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Post by zappytheviking on Jun 2, 2016 22:13:55 GMT
Zappy the FET killer seems to have inspired a modification of his own, most honoured . Will put it with the plans.
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Post by zappytheviking on Jun 2, 2016 12:32:28 GMT
3 Cheers for FREEDOM!!! Congratulations, can't wait to see what you will craft. Yes, the FETs most certainly have gone off to better pastures. Anything else to check for or just replace them? Already ordered based on the parts list, the 4410, now I see the ones on the board were 3710. Big difference between 4410 and 3710? Those are the crap pads in place right now . These ceramic pads are nearly here, been waiting 4 weeks, www.ebay.co.uk/itm/371144914592?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT . Get your farnell pads instead? Will get me rectangular Alu supports, do it right.
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Post by zappytheviking on Jun 1, 2016 20:12:06 GMT
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Post by zappytheviking on Jun 1, 2016 18:41:00 GMT
Thanks man, will check the big boys first. I suppose I can just unplug the working channels power to take it out of the equation, it seems to be fine.. A wirewound DIY resistor, that would be a voltage drop to slow things down? Not sure what to measure , voltages? I suppose if it keeps going long enough the malfunctioning part will get hot and perhaps send a smoke signal . Will start with checking the transistors on the board. Will report back soon, learning is taking place.
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Post by zappytheviking on Jun 1, 2016 18:00:07 GMT
Ok, new fuses in, no shorts to ground, immediately pops one of the 2 fuses at the power input. Any hints on what to check? At this moment my idea is to start removing components and measuring them, firstly the fets and then all the smaller semiconductors. My mind only comes up with that a large power draw is probably a fused open semiconductor, what do you guys think?
A side note, the one channel i got to listen too, having a hard time formulating an opinion. Maybe it just doesn't get in the way of the music. My olden pioneer AB amp adds things, like its forcing the midrange and the base is fuzzy. I will reserve all further ideas until i can spend an evening with the SECA, but I am intrigued after the 2min mono taste.
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Post by zappytheviking on Jun 1, 2016 13:46:34 GMT
Thanks Martin, something different, comes with its challenges. Now for today's list of progress and cockups. It all begins late last night, things are as they should be, a quiet and peaceful dusk enjoyed with a glass of scotch and a soldering iron. After some learnings, such as WHY you use hooks to measure the current on the resistor, things seemed to progress. After that scare, the baby still seems to be alive, sturdy stuff good Sir Wonfor. Adjusted the current to 175mV, those are some sensitive pots, a hairs step gives you 50-100mV. DC offset to 12mV at speaker terminals, the chews thread said 10mV, couldn't get it, I hope 12mV is close enough . The flop sweats started to fade, perhaps there is hope after all. The heatsinks seem to be up to the job, barely felt any heat buildup. The fastening bars on the FETs got to 55-60C, probably close to the package temps. I am wondering, the heatsink chart, does it refer to package or heatsink temp? Is this setup having too low a heat transfer to heatsink? A joyous occasion, the beast is ready to bellow its first roar, but alas, something is rotten in the state of denmark. I hooked up the amp to the desk speakers, my workhorses through the decades, JPW-510s. Before I started feeding signal into the amp the main house fuse popped. Well, I tried once more, now I had sound on the right side only, the left, cold as ice, dead in the water, damn. Time once more to sweat profusely, is this the end, will it ever live a full life? The hunt begins, the first thing i noticed, the amp board fuses were fried, not too surprising. I started beeping to see if there was a short. Yup, it seems the FETs feet had a direct short to ground, what the hell. I release the FETs from the heatsink, the beep is gone. Look at this craziness, did i screw it too hard? Maybe the pads just melted when they got hot, another learning. A straight bit of aluminium and FETs at an angle, not a good idea, uneven pressure. I wish I had my ceramic insulators, they are still in china post limbo. No, this was not the answer either, after a while i discovered THIS. The heatshrink had failed me, the heat softened it and the slight pressure from the alu bar caused a penetration, shorted straight to ground. Perhaps I will lift the PCBs higher so the lead is not under the bars, lets see. I will get some more fuses later tonight, I pray to the gods of magic blue electrin smoke all will be well. More to come very soon.
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Post by zappytheviking on May 30, 2016 17:40:17 GMT
Thanks for the pep guys. Will hurry as fast as I can, so eager to hear what the sound is like. Mostly done with heatsink mounts, if all goes well the first sounds will be heard tomorrow sans wood cover, the eye watering mirror finish will be 3-4 days more. Following the tips from www.audiochews.com/discussion/1666/bens-one4-wonfor-seca-build-ready-populated-boardsAnswered many questions, did not have to bug you guys with it. Quite interested to see how this setup will handle thermals.
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Post by zappytheviking on May 28, 2016 11:58:46 GMT
Case has been glued, router trimmed, sanded, stained and 4 or 5 coats of lacquer so far, now let it dry properly and sand it flat before last coats. The final bits from china just arrived, I will be ready for a test run within days, just have to crack on. Next, build supports for heatsinks and fans then start on the electronics.
