PA150 PCB assembly guide
The PA150 PCB is used in my BPA300 project which uses 2 PA150s in a bridged confirguration. The PA150 PCB can also be used non-bridged to provide 150W output at 2.7ohm load.
Step 1: PA150 PCB assembly guide
New PA150 PCB :
![](http://www.shine7.com/audio/newPA150-4.jpg)
6 WIMA 0.1uF capacitors are soldered directly at the LM3886's supply pins between the +30V, GND and -30V, GND.
Parts list for 4 PCBs and hk.farnell.com parts number :
PCB parts label
|
Farnell HK Order Code hk.farnell.com |
Qty
|
Descript_ion
|
Mftr. & Part No.
|
R2, R13, R18
|
1160203
|
12
|
RESISTOR, 0.1%, 0805 10K
|
WELWYN - PCF0805R-10KBI.
|
R3, R10, R15
|
1160275
|
12
|
RESISTOR, 0.1%, 0805 200K
|
WELWYN - PCF0805R-200KBI.
|
C10, and also director solder to 3886 supply pins
|
146902
|
28
|
CAPACITOR, 0.1UF 100V
|
WIMA - MKS2 0.1UF +/-10% 100V.
|
C2, C5, C7
|
7568509
|
12
|
CAPACITOR, M/WAVE 8.2PF 200V 0805
|
AVX - 08052U8R2CAT2A
|
C3, C6, C8
|
498609
|
12
|
CAPACITOR, 0805 220PF 100V
|
AVX - 08051A221JAT2A
|
R7, R9, R14
|
1107474
|
12
|
RESISTOR, METAL STRIP, 0.2 OHM 1%
|
VISHAY DALE - WSR-3 .2 1% EA E2
|
R4, R9, R17
|
9353305
|
12
|
TRIMMER, 25 TURN 50K
|
BOURNS - 3296W-1-503LF
|
R1 (at the back)
|
9333274
|
4
|
RESISTOR, 1%, 0805 47K
|
MULTICOMP - MC 0.1W 0805 1% 47K
|
U1, U2, U3
|
-
|
12
|
LM3886T / LM3886TF
|
National
|
C9, C12, C11, C14
|
-
|
16
|
2200uF 63V Nichicon MUSE ( or use Panasonic FC)
|
-
|
R6
|
9333320
|
4
|
RESISTOR, 0805 5K1
|
MULTICOMP - MC 0.1W 0805 1% 5K1
|
R8
|
-
|
4
|
Resistor, 2 Ohm, 1W
|
Any brand
|
C4
|
-
|
4
|
100uF 50V
|
Panasonic FC
|
C1
|
-
|
4
|
10uF or 15uF 400V Solen capacitor
|
Solon
|
J2
|
-
|
4
|
Small 2 pin connector, pitch = 5mm
|
-
|
J3
|
-
|
4
|
Big 2 pin connector, pitch = 9.5mm
|
-
|
Power connector +/- 30V and GND
|
-
|
4
|
Big 3 pin connector, pitch = 9.5mm
|
-
|
You don't have to use the same brand as I used, feel free to try your favorite components.
Connection diagram for a 150W - 3x LM3886 paralleled amplifier, showing single channel:
Connection diagram for a 300W - 6x LM3886 bridged-paralleled amplifier, showing single channel (click for full size image):
Note : The positive balanced output is connected to one PCB and then output to the negative speaker terminal. This is because the PCB is a inverted design, so the signal is inverted at the output.
BPA300 Building TIPS :
1.Use 3 LM3886s with the same printed code (don't know if it is date code or lot number)
2.You may not be able to adjust the DC offset of each LM3886 output to zero, It is ok. BUT you have to make sure all 6 LM3886 to have the same DC offset (9mV in my case) so that you won't have current flow between the 3886s and there will be no DC offset at the speaker terminal.
3.Test each non-bridged board before bridge them together.
4.Test the DRV134 board working ok before using it for bridging.
5.Since there are more ground connections in the BPA300, please be careful to avoid ground loops when you layout the boards in the case. Otherwise you will get hum.
6.To avoid ground loops - use star ground, short cables
7.Tightly twist all wires
![](https://file.pcbway.com/project/15/09/24/155303848.jpg)
Sep 24,2015
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