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R2R Shunt Volume with 3 selectable sources       
December
2014

 

INTRODUCTION

There are many methods to implement a volume control on audio system:

There are many good articles about this attenuator like the Logarithmic resistor ladder and Logarithmic Attenuator Calculator.
Two encoders near the display allow to select the input and to change the volume level.
A good infrared remote command is included and it add lcd backlight switch off, mute button and standby function (necessary a second transformer).
It can easily integrated the same chassie of your custom pre-ampl. or integrated amplifier.
The firmware has been design with standby configuration, so one little 6-7VAC 50W transformer always powered for the controller module and another bigger transformer for your pre-ampl or integrated amplifier.
I can modify the firmware on your request to have no stadnby configuration.

Quanghao sell this complete module assembled including the aluminium remote at 250$ + shipping.

 


 

 

REMOTE


RELAY POSITION
 

display (-dB) mute relay 6 relays status
0 1 111111
1 1 111110
2 1 111101
3 1 111100
4 1 111011
5 1 111010
6 1 111001
7 1 111000
8 1 110111
9 1 110110
10 1 110101
11 1 110100
12 1 110011
13 1 110010
14 1 110001
15 1 110000
16 1 101111
17 1 101110
18 1 101101
19 1 101100
20 1 101011
21 1 101010
22 1 101001
23 1 101000
24 1 100111
25 1 100110
26 1 100101
27 1 100100
28 1 100011
29 1 100010
30 1 100001
31 1 100000
32 1 011111
33 1 011110
34 1 011101
35 1 011100
36 1 011011
37 1 011010
38 1 011001
39 1 011000
40 1 010111
41 1 010110
42 1 010101
43 1 010100
44 1 010011
45 1 010010
46 1 010001
47 1 010000
48 1 001111
49 1 001110
50 1 001101
51 1 001100
52 1 001011
53 1 001010
54 1 001001
55 1 001000
56 1 000111
57 1 000110
58 1 000101
59 1 000100
60 1 000011
61 1 000010
62 1 000001
63 1 000000
64 0 000000