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Computer Audiophile

JohnSwenson

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  1. JohnSwenson

    Are You Using Rolleballs, RollerBlocks ??

    I got mine at Online Metals, they do custom cutting, but are expensive. At the time I had no tools for cutting my own. You can get 1/2" aluminum on ebay for much less, but you don't get to choose the exact size. Recently I found a place even in my small town that does metal fabrication and occasionally has scrap 1/2" aluminum that they are willing to cut to size for a LOT less than Online Metals. John S.
  2. JohnSwenson

    ISO Regen performance Improvement Cheap!

    The DC/DC switching converter inside the LPS-1.2 has nothing to do with leakage current. I have exhaustively tested that and it makes no difference. There is some capacitance in the transistors used to switch banks (bipolars BTW, the ones I use have WAY lower capacitance than any equivalent MOSFETS). The low impedance leakage is blocked completely by these transistors, but some amount of the high impedance leakage from SMPS does get through. This is the reason for connecting the SMPS negative output to safety ground, it shunts the high impedance leakage back to the mains so there is very little entering the LPS-1.2, the transistors can easily handle this. The combination produces no detectable leakage at the output of the LPS-1.2. I can detect about -150dBV, what I see is the noise floor of the system. The LPS-1.2 comes with an SMPS that already has its negative output connected to the safety ground just for this purpose. Now if you don't HAVE a safety ground or it is not connected to the neutral of the mains, then the shunt won't be working. Note there is nothing about earthing in this. It is the fact that the safety ground has a low impedance connection to the neutral (or at least it should) which provides a path for the high impedance leakage to get back to the mains rather than going through the audio system. John S.
  3. JohnSwenson

    ISO Regen performance Improvement Cheap!

    A DC cable with a leakage loop running through it (remember leakage loops are low frequency) will radiate the line frequency and harmonics which CAN be picked up by ordinary audio interconnects (the shielding on THEM doesn't stop the low frequency radiation, unless they do the shielding right). I HAVE been able to measure this. In this case the proper shielding (JSSG) on the DC cable will prevent this from happening. The LPS-1.2 will stop any leakage loops through its output, so the proper shielding should not be necessary. It MAY slightly change the inductance on the cable which MAY change sound, but that is not an actual shielding effect. John S.
  4. JohnSwenson

    ISO Regen performance Improvement Cheap!

    Here is the post where I covered shielding: It IS like a Faraday cage, that is the whole idea, making a cable behave like a Faraday cage. Read the details in the post. The other is a way to shunt high impedance leakage (note NOT high FREQUENCY, this leakage is actually line frequency related) generated by SMPS. In my studies into leakage I found that SMPS generate some very high impedance leakage that is very hard to block, it will go all over the place because the impedance is so high. BUT it is easy to shunt to ground (actually the safety ground in house wiring, EARTH connection not actually necessary). It is a very simple concept, connect the negative output of the SMPS to the safety ground and the high impedance leakage is shunted around your system. I posted some simple adapters to do this with common SMPS . This is a big issue for computer audio since most computer systems, networking equipment etc use SMPS. BTW the traditional low impedance leakage is still there on both SMPS and linear supplies, but there are ways to deal with that. John S.
  5. JohnSwenson

    Are You Using Rolleballs, RollerBlocks ??

    I have Ingress Engineering rollerblocks under most of my equipment. I used to use home built ones but these so much better and the price is very reasonable. I did a lot of listening and found that I got better sound putting the rollerblocks under 1/2" thick slabs of aluminum and putting the components on the aluminum slabs than having the components directly on the rollerblocks. I don't put the aluminum directly on the balls, I glued polished stainless steel pieces under on the bottom of the aluminum slabs at the appropriate places. I use small shaving mirrors made for camping, they are available all over the place and make a fantastic surface to put on the roller balls. This system works extremely well, the resonant frequency is quite low (about 1.5Hz) and the damping seems just about right. Because of the fairly high mass turning knobs etc is fine, much better than putting light weight components directly on the rollerblocks. You DO have to have very flexible cables for connections that go off the slab. If you have two components on the same slab they can have stiff cables between them, but any cable going to a component not on the same slab needs a flexible cable. Stiff cables prevent the slab from moving freely, significantly reducing the effectiveness of the rollerblocks. I wound up making all my own cables to get high performance yet highly flexible cables. This system yields a large increase in the "aliveness" of the sound, its rather stunning to listen to. The only downside is that I don't have any vertical isolation yet. I've been designing several systems but have not been able to try any of them yet. I'm just getting my new shop building completed so now will have the tools to start trying some of these in the years to come. John S.
  6. JohnSwenson

    Weak Internet & Options to Increase Speed

    I'm using something similar from TP-Link, the CPE210 to connect my new shop building to the house network. They are $40 at Amazon. You can either use just one at the house, but you have to be careful about the beam spread, it wouldn't cover the whole shop. So I used two, one at the house and one for the shop, with traditional switch and WAP in the shop. I didn't even need to put them outside, they worked fine going from on to the other through two walls. My sister in law lives in rural Texas with no wired infrastucture at all, they get internet over fixed LTE network from a tower about 20 miles away, it works very well and not very expensive. Of course you have to have such a carrier in your area. John S.
  7. JohnSwenson

    ISO Regen performance Improvement Cheap!

