I previously wrote about the Yamaha 10W amp I fried, and about trying to fix it. When I asked a friend - electrical engineer- what could go wrong if I have shorted the output, he told me it could be generally 3 thinghs: driver Q, main Q or power resistor (that is also a problem with some other project of mine). In problems at Yahamaha II I learned, that passives can hardly get damaged and that they're actives which fail usualy, so I was brave enough to buy both ICs which are present on the board. As I saw a lot of ceramic caps on the pcb, I also said that I would try and change them to polies, as I had scrapped a lot of them. When plugged in the amp was working. There was an old speaker box in my basement. I made a cut in the back panel and painted it. Then I made chassis for the board from my scrap metal. PCB is pretty narrow, so there was not much need for more than a faceplate - I took an old sign plate (later I found out the material is too thin). I drilled the needed holes (and made some stupid mistakes in process), found and connected power switch and reconnected the AC wiring. I used pcb and speaker from the original Yamaha amp. When connected, the result was quite impressive. Specially distorted sound is fantastic.
When revising my work, I figured out:
- faceplate is too loosely attached, so the air is "leaking" through, making annoying sounds and deteriorating the sound
- the vibrations in the box could break the poweramp IC, which is on the basc part of the chassis
- the device is quite heavy, so the screws for the handle need some help
So I later attached faceplate to the backplate with multiple screws and used some foam tape to seal the faceplate, and made a simple bracket to fix the back chassis, to keep it from vibrating. And drilled a piece of metal to support the handles from the inside.
Rich sand sounds.
Ni komentarjev:
Objavite komentar