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Nytech Audio / Ion Systems Appreciation Thread

Discussion in 'classic' started by deltaunit, Oct 17, 2011.

  1. NRWler04

    NRWler04 pfm Member

    Here are some pics from my new old Nytechs ...

    [​IMG]

    ... and my Speakers ARC050 ...

    [​IMG]

    and the pimped Crossover out of my CXA252 ....

    first with Nichicon ES :mad:

    [​IMG]

    and then with ELNA SILMIC II ....

    [​IMG]

    I replaced the original 63V 4700µF by 5 Nichicon FG 63V 1000µF each .... you can hear it :p

    And one of my CPA 602's with ELNA Silmic II & ROE Gold 4700µF ...

    [​IMG]

    Now it works :cool:

    Any ideas how to optimize the PSU? The place for 4 Nichcicon KG Gold 4700µF 100V seems to be available inside ...
     
  2. Bob McC

    Bob McC Living the life of Riley

    no pics for me
     
  3. NRWler04

    NRWler04 pfm Member

    Now?
     
  4. NRWler04

    NRWler04 pfm Member

    Very emotional party today ...

    Regards from Germany

    Good shave the Queen:p
     
  5. Bob McC

    Bob McC Living the life of Riley

    yes
     
  6. NRWler04

    NRWler04 pfm Member

    Can anybody here give me some informations why the big output caps are so important (or not?) and whether it makes sence to implement a bigger one 10000uF? If got this info from a Hifi Dealer in Germany? I 'm only a mechanical engineer and have no know how about it.

    Regards
     
  7. mudlark

    mudlark nearly half a clue

    I don't know the maths, but I offer this which may be right or wrong.

    Some amplifiers require DC to be removed from the output signal. (Quad 303 and nytech 202 are ones that I have.) The electrical way of removing DC is to use capacitor coupling. The capacitor used and the impedance of the speaker form an RC filter which means that with a low value of C the low frequency signals get attenuated. The higher the output C the better. Higher value caps are large and expensive.

    before you change an output filter capacitor get advice from someone who actually knows the facts. There could be other problems with larger coupling capacitors.

    In the netaudio improvement to the Quad 303 the output capacitors are changed from 2,000 uF. Quad fitted 2,200 uF later in the life of the amp and Net audio recommend 10,000 uF caps.

    http://sound.westhost.com/articles/coupling-caps.htm

    If you read the above you will find that the quad 303 and the Nytech amps are low fi!

    I hope this is of help, mike.
     
  8. NRWler04

    NRWler04 pfm Member

    Hi Mike,

    yes, very helpfull your info.

    But I don't agree that my Nytechs are LoFi ...:(:p
     
  9. Nytecholdie

    Nytecholdie pfm Member

    Hi all

    Without getting into a "which is best" war over output caps or no output caps. I can try and clear up some of the pros and cons of each.

    Most audio power amplifiers use DC coupling of the loudspeaker to the amplifier with the amplifier having both + and - power supplys.
    The main advantage of this is that the output circuit and loudspeaker have a very low output impedance (AC resistance). This not only means a more efficient drive to the loudspeaker but also means that the amplifier has better control of the loudspeaker particularly when the amp has to stop the loudspeaker cone moving (Amplifier damping factor is the key term here - the lower the output resistance, the lower the damping factor and control of the loudspeaker).

    The BIG downside of DC coupling (especially to people who short out fuses!) is that if the amplifier output devices fail or 1 supply fails the poor old loudspeaker gets a destructive DC current flowing through it and the life of the voice coil is usually measured in seconds!
    Putting a fuse in the Loudspeaker lead helps to protect the loudspeaker but ruins the whole point of DC coupling due to the extra resistance of the fuse!

    The alternative to this is to run the amplifier off a single supply which means that the loudspeaker feed will be at half supply with no signal so you need a large capacitor to block the DC to the loudspeaker. The advantage of this setup is that if theres an amp failure there is no danger of a destructive DC current damaging your precious loudspeaker.