    Today was our 21st anniversary, I took my wife on a dinner cruise on a river boat along the Columbia river. It was amazing. About 5 minutes out of the docks there was a FULL double rainbow across the river. This was the brightest rainbow I have ever seen, and the second bow was also full over the whole river. Simply stunning. Oh yeah the food was fantastic we had a great time. On the way home the sun set down the Columbia, we had been having storms go through the area all day so there were a lot of cloud formations all over the place. Not only did the clouds look amazing but it lit up the water of the river as well. Almost as great as seeing the rainbow. Oh yeah and while we were all looking at the glorious rainbow the PA system was playing the song "True colors". It was a fantastic day. John S.
  8. The 36W is the maximum power when running at 12V output and greater than 0.5A output current. As the output voltage goes down the maximum input power also goes down. In addition there are two charging currents, one used for less than 0.5A and one for greater than 0.5A. So under some circumstances (lower output voltage, lower output current) you can get away with a lower wattage feeder supply. Unfortunately there is no simple formula to compute how much it is going to take for a particular condition, it's a very complex situation, so we just recommend that people use a feeder supply that can handle the maximum and you will never have a problem. John S.
  9. JohnSwenson

    ISO Regen performance Improvement Cheap!

    It's going to be awhile before I can work on this. I have a whole bunch of high priority tasks right now and my wife has said I have to cut down on the number of tasks at the same time, I have been so stressed out over things my health is starting to suffer and I'm making bad decisions. So until some of the other stuff gets finished I won't be able to add anything new to the task list. I'm still doing the little PC board for the Philmore adapter (that is going out tomorrow) which will make putting together test cables a lot easier, but that is about it right now. John S.
  10. JohnSwenson

    ISO Regen performance Improvement Cheap!

    My current ideas as to what matters for a DC cable is inductance and dielectric absorption. The inductance is primarily determined by the geometry of the wires, and dielectric absorption is determined by the insulation on the wires. Starquad is by far the lowest inductance geometry, much better than twisted pair, 1/3 the inductance. PVC (a very common wire insulation) has very high dielectric absoorption, polypropylene and teflon are very low (100 times less than PVC). I think what has been happening here is that different cables have been trading these two off with each other. With the multiple twisted pairs you get inductance higher than starquad, but things like shielding, how tight the twist etc. are causing some differences in the inductance, and different cables have different dielectric materials. I really think we need to try true starquad with low dielectric absorption insulation. The Canare is true starquad but uses PVC. VH Audio is now selling just such a cable V-Quad Cu21 and Cu24 (21 and 24 AWG conductors) with true starquad and very low dielectric absorption. I think this would be a very good cable to try. It's not cheap ($24 or $27 per foot) but it may just be a very good combination. Another cable I have been using for interconnects is Belden 1804A, starquad with polypropylene, but 28 AWG. If you guys are finding that 28 AWG conductors are all right it might be a good candidate. It is a LOT cheaper than the above VH cable. Just some thoughts. John S.
  11. JohnSwenson

    DIY DC power cables

    I measured the resistance of the Philmore adapter and the screw green adapter. In both cases they were right at the limit of my test equipment (milli-ohm). So its kind of inconclusive, they were both very good. The screw one did better than I thought it would. I'm still going to make little PCBs with 4 pads for each connection (+ and -), pads to solder the adapter pins. I'll put pads patterns so you can mount the adapter either straight or right angle. It will take about a week for the boards to get here, if it all works out I'll put the design in the OSH Park store so others can have the boards made for themselves. John S.
  12. JohnSwenson

    DIY DC power cables

    There is no way under normal soldering procedures to unsolder the connections inside, you would have put a powerful iron on the pin and let it bake for several minutes. (maybe the rep thought people were going to be using one of those 200W soldering guns). John S.
  13. Not yet, that is the next phase, the clock research. I'm building a test setup with a board with 5 possible ways of dealing with clocks, a test signal generator which starts with an ultra low phase noise clock and modulates it to generate a specific phase noise marker that will never exist naturally. This clock will be used to clock various parts of the digital audio chain feeding into a DAC, whose output goes into a 24 bit ADC which is clocked with yet another ultra low phase noise clock. I've been working on a suite of software to analyze the output of the DAC which should show any actual analog differences coming out of the DAC. Everything is all up and running except for the test board, I have the raw boards but have not stuffed it yet, there are a LOT of parts on this board and I don't really want to do it by hand. I've been building a DIY pick and place machine kit and decided to place the board with this. It is all built and wired up and I'm going through the setup and calibration phase right now. I should have it up and running in a couple days and I can then assemble the last board and get this test setup actually working. So barring some unforeseen situation I should be getting results in a couple months. There is a LOT to do to get the test setup working properly. John S.
  14. JohnSwenson

    DIY DC power cables

    The pins are hollow. It looks like they start as a sheet, one gets a ring stamped out, the other gets a spade stamped out. The other end gets rolled into the pin. The sheet is fairly thick. The spade is put flush up against the center post and the ring goes around the barrel. There is a fair amount of metal involved in both connections. John S.
  15. JohnSwenson

    DIY DC power cables

    The adapters finally got here today, I did manage to dissect one (it was not a great job so I'm not posting a picture!), it is way better than the screw ones. The barrel central conductor is a thick metal stud that gets directly soldered to one of the pins. The other pin is a ring connector that just fits around the outside of the barrel and soldered to it. So no thin little wires, the exposed pins are soldered directly to the fairly thick parts of the barrel part. Much better than the screw ones. I have a 4 wire resistance measuring system that can accurately measure down below a mili-ohm, I will give that a try and see what it comes out to. John S.
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