introduce the MA-01 flexible amplifier

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

  1. Purité Audio

    Purité Audio Trade: Purite Audio

    Which modules does the Theta use?
  2. Shadders

    Shadders pfm Member

  3. fred sonnen

    fred sonnen pfm Member

    Hallo orangeart

    Interesting offer!
    For me the "6 Channel Stereo 500 W per channel" is the thing I am looking for. I own a 2x 3 channel activ speaker ;-)
    But as always, ask 5 people and you get 6 opinions.
    * I do miss Neutrik "NL4MD..." SpeakOn Ports instead of Bananas?
    * My understanding is the NC500 has flexible Input Buffer. Am I right you " just" offer the standart Hypex once?
    I would like to use Sonic Imagery's or Sparkos for the mid and high frequency range.
    Now I am using two Crofts for that range...

    What are your thoughts?

  4. Timcat

    Timcat pfm Member

    I don't think these amps use NC500 modules, as NC500s are 400W into 8 ohms and 700W into 4 ohms, whereas these new amps max out at 500W into 4 ohms and 270W into 8ohms. See:


    I have NC500 based mono block amps (Acoustic Imagery) and I can confirm that they are very neutral and detailed, at least to my ears they are anyway. I would expect these new amps to sound similar, given that they use Ncore modules, albeit less powerful ones.
  5. orangeart

    orangeart KJF Audio Ltd.

    When I designed this package it was with that sort of use in mind, Building your own amp with 6 channels is just not possible for everyone so wanted to bring the modules people really wanted to be able to use in a simple package and affordable amp.

    I needed to make decisions on which connectors to use so I could design a standard back panel. I also prefer the Neutrik connectors, however in my shop I outsell binding posts at least 100 to 1 so I had my answer there :)

    Yes the NC500 doesn't have an onboard input buffer, relying on the user to design their own. The modules used in this amp are the NC***MP modules which are an evolution of the tech in the original NC*** series. Bruno Putzney designed an on board buffer for these new modules, he's one of the most talented designers out there so I'm pretty sure they would be pretty good :) The problem with having to add a buffer board is that it potentially introduces 2 problems, firstly the buffer will be physically removed from the rest of the circuit which has the potential to introduce problems. Secondly it introduces the idea to the end user that op-amp rolling might be a good idea. Truth is an op-amp needs to live in an environment where the supporting componentry is optimised for that op-amp. At it's worst that can introduce a huge amount of oscillation which then works through the rest of the circuit. So in short no it's not possible to change the buffer.
  6. Timcat

    Timcat pfm Member

    I think that Hypex also produce an input buffer for the NC500 that is intended to maintain the amp's neutral character. As I understand it, that's what's in my NC500 based amps. Nord also produce NC500 based amps with a choice of input buffers, including the Hypex one and others.
  7. orangeart

    orangeart KJF Audio Ltd.

    That's right, they did produce one. They also I think gave out a data sheet with a buffer design which is I think what Nord originally used before introducing more buffer options.
  8. Timcat

    Timcat pfm Member

    The link in my first post in this thread (post 24) is to the data sheet for the NC500. This shows a number of buffer designs. I think that the first of these is the one they produced, or still produce(?) but I'm not sure.
  9. Ian M

    Ian M pfm Member

    I have given myself a headache comparing the prices and specification on this project with what you can get from nordacoustics.co.uk. I have not come to a conclusion other than they seem very similar?
    Given that I only require 2 channels and don’t foresee any need for expansion there doesn’t seem to much in it. Not sure if I am missing something or not? Perhaps it is the flexibility of the KJF boxes that are the main advantage?
  10. orangeart

    orangeart KJF Audio Ltd.

    Hi Ian, that's an inevitable comparison I guess, especially as the cases come from the same manufacturer. When I designed this product I wanted it to be a top quality and professional product. I wanted it to be based around a proper PCB where everything can be microprocessor controlled. I wanted to be able to provide intelligent start-up, shut down and temperature control as well as offering some clip indication, the Nord boxes on the other hand don't do that. I also wanted the cable routing to be much more standardized, keeping signal runs in the PCB as much as possible.

