Before the subs, Audio Note Amp could be on or off and it was dead silence. Now its slight static either on or off.
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.
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Before the subs, Audio Note Amp could be on or off and it was dead silence. Now its slight static either on or off. Right. Because before the subs the speakers were connected to and driven by the Audio Note only. But then you connected the speakers to the subs. Pretty sure I got it, the problem is how to explain what I think is going on. It will probably help to try and visualize the speaker/amp/sub as one circuit. From the sub to the speaker to common is one continuous circuit. The problem is this circuit has two different paths to neutral even when the power is turned off. This creates a voltage differential on the circuit. This voltage differential is what you are hearing coming out of the speakers. The power switch does not completely disconnect the component. It only disconnects the hot power coming in. Neutral and/or ground are not broken. So what you have in effect is a ground loop. Only its not an earth ground loop but a neutral ground loop. Don't know if there is a technical term for it but what you are hearing is the extremely small voltage differential between the two different paths to neutral, or utility ground. Whatever you want to call it. Ordinarily no one would ever notice. We are probably talking millivolts, if that. But you have really efficient speakers. Even so I bet you can barely hear it. |
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 |
Cheater plug still leaves neutral- has to, or no power - and that is where the voltage differential is coming from. I was going to say try a Line Out Converter. https://www.epanorama.net/circuits/speaker_to_line.html But I'm not sure even that would work. Because the LOC circuit (two resistors) is already there. All these plate amp subs that are designed to work with speaker level inputs, the first thing inside them is the same LOC. Has to be. Something has to drop speaker level down to line level, that something is a resistor, ie LOC. But I'm no amp designer, just a guy with a pretty good layman's understanding. It may be that using a LOC at the Audio Note puts the resistor in path of the speaker in a way that lowers the voltage the speaker sees way down below audibility. Can't really see how that would be, just a guess, which is why I didn't mention it earlier. If you want to try that method akwilson501 its really simple and needs only about $2 worth of resistors. A picture of the ePanorama mod in my amp is on my system page. https://systems.audiogon.com/systems/8367 |
... 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 |
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