PSW111 Causing amps to shut off.

PeteLP

I'm using a PSW111 powered Woofer, and I've tried three different amps to supply audio to the Speaker Level inputs on PSW111. (As an aside, I'm using the speaker outs from the PSW to power two other speakers)

One of those amps (a Sonos Zoneplayer) has no problems, and has been used on the PSW for almost a year.

Two of those amps consistently and automatically shut off, after running for less than an hour, but the time frame varies and is significantly shorter with movies that have heavy base and sound effects. The two amps having problems are:

1- The built in amp on a 60" Pioneer Elite Plasma display
2- An AudioSource AMP210 80-Watt 2-Channel Amp

When the pioneer shuts off it says "Shutting down because of internal protection circuits: Do You have a speaker wire short?"

When the AudioSource Amp shuts off it flashes a colored circular warning indicator light.

I've checked and rechecked the wiring. (One confirmation that it's not my wiring is that problem recurs whenever I switch the wiring back to either of the problem amps, and consistently disappears when I use the Sonos) Any ideas? Can you tell me the impedance on the PSW111? Is there a good way to test that impedance to see if it's performing to spec?

Pete

kawizx9r

Hey Pete, welcome to CP!

I'd suggest using line/preamp outputs from your sources to your subwoofer rather than using the speaker terminals.

-Freddy

[Deleted User]

Hello,
Welcome to the CP Forum. It is possible the two amps that are having a problem are reacting to a common ground connection. The speaker level inputs, on the sub, might have the right and left grounds connected. As a test try just connecting the right speaker output to the sub. Then make the left speaker output connection directly to the left speaker. The sub will play fine with just the right audio channel since bass sounds are recorded in both channels evenly.
Regards, Ken

PeteLP

kawizx9r wrote: »

Hey Pete, welcome to CP!

I'd suggest using line/preamp outputs from your sources to your subwoofer rather than using the speaker terminals.

-Freddy

Thanks for the suggestion.

The equipment I have doesn't have remote control for volume on the line out. (Only for the speaker outs) And there are some other issues as well in going with line out. So I'd really like to get this working in this fashion.

There ought to be a reason for this and a way to solve it while using speaker out.

tonyb

What gear are you working with,specificly ? Not sure exactly what your trying to do.

PeteLP

Kenneth Swauger wrote: »

Hello,
Welcome to the CP Forum. It is possible the two amps that are having a problem are reacting to a common ground connection. The speaker level inputs, on the sub, might have the right and left grounds connected. As a test try just connecting the right speaker output to the sub. Then make the left speaker output connection directly to the left speaker. The sub will play fine with just the right audio channel since bass sounds are recorded in both channels evenly.
Regards, Ken

Thanks for your response.

The PSW is providing a crossover, and reducing the bass that's being passed through to the speakers. Your suggestion would leave the left speaker with more bass than right. Also many recordings have the entire sound from certain instruments sent entirely to one channel or the other (including the full range of high to low frequencies for each of those instruments). I wouldn't want to have those instruments failing to go to the woofer.

I also have trouble understanding why a common ground could cause this problem. On the other hand, I can easily understand how the problem could relate to the PSW having a lower than acceptable impedance for each of the problem amps. I've definitely heard of that before. When impedance is too low for a given amp, or the load is too low, from the amps point of view, it's perceived as a short. But the amps are NOT attempting to send a signal accross the circuit between the two grounds so the low load should not be a problem for the amp. Also, I would certainly expect my Pioneer (which IS shutting off) to have a common ground as well. (in which case it wouldn't have any problem with the PSW's common ground, for this second reason). I'll confirm this part with an ohm meter.

Have you ever seen a case where a common ground caused an amp to shut off, and had it confirmed that this was the problem? If this really is the issue, then another possibility is to use only the left ground for both speaker inputs on the PSW. But I'd love to get some confirmation that this has actually been established as a known problem in the past, before I do a bunch of wiring in that very difficult space.

Can you also please find out what the impedance is supposed to be for the speaker level inputs on the PSW111 (as seen by the source amps) and how I can test that its impedance is consistent with spec?

Thanks
Pete

[Deleted User]

Hello Pete,
A couple of things to keep in mind. The sub doesn't have any high pass filtering, the speaker level signals pass unfiltered to the speaker out connection. In fact the speaker level in and out are directly connected. The speaker level input impedance is relatively high in order to prevent loading of your receiver. Think of sticking a soda straw into the Mississippi River. Only a small amount will flow through the straw, the other billions of gallons just keeps flowing. The same with the sub, it only allows a small amount of voltage to flow into its amplifier. The rest goes into the speakers attached. While I can't speak for every recording made I believe you can rest assured that only having one speaker level input connected will not change the sound, especially if the sub is set for a fairly low frequency.
I hope this helps.
Ken