2. digital
  3. 164531-156910

DAC as a preamp?

I need a new DAC. I use my computer for volume control, but do not trust it. I want separate volume control. The 90s me would have immediately thought preamp. But since I need a new DAC, my question stands ... DAC as a preamp?
I've posted more info about my system below.
I need some advice on the best way to go about getting volume control for these powerful asp1000 amplifiers. I've read about the high input impedance. I use a computer for my source playing Flac, wav or hi-res audio files. I'm using a very simple dongle Style USB DAC that sounds okay. I have choices, but do not know what my best bet is. For simplicity, it would seem I should just buy a better desktop DAC, such as and SMSL M500 and use the volume control knob on front. Or ANY other DAC with a volume control for that matter. I know I can use my volume control the USB. Provides through the keyboard on my computer. But with amplifiers this powerful, I figure I should have a volume control to prevent issues such as full volume noise blasts, which have happened before when the computer glitches. My second option would be to purchase a regular preamp. This would be the most expensive option, as I would want something at least as good as the Schitt Freya +, and that is $900! I would still need a decent DAC upgrade. This gets expensive with my health issues at hand. The last way I could go, is something like an all tube gain stage. I would still need a DAC, but a simple gain stage kit should only be a few hundred at most. The other two options I can think of, would be the pass B1 buffer clone kit preamp for 150 dollars, but I don't know if it would play nice with a high input impedance of the icepower amp. The most simple and cheapest route, would be be using the Sure digital volume control option. But I do not know how high fidelity that would be. I could really use some help. I've been out of this hobby for about 10 years now. I feel a bit lost and appreciate everyone who has helped so far.
flaxxer

Showing 11 responses by unsound

unsound
7,344 posts
 
OK, enjoy!
unsound
7,344 posts
 
In a recent past post I suggested that one could expect 12 dB attenuation per bit. I posted that in in reference to a recently read report by ESS regarding their “hyper threading” Saber 32 bit DAC. I can’t seem to find that report to offer a hyper-link, This might or might not be specific to that brand’s internal chip algorithm. It might be misleading to suggest this is to be commonly expected. The standard rule of thumb for 16 bit attenuation is 6 dB per bit. Still even with 6 dB of attenuation per bit, with  a 32 bit DAC, there will probably be plenty of bits to spare before bit stripping occurs at critical listening levels with standard output and input voltages.
I offer my apologies if any one was previously misled.
unsound
7,344 posts
 
I suggest trying the DAC direct, you might find the pre superfluous, perhaps even less satisfying than going direct. You might want to confirm return policies and restocking fees for the pre and extra cabling before committing.
unsound
7,344 posts
 
I’m fairly confident that you won’t have issues with the two lower sensitivity speakers, the higher ones might (?) be a bit more challenging. Still, with a 32 bit DAC you’ll have at least (!) 8 bits to spend without worry of bit stripping and each bit is worth about 12 dB of attenuation; that’s 96 dB worth of attenuation before bit stripping occurs. You might not get silence before bit stripping occurs, but the lowest levels will probably be well below critical listening levels. I say give it a try. The speakers will only draw the power it needs to handle the signal. While balanced certainly has it’s advantages, singled ended will be worth trying.
unsound
7,344 posts
 
Only a few R2R's with the extra bits that Delta Sigma have towards volume attenuation. 
unsound
7,344 posts
 
@flaxxer, are they spec’d at 1 Watts @ 1 meter or
2.83 Volts @ 1 meter?
Are those the nominal or minimum impedances?

BTW, the 4 Volt output on the DAC is via it's balanced XLR output, the passive Schitt and buffered First Watt B1 will only accept the 2 Volt RCA output from the DAC. 
unsound
7,344 posts
 
@flaxxer, what is the sensitivity of your speakers?
unsound
7,344 posts
 
@flaxxer, technically the $49 Schitt is not a buffer. A buffer is an active stage without gain. Schitt offers a buffer option on their more expensive units.
Why are you so doubtful? What is the input sensitivity for full output on your amp? 
The standard output of 2 Volts single ended and 4 Volts balanced of your new DAC would work with most amps. The DAC has 32 bits, the highest commercial rez media uses 24 bits, and in practice the maximum number of bits used is 21. One can usually expect about 12 dB attenuation per bit. You'll probably have plenty of bits to spare before bit stripping occurs. Again, if you do need further attenuation you can do so without the redundancy of extra volume controls with attenuators such as the Rothwell's;  
Attenuators (rothwellaudioproducts.co.uk)

unsound
7,344 posts
 
@georgehifi, Would that in turn mitigate the interconnect capacitance concerns associated with passive analog volume controls, allowing for greater choices and useable  lengths for interconnects?
unsound
7,344 posts
 
@georgehifi, would there be less impedance variability with a DAC’s digital volume control than through a typical passive analog volume control?
unsound
7,344 posts
 
Choosing a DAC with with extra bits such as the plethora of 32 bit DAC's available and a maximum output voltage that is commensurate with the input sensitivity for full output of your amp, will give you greater range of your volume control with less chance of bit stripping without sacrificing the power potential you paid for.
If further attenuation is needed you can try something like this:
  Attenuators (rothwellaudioproducts.co.uk)
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