gslikker:
Post 19 so-ein-pech confirms the Alps switch is the same on small SX Pioneers as I pictured from a Laffer / Setton series.
I suggested removing the snubber as:
It is no longer needed as there is no arc to quench.
It is another failure point gone
It leaks a minor amount of AC - just picking nits.
If there is a pop "power down" on the Lafayette / Setton the protection circuit is not functioning correctly. The electronics, welded relay contacts or switch (Alps / Wafer) not making contact to common would be the top guesses.
Pop on "power up" the protection circuit is also not working correctly. Possibly the power on delay / hold off cap. On the Laffers / Settons I increased the capacitance to increase the time on delay. I am not in a hurry for power on and wanted the power supplies and PA stable before hooking up the speakers. The PAs oscillate a bit on power up. Some longer / worse than others. I know I watched the PA voltage before the protection relay contacts on a scope and may have dug out my old Brush 2 channel pen dragger and run a few charts.
Mr.White:
Only adverse effect that comes to mind is the pop you mention. The +/- rails decay at different rates. The + has a slightly higher load so decays faster. Have not checked for oscillations while shutting down. Not sure how much you have invested in your cans, or if the DC voltage across them on decay will hurt them or not. The headphone jacks have 270 Ohm resistors in series which may be enough to protect your cans.
With the AK knowledge base I expect someone here to know that answer!:scratch2:
The Lafayette uses the N/C contacts on the power switch to trip the protection circuit relay at the same time the N/O contacts open the AC power thus opening the speaker (and phone) leads.
I believe you also mentioned somewhere you do not use the switched AC outlets on the back so no issue there.
There are a few times I like the switched AC socket. Always a possible path to trouble. At first I used extra contacts on an ice cube relay. The TRIAC is way cheaper than a relay if you buy new and fine for the switched AC socket also. Either way the switch is protected from dumb mistakes / Murphy.