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Hypex UcD180AD amplifier review...

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  • Hypex UcD180AD amplifier review...

    Provided Link: Review of the Hypex UcD180AD amplifier modules


    See the link below.

    Please comment freely on my evaluation, I appreciate the feedback.

    Thanks.
    RJB Audio Projects
    http://www.rjbaudio.com

  • #2
    Re: Hypex UcD180AD amplifier review...


    > See the link below.

    > Please comment freely on my evaluation, I
    > appreciate the feedback.

    > Thanks.

    Very nice review. Thank you for the detailed description of your testing setup!

    Kevin at DIY Cable has some interesting multichannel amplifier designs using the Hypex modules, and they have been getting raves from many users. I have not had a chance to hear them yet, but your adds another positive opinion to a growing list...

    Comment


    • #3
      Re: Hypex UcD180AD amplifier review...

      Provided Link: The Amplifier Guru speaks: Bob Cordell


      What? You couldn't clearly hear the difference in the rhythm and pace between the two? Obviously youíve let your subscription to stereophile elapseÖ ;^)

      Iím pretty firmly entrenched in the Bob Cordell camp when it comes to amplifiers, with the exception that Iím thinking class D, as exhibited in the Hypex designs, may just be the brass ring, or at least an easy DIY way to get very close to itÖ

      Iíve got a UcD400 amp project in the wings myself, so I will postpone any other thoughts I have until Iíve brought that project to fruition, and had a good listen myself.

      See Pjayís interview with Bob below:

      C

      Curt's Speaker Design Works

      "It is the mark of an educated mind to be able to entertain a thought without accepting it."
      - Aristotle

      Comment


      • #4
        Re: Hypex UcD180AD amplifier review...


        I've been keeping track of your questions and choices on both boards. Very nice writeup. I know you're busy, but could you add some pictures of how you did this along the way. Like gutting the old HK, adding components to it, final without cover, and one with the cover. Also, how hard was this to do and could someone like myself do something similiar with guidance from someone who has the knowlege? I ask because I have a hugh Pioneer SX830 Stereo Reciever where the amps work put the tuner is shot. I could gut it and just use it as a straight amp.

        Comment


        • #5
          Thanks! *NM*



          RJB Audio Projects
          http://www.rjbaudio.com

          Comment


          • #6
            Re: Hypex UcD180AD amplifier review...


            > What? You couldn't clearly hear the
            > difference in the rhythm and pace between
            > the two? Obviously youíve let your
            > subscription to stereophile elapseÖ ;^)

            LOL!

            ---------------------------

            > Iím pretty firmly entrenched in the Bob
            > Cordell camp when it comes to amplifiers,
            > with the exception that Iím thinking class
            > D, as exhibited in the Hypex designs, may
            > just be the brass ring, or at least an easy
            > DIY way to get very close to itÖ

            Yeah, I agree with just about everything he said and learned a bit as well. I'm still early in my amplifier experimentation phase but it helps to make educated decisions when picking a new amp to try. One thing that I'm curious about is the use of feedback and I started buying into the theory that too much feedback is bad. I've found that amps with a lot of feedback can often have a soundstage that is too flat but I might be misdiagnosing the symptoms. My friend and I talked about this and he said that there can be phase issues with amps that have feedback especially if the speaker load is too capacitive because it will delay the feedback signal and the "distortion cancelling" mechanism of the feedback design won't work as well due to the phase misalignment. I thought that maybe these phase interactions could interfere with the soundstage.

            -----------------------------

            > Iíve got a UcD400 amp project in the wings
            > myself, so I will postpone any other
            > thoughts I have until Iíve brought that
            > project to fruition, and had a good listen
            > myself.

            I'm curious why Bob feels that class D amps will always fall short of the optimum class A-B amps? I'd like to learn more about the shortcomings of class D amps in this regard. If dynamics is the issue then maybe this is why my Yamaha has a very very slight edge in that category.

            -----------------------------------------

            > See Pjayís interview with Bob below:

            > C

            Thanks,
            Roman
            RJB Audio Projects
            http://www.rjbaudio.com

            Comment


            • #7
              Re: Hypex UcD180AD amplifier review...


              > I've been keeping track of your questions
              > and choices on both boards. Very nice
              > writeup. I know you're busy, but could you
              > add some pictures of how you did this along
              > the way. Like gutting the old HK, adding
              > components to it, final without cover, and
              > one with the cover. Also, how hard was this
              > to do and could someone like myself do
              > something similiar with guidance from
              > someone who has the knowlege? I ask because
              > I have a hugh Pioneer SX830 Stereo Reciever
              > where the amps work put the tuner is shot. I
              > could gut it and just use it as a straight
              > amp.

              I'll probably add some pics to my review but for now I'll email you some of the ones that I have of me gutting it. I don't have any pics of the finished amp with the cover off but I'll have to remember to take some when I upgrade the muting circuit.

              The Harman Kardon was a very easy amp to work with because it was a kit to start with and it is very modular. Your Pioneer receiver might be much trickier to work with. The main things that I used from the HK were the chasis and the transformers. If you want to gut your Pioneer the first thing to do is to determine the DC voltage capabilities of the transformer as well as the max power output. You can usually determine the voltage by measuring across the large power supply filter caps. The HK has two large transformers each providing +/-39VDC which works with many different amp kits/modules.

              The first thing I would do is determine how the Pioneer sounds now by comparing it to your Harman Kardon home theater receiver. If it sounds better than keep it but if not it might be worth upgrading. However, I recall that you use this amp for measurements and sound quality doesn't matter much for measurements (as long as you have an amplifier reference signal sent back to your soundcard during measurements.... which is one thing I've been bugging you about because you don't use a Wallin Jig II). The best way to compare amps in my opinion is using a relay switchbox for immediate transitions between amps because otherwise psychoacoustics can bias your opinion. I always say that you can't have too many amps, especially when speaker projects begin to pile up and the number of speakers outweighs the number of amps. Also extra amps are nice if you want to bi-amp a speaker and independently control the bass level.

              Personally I don't think the Pioneer would be the greatest chassis to start with but if the transformer is big enough and the voltage is right then it is at least possible to try a new amp kit/module in it. Redesigning the power supply is pretty simple until you go into muting and protection circuitry (but some kits/modules have some of this built in and if you are careful enough some of it isn't necessary and might actually hurt the performance of the amp).

              I gather old amps just for the transformers because they don't go bad (usually) and are usually the most expensive part of the amp. The key is to get the right size transformer for your application. My next amp project might be to take an old Dynaco ST-120 (60wpc) amp and install the Amp1B Tripath TA-2022 60wpc stereo amp kit in it just to see how it sounds. The ST-120 only has a single transformer but the TA-2022 is a stereo chip so it only requires one transformer (unless you bridge it and use two for stereo).
              RJB Audio Projects
              http://www.rjbaudio.com

              Comment

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