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John Atwood

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  1. To shut down Speed Step, I went into the BIOS (pressed Del after booting) and went to the "Advanced", then "CPU Configuration" menu. At the bottom of the screen was a line where I could disable Speed Step. Different motherboards and BIOSes may have different ways of handling this. I hope this helps. - John
  2. I had a lot of problems with clicks and pops when I upgraded my motherboard and OS to Win 7. It turns out that aggressive power management on the motherboard was the problem. See my earlier posting on this at http://www.computeraudiophile.com/content/Power-management-causing-clicks-and-pops. This may not be your problem, but it is worth checking. Windows 7 seems very prone to audio drop-outs, so all unnecessary background tasks should be halted. Good-luck, and let us know any solutions you find! - John Atwood
  3. In the thread I mentioned above in the Lynx forum, there is a link to a much more informed discussion of the power management vs sound issue going on in the Cakewalk forum - it is worth reading: http://forum.cakewalk.com/tm.aspx?m=1939514 - John Atwood
  4. I just came upon something that may be helpful to this group. I first posted this to a Lynx forum (http://www.lynxstudio.com/forum/forum_posts.asp?TID=3062), so to save time, here is the posting: ****************************************** ... I recently upgraded my music server with a new CPU and motherboard (Intel Core Duo E8400) and at the same time thought I would upgrade from WinXP to Windows 7. I am using a Lynx Two card and am primarily using the AES/EBU output for playback, and use Foobar2000 as my media player. When everything was set-up, I was plagued by occasional random ticks and pops on music playback (not when silent but only during signal output). This never happened before on my old system running WinXP. I tried disabling services, lengthening buffers, etc. but nothing helped. BTW, I was getting the same ticks and pops on an on-board SPDIF output, so I didn't think the problem was with the Lynx board or driver. When I changed hard drives and re-loaded Windows XP, the problem went away, but it came back when I switched back to Windows 7. After lots of Google searching, I found several references in forums to this problem and its apparent cause: The aggressive power management in the newer CPUs (both AMD and Intel) can cause glitches when controlled by the OS. The solution: disable OS control of power management. In my case, I disabled "SpeedStep" in the BIOS, and the problem went away! I was worried that the processor would permanently run hot, but this isn't the case - it seems to control things on its own, and it only gets hot when running a stress test. There is no acknowledgment of this problem or its solution by Microsoft. However, it just about made me abandon Windows 7 and return to WinXP. I still have a few problems with Windows 7 (such as not getting bit-perfect output), but I am still working on these. ****************************************** David Hoatson, Chief software engineer at Lynx has verified this solution to the problem. As I mentioned above, I am still having a few issues with Windows 7, and if I can't figure them out, I'll post my problems here. Although my system is a conventional Windows system, David Hoatson noted the problem existed on an Intel-based Mac running Windows 7 under boot camp. Since he doesn't have a BIOS, he fixed the problem by changing the power options from "Balanced" to "High Performance". - John Atwood
  5. "Also, I live in an old building, what is the difficulty level of running a dedicated circuit for my AV gear? Any prefered wire or just Home Depot 20 amp romex?" The difficulty all depends on your house and construction. In my case, the sheetrock around the circuit breaker box had already been removed to add a large conduit for a geo-source heating/cooling system, so it was pretty easy to add the new circuit. If you have lath & plaster or masonry walls or your listening room is far away from from the breaker box, or even worse, all the breaker slots are filled-up, you will have more trouble. You really need to conform to your local building codes, which usually requires the use of a certified electrician to do the work or at least have a city or county inspector inspect the job. In my case, I did the wiring myself, but conformed to the 2005 NEC ("National Electric Code"). The code specifies the minimum wire size as well as the type of insulation. This pretty much restricts you to approved wire, but there is nothing keeping you from using bigger wire, say #10 instead of the code-required #12 for a 20Amp circuit. If you put in a 240V circuit, you will have to use an approved outlet for the ratings of the breaker. Make sure your connections are tight and you might want to use an anti-oxidation paste on the connections. If you are not familiar with the NEC, don't do this work yourself - get someone experienced to do the job. - John Atwood
