Atom Feed - Twisted Pear Audio Support - Topic:Noise when powering off - DC Spike? - 20Twisted Pear Audio Support - Atom Feedurn:twistedpearaudio-com:AtomFeed:TwistedPearAudioSupport:Topic:Noisewhenpoweringoff-DCSpike?-20:1Copyright 2024 Twisted Pear Audio Support2024-03-29T05:04:18Zhttp://www.twistedpearaudio.com/forum/Images/YAFLogo.pngForum Adminhttp://www.twistedpearaudio.comfeedback@twistedpearaudio.comtdmckellarhttp://www.twistedpearaudio.com/forum/profile/26725-tdmckellartdmckellarhttp://www.twistedpearaudio.com/forum/profile/26725-tdmckellarBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-Donegantdmckellarhttp://www.twistedpearaudio.com/forum/profile/26725-tdmckellartdmckellarhttp://www.twistedpearaudio.com/forum/profile/26725-tdmckellartdmckellarhttp://www.twistedpearaudio.com/forum/profile/26725-tdmckellarYetAnotherForum.NETurn:twistedpearaudio-com:ftPosts:st1:meid25763:1Noise when powering off - DC Spike?<table class="content postContainer_Alt" width="100%"><tr><td>No problem thank you for your reply. <br /><br />In reply to the above, the relay controls AC input into both the Placid HD and the Bipolar, powering them up and shutting them down at the same time. <br /><br />Wondering whether it has anything to do with using a AVCC SR (which was a replacement for a broken AVCC version) while also using the V3 Tridents?<br /><br />I have tried as you suggested by removing the ground connection from the IVY to the XLR connector but it does not have any effect. I tried powering the IVY on it’s own and it still produces the same noise, although a little quieter. <br /><br />Is there anything I can add in the outputs on the IVY to suppress this and would it effect the sound, or would an upgrade to a Mercury solve the issue?</td></tr></table>2019-11-25T19:40:34-07:002019-11-25T19:40:34-07:00tdmckellar<table class="content postContainer_Alt" width="100%"><tr><td>No problem thank you for your reply. <br /><br />In reply to the above, the relay controls AC input into both the Placid HD and the Bipolar, powering them up and shutting them down at the same time. <br /><br />Wondering whether it has anything to do with using a AVCC SR (which was a replacement for a broken AVCC version) while also using the V3 Tridents?<br /><br />I have tried as you suggested by removing the ground connection from the IVY to the XLR connector but it does not have any effect. I tried powering the IVY on it’s own and it still produces the same noise, although a little quieter. <br /><br />Is there anything I can add in the outputs on the IVY to suppress this and would it effect the sound, or would an upgrade to a Mercury solve the issue?</td></tr></table>urn:twistedpearaudio-com:ftPosts:st1:meid25760:1Noise when powering off - DC Spike?<table class="content postContainer" width="100%"><tr><td>Sorry for the delayed response. I have been out of town visiting family....<br /><br />A couple questions:<br /><br />1) Does the power relay control the AC input to the Placids, or the DC outputs?<br />2) Does it control power to both the DAC and the IVY?<br /><br />It sounds like the IVY is staying on while the DAC powers down. There are relays on the IVY to prevent thumps, but I think you are hearing the DAC output (which has a virtual ground created from the 3.6VDC AVCC supply) collapsing before the IVY turns off.<br /><br />I would try removing the GND output from the IVY to the XLR, and keeping the XLR isolated from the chassis to see of that helps.</td></tr></table>2019-11-25T15:20:37-07:002019-11-25T15:20:37-07:00Brian Donegan<table class="content postContainer" width="100%"><tr><td>Sorry for the delayed response. I have been out of town visiting family....<br /><br />A couple questions:<br /><br />1) Does the power relay control the AC input to the Placids, or the DC outputs?<br />2) Does it control power to both the DAC and the IVY?<br /><br />It sounds like the IVY is staying on while the DAC powers down. There are relays on the IVY to prevent thumps, but I think you are hearing the DAC output (which has a virtual ground created from the 3.6VDC AVCC supply) collapsing before the IVY turns off.<br /><br />I would try removing the GND output from the IVY to the XLR, and keeping the XLR isolated from the chassis to see of that helps.</td></tr></table>urn:twistedpearaudio-com:ftPosts:st1:meid25759:1Noise when powering off - DC Spike?<table class="content postContainer_Alt" width="100%"><tr><td>Can anyone help?<br /><br />Tested further and think it is DC offset not a signal grounding issue. <br /><br />Would a relay or suppression capacitors at the output solve the issue or would this effect the sound?</td></tr></table>2019-11-24T13:03:11-07:002019-11-24T13:03:11-07:00tdmckellar<table class="content postContainer_Alt" width="100%"><tr><td>Can anyone help?<br /><br />Tested further and think it is DC offset not a signal grounding issue. <br /><br />Would a relay or suppression capacitors at the output solve the issue or would this effect the sound?</td></tr></table>urn:twistedpearaudio-com:ftPosts:st1:meid25756:1Noise when powering off - DC Spike?<table class="content postContainer" width="100%"><tr><td>Tested further...<br /><br />Unplugged the XLRs to my 2 NCore amplifiers and there is no noise, silent power on and power off. This leads me to believe it may be a grounding issue (I had thought of this but assumed noise due to a ground loop would be heard constantly and not just during powering down, unless it being tied to the IVY-III signal ground was dealing with it while the unit was on - and then it discharging as it was shut down?).