    It's also worth pointing out that in larger 6 channel builds the domestic electricity supply at 13 amps is only just man enough. Although class D amps and SMPS are much more efficient, there is still a potential to produce a lot of heat. Probably not a great concern at normal volume level but at party levels I'd not want an amp with this much power to not have some active cooling. The cooling in these amps is quite intelligent, it monitors the temperature of the output devices, the all but silent fans start to turn slowly as the limit is approached and turn faster still if the temperature continues to rise. Ultimately the amp would shut down. Nice to know to protect your investment, even if the amp is unlikely to start turning in normal operation.

    In short I wanted to achieve the pricing available at companies like Nord et al while providing the best functionality and engineering that often isn't available even in the very high end iterations.
  11. Ian M

    Ian M pfm Member

    Thanks Stefan for a detailed answer. I think I am more inclined to go with you than nord having already built your excellent FG Mk3’s which I much prefer to my Totem Arros.
    orangeart likes this.
  12. orangeart

    orangeart KJF Audio Ltd.

    Thanks for the vote of confidence Ian
  13. orangeart

    orangeart KJF Audio Ltd.

    We are 10 days in and I've never been so busy. We've only actually got one backer so far, but I'm still expecting us to meet the target. I've spent the last couple of weeks speaking to audiophiles and studio engineers via forums and e-mail from all over the world who have been looking for a project just like this. We have had contact with online magazines from across the audio spectrum and have been featured in lots of audio blogs as well. HiFi Pig, Paul Rigby, Gearslutz, Stereo & Video, Stereo Sound & Vision, Hi-Fi and Audio-Video Online have all featured the new amplifier. My alerts have shown it cropping up in discussion on Facebook, Flipbook, Twitter, the forums and other social media. Maybe it's just an ego thing but it's been ridiculously exciting to see the fruits of my labour spread far and wide. Here is hoping we do meet the funding goal and get this project over the line. Don't forget you fellas can help by sharing the project out to your own social circles.

    Have a great Christmas.

    Mintsauce, Old Valve Git and Ian M like this.
  14. Ian M

    Ian M pfm Member

    Come on people, 2 weeks to go and I’m the only backer!
    orangeart likes this.
  15. orangeart

    orangeart KJF Audio Ltd.

    I have been told in a higher value project like this that pledges normally come at the end. I've had quite a few enquiries so am still expecting a positive result.

    Sharing the Kickstarter page will help me no end though. :)
  16. DimitryZ

    DimitryZ pfm Member

    Perhaps it is this community's experience with funding audio projects that may explain the less than fully enthusiastic response.
    s1h1 likes this.
  17. orangeart

    orangeart KJF Audio Ltd.


    Maybe, was there a particular project you are thinking of?

    I hang out in the DIY room mostly and the group buys always seem to go OK there but there was one that went pear shaped that left folk a bit bitter. That was one of the reasons I did Kickstarter as its got built in protections. Firstly I have to have a fully functioning prototype with most of the kinks ironed out before the project gets accepted. Once accepted and live, none of the money goes direct to me until (if) all of the money is raised. Lastly I'm a proper company with a good track record of delivering stuff people pay for.
    Last edited: Dec 28, 2018
    Old Valve Git likes this.
  18. Ian M

    Ian M pfm Member

    I’m sure Dimitry is only thinking of only one project which has been running for 5 years or more and is more like a religious experience. It’s running on faith, we need to believe the end is in sight.
  19. orangeart

    orangeart KJF Audio Ltd.

    This definitely won't be running in 5 years

    Is this 'religious experience' a certain DAC upgrade?
  20. Kraus

    Kraus Member

    Just looked at your Kickstarter page and I do not think "Bleeding Edge" doesn't means what you think it does.

    Definition -
    What does Bleeding Edge mean?
    Bleeding edge refers to technology that has been released but is still not ready for the general public due to the fact that it has not been reliably tested. Bleeding edge technology is released in beta to early adopters in order to smooth out compatibility issues, user interface problems and other underlying design flaws and bugs that slipped through early testing.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice