Specifications

AMP2-T assembly instructions. © 41Hz Audio / www.41hz.com Revision 1.0T boards
Calculating the over current sense resistor values
Description Current limit trip point Component
I
sc
Over-current trip point
6A 10A 12A 16A 22A
R
sense
Current sense resistor
0.01  0.01  0.01 0.01 0.01
R51, R52, R53, R54
R
orc
=3473/(R
sense
* I
sc
+0.0716)
27K 20K 18K 15K 12K R111, R211
Voltage limiting
The TK2350 chipset also has over / under voltage sensing. The voltage values are set with four
resistors in the 0805 size. If the voltage is outside the specified values, the amplifier will mute.
Unlike the over current sensing the voltage sensing is non latching i.e if the amplifier is un-
muted it will mute when outside the specified range and go back to the un-muted state as soon as
the voltage is within specified values again. Please again note that that the over voltage sensing
sets the chipset in mute and can prevent damage by stopping instable conditions like power
supply transients. However it can not protect the chipset from severe over voltage damage; the
maximum chipset voltage is +/- 70V also when muted.
The voltage limiting trip point resistor values
Description Value in the AMP2 kit Component in AMP2
Vpp Rail voltage (positive) (+40 to +60V)
Vnn Rail voltage (negative) (-40 to -60V)
I
vppsense
Positive sense current from data sheet (0.162mA)
I
vnnsense
Negative sense current from data sheet (0.174mA)
R
vpp1
= Vpp / I
vppsense
422 K R112
R
vpp2
= Vpp / I
vppsense
422 K R113
R
vnn1
= Vnn / I
vnnsense
392 K R115
R
vnn2
= 3xR
vnn1
1.18 M R114
The tolerances of the voltage sensing and limiting are not very tight so there may be variations in
the actual trip points. Please see the TK2350 chipset datasheet for details.
The resistors supplied with the AMP2 component kits will set the lower voltage limit to about
+/- 33 volts and the upper limit to about +/- 65 volts.
Note you should have a margin of about 5V from the nominal power supply voltage, or the
voltage protection may mute the amp due to voltage transients and component tolerances.