I finally got to work on this project over the past couple of days. I had been meaning to make another 3020 amplifier from a 1020 preamplifier. Since I used all my spare 1020 front panels on other amps that I sold, I had a new front panel CNC machined from blue anodized aluminum. To mount the front panel I just tapped out four of the front sub panel screws with an M3 tap, and used some threaded standoffs.
The circuit board came from a 1020 preamp that I believe I sold to @moosteve and then bought back from him. The power amp has all new components obviously as there wasn't anything there before. Wima films, TDK ceramics, Nichicon electrolytics, 1% metal film resistors, Bournes trimmers, all new transistors including the outputs.
The chassis and transformer came from 3120 that I bought from eBay that arrived with a cracked circuit board. This has the luxury of the 4/8 ohm switch on the back, which far from being a power reduction device, actually runs the supply rails at a higher voltage than the "regular" 3020.
The power meter board was in my box of spares, I added the blue LEDs. Since there were no mounting points on the new front panel, I had to add little strips of steel to the sub-panel, and mount it to that.
The extra circuit board inside is one of my protection circuits. I've upped one of the caps to 220uF which gives a nice long turn-on delay.
I couldn't decide between using the flash or not, so I've uploaded both pics. I also uploaded a video to YouTube. I had the amp running like this for about an hour into those 6x9s with the loudness on and the bass up a little. It got hot, but it was loving it!
Lee.
The circuit board came from a 1020 preamp that I believe I sold to @moosteve and then bought back from him. The power amp has all new components obviously as there wasn't anything there before. Wima films, TDK ceramics, Nichicon electrolytics, 1% metal film resistors, Bournes trimmers, all new transistors including the outputs.
The chassis and transformer came from 3120 that I bought from eBay that arrived with a cracked circuit board. This has the luxury of the 4/8 ohm switch on the back, which far from being a power reduction device, actually runs the supply rails at a higher voltage than the "regular" 3020.
The power meter board was in my box of spares, I added the blue LEDs. Since there were no mounting points on the new front panel, I had to add little strips of steel to the sub-panel, and mount it to that.
The extra circuit board inside is one of my protection circuits. I've upped one of the caps to 220uF which gives a nice long turn-on delay.
I couldn't decide between using the flash or not, so I've uploaded both pics. I also uploaded a video to YouTube. I had the amp running like this for about an hour into those 6x9s with the loudness on and the bass up a little. It got hot, but it was loving it!
Lee.
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