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ESP Project 101 Lateral MOSFET Amplifier

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  • ESP Project 101 Lateral MOSFET Amplifier

    As you can see, I've been bitten hard by the amp bug lately. All my speaker projects have taken a back seat to amplifiers. Craig Salin and Bob Cottiers are not helping either by constantly bringing up the virtues of tube amplifiers, and coaching me in the background.

    After extensive listening to my Chinese made MOSFET amp, and really loving the sound quality, I decided to build a truly reliable Class AB amp, and picked Rod Elliott's Project 101 Rev. C. The total cost of 2 PCBs, plus shipping to California was $52.00. The lateral MOSFETS were $25.00, and the BOM for the rest of the passive components were $48.00, so the total for just the amp came out to $125, a complete bargain for a high power, high quality amplifier. This amp is capable of producing 180W RMS into 8 ohms, and 250W RMS into 4 ohms, with short term power of 240W and 380W respectively using +/-56V rails.

    The PCBs were shipped by Rod very quickly from Australia, and made it to CA in 7 days. The build was straight forward because of the complete instructions, and the great email support I got from Rod over the course of 2 weeks. I've never performed a bias adjustment on an amp, but Rod made it easy with his pictorial instructions. Try to get that on eBay!

    With Chinese amplifier kits, making the finished product work is sometimes a crap shoot. Hum, hiss, blown transistors, non working components, and extensive modifications are the norm. On the other hand, P101 is simply a piece of cake to put together. The MOSFETs are mounted on the opposite side of the passive components, and are isolated with mica from the heat sink. The PCBs do not have holes for stand offs, and can be mounted vertically on the heat sinks. I elected to mount them on a 1/8" thick aluminum right angle, then attached them to the heat sink. This way, the amp is horizontally positioned, and adjustments can be made with ease. With earth ground and the PSU ground in place, speakers attached and source material on pause, the amp is just dead silent. When the music came on using high quality FLAC, the sound is insanely awesome, and that's going to be the extent of my subjective assessment of this amplifier. At high volume, I like it so much better than my Sure IRS2092, especially with female vocals and strings. Screw the efficiency and small heat sinks, I like my Class AB amps.

    Hong
    Attached Files
    Some people are addicted to Vicodin. I'm addicted to speaker building.

    The Chorales - Usher 8945A/Vifa XT25TG Build
    ESP Project 101 Lateral MOSFET Amplifier
    LM4780 Parallel Chipamp
    Sonata Soundbar Project
    The Renditions - Active/Passive Towers

  • #2
    Re: ESP Project 101 Lateral MOSFET Amplifier

    More pics...
    Attached Files
    Some people are addicted to Vicodin. I'm addicted to speaker building.

    The Chorales - Usher 8945A/Vifa XT25TG Build
    ESP Project 101 Lateral MOSFET Amplifier
    LM4780 Parallel Chipamp
    Sonata Soundbar Project
    The Renditions - Active/Passive Towers

    Comment


    • #3
      Re: ESP Project 101 Lateral MOSFET Amplifier

      Looks good. I think I would have rotated the PCB's such that both pairs of MOSFETS are against that heatsink. You might have differential temperatures as-is, which means "optimal" bias might be too high for the nearest pair and too low for the farthest pair. Being MOSFETs, you could just crank the bias up and get a larger region of Class A operation, at the expense of more heat at idle.

      The heatsink looks small for the power rating, but you do have a fan on it.

      Out of curiousity, what is the function of all those blue LED's?

      Regards,

      Rob

      Comment


      • #4
        Re: ESP Project 101 Lateral MOSFET Amplifier

        Originally posted by weinstro View Post
        Looks good. I think I would have rotated the PCB's such that both pairs of MOSFETS are against that heatsink.
        Yeah- and I would have used a vertical-fin or rotated it so the sink was on-top.
        Later,
        Wolf
        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

        *InDIYana event website*

        Photobucket pages:
        http://photobucket.com/Wolf-Speakers_and_more

        My blog/writeups/thoughts here at PE:
        http://techtalk.parts-express.com/blog.php?u=4102

        Comment


        • #5
          Re: ESP Project 101 Lateral MOSFET Amplifier

          Crap. I shouldn't have looked. Now I want one. :D

          Good job.

          Comment


          • #6
            Re: ESP Project 101 Lateral MOSFET Amplifier

            Rob's got some good stuff on his website - plenty of articles and infomation for beginers and more advanced readers alike.
            I bought a couple pcb's from him (pre and power amp) for a project as part of a high school assessment:

            Click image for larger version

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            Very unfinished in that picture, but you can see that the output devices are mounted on the trace side on mine as well, mounted the board straight onto the sink which is bolted onto the chassis.
            Oh and when it comes to customer service - top notch. Back when I bought these I knew more or less nothing about amps or speakers but Rod was very tolerant of my newbie questions (I asked him if I could use a normal pot as a speaker level volume control haha :applause: )
            When you consider the pain and suffering we go through, the compromises we make - It makes you wonder how anybody could want to be an audio enthusiast...

            Comment


            • #7
              Re: ESP Project 101 Lateral MOSFET Amplifier

              That pic wasn't upside-down when I uploaded it... :/

              Try again:
              Click image for larger version

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              EDIT: I give up, uploading an inverted version made it *surprise surprise* inverted...
              Attached Files
              When you consider the pain and suffering we go through, the compromises we make - It makes you wonder how anybody could want to be an audio enthusiast...

