Senin, 23 November 2009

MP3 USB-MMC Reader

This is my recent DIY audio thing. I found this USD 7,- little handy MP3 player that fits me and my family needs. My car audio head unit, a Sony cdxGT700d has lost its CD mechanism for quite a while, so no CD or MP3 anymore.

I'm also tired of using my old Sony discman as source in car. Sounds quite ok though, after some blue- tack tweak, but I have to put it on my lap when driving or the player just sputter, cough and more when I hit road bumps. Here is the 'replacement', a simple cheap USB-MMC reader, feed with 5VDC. Add a 5Volt regulator such as 7805 off you go.

There is an Aux in, it can only reads MP3's put on the root directory of your MMC/USB. Read the file in sequence only, no shuffle thing, its ok for me and many motorcycles rider who use it. At the beginning of each track the volume increased to full level in a second or so and gradually soften when track skipped, one at a time. It also memorized the last track it plays after shutdown.

For my kids, there is another version, bit more expensive but still below USD10 :). Provided with a remote control, FM tuner, display, EQ function, maybe shuffle thing as well...

Some tweaks are needed after listening familiar MP3 ed tracks. Four very small electrolyte caps, 10V, 100uF replaced by good Elna Cerafine, 16V, 100uF I have on hand. Boom...the sound goes to higher level!. Add blue tacks on top of the chip, the crystal and the sounds settles in orderly manner. Definitely it sounds better than my brother stock Simbadda MP3 player.
I have learned though, that how you rip the CD is very important for the sound quality. My first test rip is using Cowon Jet-audio. The result is quite OK, but after comparing with the original CD you missed quite a lot, especially in staging. Even I have ripped in dual stereo. Then a friend told me about EAC, Exact Audio Copy. I have read it in 6moons some month back..I'll try this for sure..

After a few days of use, I decided to give this cute player a cute casing, a beautiful solid teak one!, finished just with..teak oil...hmmm..

Jumat, 20 November 2009

Analogue Volt Meter, Revived

Sometime, we in our workshop just throw away damaged things into a drawer. The same goes with this cheap Heles AVM, after a few use it's just don't swing anymore, goes into one drawer some years back. When I bought old capacitors recently, I need to see needle swing on the meter, Digital Volt Meter is no swinger :). So, in line with my principle 'use whatever you have' , old Heles is my operation target.

The problem turns to be a loose copper wiper and wobbly shaft of the disk. Thewiper was just fastened by 2 plastic pins that was melted by a solder to clamp the wiper down. Well, this is a good plastic design practice for non moving part, for moving part you need larger pins or a long rib.

So here are the fix, add a screws to the shaft and wiper. Now the needle swings !.

But the fix brings new always, a solution creates new problems :(. There is no room for the screws, so a 30 minutes fix became 1.5 hours... Bottom of the casing is drilled, then cut a jelly cup bottom (remember..use whatever on hand..), epoxy-ed them..voila!..

Another problem, the meter just does not want to stay put , so add 4 rubber pads, cut from black foam I have in my garage-double tapes them..

finito..and still fit in the old box ..., mother earth and my wallet is saved again, just 2 things I have to throw away..the casing cut out and a jelly cup with no lets swing!