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Computer Audiophile

JohnSwenson

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About JohnSwenson

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  1. CLOCKS, what should we look for in next generation

    This is just a "breakout board", you still need to get the oscillator in question and solder it into the board. Then you have to feed it with ultra low noise power. Getting some company to sell you,an individual, not a company, one of their top notch oscillators to put on this board is going to be extremely difficult. So by itself it doesn't give you anything. Now if you can buy this board with the oscillator already installed, THAT would be much more useful, then all you have to do is build or buy and ultra low noise power supply to feed it. What they SHOULD do is have the board with ultra low noise regulators AND the oscillator, THAT you could probably use. John S.
  2. CLOCKS, what should we look for in next generation

    I spent years doing this in my day job in the semiconductor business. Take one of the most difficult, 64 arm processors, a large complex switch fabric handling very high speed serial streams between processors. The clocking for this was incredibly tight, they called me in to design and implement the clock network for this. As with everything in this space the power for this is very critical, no way can you meet the spec using the "normal" power distribution network used for the "processing" elements. It takes a whole separate network driven by its own ultra low noise LDOs, special very low noise PLLs . The whole thing is a differential clock distribution where the whole thing has to be balanced to within a fraction of a micron. Complex shielding systems are employed to protect the clock signals form other stuff going on nearby. The whole thing including the power networks and PLLs has to be spiced multiple times to make sure it is doing what it is supposed to. This took a lot of work to get it right (many months of work), but it worked perfectly the first time. One thing very different about doing this on a chip rather than a board, there is no way to go in and analyze the signals on the chip, measure the jitter etc., all you get is if the system works or not. So it generally tends to be over engineered to make sure it will work, but that makes it even harder to design. So yeah I actually did learn this stuff on the job. There was never any official learning for this stuff, you pick it up as you need it wherever you can. I wound up getting different parts from different people over time as I worked on different projects. There was no course on "ultra low jitter clock networks for CMOS chips". Just bits and pieces from different sources and putting it all together to make things work. John S.
  3. SMPS and grounding

    Yeah, I'm getting old here, sometimes I just can't think of a specific term so I fall back on the generic technical terms. John S.
  4. SMPS and grounding

    You should be able to drive 5 LPS-1s from that supply (4 off the 12V and 1 off the adjustable set fro 9V or so). It explicitly says the output grounds are not connected to AC ground or to each other, thus is you want to use one of the outputs to drive one of approved switches you must ground the output that is powering the switch, the others do not have to grounded. John S.
  5. SMPS and grounding

    No, if you use an LPS with the switch, the output of the LPS has to be grounded, either inside the LPS, or with a separate grounding device as shown in this thread. You use EITHER a grounded SMPS (again either internal or with separate grounding device) OR a grounded LPS. The only time you use one power thingy driving another is if you use an LPS-1. It has to be supplied DC power from some other DC power supply. John S.
  6. SMPS and grounding

    This PS looks very nice. The 9V and 12V outputs can each power an LPS-1 (IF the ratings are true). The LPS-1 is not designed to work from a 5V input so should not be used with the 5V output. This looks like a very well built robust supply, it probably has enough juice to power a couple LPS-1s. Some customers have found that some inexpensive LPS have specs that are not true, the voltage sags when powering an LPS-1. But from just looking at it, it looks like this supply will not do that and should power LPS-1s just fine. But you really don't know until it is tried out. John S.
  7. SMPS and grounding

    first off if you use a linear supply, the output still has to be grounded. It is the grounded power supply that allows the switch to shunt the leakage from other devices. In general a decent linear supply is always preferred over an SMPS, but they can cost a lot more. In situations like the switch the LPS is probably not going to be much of a difference sound wise so spending hundreds of dollars on an LPS VS $12 for an SMPS may not be a good tradeoff. But you still have to look into whether the output of the LPS is grounded. If it is NOT grounded you need to use one of the grounding schemes to ground its output in order to shunt the leakage from other devices. Just as an example in MY system using one of approved switches with a grounded SMPS made a significant difference in SQ VS using the SMPS without grounding. Using an un-grounded very good LPS sounded worse than the grounded SMPS, the grounded LPS was no better sounding than the grounded SMPS. Thus there was no reason to go with the LPS FOR THE SWITCH, this does NOT mean I'm saying that LPS are useless. For DACs, streamers etc the LPS was always much better than the SMPS. For your system a grounded LPS may sound slightly better, but the only way to tell is try it yourself. John S.
  8. SMPS and grounding

