Oh wait, the owner wanted to know if it added latency to pipeline. The inline nature of the Intona has a light cost in that it saps some USB power resulting in slightly reduced output level in the Modi 2 (from 1.62 volts to 1.56 volts). That impact improves SINAD by just 0.4 dB which is nothing to write home about. We still have the spray of that junk but the floor of them has moved down. Here is what happens when I route the USB cable through Intona: Instead we have some harmonic distortion (to be expected) and a ton of other junk from low to high frequencies. The main tone at 1 kHz is all that we want to see. Here is the Modi 2 directly hooked up to my PC: ![]() After much frustration, I pulled out my old and discontinued Schiit Modi 2 USB which I know is sensitive to USB (power) noise and managed to eek out a bit of difference. They continued to work just as well as they did without Intona. None of the high-end DACs cared one way or the other. I literally spent hours trying to find DAC whose performance could be improved with this device. Not that this matters with Audio DACs since they almost all are USB 2.0. And of course much more convenient to use.Īlso, until recently all such isolators were USB 2.0 so having a 3.0 version is quite cool. This is very good because there is no risk of ground loops created (common problem with typical USB audio tweaks with external power). The Intona uses the incoming USB power and regenerates it on the isolated side. In some cases things like the ifi or similar working devices could reduce issues.Look carefully and you notice that there is no input for power supply. For the latter one should choose the one you need. This all depends on the actual implementation of the USB receiver in the DAC.įor that reason, if one has an audible ground loop then the most obvious action is to see where it occurs and then take the best action.Ĭould be changing of equipment, could even be interlink cables, could be going balanced (if possible) or using isolation devices in the audio path (line-level audio transformers), using optical inputs (if possible and circumstances allowing) or SPDIF out via an data isolation transformer (when it isn't present) or when using USB by using a real USB isolation device. Sometimes ground is needed to make 'first contact' and afterwards is of less importance. Also depends on how the USB side is implemented in the DAC. It could well be there is a voltage exceeding a required voltage difference in which case disconnecting the ground does not work.Ĭould also be well within just a few volt difference. When a ground loop is present the ground is present on both sides (assuming V+ is disconnected as well) via the ground coming from both sides. ![]() So feeding with a 'clean' 5V while coupling the grounds won't make any difference unless you have a really crappy DAC or the 5V coming from the USB bus is well below 5V. For HF garbage they have 'the same potential'. In this case even the enumeration often works without a direct GND as the remote GND path is low enough impedance and voltage differentials are in bounds.Ĭlick to expand.Yes, that's what I said.Įven when the 5V is disconnected but the ground connection is not the +5V does not matter. The impedance and voltage compliance range is large enough, though, when the balancing current is from a PE-to-PE connection (all devices class-I), the classic "ground loop". The connection is potentially unsafe and still doesn't block the leakage currents, that is. But even if the output impedance were very high, the signal pins still do only have limited voltage range where they can freely spin so whenever the voltage signal seen on the line approaches or tries to exceed the supply rails the communication breaks. ![]() I seem to remember has a gadget which opens the GND/Supply path after enumeration and refreshes the data line signals.Īnd the current sources are lousy, just a few kOhms of output impedance, still no brake for balancing current coming from a high impedance high voltage potential like capacitive coupling in a class-II "isolated" mains PSU. For USB enumeration a reference to GND is required as the signaling is not the current-source differential scheme used for the actual USB packets later. As long as either GND or 5V_bus are connected to the device there is a low impedance AC path for the balancing current.ĭisconnecting 5V_bus and GND at the device does works sometimes yet other times it does not. ![]() 5V_bus and GND are tightly coupled together by a regulator and bypass cap at the source and bypass cap at the sink (the device).
0 Comments
Leave a Reply. |