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Lepai T2020A+ Repair/Upgrade

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  • #16
    Re: Lepai T2020A+ Repair/Upgrade

    Originally posted by PWR RYD View Post
    Precisely. Now to find exactly which one of those these amps use and to find a 12V 5A power adapter that costs under an arm and a leg. I have a ton of old Dell power adapters I might be able to use if they're 12V.

    I read more through the thread on diyaudio and I was surprised at how many people modded these things. They replaced what appears to be all the caps, some with much larger ones, they replaced the inductors, and a few other things I have no knowledge of. However, despite the dozen or more people who modded these things quite nicely, there isn't a single thread that describes what can be done, what improvements can be had, what specific parts should be replaced with what specific replacements, or anything of that sort. Its all just a bunch of "hey look what I did, isn't it cool?" threads with no explanation to help anyone else.
    Modding the Lepai T-Amp

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    • #17
      Re: Lepai T2020A+ Repair/Upgrade

      Maybe take an amp with you to Radio Shack and try out what they carry:

      http://www.radioshack.com/family/ind...goryId=2032284
      Craig

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      • #18
        Re: Lepai T2020A+ Repair/Upgrade

        Originally posted by PWR RYD View Post
        Maybe take an amp with you to Radio Shack and try out what they carry:

        http://www.radioshack.com/family/ind...goryId=2032284
        Not a bad idea. I wonder if fry's electronics carries things like that. I know they have a pretty large diy electronics section. I'll bring one of these with me one day. I'm going to have to make a project thread for this since it seems that despite having been around for 2+ years, not a single person who has modded one has made a thorough writeup on what they did and why.
        Modding the Lepai T-Amp

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        • #19
          Re: Lepai T2020A+ Repair/Upgrade

          Here's another bit I found:

          All right, the capacitors for the tone circuit and the toroids arrived yesterday. I first did the tone circuit and repeated my "poor man's frequency response test". The curves look much better now, and approximate the ones from the simulator. And of course it sounds a whole lot better.
          Seems like the output line will make the biggest difference, and there are caps there as well. Perhaps putting some higher quality caps in there would improve the sound quality quite a bit. I'll have to check what the values are. Would there be any benefit or any change in putting slightly higher value caps? I did see someone who had 2.7uf caps and upgraded to 3.3uf caps.
          Modding the Lepai T-Amp

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          • #20
            Re: Lepai T2020A+ Repair/Upgrade

            Higher value caps can possibly improve bandwidth as long as it doesn't create instability issues. Higher quality caps on the input side can certainly improve SQ to the point of diminishing returns. I speculate that one of the biggest factors in SQ on class D/T amps is the quality of the output inductors. Unfortunately if I am correct, you're kind of SOL when it comes to swapping out the magnetics :(
            Craig

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            • #21
              Re: Lepai T2020A+ Repair/Upgrade

              Why wouldn't I be able to swap the inductors? Doesn't seem all that difficult, and it was done on the previous version of the amp...
              Modding the Lepai T-Amp

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              • #22
                Re: Lepai T2020A+ Repair/Upgrade

                Got all the cap values. Anyone know how I can figure out what the inductor values are?
                Last edited by XtremeRevolution; 04-21-2011, 04:08 AM.
                Modding the Lepai T-Amp

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                • #23
                  Re: Lepai T2020A+ Repair/Upgrade

                  lcr meter. the wt3 will also measure them. its on sale too.
                  http://www.mcmelectronics.com/product/72-8155
                  " 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/

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                  • #24
                    Re: Lepai T2020A+ Repair/Upgrade

                    Oh boy. Not sure if I want to spend $55 plus shipping to test the inductors on my Lepai amp so I know what to replace them with. Any other way I can figure it out? I was able to figure out the capacitors by reading the capacitor code written on them and doing some research on those codes, but the inductors only say "100" with the letter "K" right below that number. That has to signify something...

                    Edit..figured that out too. Code 100 = 10 x 10^0uH = 10uH. K = +/-10%. So based on that, these inductors are 10uH with a tolerance of +/-10%.

                    The parts list is as follows:

                    Input cap
                    1 x 16v 3300uf

                    Other/Output electrolytic caps
                    2 x 16v 100uf
                    1 x 16v 470uf
                    2 x 16v 220uf
                    2 x 50v 1uf
                    2 x 50v 1.7uf

                    Other/Output film caps
                    1x 63v .1uf - 104j
                    6x ?v .47uf - 474z

                    Inductors:
                    5 x 10uH - 100k
                    Last edited by XtremeRevolution; 04-21-2011, 01:35 PM.
                    Modding the Lepai T-Amp

                    Comment


                    • #25
                      Re: Lepai T2020A+ Repair/Upgrade

                      This is awesome, can't wait for the writeup. Hopefully you get some good results. A buddy of mine once gave me a stereo receiver because he couldn't get it to turn on. I opened it up and found that a tiny 1/4W resistor had popped for no particular reason and I replaced it for 25 cents. I felt bad though and gave it back to him. He was grateful. So I like making something out of nothing...that way there's no risk involved.