              Comment


              • #8
                Re: ESP Project 101 Lateral MOSFET Amplifier

                Interesting observation about the 2092 amp vs this AB mosfet. I can't believe your production rate on these amps!
                Seems like 1 amp per month, and all with beautiful custom work. Gives me something to strive for.

                I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
                "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

                High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
                SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
                My Voxel min sub Yet-another-Voxel-build

                Tangband W6-sub

                Comment


                • #9
                  Re: ESP Project 101 Lateral MOSFET Amplifier

                  Yes, you are making some very nice projects.

                  Comment


                  • #10
                    Re: ESP Project 101 Lateral MOSFET Amplifier

                    Are you including the cost of the transformer in you BOM? If so what is your source?!?

                    Comment


                    • #11
                      Re: ESP Project 101 Lateral MOSFET Amplifier

                      Hi Rob,

                      The aluminum angle dissipates heat quite well, so I have not seen any ill effects because of the set up. And yes, the fan keeps the temp around 120F while driving 4 ohm loads. On the the bias issue, I've been told that I can crank it up to 500mA, which equates to 330mV. I'm at 100mA currently, or 66mV, per Rod's instructions. What is yours at? Thanks.

                      PS. The blue LEDs are just for show. The top of the amp is clear acrylic.

                      Originally posted by weinstro View Post
                      Looks good. I think I would have rotated the PCB's such that both pairs of MOSFETS are against that heatsink. You might have differential temperatures as-is, which means "optimal" bias might be too high for the nearest pair and too low for the farthest pair. Being MOSFETs, you could just crank the bias up and get a larger region of Class A operation, at the expense of more heat at idle.

                      The heatsink looks small for the power rating, but you do have a fan on it.

                      Out of curiousity, what is the function of all those blue LED's?

                      Regards,

                      Rob
                      Some people are addicted to Vicodin. I'm addicted to speaker building.

                      The Chorales - Usher 8945A/Vifa XT25TG Build
                      ESP Project 101 Lateral MOSFET Amplifier
                      LM4780 Parallel Chipamp
                      Sonata Soundbar Project
                      The Renditions - Active/Passive Towers

                      Comment


                      • #12
                        Re: ESP Project 101 Lateral MOSFET Amplifier

                        Originally posted by donradick View Post
                        Interesting observation about the 2092 amp vs this AB mosfet. I can't believe your production rate on these amps!
                        Seems like 1 amp per month, and all with beautiful custom work. Gives me something to strive for.
                        Don,

                        I just stick to a few very simple formulas to crank them out:

                        1. A low noise power supply
                        2. Simple, inexpensive, easy to build soft start
                        3. Effective speaker protection
                        4. Good grounding scheme

                        My goal is to build an amp that starts up quietly, does not "pop" the speakers, produces zero hum or hiss when you pause the music, and shuts off the music the instant you turn off the amp without again popping the speakers. Trust me, building speakers are much more difficult. Thanks.
                        Some people are addicted to Vicodin. I'm addicted to speaker building.

                        The Chorales - Usher 8945A/Vifa XT25TG Build
                        ESP Project 101 Lateral MOSFET Amplifier
                        LM4780 Parallel Chipamp
                        Sonata Soundbar Project
                        The Renditions - Active/Passive Towers

                        Comment


                        • #13
                          Re: ESP Project 101 Lateral MOSFET Amplifier

                          I think you need a support group. You have become and amp machine!
                          " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                          Quote Originally Posted by hongrn. Oct 2014
                          Do you realize that being an American is like winning the biggest jackpot ever??

                          http://www.midwestaudioclub.com/spot...owell-simpson/
                          http://s413.photobucket.com/albums/pp216/arlis/

                          Comment


                          • #14
                            Re: ESP Project 101 Lateral MOSFET Amplifier

                            Originally posted by eyekode View Post
                            Are you including the cost of the transformer in you BOM? If so what is your source?!?
                            The BOM is just for the amp. The case is from the previous project (in my signature "Class AB MOSFET Amp Build"). The toroid was acquired used from one of the forums, so if you lurk around enough, you'll find what you need. If not, Antek's transformers are very cost effective. The big caps are from Apex Jr. Let me know if you need more info. Thanks.
                            Some people are addicted to Vicodin. I'm addicted to speaker building.

                            The Chorales - Usher 8945A/Vifa XT25TG Build
                            ESP Project 101 Lateral MOSFET Amplifier
                            LM4780 Parallel Chipamp
                            Sonata Soundbar Project
                            The Renditions - Active/Passive Towers

                            Comment


                            • #15
                              Re: ESP Project 101 Lateral MOSFET Amplifier

                              Originally posted by [email protected] View Post
                              I think you need a support group. You have become and amp machine!
                              Support group??? I have you guys already. By the way, speaking of machine, you've been working a lot harder than I have, from the looks of those incredible MDF baffles!!
                              Some people are addicted to Vicodin. I'm addicted to speaker building.

                              The Chorales - Usher 8945A/Vifa XT25TG Build
                              ESP Project 101 Lateral MOSFET Amplifier
                              LM4780 Parallel Chipamp
                              Sonata Soundbar Project
                              The Renditions - Active/Passive Towers

                              Comment

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