Does my Pass amp dislike my Meridian preamp?

Q1) I would expect that the Pass amp is designed to tolerate a large amplitude input signal while in standby mode, but presenting that question to Pass would probably provide the best answer.

Q2) Assuming that you don't see any significant voltages intermittently appearing during the two-day test period Ralph suggested, and assuming the pops do not appear when the amps are powered up, and assuming the G68 does not develop any new symptoms, I can't envision a means by which damage could occur.

Best regards,
-- Al

Thank you again, Al. I have put the G68 back in the system to test it. I will report back with my findings.

Another development: I spoke with the G68's modder yesterday, and he had a simple theory to explain why it might be freezing up: heat. Other than the analog output stage, the G68 is basically a computer. And it packs a lot of circuitry into a small space. So maybe it exceeds its operational limits and freezes.

With that in mind, yesterday I did some modding of my own: I removed all the video circuitry, the multizone circuitry, and the tuner, none of which I use. The G68's architechture is modular, so this was actually quite simple. Altogether, I removed about 1/3 of the total circuitry of the unit. I left the lid off for maximum cooling and placed it back in the system. I played some music through it to make sure that it still works and, to my surprise, it not only works, it sounds audibly better. The sound improvement was obvious within about ten seconds.

Now that it is operating under cooler conditions, I am going to run it continuously and see if it freezes. I will also test the outputs after two days, as Ralph suggested, to see if I can detect anything unusual.

Bryoncunningham, the fact that it sounds better suggests that someone (not you) has not done their homework... I think your approach here is a good move.

If it seems to be OK- you might have the cause narrowed to the computer and the power supply, but the possibility also exists that it could be a defect in one of the modules that is locking up the computer or draining the power supply. FWIW, just because the power supply has been replaced is no guarantee at all that it works right!

...the possibility also exists that it could be a defect in one of the modules that is locking up the computer or draining the power supply.

With that in mind, I think I am going to remove more excess circuitry from the unit. The fewer modules in place, the better the odds that the defective module, if it exists, will be out of the loop. If this works, it will be the solution to the Gordian Knot.

Thanks again, Ralph.

Bryon

Update: I have left the G68 powered up for several days and retaken the measurements at the outputs. There is no AC or DC voltage coming from the outputs.

The G68 has not frozen up since I removed half the circuitry and left the lid off. That is consistent both with the heat theory and with the bad PCB theory.