This is often a frequently debated question. As with most things the correct answer depends on the context. I came across the video listed below which provides the best answer(s) I have heard. In the case of Cascade users, with high input impedance amplifiers, the answer is clearly no unless you’re looking for tube “warmth” (i.e. second order harmonics).
I have the Discrete DAC, and I have been reliably informed that the digital volume on this DAC is very transparent. So, my question would also be if a preamp is necessary in my system which is solely digital at the source front-end. Not sure though how much attenuation there would be on the Discrete digital volume in terms of resolution and signal integrity, and from what level on the volume is safe in terms of attenuation.
Robert Harley, of The Absolute Sound, in his book writes that if a DAC has a digital-domain volume control, one should consider running it at 3dB of attenuation rather than at maximum level. Although attenuating the volume with a digital-domain volume control theoretically reduces resolution, most digital filters sound better when not processing full-scale signals. The very slight reduction in resolution is more than made up for by the greater sense of ease when a few dB of attenuation are applied. Presumably, this would apply when hooking up one’s DAC to a preamp or integrated amp. Interested in knowing if this would also apply to the Discrete DAC, given that the low output setting already has 6dB of attenuation.
I have a Cascade, pulled my preamp out, never looked back. If you have enough gain there’s never a reason to have a preamp unless the rest of your equipment needs some editorializing in some way.
I suspect there are many different answers to this question depending on what DAC/Pre and other equipment one has.
I recently tried my Premier + Digital Director direct to my Block Mono amps. The system was very clear with more direct/forward energy.
I prefer my Premier connected to my Block Line Stage as the sound is equally detailed but more relaxed and flowing. Not as direct and in my face.
One man’s experience.
In the end I don’t think there is a single sound goal (the absolute sound) that we should all chase. Instead we pursue our personal preferences. That’s a good thing. It’s also clear the preamp adds to the sonic signature beyond what is portrayed by the music file via the DAC.
I like this video a lot, but there are two important issues it does not address. First, most amplifiers these days have too much gain. This is especially a problem when paired with highly efficient speakers. Using only a digital volume control with a high gain amplifier usually requires throwing away a lot of dynamic range in the DAC to bring volume levels down to listenable levels. Some form of analog attenuation is usually warranted, even if it is just a pair of passive XLR attenuators sized to allow the digital volume control to operate towards the high end of its range. The MSB DACs with digital volume control have a feature like this built in via the selection of high or low output mode. Nice.
The second unaddressed issue in the video is a lot of people have amplifiers with way more power than they need. So saying It is ideal for the DAC’s maximum voltage output to equal the amplifier’s input sensitivity required to produce full power is not always correct. The DAC only needs to produce enough voltage to reach the desired SPL level given the amplifier, speakers, and listening distance. This will again allow the DAC’s digital volume control to operate in its ideal range. Yes that means the full power of an oversized amplifier will not be usable, but that is the better trade off than excessive digital attenuation.
I used the digital volume control in my Discrete DAC for a few years. I eventually added a preamp back into my system because the variability in recording levels and my desired listening levels created a need for a wider attenuation range than is ideal for digital volume control. I believe a good preamp is better suited to deal with a wide range of attenuation.
I do have a system with 95db speakers, and 100 watt amps. I found the volume control in both my prior Bricasti, and the MSB Premier, to decrease SQ too much. The sound was deadened, or less energetic.
I helped my problem 2 fold: I got a tubed Pre, and inserted attenuators right before the amp input. At some point, I will get the Pre modified to lower gain. (Manufacturer changes a couple of resistors)
Now, I’m sure that the upper level MSB DACs have a better preamp section than my Premier sports, but even the Premier, with correctly matching amps, and speakers can be wonderful. As I use my turntable for about 50% of my listening, I need preamp input switching, and the Cascade is not currently in my budget.
I would agree as I believe the Discrete uses a digital volume control unlike the Cascade which is analog.
Discrete and Premier have digital volume control, Reference “basic” the same, Reference with preamplifier module and Select have analog volume control (and also very sophisticated: with constant impedance!). Of course the Cascade has analog volume control…