[EliasGwinn]

Quote:

Originally Posted by omegared /img/forum/go_quote.gif Hi Elias, I have some synchronization issue with my DAC1 USB to my HTPC. Every now and then, my HTPC is having trouble synchronizing with my DAC1 USB. On my DAC1, I can see the LED blinking for awhile and later the lights are off. I need to unplug and replug in the USB cable in order to make it work again. Is there anything I missed here? Any XP settings needed to be done? Does anyone have the same problem?

Thats odd...does it happen while you're playing audio?

If I was to wager a guess, I would say that your power management is shutting down the USB ports.

How often does it happen?

Thanks,
Elias

 

[EliasGwinn]

Quote:

Originally Posted by bralk /img/forum/go_quote.gif Yes - I have the same problem, feeding the dac1 usb from a Macbook G4 running Leopard and iTunes 8. cheers Tom

Tom,

I'm also curious about your experience. When does this problem happen? Whil playing audio? While idle? After its been on for a long time? Not long after power-up?

Thanks,
Elias

 

[omegared]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Thats odd...does it happen while you're playing audio? If I was to wager a guess, I would say that your power management is shutting down the USB ports. How often does it happen? Thanks, Elias

It happens at random interval. Sometimes during playing audio, sometimes leaving my pc idle. I have ensure that the checkbox is unchecked. That means it "should not" power down when idle.

 

[omegared]

Quote:

Originally Posted by bralk /img/forum/go_quote.gif Yes - I have the same problem, feeding the dac1 usb from a Macbook G4 running Leopard and iTunes 8. cheers Tom

Anyone else encounter the same problem?

 

[bralk]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Tom, I'm also curious about your experience. When does this problem happen? Whil playing audio? While idle? After its been on for a long time? Not long after power-up? Thanks, Elias

Hi Elias

The problem i not occurring regularly. If I play without changing playlists/tracks (using iPod Touch as a remote) there is no problem. But sometimes after having made some changing around between playlists the usb connection dies. When I check the audio/midi panel the Benchmark is still listed as active - but after this check the usb connection is reestablished. Just opening and closing the audio/midi panel solves the problem.

The problem occurs perhaps once every second day.

I will change to my macmini to see if it is a problem with my G4.

I will aso try using a shorter usb cable ( now using 15 feet which is perhaps
too long ?)

cheers

Tom

 

[Quaddy]

this used to happen to me with my dac1 pre fairly frequently via USB when i was using a dell latitude x300 as source, and a G3 imac

now i use a newer imac and a trick usb cable and it hasnt happened once, rock solid connection

so rest assured its not the doing of the DAC1 pre, but the randomness and wide ranging computer environments we all have.

ensure ALL usb hubs in device manager (view by connection off the dac1) are not allowed to power save as elias stated.

and if you have vista, dig deep to disable the selective usb suspend settings.

i also seem to remember running my wav files off an external USB hard drive wasnt helping matters, i switched to firewire external as well, and not had it since.

 

[EliasGwinn]

Quote:

Originally Posted by omegared /img/forum/go_quote.gif It happens at random interval. Sometimes during playing audio, sometimes leaving my pc idle. I have ensure that the checkbox is unchecked. That means it "should not" power down when idle.

Do you have another computer that you could try this on? I'm curious to see if your DAC1 works well with other computers.

Thanks,
Elias

 

[omegared]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Do you have another computer that you could try this on? I'm curious to see if your DAC1 works well with other computers. Thanks, Elias

Unfortunately no. Let me try what Quaddy suggested first to ensure ALL usb root hub do not have power save enabled. Will update you again.

 

[BitPerfect]

Greetings DAC1ers and head-fiers,

Before I ask my question, I'd like to add my voice to those praising Elias Gwinn's remarkable contributions throughout this looong thread. Like others, I've read through the whole thing and I've never seen such a high light/heat ratio in any prolonged forum discussion. Just exemplary.

OK, so I think I have too much gain in my system and I'm wondering what to do about it.

I recently replaced a DAC1 with a DAC1 Pre, allowing me to eliminate both an M-Audio S/PDIF to USB box and a preamp (for vinyl listening) and get back to balanced connections between DAC1 Pre and my ATI 3002 power amp. Most of my listening is sourced from my music server (Apple Lossless files).

In my listening room, I typically source through a Squeezebox Duet through digital coax into the DAC1 or via USB from my Mac laptop when listening to 24/96 content.

I have the DAC1 built-in pads at 30dB. In this setup, I find that if I turn off digital attenuation in the Duet and in iTunes on the laptop, I can't set the DAC1 volume above 9 or 10 detents for comfortable listening. My power amp has 28dB gain and my speakers (Spendor S8e) have 89dB sensitivity.

Looking at the volume control graphs in the DAC1 manual, I'd much prefer to see the DAC1 volume control at the 12 o'clock position rather than 9:45. I could turn it up and digitally attenuate the Duet and/or iTunes, but I don't know how much dynamic range I might be losing that way.

Does it make sense to consider adding a passive attenuator pads of some kind between the DAC1 and power amp?