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Post by zappytheviking on May 21, 2016 3:50:54 GMT
Great thread Zappy, looks like your doing a Stirling job. I've got to get my arse in gear and crack on with my build, but I've had a couple of wee issues to get out of the way first. Best of luck with the build. Thank you. Can't wait to see how the Wonfor tower of power will turn out, inspirational. Waiting on the chinese, binding posts and ceramic insulators are yet to arrive, I want so badly to hear this beauty sing for the first time, just a little while longer. I bought a case, some assembly required.
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Post by zappytheviking on May 16, 2016 23:19:24 GMT
It doesn't need a fan speed controller, just an NTC thermistor in line with the fan feed, connected to the heat sink. That would be so much simpler, I tried calculating voltage drops etc. What value, 100ohm? Most of them had a max dissipation of 450mW, voltage drop of ~6v gives 0.7w, so would have to get a few of those , make a little grid. Close? Fans are 12V 0.25A.
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Post by zappytheviking on May 16, 2016 20:46:08 GMT
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Post by zappytheviking on May 16, 2016 20:15:30 GMT
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Post by zappytheviking on May 16, 2016 19:59:01 GMT
Yes I was just being dumb using internal links, thanks for the attempt though.
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Post by zappytheviking on May 16, 2016 19:43:32 GMT
Thanks martin , I did use the wrong one, will fix momentarily, just spotted the correct link.
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Post by zappytheviking on May 16, 2016 17:40:27 GMT
Case design, Here is what all the goodies look like laid out.
Measurements are about 43x43x15cm ID so 45x45x20 OD. Here is a super easy case to build I saw on Ebay, rather smitten with it. Still, might just go full wood with dark stain, put a nice thick lacquer coat on it.
Do you guys think there will be interference from the fan motors? Current thoughts on airflow.
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Post by zappytheviking on May 16, 2016 17:10:05 GMT
Today started with polishing some old LGA775 heatsinks, get them all nice n spiffy. Did a test on those heatsinks, they are supposed to handle a 100W TDP CPU. Made an emergency resistor out of kanthal thread that drew 50W, standing up and passive the heatsink got 65C(20C ambient). Totally different story with a fan on it, immediately dropped to 30C. From what I understand the max heat output of a full module is 100w, I assume it's 50W for Fet and 50W for darlington. I am hoping to put a button on the front of the case, go from passive low power 10W, then switching on fan circuits to get ~30W, thermistor cools down and turns up the juice. Just flip on the fan circuit and whammo more power. No fans might overheat the PSU board, will have to see when its time, with luck the passive draft will be enough. Got a bit lazy with the last ones, but hey, they are flat now.
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Post by zappytheviking on May 16, 2016 16:56:53 GMT
The parts are arriving from all over the globe, there is a pile of notes with ideas, a few good ones hopefully Just got a veritable truckload of goodies from Colin with a few bonuses, much appreciated. I will be posting thoughts, picture and progress. Some dumb, some usable, feel free to give me pointers. This is a sizeable project for me but, as it is said, I think I can I think I can . First on the task list is get the amp and cooling going, test things out. Picking a case, leaning towards having a shop bend 3mm aluminium and doing wooden sides, not sure yet. Getting a passive cooling 20kg behemoth case is not in the budget until later so will be committing HiFi heresy, might as well put PC case LED strips in there, nice red blinky lights. The PSU and protection boards will get done a few months on, got to dimension the case for it ahead of time. Wooo excited, I suspect this will displace my old workhorse the illustrious Pioneer A-509R .
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Post by zappytheviking on May 4, 2016 17:48:03 GMT
It's a crime *not* to take advantage of the prices It's the classic, look at how much I saved, THOUSANDS hehehe, works for me, as good an excuse as any.
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Post by zappytheviking on May 4, 2016 17:45:11 GMT
Thanks John, I hope it will at least be entertaining.
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Post by zappytheviking on May 4, 2016 16:28:05 GMT
Yes, bypassing the wholesales and boutiques, the sweetest nectar. Thats some proper name brand gear, I can imagine going from the "usual" price.
I will have to try mains cables one day, skeptical but will give it a go. Mains Filters, wouldn't mind a proper one, I get these nasty pops when the fridge and water heater kick into action, I have made some plans for an isolation transformer, still in the works. I am quite sure the differences you are going for with mains filtering aren't quite that simple. I tend to see main filters and look at the parts that go into them and shake my fist when they are 4x more expensive in a marketed and assembled product. Makes me feel like an old grandpa yelling -You Youngsters with your hair, get off my lawn!!! (not that old, only halfway).
HOOOLY crap that Chord amp is some serious gear, sexy
Nice tip on the Kimber basic cables, very reasonable, if I can resist buying raw leads and contacts I will def give it a go.
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