11v DC power-on thump

nadams

I'm assuming this will damage my Polks. Granted it's only for about 1.5seconds....

I'm still trying to trace down the cause, but I believe it's the receiver's power supply. It thumps even with volume at 0 and nothing else connected to it.

nadams

brettw22

Are you sure that it thumps for a second and a half? Timing that out, that's pretty excessive. My B&K AVR307 will thump if I totally power it down, but it's a very short, brief thump that doesn't hang. Has your amp/receiver always done it, and if not, I'd take it in for service to at least just have it checked out.......

nadams

This is on a Marantz receiver that I picked up at a thrift store (i'm not looking for any comments on the quality of the receiver, Mr. Grand has done that already :-))

A second and a half is a bit excessive. The speakers are in motion for at least 1.5 seconds. The thump itself is just that, a thump. The highest voltage I've seen so far in my testing is 20vdc. It seems that the longer it sits being plugged in but not turned on, the greater the voltage...

nadams

jrausch

Since a speaker’s impedance is around 8ohm's it's probably the current you need to measure. 20Volts seems excessive. I just posted this on another thread, but most amplifiers have a delay circuit that waits until the unit is fully charged before a relay transfers the power the speaker terminals. This keeps that in rush of power from possibly causing damage to the speakers. If the relays are damaged or were never built into the receiver, this will cause some damage over time. I would look for another power source that has this feature.

Airplay355

my relays on my aiwa (also not looking for coments on my receiver) were damaged. the unit would turn on for 3 seconds max and then turn off again. i needed to have the power supply replaced, total bill was $90. good luck solvin that problem

nadams

my main JVC amp does have the relay circuit, but this Marantz does not. Since this amp is not vital to the operation of my system, and I paid $6 for it, it is not crucial enough to me to justify paying ANY money to fix it. I just wanted to beat it up a little more with my towers of speakers :-).

nadams