Benchmark DAC1 now available with USB

[ted betley]

To eweitzman: yes I would like to know more, specifically what I can try to rid my sys of these nasty pops. I did take out my opticis cable and am running pop free but I won't declare victory until I get 3 days of no pops.

[Wavelength]

Ted,

One thing that has been a problem for some PC's is that the USB driver is generic instead of specific.

If you go to Control Panels: Device Manager : Universal Serial Bus controllers

You can then click on the Host Controller and look under the Driver and make sure it was written by the company and not the Microsoft generic one.

Also you can check to see if it is the latest one. Here you can also kinda tell were your dac is plugged into.

On a side note with the Opticis. I use these at shows all the time. I have never really had a problem with these. I use a custom linear regulated supply on mine. But several users are using the battery supply like yourself.

Elias,

HUH... on the Firewire brand new MacBook Pro into Metric Halo ULN2 worked fine yesterday after we updated the DSP and firmware in the ULN2.

As for the cheater plug thing it should not be a problem to remove this. The DAC1 does not constitute allot of current. The floating ground will then permit the single point ground at the preamp/integrated amplifier.

Shun Mook who have a pretty radical idea of grounding float everything to one central point. Then they run a 18ga wire to a post in the ground. They also put these ferric sleves around all power lines. Funny story Jonathan Valin of TAS had them do his house. The power company terminated service when they saw the ferric sleeve (bright purple and red) around the incoming service.

Gang I have seen allot of Computers causing ground loops. Some have 2 wire plugs that are polarized and some 3. In general all the items hooked together will require the same power from the same outlet. Even common power on seperate outlets can cause hum. It's best to get a good power stripe and plug everything into it.

Thanks
Gordon

[ted betley]

Gordon:
One thing that has been a problem for some PC's is that the USB driver is generic instead of specific.

If you go to Control Panels: Device Manager : Universal Serial Bus controllers

You can then click on the Host Controller and look under the Driver and make sure it was written by the company and not the Microsoft generic one.
[under control panel ... it says Generic usb audio; driver provider microsoft]

Also you can check to see if it is the latest one. Here you can also kinda tell were your dac is plugged into.
[How do I tell if it is the latest one?]

On a side note with the Opticis. I use these at shows all the time. I have never really had a problem with these. I use a custom linear regulated supply on mine. But several users are using the battery supply like yourself

[Once while I was using the opticis I demagged a cd while being roughly 3 feet from a portion of the opticis and I heard an induced pop directly correlated with my demagging action. Yes the demag device was powered by the same a/c circuit as my entire front end--dac,opticis battery charger, dbx crossover]

[eweitzman]

Originally Posted by ted betley

To eweitzman: yes I would like to know more, specifically what I can try to rid my sys of these nasty pops. I did take out my opticis cable and am running pop free but I won't declare victory until I get 3 days of no pops.

Ted,

I'd recommend *against* removing ACPI unless you're sure it's the problem because removing it requires major surgery on your operating system. I'd recommend diagnosing the problem in detail by running RATTV3. Google for it and you'll find it at Microsoft's website. RATTV3 is not a simple system to run, but once you get the hang of it, it will reveal any latency problems in your system.

A better understanding of latency issues can be gained by reading about and then running a program called "DPC Latency Checker". You can get it here. It's not as good a tool for pinpointing the problem but will reveal if your machine has latency problems.

- Eric

[eweitzman]

Here's my email to Elias from March after I solved the latency/pop mystery on my five year old IBM X22 laptop. The procedures involved apply to Windows XP only AFAIK.

- Eric

Elias,

I have great progress to report. Complicated, but great. I can use the
DAC1PRE with my old IBM X22 laptop without dropouts.

I created a new partition on my X22 laptop's hard drive and installed
a clean XPSP2. Still had dropouts. Turned off services, etc, still had
dropouts. Seems the "reduce load and complexity" approach doesn't work
with this machine.

So I turned on the DPC/latency monitor program RATTV3 for a very short
time while playing a 24/96 file that normally drops out for 5-10
seconds at a time and got a snapshot of just a few seconds of the
machine when a long dropout occurred. The log shows very long times
spent handling interrupts in ACPI.sys. This is the driver for the
Advanced Configuration and Power Interface. ACPI allows the OS to
control the power management functions of the hardware.

Searching around the net, I found that disabling ACPI was a hot topic
about five years ago. It is not a simple driver that can be disabled:
it's part of the hardware abstraction layer (HAL) that the OS runs on
top of. When installing XP, it detects the machine type and installs
the HAL before installing anything else. HALs can be selected during
setup with a judiciously pressed F5 when setup is prompting you to
press F6 to install additional device drivers. This is the clean way
to not have ACPI: select "Standard PC" at this point and no ACPI
support will be installed. Alternatively, after the OS is installed
with the ACPI HAL, you can expand the "Computer" node in Device
Manager to the ACPI computer "device", then open it's properties,
update (or remove?) the driver, select the "Standard PC" HAL and
reboot. XP will then redetect much of the hardware after starting,
reassign IRQs and so on, then it needs another reboot. After that,
there's no ACPI layer, and probably a mangled hardware hive in the
registry.

In any case, without ACPI (clean install or removed), the DAC1 runs
trouble-free with XPSP2 on this machine. But there's a price: no XP
power management functionality, no hibernate and standby support. The
older APM power management functions can be turned on (at least on my
laptop) without ACPI so there's some power management when running on
battery, but still no hibernate/standby. These are hardware functions
availalbe via ACPI only.

Google for "disable ACPI XP" and you'll find detailed procedures for
removing it. Here's Microsoft's note on forcing install to use the
Standard PC HAL instead of the ACPI HAL:
http://support.microsoft.com/kb/299340/en-us

- Eric

[ted betley]

cool I'll try it

[ted betley]

I d/l ed dpc latency checker and already noticed a spike that took me right up to the red line (max latency of 1932 usec). I use cicsplay which is a ram playback system and since I have 1 gig of memory I usually analyze windows task manager and end processes not critical to playback while during playback. So when I got my 1932 spike was when I ended msmgs.exe (I never the use message manager how do I disable completely?)/ Maybe my process ending process is spike inducing?

[ted betley]

To eweitzman: I got dpc latency checker and yes something is amiss somewhere. Some dpc's > 4000usec. I d/l ed ratvv3 and it is apparently open and running but how do I get the report? Does it just come or must I query for it? Where is the report deposited?

[eweitzman]

Ted,

IIRC, the RATTV3 report file is re-created automatically after each run cycle, about every 3 minutes. The report is created in the %SYSTEM32%\logfiles\rattv3 directory. Check the README file in the RATTV3 group in the start menu to be able to interpret the report. For example, the report file on my machine is C:\WINDOWS\system32\LogFiles\RATTV3\MTW.cswa-accumulator-report.txt.

Another "IIRC"-qualified answer is how to turn off msmsgs.exe, aka Windows Messenger. Even if you shut it off using the Services management console, XP will turn it back on next reboot. If you never use it, just uninstall it. Go to Control Panel > Add or Remove Programs > Add or Remove Windows Components. Uncheck "Windows Messenger," press "Next" and follow along You might need to have your XP installation CD handy.

- Eric

[ted betley]

Got the file accumulator report but the format/text is not decipherable. Any hints on how to open? When it asked me what program made the report I answered notepad. I guess that was not right.