John Warren Posted March 11, 2023 Share Posted March 11, 2023 This was a cool project. Gent purchases an MA6100 from an estate sale. The amp is new, never used, still wrapped in plastic bag but it's missing the power supply board. So he needs a board and contacts me. I do not have these boards just lying around. There's two ways to solve this, buy a "donor" amplifier and hope it has a good board or design a new one. When he sent me an email, I intially said I wasn't interested. We chatted a bit more and I decided to do it and, as it turns out, wasn't really that difficult. Since I too own a 6100 I decided to design a board for my unit and his. So here's the factory original: And the replacement: Board pulled from the amplifier: Board ready for install: 5 Quote Link to comment Share on other sites More sharing options...
richieb Posted March 11, 2023 Share Posted March 11, 2023 — wish I had the skills/knowledge to somewhat casually say “ decided to design a board” - . Nice work. I’ll know where to go should my 6200 need a look see - Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 11, 2023 Author Share Posted March 11, 2023 Thank you. On the difficulty scale this board is a fairly straightforward effort. I also have a few design tools that help in identifying trouble spots before I commit funds to board production. I do have a second iteration of the board designed but will wait until I have another 6100 in for service before ordering it. One more photo of the installation: 1 Quote Link to comment Share on other sites More sharing options...
Zappa Freak Posted March 12, 2023 Share Posted March 12, 2023 Very clean nice job how long did it take........ I W H FK I up.. Quote Link to comment Share on other sites More sharing options...
henry4841 Posted March 12, 2023 Share Posted March 12, 2023 I admire a tech that can do such, design and have a board made. I am not good enough on the software programs to design a board myself. Played around with programs some but found out just not my thing. Nice having you as a member here. Nice work. Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 13, 2023 Author Share Posted March 13, 2023 21 hours ago, henry4841 said: Nice having you as a member here. Awesome, thanks! Next questions, how can this relatively simple design be improved? There are a few modifications that can be made but there's also space constraints. That requires going to the simulator. Will detail that on the forum below. MA6100 Power Supply Board (northreadingeng.com) Quote Link to comment Share on other sites More sharing options...
henry4841 Posted March 13, 2023 Share Posted March 13, 2023 1 hour ago, John Warren said: Awesome, thanks! Next questions, how can this relatively simple design be improved? There are a few modifications that can be made but there's also space constraints. That requires going to the simulator. Will detail that on the forum below. MA6100 Power Supply Board (northreadingeng.com) Not everyone here frequents technical sites so share what you find here on a social forum as well. I am sure there is interest among electronic novices like myself. Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 26, 2023 Author Share Posted March 26, 2023 Here's the revised design (R1.1). A bit tidier. The caps can be ceramic disk of film type. Caps across rectifiers should be either ceramic disk or polypropylene. I kept the ceramic disks because I have them. If they're film, the must be polypropylene given the application. It's a significantly better dielectric than polyester, far better insulation and dielectric behavior. The board will accommodate a WIMA PCM5 AC pulse type. For the output stage RC filter a WIMA general purpose polyester (PET) is ok and what's installed. It's also in the PCM5/7.5mm package replacing the ceramic disk (easier to install and I have them). Polyester caps are fine for decoupling and noise suppression and they're low cost. They pick up moisture and that changes the behavior as a function of frequency. They have rates about 40X higher than polypropylene. As a general rule you can replace polyester with polypropylene but not the other way around. 1 Quote Link to comment Share on other sites More sharing options...
henry4841 Posted March 26, 2023 Share Posted March 26, 2023 " The caps can be ceramic disk of film type" Was not aware such existed. Learn something new everyday. Unless a circuit is very critical I have no problem with a polyester cap even replacing a polypropylene. Dielectric absorption is better with a polypropylene but in most circuits it does not matter. Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 1, 2023 Author Share Posted April 1, 2023 On 3/26/2023 at 7:31 AM, henry4841 said: Dielectric absorption is better with a polypropylene but in most circuits it does not matter. Capacitance changes with changes in frequency, voltage, humidity and temperature between the two "film" types are significant. Companies like WIMA, KEMET, Vishay and many others have factories dedicated to the fabrication of either polyester or polypropylene film caps. There's manuals, application and usage guidelines specific to each type. The selection of the wrong film in many applications (power supplies as one example) will determine the failure rate. The point being, it really does matter. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted April 3, 2023 Share Posted April 3, 2023 Awesome work @John Warren as always and thanks for sharing…!!! miketn 2 Quote Link to comment Share on other sites More sharing options...
John Warren Posted April 4, 2023 Author Share Posted April 4, 2023 On 4/3/2023 at 11:38 AM, mikebse2a3 said: Awesome work @John Warren as always and thanks for sharing…!!! miketn Thank you. Quote Link to comment Share on other sites More sharing options...
Liem Posted September 17, 2023 Share Posted September 17, 2023 Hi, John Warren Do you have spare volume conttol for MA 6100? Please kindly help me. Mine is not original and distorting when turned. Thank you, Liem KF Quote Link to comment Share on other sites More sharing options...
billybob Posted September 18, 2023 Share Posted September 18, 2023 @John Warren Quote Link to comment Share on other sites More sharing options...
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