DIY amps (part two)
The first page is already too long so I'll start adding my newer amps in here.
My P101 amp which uses ESP boards. It puts out about 180 watts RMS into 4 ohms or 120 watts RMS into 8 ohms. thermally controlled fans, the ESP suggested PSU but with six 6800uF 63V caps. all electrolytics (except for PSU caps) are 105�C. The tranny is 400VA with 35-0-35 and single 12V secondaries.
View from front (if you noticed, there is a loopbreaker circuit on the left of the board holding the speaker terminals.)
View from the back, These pictures show how the amp was laid out and wired. There is a diode (1N4004) clamped in the middle of the heatsink as the temp sensor. The fan is about 4" square. due to the large size, it runs at very low speed which is very quiet and inaudible at low listening levels but still keeping the heatsink cool.
View of rear panel, the AC outlet is unswitched and unfused. You can see the exhaust with some screen. The speaker terminals didn't come with insulating bushes so I mounted them on a PCB.
View from the side showing the ESP boards.
Another angle, showing my P42 board which contains its PSU and LED outputs.
Here are pictures of my dual P3A car amp which runs with +/-35V rails @ 13.8V input. It drives the front speakers of my ride (MB Quart separates) and the sound quality is excellent. It has proved reliable (I have pushed this amp really hard that it could damage my hearing) for months of use up to present without any problems even if sink temp reaches ~70�C at hot days. the pics show the amp installed, bolted behind the back seat.
power/speaker side of car amp showing the power and speaker terminals. You can also see the hot air exhaust below the connectors. Air goes into the amp through the space between the acrylic cover and the sides.
input side of car amp, the gain pot is right above the RCA jacks if you notice the hole.
view from top. The top is a 3/16" piece of acrylic plastic. the fans have three SMT blue LED's mounted beside them so at night, the amp glows the same color as under the SUV. the fans, LED's and mute relay are wired to a delay circuit which applies power to them after about 2sec after the remote turns on. The tiny little black PCB bolted to the case is the P108 module that I mentioned in the ESP article. The amp is separated into three modules (in separate boards) internally. from left to right; 200W SMPS, two P3A channels, P108 module, then the fans and gain pots.
Page created and copyright R.Quan © 20 Jan 2011.