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I'm trying to use this generic USB audio interface https://www.jaycar.com.au/usb2-0-to-3-5mm-audio-converter/p/XC4953 so I can use this headset microphone https://www.amazon.com/Beyerdynamic-COP-Headset-Gear-Microphone/dp/B00DHBVUCQ?th=1 for video conferencing in MacOS and Windows. It says it has a microphone interface, but I believe this is inaccurate. In MacOS the input label reported by the device is just "LINE". Plugging in a line-level source works fine, but my microphone is barely audible and way too low for actual use. I purchased this pre-amplifier https://www.altronics.com.au/p/k6044-champion-pre-amp-kit/ kit hoping it would raise the microphone to line-level. Testing it with my phone's headphone output, it does *work*, so I don't think I have hosed up the construction; at full amplification it noticeably increases the volume coming in from my phone. Unfortunately, it doesn't do anything at all for the microphone, and in fact I can't hear anything at all with the microphone plugged in. According to the Amazon listing the microphone is a "High quality Condenser (back electret) microphone with gooseneck, 20 -20k Hz". I tried reading up on electret microphones but just came away more confused. This is part of the circuit description and diagram from Silicon Chip Magazine which originally published the design. Note that I'm only using the pre-champ side.  quote:Fig.1 shows the complete circuit Naively reading it, it sounds like I could increase the value of the 2.2MΩ resistor to increase the sensitivity of the input? Or is there some fundamental incompatibility using this type of microphone with this type of preamp? It's also very likely I'm in way over my head here and should just buy a better USB audio interface, but I wanted to try and use what I have on hand and maybe learn something in the process. EDIT: I somehow missed this at the end of the magazine article: quote:Microphone bias current Going to give that a shot. EDIT 2: That worked a treat! Going to make a nice box for it all now. Granite Octopus fucked around with this message at 02:33 on May 24, 2020 |
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May 24, 2020 00:48
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syntaxrigger posted:I was just curious how others managed the expense of electronic components and if there was something I was missing about keeping the cost down. If you're serious about keeping costs down and doing dumb little projects, I'd suggest scavenging. Printers are a constant feature on footpaths around here, and I grab them whenever I can. A great source of motors, gears, wire, springs, sensors etc. Need a raspberry PI? Any old computer with a parallel port will do the same thing. It can be hard to know when you're hoarding junk vs collecting specialist hobby resources but if you have a bit of space it's never been a better time to collect e-waste. Personally I don't really like buying new stuff just to do a project, both from an economical and environmental standpoint, so scavenging makes much of my stupid bullshit possible.
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May 25, 2020 01:26
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Not sure if there are any hifi wizards that read this thread.... I’ve got a small Sony micro system DHC-MD373 which has trouble playing CDs. It’ll work for the first couple seconds of a song then start skipping forward every couple of seconds for the rest of the disc. It almost always skips forward, sometimes by a few seconds, sometimes the whole rest of a track. It has no trouble reading the TOC of any disc and I’m able to jump through the tracks fine. What I have tried with no change; - Multiple CDs, all clean and free of defects, some commercially printed, others burnt - Replaced the laser pickup assembly with a brand new unit - Cleaned and lubricated all the internal guides, though there was no obvious buildup or damage. I’ve noticed that if the table its on vibrates even slightly it has a far higher tendency to start skipping, but still skips even with things perfectly still, just not as much. Ordinarily I wouldn’t care about trying to fix something like this, but its got a minidisc drive and the rest of the unit works perfectly. Is there anything else I could try? I have beginner/moderate electronics knowledge. I know how to solder, use a multi-meter, understand basic circuits. I don’t have an oscilloscope or other specialty gear though. Edit: came across this page https://www.repairfaq.org/REPAIR/F_cdfaq7.html which has some good info. Seems like there isn't much else I can do, aside from maybe fiddling with the tracking/gain controls. Granite Octopus fucked around with this message at 05:50 on Sep 7, 2021 |
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Sep 7, 2021 05:31
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babyeatingpsychopath posted:Crazy orthagonal thought, but could it be the "skip forward" button is broken and bouncing? It could be that it's nothing in the CD playback stream at all, just a broken switch in the UI section. I actually had the same thought when I was testing it earlier today. I don't think so, since the same buttons are used for skipping through MD tracks, radio stations etc, and they function normally. Wish it was something that simple!
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Sep 7, 2021 06:52
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