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About JohnSwenson

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  1. That was the right choice. What the GPSDO brings is much better stability over very long time frames, something that is not needed for audio and adds a LOT of complexity and potentially more noise. I have a good GPSDO (well actually two!) but that is for use as a time base for my very sensitive time measuring equipment, not as a clock for digital audio. Yep getting a good signal to the GPSDO is a major pain. I just bought a new one because it has a MUCH better GPS receiver than the old one, which meant I didn't need an outdoor antenna, one in the window works fine. John S.
  2. Just swapping the connectors to 75 ohm is not sufficient, the output circuit has to be adjusted to also be 75 ohm. It may just be just changing a resistor, it depends on what the output circuit is. John S.
  3. The safety grounds on all the circuits in your house are SUPPOSED to be connected together, so it doesn't matter if the two power supplies are connected to the same circuit. In many cases connecting to the same circuit will sound Better than separate circuits. But there is no hard and fast rule about that. This sort of thing is very system specific. My usual suggestion is plug the power supplies into whatever is convenient. Most of the time that will get you quite close to "the absolute best no matter what" so just make it easy and don't worry, unless you have a LOT of money and time and don't know what to do with them.
  4. There is an interesting trade off here, hotter parts can can generate less noise, but hotter parts can have a higher probability of failing over time. The semiconductor parts used today generate noise when they switch, the faster they switch the more noise they generate. They run slower the hotter they are. BUT the slower they switch the more jitter they have so there is an "optimal" point where the noise and jitter are at their lowest. I can't tell you what this point is, due to manufacturing tolerances, it varies a lot from chip to chip. There is a BIG impact on longevity produced from turning things on and off, every time you turn a device on and off things expand and contract. Over time this can cause solder joints to fail. The hotter things are the more they expand and contract each time they are turned on and off. So if you turn the device on and off every time you listen, you should probably opt for a cooler temperature if you want the device to last a long time. If you leave it on all the time you can run it hotter and still have good longevity. At the temperatures we are talking about the parts themselves will last a very long time, it's the solder joints that usually cause failure. John S.
  5. There is also another possibility, we have found that NAA can do weird things if the port on the computer that is running HQP is gigbit, but a switch along the way converts to 100M (such as the ER) flow control is turned off and problems in playback occur. What seems to be happening is HQP sees it is connected to a gigbit port so it turns off flow control and sends data out in high speed bursts. But with a gig to 100M switch in the path the 100M side can't keep up with the that high speed burst, data is lost, and since flow control is turned off it can't tell HQP to slow it down. IF this is what is happening you might be able to fix it by putting a 100M max switch between the HQP computer and the A side of the ER. That way HQP sees it is connected to a 100M port and sends the data out slowly so it doesn't have a problem when it gets to the 100M port on the ER. John S.
  6. As far as I can tell these "grounding" boxes are really noise injectors, BUT with phase adjusted so it tends to cancel out noise already in the system. The box is an antenna which picks up the AC line frequency already in pretty much all environments and injects it into the "ground" of your system. If this is done properly it CAN cancel out some of the existing ground noise, but it can also increase it if things are not right. The upshot is that if you have setup these boxes and tuned things right and them you use something to decrease the ground noise (such as an EtherREGEN) you may find that things sound worse, because now the injected noise from the ground box doesn't have anything to cancel out. So I would recommend trying the EtherREGEN both with and without the ground boxes and see what you prefer. John S.
  7. Which 2960 do you have? There are both mostly 100Mbit and gigabit versions out there. The mostly 100Mbit has 1 gigabit port and the rest are 100Mbit. There may be an issue with this. Have you tried plugging the B side to different ports on the 2960 to see if that makes any difference? The 2960 takes a VERY long time to boot up, if the devices are already connected to the A side of ER (which is powered up) and THEN you turn on the 2960 the slow boot may cause devices to time out before they connect. Just a possibility. I would make sure the 2960 has been powered up for a long time (several minutes at least) before turning on anything else. My preferred sequence would be 2960 then ER then other devices. This should make sure the network is up and running before other devices try and connect. John S.
  8. They don't say they use autoformers so I presume they are transformers. In general autoformers have wider frequency range and flatter frequency response, but are lot galvanically isolated. True transformers are galvanically isolated. As with anything a really good transforer can have better response than a so so autoformer, but a really good autoformer will propbably outperform a really good transformer. The autoformers are usually smaller and less expensive than a true transformer. John S.
  9. Hi Chris, I spent MANY years trying to find a volume control I really liked, pots, discrete resistors, active, passive but none of them seemed to get it just right, until I tried autoformer attenuators by Dave Slagle from Intact Audio. The ARE just the transformers, you have to add a box and connectors, but for me that is easy. Using the autoformer passives is VERY different than resistor based passive controls, you don't need the super short cables etc. In my main system my passive "preamp" cost about $500, the SlagleFormers, an aluminum box, some really good connectors and a switch for the two inputs. To me in my system this sounds better than anything else I have ever heard, no matter what the cost. Bent Audio used to sell a passive preamp using these autoformers that have balanced ins and outs, but now it is just on the used market. that Townsend one mentioned earlier looks like a promising one, but I have not heard it. It looks like it is well done. If I was in the market for buying a commercial one I might go for that one. I would highly recommend looking into autoformer based volume controls, to me they beat out anything else. John S.
  10. Technically I don't see an issue, the main problem I see is that for this to work the original unmastered "raw tapes" (or whatever) have to be sent to the end user, I don't think that is EVER going to happen. Just starting from whatever is already out there and trying to "de-master" it so it can be remastered I don't think is going to be very useful, more than likely too much of the "goodness" of the original raw recording is already gone by then. John S.
  11. Yes, powering the EtherREGEN and an A side device from the same JS-2 is fine Yes, powering an EtherREGEN and an A side device from the same JS-2 is fine. The JS-2 negative outputs are isolated from the Safety ground on the AC power cord. You might want to try grounding the "ground screw" on the EtherREGEN ans see if it makes any difference. John S.
  12. The digital circuits used in audio will WORK (properly transport data) over a very wide range of master clock frequencies , somewhere in the several parts per thousand range for sure. Even an uncompensated oscillator such as the 575 will meet that over a very long time. To get outside of that range takes drastic measures like pounding with a hammer, putting it in the flame of a torch etc. Not "normal" usage. ANY OCXO is WAY WAY WAY better than that! John S.
  13. I don't recommend these supplies, they have the highest leakage of any supply I ever tested, MUCH higher than the one UpTone supplies with the EtherREGEN. John S.
  14. Correct, I'm working on DAC output as well. None of this stuff is easy. We are trying to measure a DAC output using ADCs, to do that requires an ADC that has lower clock jitter than the DAC we are trying to measure, this is NOT easy to do! The off the shelf audio analyzers are nowhere near close enough. So as with everything else related to this I have to make my own. It's not easy and it's not cheap. I have something up and running which still needs a lot of more work to lower ADC jitter and prevent external signals from getting in, but it DOES actually get signal through. Maybe within the next week I'll try it with real audio DACs and see how things are at this point in the development process. My ultimate goal is to show the whole process from ground plane noise, to DAC clock jitter to DAC analog output. I WILL get there, but it is going to take a significant amount of time to get there. John S.
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