Hi
The ICS Basic controller can take a bias voltage of 30v or so without
any noticeable
effect on the audio and no damage to the controller.
www.ics-ctrl.com
73
Brian
ka9pmm
[EMAIL PROTECTED] wrote:
At 10/18/2007 14:11, you wrote:
>But you have a chicken and egg situation, is it the controllers fault
>or the radios? Not all radios have bias and not all controllers charge
>caps backwards. You can solve the problem by removing the mic bias
>resistor from the radio,
I'd like to do that, but I think I just discovered a difference
between the
MVP & Mastr II exciter boards: the Mastr II supplies bias via a resistor
connected to pin 11 of U101 (audio processing IC), whereas in the MVP
there
is no resistor - the bias appears to provided internally within the
IC. This is a problem because there doesn't appear to be any way to
remove
the bias.
> installing a non-polar cap anywhere in the
>audio path
I suppose that's the only choice I have, but since there's already a 1 µF
cap in the controller, the 2nd series cap needs to be a significantly
higher value to avoid the combination of the 2 causing another high pass
rolloff.
> or replacing the polar cap with a non-polar.
Can do that, but then I have a 2nd big ugly leaded cap hanging off the
bottom of the SMC board.
>Take a look at the schematic I posted earlier, it will suit your needs
>but I do not program that well, hence the open source of the hardware.
>If there is any intrest I will finish the PCB, which will measure 1.9"
>X 2.5" and about 0.5" tall and doesn't use any surface mount
>components.
I appreciate the effort, but for this task I need a ready-to-go solution.
Bob NO6B
