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Subwoofer Causing Amp to Stay On

I have an Audio Note Kit 1 300b SET Amplifier driving a pair of very efficent full range drivers. My entire system is plugged into a psaudio p5 regenerator, which plugs into a synergistic research orange duplex(floating ground). I recently added a pair of Klipsch C-310ASWi subwoofers(ungrounded) into my system via hilevel input, connected from my speakers binding posts. I’ve noticed that now that the subwoofers have been added, when I shut my entire system down, my speakers remain on with a slight hiss or static sound. The hiss will stop, and the speakers will turn off, if I unplug the power cord from the Audio Note, or unplug the subwoofers. I was not having this problem before the subs. So obviously they are the culprit. Anyone know what’s going on here? Old school style amp not liking the newer type amplifier inline? What are my options other than go wireless? Should I go wireless(subwoofer has built in option)? I also get slight transformer buzz from time to time from the psaudio p5, and now that my speakers wont shut up when off, it gets expelled through drivers and amplified into the room.
akwilson501

Showing 3 responses by almarg

almarg's avatar
almarg
9,670 posts
 
... neutral ... is where the voltage differential is coming from.

Not sure about that. As is the case with most audio components AC neutral just goes to the primary winding of the power transformer in the amp and the subs, and nowhere else within those components, aside possibly for some sort of AC filter in the case of the sub. (Based on a schematic of one of the versions of the Kit1 amp that I looked at it does not have a filter on the incoming AC). And as shown in that schematic safety ground is connected directly to the amp’s signal/circuit ground, and therefore to all kinds of circuit points within the amp. And the same may hold true in the case of the sub, if it has a three-prong power cord and IEC receptacle. Or if safety ground is not connected directly to the sub’s circuit ground chances are it is connected to it via some low resistance, as is done in many designs. With that circuit ground connection in turn very probably going directly to the sub’s negative speaker-level input terminal, and from there to the speaker’s negative input terminal and the amp’s negative output terminal for the corresponding channel.

In any event, the cheater plug experiment is easy enough to do, and might be informative.

Regards,
-- Al


almarg's avatar
almarg
9,670 posts
 
OK, so the problem occurs even when the amp is in fact turned off, and is incapable of providing any power to the speakers. And it also occurs when the subs are turned off. Given that, I believe Miller's analysis is correct.

If you already haven't done so, as an experiment try putting a cheater plug on the power plug of the amp, to temporarily defeat its safety ground connection. And do likewise with the sub's power plug, if it has a three-prong power plug and a three-prong IEC receptacle.   (Although based on this photo it appears that the sub's IEC receptacle is two-prong. Let us know if that is or is not the case).

Let us know the results. Regards,
-- Al
 
almarg's avatar
almarg
9,670 posts
 
Some additional questions:

1) Are the tubes in the amp lit up when this occurs?

2) Am I correct in assuming that when you refer to turning the entire system off you are doing so by means of the front panel power switch on the P5?

3) How are the delay modes of the four zones of the P5 programmed, among the six different modes that are possible for each zone?

4) Which components are plugged into which zone on the P5?

5) Depending on the answers to those questions I wonder if putting the sub’s power plug on its own zone, and shutting it off with the front panel function which controls power to only that zone (i.e., touching the corresponding receptacle icon) prior to turning everything else off, might help.

Regards,
-- Al
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