- I built the SoftRock RXTX 80/40 over the holidays and have been playing with it using an old laptop for the processing. I started looking for a better audioMessage 1 of 41 , Jan 1, 2008View SourceI built the SoftRock RXTX 80/40 over the holidays and have been
playing with it using an old laptop for the processing.
I started looking for a better audio processor and ran across this
He used a USB DAC module for a specific purpose but looking at the
board, it occurred to me that it would be easy to modify it (like
un-ground the inputs) to build my own USB DAC to use with the SoftRock.
Then it dawned on me that it would be even better to go one step
further and build the DAC _into_ the SoftRock and get RID of the audio
cables and module entirely.
Yes, it would require a bit of redesign of the board and soldering a
few more SMDs, but they were really much easier to solder than I
It would raise price a bit, but bandwidth can be optimized and noise
level reduced. Seems like a win, all the way around. With a bit more
thought, full control of the SoftRock can probably be accomplished via
the same USB line.
Am I missing a 'downside'?
73 de N5bz
- On pin 1 (top left of U8) I have 4.9 volts! :( and on pen seven I have 2.48 volts :) I am testing things out now and had to pull this thread and info out ofMessage 41 of 41 , Jan 21, 2008View SourceOn pin 1 (top left of U8) I have 4.9 volts! :(
and on pen seven I have 2.48 volts :)
I am testing things out now and had to pull this thread and info out
of another topic....
Tony does this mean that U8 needs to be replaced?
I see the same things on both sides.
> No RX image rejection results when one of the I / Q signals from theRXTX board is not getting to the stereo soundcard line-in input. The
problem could be on the RXTX board, in the cable or at the soundcard.
Also, if I and Q signal lines are shorted together no image rejection
will be the result.
>output signals were connected to a soundcard when an AC voltage
> There have been a few cases of U8 failing when the RXTX board I / Q
difference existed between the soundcard ground and the ground on the
RXTX board. Please check the DC voltages at pins 1 and 7 of U8 to see
if the two pins are still at about 2.5 volts with reference to circuit >