[barrows]

It seems to work for a lot of people.

However, depending upon the source, you should be fine. But if someday down the road, your amp goes bad, it's been wrecked by out-of-bandwith garbage (that a good pre-amp will filter out) being dumped into your amp.

This should never happen with a properly designed DAC.  DACs have analog filters in their output stages specifically to prevent high frequency garbage getting to the next component.  Only a very poorly designed DAC (or perhaps some NOS designs, beware) are going to have the kind of high frequency components which could be harmful to certain amplifiers.  Indeed, most amps will also not be damaged by high frequency components as well.  One would need to have a "perfect storm" of mis matches for this to be a problem, and this kind of problem could also occur with a pre amp as well.
I am not suggesting it could never happen, but almost never, and only with very unusual components.

[konut]

Haven't used a pre for 20 years. Ancient Creek OBH-12 > Bryston DAC1 > W4S SX500 monos> Timepiece Minis. Would love to find a balance attenuator that didn't cost an arm and/or leg.

[geowak]

It seems that if one had a very simple audio system, and could bypass or eliminate un-needed functions/ components and thus keep the signal path shorter, perhaps more pure that this could yield much better sound. There must be many ways to do this now...

[Russtafarian]

I noticed (with my system) that going directly from my Benchmark DAC/Preamp to my amplifier yielded much better resolution, dynamics and clarity. J

Agreed.  Not all DACs have the output stage to pull this off, but the Benchmark DAC2 does.  In my system it drives multiple amps with long cable runs.  It also has two analog (not digitized) inputs for my phono stage and multi-channel source.  Turns out it sounds more transparent with analog sources than my previous preamp. 

One last thing, it's the best sounding digital I've heard in my system.  The DAC2 HGC has been a huge win for me.

Russ

[Hank]

Some guys are taking the analog out of their OPPO BDP105's straight to their power amps for absolute cleanest signal.  Those analog outputs are level adjustable.

[ralpheburns]

I'm using a very nice AMR DP-777 which has tube in / analog tube pre out. Source is Squeezebox touch.

[krikor]

Awhile back I switched from a Cullen modified PS Audio GCC-100 integrated and went directly from my Wyred4Sound DAC-2 into a pair of ClassDaudio SDS-450 mono amps. The DAC-2 has digital domain volume attenuation and with its 32-bit architecture I never noticed any loss of resolution - rather, this combination sounded absolutely fantastic to me.

One important consideration if going to digital attentuation is that you are able to match the gain of your amps to the DAC/Pre. This is easy with the SDS amps since they have a pot for adjusting the amp gain. I simply set them to match the loudest I would generally to listen while running the DAC-2 wide open to minimize the amount of digital attenuation I'd have to employ.

But all was not well in paradise.
The DAC-2 also has a HT bypass which I used with analog preamp for my turntable rig. Seemed like the best of both worlds - DAC-direct for digital sources along with an analog pass-through for my vinyl moods. However, I was never all that happy with the sound of the vinyl rig used in this manner. It always seemed kind of flat, lifeless, compared to what I had previously heard. This was regardless of whether I was using an active or passive pre into the HT bypass of the DAC-2.

Just recently I ditched the DAC-2 and put the W4S mPRE into the mix and BLAMO, vinyl sounded great again! After some digging I came to understand that the DAC-2 achieved it's HT bypass by simply connecting the analog input directly to the output jacks. It does not get buffered in any way, as I had wrongly assumed, and therefore your analog source simply sees the input impedance of the amps. Not usually a problem, but I was using the balanced outputs for my main amps (47K input impedance and the negative leg is simply inactive when using the HT bypass) as well as driving a pair of subs with the single-ended outputs (10K input impedance).

My guess as to why vinyl wasn't making my foot tap was because my analog source was seeing something like only an 8K net input impedance. That's all changed with the mPRE which is fully buffered in/out (100K input), though I will say miss the sound quality of the DAC-2 on digital sources - luckily the mPRE has an available XLR input I can use with a possible new DAC in the future

Up shot of all this - check your amp gain to see how well it matches your DAC/Pre and keep an eye on input impedances if necessary.

[krikor]

Agreed.  Not all DACs have the output stage to pull this off, but the Benchmark DAC2 does.  In my system it drives multiple amps with long cable runs.  It also has two analog (not digitized) inputs for my phono stage and multi-channel source.  Turns out it sounds more transparent with analog sources than my previous preamp. 

One last thing, it's the best sounding digital I've heard in my system.  The DAC2 HGC has been a huge win for me.

Russ

And as I learned, they may have the output stage needed for your digital source, but not perhaps for the analog source. Though twice the price, I'm wondering if the Benchmark HGC might have been a smarter move for me than the W4S mPRE since it would have given me great digital (DSD to boot) along with a great analog pre.

