Modifying cheap USB-Recorder for better quality
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Woody
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Modifying cheap USB-Recorder for better quality
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Last edited by Woody on 12 Jan 2022 13:14, edited 1 time in total.
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reggind
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Re: Modifying cheap USB-Recorder for better quality
A few other things you may want to consider.
One is getting a better mic for the unit. They are just electret condenser mics. Panasonic makes tons of them, and a couple are pretty good. A company called Primo makes the best.
If you want higher quality, the mic wants a higher bias voltage than the stick provides. You can add this with a 9V battery, a resistor and a capacitor.
You also may want to tack some shielded cable onto the unit and give the mic a bit of a gooseneck. One that I made years ago had a Panasonic capsule and thin shielded cable but that last few feet had some thick (about .125" or thicker) solid aluminum "ground" wire heat shrinked in with the cable, and heat shrink over the side of the capsule. This let me both snake it into places, and also tape it to something like a chair and use it as a recording mic with a gooseneck.
And last, you can hack a bigger lithium cell onto it for greatly increased recording time. A friend gave me a few of those little cube cameras that record onto SD cards that have dead batteries. Judging from the size I figure one 18650 cell (obviously not in the little case anymore...) should boost the recording time up from 20 minutes or so when the on board battery was new to over a couple of hours.
And don't forget you can combine all of these. Put the stick in a project case, bigger battery, and a jack for plugging an external mic in.
BTW, thank you for the pictures of the guts. Can you post one of the other side of the thing with the chips on it?
One is getting a better mic for the unit. They are just electret condenser mics. Panasonic makes tons of them, and a couple are pretty good. A company called Primo makes the best.
If you want higher quality, the mic wants a higher bias voltage than the stick provides. You can add this with a 9V battery, a resistor and a capacitor.
You also may want to tack some shielded cable onto the unit and give the mic a bit of a gooseneck. One that I made years ago had a Panasonic capsule and thin shielded cable but that last few feet had some thick (about .125" or thicker) solid aluminum "ground" wire heat shrinked in with the cable, and heat shrink over the side of the capsule. This let me both snake it into places, and also tape it to something like a chair and use it as a recording mic with a gooseneck.
And last, you can hack a bigger lithium cell onto it for greatly increased recording time. A friend gave me a few of those little cube cameras that record onto SD cards that have dead batteries. Judging from the size I figure one 18650 cell (obviously not in the little case anymore...) should boost the recording time up from 20 minutes or so when the on board battery was new to over a couple of hours.
And don't forget you can combine all of these. Put the stick in a project case, bigger battery, and a jack for plugging an external mic in.
BTW, thank you for the pictures of the guts. Can you post one of the other side of the thing with the chips on it?
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Woody
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- Joined: 30 Aug 2019 04:03
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Re: Modifying cheap USB-Recorder for better quality
empty
Last edited by Woody on 12 Jan 2022 13:14, edited 1 time in total.
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reggind
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Re: Modifying cheap USB-Recorder for better quality
The small chip is an mp3 chip, I am assuming the larger chip is the flash memory chip. I have had a couple of these and they never went more than a couple of hours on a charge, thus the thought of a bigger battery.
I was surprised when I was screwing around with the mic element I was playing with. I had planned on setting up a simple voltage divider to drive it as the supply was 15v and the mic was rated something like 1.5 to 9v, and I spaced out and hooked the bias resistor to the 15v rail and it it not only did not kill it but it seemed to be very sensitive. Much more so than running it off the 1.25V reference the chip provided.
I think these may be another one of those items from China that are pretty good but have some rough edges that are not too hard to mediate.
I was surprised when I was screwing around with the mic element I was playing with. I had planned on setting up a simple voltage divider to drive it as the supply was 15v and the mic was rated something like 1.5 to 9v, and I spaced out and hooked the bias resistor to the 15v rail and it it not only did not kill it but it seemed to be very sensitive. Much more so than running it off the 1.25V reference the chip provided.
I think these may be another one of those items from China that are pretty good but have some rough edges that are not too hard to mediate.