    The downside of this is that the output capacitor has impedence as well which is why it should be as big as possible (a 2200uF has an impedence of about 1.5ohm at 30Hz). This extra resistance can significantly affect the damping factor and AC coupled amps tend to have less control over the loudspeaker and can sound less "tight" on very low bass.
    Its one of the reasons that AC coupled amps like the Nytech tend to work better with Infinite baffle (sealed box) loudspeakers as these speakers are heavely damped by the sealed box.

    It also creates a whacking great thump when you swich on which wont damage the loudspeaker but it is a bit of a shock if you're not used to it
    (The little add on boards on some of the pictures on the forum are "anti thump" circuits designed to reduce this thump - The later Ion oblisk amps had them built into the main circuit)

    One of Richard Hay's (Nytechs original co founder) brilliant ideas was to include the output capacitor in the feedback loop. Therefore the gain of the amplifier increased slightly at very low frequencies as the feedback reduced due to the increasing impedance of the output capacitor (-ve feedback so less feedback, more gain). It also improved the damping factor (although not as much as a DC coupled amp could).

    This technique certainly contributes to the charictaristic sound of a classic Nytech amp but does also mean that theyre not at their best driving a modern ported or transmission line speaker due to their higher damping factor.

    In answer to NWRlers question - Because the output cap is included in the feedback path, the effect of a larger capacitor will just mean less feedback at VLF so as long as the feedback is able to compensate for the capacitor then theres theoretically no improvment in doing it. However a larger capacitor generally has a higher ripple current capability which will help improve the damping factor slightly. You will also get a much bigger switch on thump!

    I tried 4700uF o/p caps instead of the original 2200uF ones in my CPA602 and could not detect any difference! - Going to 10000uF appeared to tighten the bass at VLF (couldnt hear any differnece on my 050's - Only noticed it on the 202's) but the caps were too big to get on the board :)

    I'm not going to venture which setup is best - There will be as many different views on that as there are people on the forum :) However I've lived with my Nytech setup for 32 years now and it still sees off a lot of the modern equivilents so "low fi" it certainly aint!

    I've now got the CPA 602 power amp and EXO102 Crossover board circuit diagrams finished and I'll upload them to the forum (as soon as I've figured out how to do it :)
     
  10. oldgit

    oldgit pfm Member

  11. Bob McC

    Bob McC Living the life of Riley

    For completists I hope this is useful


    [​IMG][/url] by , [/IMG]



    and



    [​IMG]
    by ,
     
  12. NRWler04

    NRWler04 pfm Member

  13. NRWler04

    NRWler04 pfm Member

  14. NRWler04

    NRWler04 pfm Member

    Nobody intersted in my new project? Tooo bad ...

    I like the idea to bring the CPA602's into 2012 ....
     
  15. mudlark

    mudlark nearly half a clue

    Have you access to software that does electrical circuit simulation?

    Do the boxes come in steel or aluminium? I like the idea of the cooling slots at the rear, within the overall amplifier size. I take it there are slots below to forma chimney.

    I take it the fronts are plastic. I am not an expert at industrial design, but like the idea of a classy light show/logo shining through the front. Have you decided on a name? Something to make a boring power amp attractive/interesting.
     
  16. NRWler04

    NRWler04 pfm Member

    No, actually I don't have a SW for circuit simulation. I'm looking for it ...

    The box is made from aluminium. Aluminium heat sinks will be connected from outside over the whole length. The power transistors will be placed at the end where the holes are in the top.

    I'll post a pic when they are finished.

    The front is black or white plexi glas. This is not transparent ...

    For the name there is just an idea: because we burnt our first recapping 602 .... NEROTECH AUDIO - SA1 ....(.Stereo Amplifier )

    Only crazy ideas ....
     
  17. mudlark

    mudlark nearly half a clue

    The box looks good. Rega do aluminium sides that are heat sinks and steel top and bottom. The front is plastic with lights shining through. It looks cool. A bit retro, but with modern design.

    Nero is safe due to protection from the caps! Nero seems to be doing well.
     
  18. NRWler04

    NRWler04 pfm Member

  19. NRWler04

    NRWler04 pfm Member

    The name will be NERO SA-1 for the Stereo and NERO MA-1 for the Mono designed amplifier.
     
  20. NRWler04

    NRWler04 pfm Member

    Whom it may interest ....

    [​IMG]
     

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