                      Xtreme, you mentioned a Fry's electronics earlier...I know they're in a few states but you wouldn't happen to live in the Houston area would you? If you do, then you can also go to EPO (Electronic Parts Outlet) on HW3 between Nasa Road 1 and Bay Area Blvd. They have probably everything you need except for the inductors (don't know why they don't carry the small ones at least).

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                      • #26
                        Re: Lepai T2020A+ Repair/Upgrade

                        Originally posted by Wokoran View Post
                        This is awesome, can't wait for the writeup. Hopefully you get some good results. A buddy of mine once gave me a stereo receiver because he couldn't get it to turn on. I opened it up and found that a tiny 1/4W resistor had popped for no particular reason and I replaced it for 25 cents. I felt bad though and gave it back to him. He was grateful. So I like making something out of nothing...that way there's no risk involved.

                        Xtreme, you mentioned a Fry's electronics earlier...I know they're in a few states but you wouldn't happen to live in the Houston area would you? If you do, then you can also go to EPO (Electronic Parts Outlet) on HW3 between Nasa Road 1 and Bay Area Blvd. They have probably everything you need except for the inductors (don't know why they don't carry the small ones at least).
                        Nah, I'm in Illinois, Chicago area. I'll probably end up buying them online wherever I can find them, once I figure out what to replace with what.
                        Modding the Lepai T-Amp

                        Comment


                        • #27
                          Re: Lepai T2020A+ Repair/Upgrade

                          I'm very interested in modding these as well. I got 2 free from PE when I got them with the bad 13.5V adapters. Bought two 12V 5A LCD adapters to run these, $6 each, but I noticed no improved SQ.

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                          • #28
                            Re: Lepai T2020A+ Repair/Upgrade

                            Originally posted by mintos View Post
                            I'm very interested in modding these as well. I got 2 free from PE when I got them with the bad 13.5V adapters. Bought two 12V 6A LCD adapters to run these, $6 each, but I noticed no improved SQ.
                            Where did you get those adapters? I'm interested in getting some myself. The fact that my volume knob LED was dimming when hard bass beats hit certainly indicates a power issue; either I need a larger input cap or I need a larger power supply, or both.
                            Modding the Lepai T-Amp

                            Comment


                            • #29
                              Re: Lepai T2020A+ Repair/Upgrade

                              http://www.amazon.com/Replacement-Mo.../dp/B0023Y9EQC

                              http://www.amazon.com/Replacement-ad.../ref=pd_cp_e_2

                              similar to these. I'm not a EE major, so I don't know if these power supply is good for amps. All I know is that they supply 12v 5a DC when I measured them. I see stuff around that says amps need switching power, but I don't know if these are switching or not.

                              Comment


                              • #30
                                Re: Lepai T2020A+ Repair/Upgrade

                                Originally posted by XtremeRevolution View Post
                                Oh boy. Not sure if I want to spend $55 plus shipping to test the inductors on my Lepai amp so I know what to replace them with. Any other way I can figure it out? I was able to figure out the capacitors by reading the capacitor code written on them and doing some research on those codes, but the inductors only say "100" with the letter "K" right below that number. That has to signify something...

                                Edit..figured that out too. Code 100 = 10 x 10^0uH = 10uH. K = +/-10%. So based on that, these inductors are 10uH with a tolerance of +/-10%.

                                The parts list is as follows:

                                Input cap
                                1 x 16v 3300uf

                                Other/Output electrolytic caps
                                2 x 16v 100uf
                                1 x 16v 470uf
                                2 x 16v 220uf
                                2 x 50v 1uf
                                2 x 50v 1.7uf

                                Other/Output film caps
                                1x 63v .1uf - 104j
                                6x ?v .47uf - 474z

                                Inductors:
                                5 x 10uH - 100k
                                Be careful with those output inductors. You must use shielded types or cross-coupling effects rise dramatically and you will negatively affect SQ. Even toroids couple badly if parallel to each other. Also, you have to use the correct material to avoid saturation. You'll need to know the filter's corner frequency.

                                And the best output filter capacitors are X7R. Lowest DA and lead inductance for the application.

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