Thanks!

 

[EliasGwinn]

Quote:

Originally Posted by BitPerfect /img/forum/go_quote.gif ... OK, so I think I have too much gain in my system and I'm wondering what to do about it. ... I have the DAC1 built-in pads at 30dB. In this setup, I find that if I turn off digital attenuation in the Duet and in iTunes on the laptop, I can't set the DAC1 volume above 9 or 10 detents for comfortable listening. My ATI 3002power amp has 28dB gain and my speakers (Spendor S8e) have 89dB sensitivity. ... Does it make sense to consider adding a passive attenuator pads of some kind between the DAC1 and power amp?

Hello BitPerfect! Welcome to "The Thread"!

If the volume control of your DAC1 PRE is set at the 10th detent (-15 dB gain), and the attenuators are set at 30 dB, there is a total of 45 dB of attenuation before your power amp. That means your amp is seeing a maximum input of -20 dBu (give or take).

If anything over -20 dBu is too loud for your amp, then your amp has too much gain / power.

Are you absolutely sure that you have all four XLR jumpers set at the -30 dB postion? The -30 dB postions in the DAC1 PRE are the jumpers closest to the XLR connectors.

Thanks,
Elias

 

[BitPerfect]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Are you absolutely sure that you have all four XLR jumpers set at the -30 dB postion? The -30 dB postions in the DAC1 PRE are the jumpers closest to the XLR connectors.

Yes, I'm sure. As a sanity check I popped the top and looked again the other day. But I appreciate the confirmation of the position. On my original DAC1 "classic" I seem to remember those jumper positions being marked, but not on the Pre, unless my eyesight is failing.

I can live with it. The power amp delivers 300wpc into 8 ohms. That may be contributing to the issue. But I really like that effortless power when the time comes to crank it up a bit.

Most likely, I'll just brave the balance uncertainties down the curve of your volume control, because my ears tell me that the Duet's digital control is messing with the sound. I do wish that more consumer power amps (or any) offered input attenuation like some of the pro stuff.

Thanks again for being such a help, Elias.

 

[Scrith]

Also on an gain-related note, I switched my DAC1 USB's attenuation to -30db (from the default -20db) awhile ago because I found that most of my listening was happening at around the 9 o'clock position on the DAC1's volume control. I now listen to it at around the 12 o'clock position, but something seems to be lacking (and I fully appreciate that this is merely a subjective test result). Could one hear a difference between -20db and -30db settings when adjusting for the same volume?

I am using Jeff Rowland Model 201 monoblock amps (set to the default 26db gain).

 

[EliasGwinn]

Quote:

Originally Posted by BitPerfect /img/forum/go_quote.gif On my original DAC1 "classic" I seem to remember those jumper positions being marked, but not on the Pre, unless my eyesight is failing.

The marking is actually below the jumpers, just beside the XLR connector. It's tucked away...thats why I thought I'd ask you to double check...but it apparently you already had!

Quote:

Originally Posted by BitPerfect /img/forum/go_quote.gif Most likely, I'll just brave the balance uncertainties down the curve of your volume control, because my ears tell me that the Duet's digital control is messing with the sound. I do wish that more consumer power amps (or any) offered input attenuation like some of the pro stuff.

Yeah, there is no reason an amp should be built with 28 dB of gain at the input stage. It's detrimental to signal-to-noise ratio. Proper gain-staging means sending the hottest signal possible from one device to the next, and using as little gain as possible.

I would suggest using a passive attenuator in your case. Try to use one that has as little output impedance as possible.

Thanks,
Elias

 

[Scrith]

Well-known high-end audio manufacturer Ayre will soon be releasing a DAC supporting USB input that supports an asynchronous USB mode (via USB firmware licensed from Wavelength Audio, I believe). This asynchronous USB mode allows clock(s) on the DAC to determine the transfer rate of data from the computer, rather than relying on the computer's (inaccurate and jitter-prone) clock(s) to determine the rate at which data is received (and thereby necessitating resampling on the DAC side to overcome this poor timing). This new firmware is particularly interesting because it works with the existing Windows and Mac USB drivers.

I mentioned this a few months ago and haven't heard much about it since then, so I'm wondering if there is any update. Does Benchmark have any plans for a new DAC (or an update to the firmware for existing DAC(s)) that supports this new variation on USB audio data transfer? This evolutionary step seems very important, because it finally eliminates all computer clock related jitter from the source (without providing a band-aid solution like resampling or intermediate buffering).

 

[BitPerfect]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif I would suggest using a passive attenuator in your case. Try to use one that has as little output impedance as possible.

Cool, I'll give that a try then. I see Hosa and others have inline balanced attenuators that are switchable to 20, 30, and 40 dB. Means I'd need to buy two of them. That feeds perfectly into my finely tuned neurotic-audio-obsessive personality. I can lose at least two nights sleep wondering if they're perfectly matched.

No mention of output impedance on most of them, but the amp has 28 kOhm nominal input impedance, and the cables are short, so I should be alright. I'll probably only lose one night's sleep over that one.

Thanks!