DAC/AMP + Powered Speakers Install Help

[j.yonke]

I have recently decided to upgrade the audio setup on my desktop PC. I decided on a set of powered Micca PB42X bookshelf speakers along with 12" Monoprice Subwoofer. I have been eyeing the SMSL SD793-II DAC/AMP combo and have been contemplating on how I would go about hooking it up. Prior to the SMSL addition I planned on running analog out on the motherboard to line in on the Monoprice subwoofer, and then line out from the subwoofer to line in on the Micca's. I would set the levels on each speaker and then use windows volume for control. The issue I think I am going to have is if I add this DAC/AMP to power some headphones and use the line out to my speakers, when I plug in my headphones sound will continue to come out of the speakers. I do not believe when a headphone jack is plugged into the SMSL unit it mutes the line out.

Can anyone offer some advice to alleviate this scenario? I have not purchased a DAC at this point.

 

[khlae]

For unrelated reasons, I would not use a spdif dac like such on your computer without buying a better digital audio output.


If your speakers/sub will play nice with being switched at the AC socket, you could (ideally) plug them into a timed power control unit that would switch them on and off in the correct order. Alternatively, you could insert a double pole double throw switch that would switch the sub line in between DAC line out and some dummy resistor to signal ground to mute them. A speaker management setup would likely defeat the purpose of buying a DAC in the first place, so thats a third option.

 

[j.yonke]

For unrelated reasons, I would not use a spdif dac like such on your computer without buying a better digital audio output.

Can you expand on that some? I am pretty new to DAC's in general, and assumed digital was digital and a separate sound card with digital out would not help me.

If your speakers/sub will play nice with being switched at the AC socket, you could (ideally) plug them into a timed power control unit that would switch them on and off in the correct order. Alternatively, you could insert a double pole double throw switch that would switch the sub line in between DAC line out and some dummy resistor to signal ground to mute them. A speaker management setup would likely defeat the purpose of buying a DAC in the first place, so thats a third option.

I was hoping for a more elegant solution, haha. Ideally I would like to find a DAC/AMP combo unit that muted the line out when headphones are plugged in.

 

[khlae]

So, the shortcoming with coax/spdif DACs relies on the fact that they recover the clock from the digital signal and most DACs then use that clock. That means that an external DAC with a good clock will typically use the poor quality clock from the integrated sound card, negating some of the benefits you paid for. Given that USB DAC/amps that will be more capable in this area exist at a comparable price point, those will be a better choice.

Yeah, the DAC/hpAmp units that do this are either expensive or less common. The information is a bit ambiguous, but the monitor 02US might do what you want.

 

[|Tch0rT|]

So, the shortcoming with coax/spdif DACs relies on the fact that they recover the clock from the digital signal and most DACs then use that clock. That means that an external DAC with a good clock will typically use the poor quality clock from the integrated sound card, negating some of the benefits you paid for. Given that USB DAC/amps that will be more capable in this area exist at a comparable price point, those will be a better choice.

On a technical level an asynchronous USB DAC would be better but unless he goes HiFimeDIY the DAC will cost more than his entire setup. Jitter isn't the problem it used to be. That DAC the OP listed is probably just fine.

To the OP: I wouldn't recommend that sub with those speakers just due to the fact that the sub probably doesn't crossover the Micca's so the Micca's and the sub will both be playing bass frequencies which will do more harm for the sound than a non asynchronous DAC. You don't generally see this on home audio subwoofers as they are usually used on a dedicated LFE output on a receiver which handles the crossovers. You'd probably have to go to a studio monitor subwoofer to gain that feature however studio monitors are pro audio which expects different gain standard. Also I would not recommend using Windows volume control, you need to maximize signal to noise ratio and not to mention software can override it and next thing you know you've got a blown tweeter. I recommend maxing out Windows volume and putting passive pre-amp between the line out of the DAC and the speakers like these:

Schiit Sys
http://schiit.com/products/sys

Emotiva Control Freak
https://emotiva.com/products/electronics/control-freak

There's cheaper ones aimed at car audio that will work like this:
http://www.amazon.com/PAC-LC-1-Remo...653764&sr=8-3&keywords=passive+volume+control

 

[j.yonke]

On a technical level an asynchronous USB DAC would be better but unless he goes HiFimeDIY the DAC will cost more than his entire setup. Jitter isn't the problem it used to be. That DAC the OP listed is probably just fine.

To the OP: I wouldn't recommend that sub with those speakers just due to the fact that the sub probably doesn't crossover the Micca's so the Micca's and the sub will both be playing bass frequencies which will do more harm for the sound than a non asynchronous DAC. You don't generally see this on home audio subwoofers as they are usually used on a dedicated LFE output on a receiver which handles the crossovers. You'd probably have to go to a studio monitor subwoofer to gain that feature however studio monitors are pro audio which expects different gain standard. Also I would not recommend using Windows volume control, you need to maximize signal to noise ratio and not to mention software can override it and next thing you know you've got a blown tweeter. I recommend maxing out Windows volume and putting passive pre-amp between the line out of the DAC and the speakers like these:

Schiit Sys
http://schiit.com/products/sys

Emotiva Control Freak
https://emotiva.com/products/electronics/control-freak

There's cheaper ones aimed at car audio that will work like this:
http://www.amazon.com/PAC-LC-1-Remo...653764&sr=8-3&keywords=passive+volume+control

What about adding a pair of Harrision Labs inline 100 Hz HP crossovers? Those are reasonably inexpensive, and from what I can tell Harrison Labs is a well respected company. I am not really finding any other subwoofer in that price range with that HP feature.

Thank you for the insight on windows volume control, I really like that Emotiva pre-amp knob. The only real reason I wanted to use windows volume was my keyboard has a built in roller to easily control it, but it looks like that issue can be alleviated with that knob.

 

[khlae]

The Monoprice subwoofer has an integrated crossover.

 

[j.yonke]

The Monoprice subwoofer has an integrated crossover.

I believe that is only a LP crossover and full range would still be sent to the Micca's. Here is what I was thinking by using the line in and line out RCA ports on the Mono price unit. Only other option I see is to just "Y" off the pre-amp to both the Micca's and MP Sub at the same time, not sure if either way has any big downsides.

 

[|Tch0rT|]

What about adding a pair of Harrision Labs inline 100 Hz HP crossovers? Those are reasonably inexpensive, and from what I can tell Harrison Labs is a well respected company. I am not really finding any other subwoofer in that price range with that HP feature.

Thank you for the insight on windows volume control, I really like that Emotiva pre-amp knob. The only real reason I wanted to use windows volume was my keyboard has a built in roller to easily control it, but it looks like that issue can be alleviated with that knob.

Yup that Fmod would work just fine. I forgot about those... Your diagram is how I'd hook it up.