<br /><br />Anyway, the outputs from the IVY-III are wired with the Positive, Negative and GND all connected from the output stage to the Neutrik XLR Chassis Connectors. Pin 1 is not tied to the chassis at the connector. On the NCore Amplifier side, Pin 1 is connected to the chassis. On both the amplifiers and the DAC power GND is tied to the chassis. <br /><br />I tried this morning disconnecting pin 1 from the chassis but it doesn’t make any difference. I think perhaps something I overlooked is that the Neutrik XLR Chassis Connectors are connecting Pin 1 to the chassis and perhaps I need a connector with an isolated ground? The issue is only with power off. When on it’s all dead silent with music playing wonderfully. <br /><br />Does this theory make sense as to the issues I am having? Next chance I get I plan to disconnect the XLR connectors from the chassis and try hooking it all up to see if that makes a difference. Other than that I am a little lost as to what to do. Any help would be appreciated!</td></tr></table>2019-11-24T12:51:01-07:002019-11-24T12:51:01-07:00tdmckellar<table class="content postContainer" width="100%"><tr><td>Tested further...<br /><br />Unplugged the XLRs to my 2 NCore amplifiers and there is no noise, silent power on and power off. This leads me to believe it may be a grounding issue (I had thought of this but assumed noise due to a ground loop would be heard constantly and not just during powering down, unless it being tied to the IVY-III signal ground was dealing with it while the unit was on - and then it discharging as it was shut down?).<br /><br />Anyway, the outputs from the IVY-III are wired with the Positive, Negative and GND all connected from the output stage to the Neutrik XLR Chassis Connectors. Pin 1 is not tied to the chassis at the connector. On the NCore Amplifier side, Pin 1 is connected to the chassis. On both the amplifiers and the DAC power GND is tied to the chassis. <br /><br />I tried this morning disconnecting pin 1 from the chassis but it doesn’t make any difference. I think perhaps something I overlooked is that the Neutrik XLR Chassis Connectors are connecting Pin 1 to the chassis and perhaps I need a connector with an isolated ground? The issue is only with power off. When on it’s all dead silent with music playing wonderfully. <br /><br />Does this theory make sense as to the issues I am having? Next chance I get I plan to disconnect the XLR connectors from the chassis and try hooking it all up to see if that makes a difference. Other than that I am a little lost as to what to do. Any help would be appreciated!</td></tr></table>urn:twistedpearaudio-com:ftPosts:st1:meid25755:1Noise when powering off - DC Spike?<table class="content postContainer_Alt" width="100%"><tr><td>My build consists of a B3 DAC and IVY-III with the Placid HD and HD Bipolar power supplies. I also have an AMB Sigma11 PSB which powers a raspberry pi and arduino controller. This PSB is effectively always on. The arduino controls a cheap relay which provides an on/off switch to the Placid power supplies which turn off the audio components. <br /><br />I completed my build around a year ago, but typically turn off the power to my amplifiers first then power off the DAC. The other day I turned off the DAC first and noticed a loud pop through the speakers as soon as the relay clicked off, then a strange sort of high-frequency garbled noise for half a second. This doesn't happen when powering on the Sigma11, just when the power is applied through the relay to the Placid's. <br /><br />I measured for DC offset at the loudspeaker terminals. With no music playing and with the Placids off, I get a reading of around 23mV. When on, this is around 24mV. When I power off, I get a spike for half a second up to around 150mV, dropping to around -24mV then back to 24mV. These measurements were from the Right Channel, strangely, the Left Channel measured at 5mV more.<br /><br />Can someone please advise what the issue is and how to fix this?<br /><br />I am thinking it may be an issue caused by the relay, and perhaps a better quality one incorporating a soft start module or perhaps simply a safety capacitor across the primaries of the transformers may help?<br /><br />Thank you.</td></tr></table>2019-11-19T09:04:16-07:002019-11-19T09:04:16-07:00tdmckellar<table class="content postContainer_Alt" width="100%"><tr><td>My build consists of a B3 DAC and IVY-III with the Placid HD and HD Bipolar power supplies. I also have an AMB Sigma11 PSB which powers a raspberry pi and arduino controller. This PSB is effectively always on. The arduino controls a cheap relay which provides an on/off switch to the Placid power supplies which turn off the audio components. <br /><br />I completed my build around a year ago, but typically turn off the power to my amplifiers first then power off the DAC. The other day I turned off the DAC first and noticed a loud pop through the speakers as soon as the relay clicked off, then a strange sort of high-frequency garbled noise for half a second. This doesn't happen when powering on the Sigma11, just when the power is applied through the relay to the Placid's. <br /><br />I measured for DC offset at the loudspeaker terminals. With no music playing and with the Placids off, I get a reading of around 23mV. When on, this is around 24mV. When I power off, I get a spike for half a second up to around 150mV, dropping to around -24mV then back to 24mV. These measurements were from the Right Channel, strangely, the Left Channel measured at 5mV more.<br /><br />Can someone please advise what the issue is and how to fix this?<br /><br />I am thinking it may be an issue caused by the relay, and perhaps a better quality one incorporating a soft start module or perhaps simply a safety capacitor across the primaries of the transformers may help?<br /><br />Thank you.</td></tr></table>