  6. "I often read that you should not plug your power hungry amps into a power conditioner because it will limit the dynamics." It all depends on the power conditioner. As I mentioned in an earlier post, passive filters, if they aggressively filter lower frequencies, can severely limit current flow during the peak of the waveform where the ubiquitous capacitor-input filters in most power amps draw their current. Depending on the filter implementation, the result can be sags, odd waveforms, or even destructive high-voltage glitches! Active conditioners are limited by their peak current capability. If you don't exceed the peak current rating, active conditioning will be better than none, since it keeps the voltage to the load from dropping. To really know if you will have a problem, you need to know the power amp's peak current draw during the worst-case large-signal conditions and make sure it can be handled by the conditioner. This is something that is rarely specified, probably because it would be embarrassingly huge for most big amps! By the way, another advantage of active conditioning (either of the regeneration type or the Elgar-style waveform correction type) is that it regulates the line voltage. This keeps any jumps in line voltage from shifting operating points, bias settings, or otherwise disrupting analog signal paths. This is especially useful on vintage equipment or analog equipment that doesn't use voltage regulation, because the conventional C-R-C or C-L-C filtering schemes have almost no effect at subsonic frequencies. - John
  7. machinehead - You are right - you don't want the digital noise to "pollute" your power. In my system, the computer and its digital accessories are on a different circuit than my Elgar-conditioned analog loads. The connection on playback between the two is through the AES/EBU interface on the Alpha DAC, which isolates the different sources pretty well. For analog recording, such as recording LPs to the computer, I rely in the common-mode rejection of the Lynx TWO analog inputs to break the link between the digital and analog domains, which isn't perfect. I wish the Berkeley Audio Design guys would come up with an A/D converter box to match the quality of their Alpha DAC! - John Atwood
  8. Bryan, yes the highs got clearer. I didn't really notice any noise before using the power conditioner, but I've found that subtle effects (in this case, HF noise reduction) that can't be heard on their own will alter the psycho-acoustic processing in the brain. The sine wave is what all equipment is designed for - different waveforms will create different voltages and power, depending on the power supply circuit. Also, even a smooth non-sine wave has harmonics which are easier to hear than the fundamental. The problem with just doing passive filtering is that if the filtering is good enough to get rid of the harmonics, then a non-linear load current will raise hell. Nearly all audio equipment present non-linear loads to the power source - primarily in the form of current pulses caused by capacitor-input power supplies. Big solid-state amps are the worst in this respect. In equipment I've been building for myself, I've been trying to use choke-input filters when possible. These are much nicer players on the power line. By the way, you can see my P-P 300B amp at: http://www.one-electron.com/JAtwood/Sys0304_300B.jpg - John Atwood
  9. I have been intrigued with the Accuphase power conditioners (such as their PS-1210) for a long time. Instead of recreating the power from scratch, they basically put an audio power amp in series with the power line (after passing through an isolation transformer) and use the difference between the output and a locally-generated pure sine wave to drive the amplifier. The net effect is that the amplifier adds or subtracts from the waveform whatever is necessary to make it a sine wave. This is quite a bit more efficient than total regeneration. However, the Accuphase units are quite expensive, as can be imagined. About a year ago, I stumbled upon a Elgar 6006 power conditioner on eBay, and after downloading the manual (still available on the web, although Elgar is gone), realized it is probably what inspired the Accuphase power conditioners - it uses the same concept, except it is made for industrial and scientific use. I got it for about $270 and it turned out to be in great shape and worked very well. The only problem was that it has a terrifically noisy fan and a lot of mechanical buzz. While testing and aligning the Elgar unit, I realized how bad the local power has become. I live in rural Nevada, at the end of the power line. When I first moved here about 12 years ago, the waveform of the power was basically a sine wave, although with a few glitches in it. It has now degraded to something definitely not a sine wave - the top and bottom are flattened and there is an odd kink near the zero-crossing. I called up my friend Wally in Sunnyvale, Calif. (Silicon Valley), and he reported nearly the exact waveform at his house. I think the degradation is due to the incredible amount of capacitor-input power supplies, from PCs to CFLs, now loading the power line. The Elgar conditioner puts out a near-perfect sine wave (THD
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