    See the post right above yours, it seems there are some power conditioners that do not work well with grounding scheme, I have no idea why, I don't have any of these to try out, and personally I don't really want to get into testing such things right now. If the grounding doesn't work with the power conditioner and it does work when plugged into a regular (non-conditioned) outlet, then listen to both ways: non-grounded SMPS plugged into conditioner, powering the LPS-1 grounded SMPS into regular outlet, powering LPS-1 Whichever sounds best, go with that. John S.
  9. SMPS and grounding

    You can have multiple ground wires coming out of one plug, no need for multiple plugs. John S.
  10. SMPS and grounding

    You should be using heavy wire for the two short pieces between male and female barrel connectors. The 24AWG wire is fine for use to the AC wall plug. See the pictures in the original post.: big heavy bare wires between barrel connectors and thin wire to AC plug. John S.
  11. SMPS and grounding

    Hi Ted, I think this is a combination of the shunt and what the LPS-1 does under high load. What you are witnessing can happen when the LPS-1 is feeding current right at the edge of what it is capable of. This causes it to bank switch quickly (about 3 seconds between switches). The current the LPS-1 pulls from the Meanwell is not constant. When charging a bank the current is low then quickly ramps up to a maximum. At the maximum it is drawing close to the maximum the Meanwell can supply. The shunt adds a little bit of extra resistance to the path from Meanwell to LPS-1, dropping the voltage a little bit, which causes the LPS-1 to pull more current which drops the voltage even more. At this point the Meanwell is REALLY struggling to supply enough power to the LPS-1 which is why the LED dims, you get buzzing etc. First off you want to check your shunt, make sure you are using thick wires between the connectors and that the screws on the connectors are really tight. Most likely you just have too much resistance in the path. If you are already using the biggest wire you can fit in the connector and everything is really tight then you might need to switch to something like the Groundhog which clips onto the barrel of the existing plug. I have extensively used the shunt with Meanwell and LPS-1 and not seen this problem, so it is most likely either too high a resistance in the shunt or just some normal tolerances in either the LPS-1 or Meanwell, either the LPS-1 is drawing slightly more current than normal (there is a 1% tolerance on the components determining the current), or your Meanwell can supply just slightly less than others. John S.
  12. DIY DC power cables

    These Wago connectors are very nice, I used them inside my latest AC power box to implement the star wiring. They work great and super easy to use. John S.
  13. SMPS and grounding

    That is a very good question. In a situation with UTP (or STP with shields not connected) leakage current goes through one transformer to the ground plane which is "earthed". This combination works. If you use shielded cable and connect the shield at both ends you bypass the transformer in the switch. Whether this will still shunt the high impedance leakage from other devices I have no idea. It may, it may not, it depends on the mechanism for how this happens. What I can say is that if the shield is NOT connected the upstream high impedance leakage IS shunted, if you want to use connected shield I cannot say that. You are certainly free to try whatever you want, I just can't guarantee that the connected shield configuration will behave in the same way. I CAN say that if you use a connected shield cable from the switch to the endpoint, all the leakage will NOT be blocked. John S.
  14. SMPS and grounding

    Yes a separate shield around the existing cable, when properly connected with a wire end to end will block a large amount of the emissions from the existing cable. John S.
  15. SMPS and grounding

    PoE is done very differently to USB power. USB has separate + and - power wires (Ground and VBUS), PoE is sent over the data wires, using the Ethernet transformers to separate DC from signal. All the PoE powering systems I have ever seen use SMPS to power things, PoE can use quite high voltages which makes things a little difficult for LPS powering, but certainly could be done if someone wanted to work hard enough at it. I have not spent any time measuring a PoE system for leakage and leakage ration from cables, but just a quick thought on the subject does not point at there being any significant difference than non-PoE systems. John S.
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