It has nothing to do with amplifiers, the pop is a side effect of the player shutting down improperly, which traditionally is caused by the power control PIC crashing (remedied by the diode cable for early empegs, never an issue with Rio's).

Thanks. I did initially consider the amp (ie examine all your own stuff first before blaming the software ) but ruled it because the unit also wasn't going into standby.

Seeing as you are reading this, let me put all the symptoms in one place, in case it leads to an epiphany (?)

All symptoms apply to "in car" running unless otherwise stated.

When the unit is playing and ignition is shut off there is a distinctive (not too loud, but loud enough to be disturbing) pop.

The screen goes dark immediately. There is no standby light.

When restarted, it picks up from about the same place in the current song. I'm not sure whether this means that part of the shutdown is being handled correctly, or its a feature of the "last state" stuff.

If I put the unit into standby manually, (ie hold down the top button, wait till screen goes dark, observe blue light) and then kill ignition, there is no pop - however the unit seems to shutdown completely. Blue light goes out.

When I then re-apply ignition, the unit comes up in standby mode.

When in the car, I always get the Dimmer menu setting (I seem to remember reading that this was only offered if the unit detected that it was in the sled)

I have proven that the yellow wire has permanent volts and the orange wire has volts when the ignition is on and no volts when the ignition is off.

Both tests were done at contacts on the sled.

A thought
I tested using a test light, as opposed to a multimeter. I wonder if there is a variance in the permanent supply or ignition sense levels when the ignition is turned off. I will test later with a multi meter.

The pop does not occur when running in the home using the supplied 12v power pack and line out cables.

The problem occurs on every shutdown. The problem is specific to 2.0b3. I have downgraded twice to 1.0 and upgraded three times to 2.0b3. The problem is consistently present on 2.0b3 and never occurs on 1.0.

1.0 has always gone into standby correctly.

Its particularly annoying, because I just coughed up for wireless lan hardware, so I could rip and sync while the unit was still in the car, and the damm thing won't go into standby.

I am more than happy to try an early copy of the Beta 7. I am a software developer by trade, so I understand the concept of alpha release - but I may also be able to provide some additional, useful feedback.

Any additional thoughts/suggestions would be appreciated.....

Peter