[cloudbaseracer]

I am questioning the benefits of this at this time myself.  I was pretty well convinced that I could eliminate a piece of gear by getting a DAC with built-in pre functions but everything I read now seems to point to the use of a high quality pre improving the sound. 

Even the manufacturer/designer of the Auralic Vega says that his unit is better with a pre in the mix in this review -- http://www.6moons.com/audioreviews/auralic5/3.html  --

"The ES9018 is a true 32-bit DAC with true 32-bit volume control. It won't compromise dynamic range like the earlier generations of digital volume controls did. Mark Mallinson already gave a detailed explanation of it in your prior Invicta review but I'll add a few things. First, to fully use the ESS volume control, the analog power supply of the chip must be an ultra low-noise design or the chip itself won't exhibit ultra-low noise. That degrades dynamic range. That's why we revised the DAC's analog power supply five times. Only the final version exhibited the extremely low noise which met our requirements. Such low-noise circuit design is very costly. Second, the post-DAC analog circuit too must be an ultra low-noise design or dynamic range in the preceding DAC is compromised yet again. To meet this requirement we changed the I/V and low-pass filter opamps from LM4562 to OPA1612. The latter's price duly tripled. In the final analysis I don't believe that current digital volume, even ours, compares to high-end analog types. But it's already superior to most ordinary preamps. If you're seeking true high-end sound or very steep attenuation rates, you're still better served with a well-designed analog preamp. Our Vega/Merak combo is deliberately based on the simpler-is-better paradigm for the highest possible value.

So at this point I am back to researching the highest quality pre I can get that is reasonably priced.  I keep going back the the Parasound JC-2 as I have heard nothing but stellar reveiws on this piece.

Cheers,
James

[geowak]

When I purchased the Benchmark USB DAC1 some years back, it was the single biggest improvement in sound quality I had made to my humble HiFi system. It was also the most versatile and useful component I had to use. The newest DAC has to be tremendous, if it is as good as mine. Not knocking W4S or any other DACs on the market. It just seems to me that one knows how good it will be if a Benchmark DAC is added to a HiFi system. IMHO

[firedog]

I'm using my Mytek 192 DSD DAC as a pre, using the analog volume control. I think it sounds fine. I've used a couple of modest audiophile pre's (Musical Fidelity pre and a Goldpoint Passive Pre), and run the DAC to them just as a DAC. I didn't find an improvement.

I also tried a control power amp (Amp with an Alps volume control, basically a power amp with a passive pre built in)
and also didn't think it sounded better - either used with or without the power amp volume control being used.

So my conclusion is that I'd have to get quite a good separate pre (say something costing $2k or more) to beat the pre in the DAC.

I'm about to get a new power amp, so I'll do the experiment again. My conclusions may be different this time.

Not to insult anyone, but I think some (note some) people who prefer a pre actually prefer colorations introduced by their pre. When they hear the system uncolored, they don't like it. I also think this is true in my case, as Mytek says the digital volume control measures better, but pretty much everyone prefers the sound of the analogue volume control.

But I also believe there are some really good preamps that don't color the sound and improve the system they are in. I'd tend to agree with the manufacturer's quote above "If you're seeking true high-end sound or very steep attenuation rates, you're still better served with a well-designed analog preamp". But I think that means truly high end, which costs big bucks. I wish I could afford to try some really high end ones.

As for the future, I think we are headed for Direct Digital amplification and the end of preamps as we know them. To be good, such amps will have to have a high quality analog out section, but in another 5 or 10 years I think direct digital will own a good chunk of the high end amp market.

[DaveC113]

It definitely depends on the associated equipment and whether gain or buffering is needed.

You used to NEED a preamp to be able to have enough voltage to drive an amplifier, but these days most amps have <2V input sensitivity. So, gain is usually not needed and in fact is detrimental. A zero gain buffer that can better match the impedance of the amp and drive cables may improve the sound though... so IMO most people are better served looking into zero gain tube buffer rather than an active preamp with gain.

In my system, I tried direct to amplifier vs. using an active pre, and my system sounded better with the pre, but it's a diy Aikido that cost about $1k just in parts and uses a high quality stepped attenuator. Then I tried pre >amp with the driver stage of the amplifier bypassed because I didn't need all the gain... This ended up being FAR better than running the amp by itsself, but left me with an amp with about a 15V input sensitivity so a preamp is actually necessary.

[geowak]

Yes the JC preamps from Parasound are very, very good. But you pay the price for this as that line ofvthe Halo series is expensive. I'd like to get the JC preamp and the JC mono amps, but I'd have to trade in my car and bike to work everyday!

[Russtafarian]

Not to insult anyone, but I think some (note some) people who prefer a pre actually prefer colorations introduced by their pre. When they hear the system uncolored, they don't like it.

This is definitely a factor with DAC preamps.  I had to get used to the sound of my system with the Benchmark DAC/Pre in place.  Some of the colorations I like weren't there any more.  I thought about hanging a tube buffer stage on the output of the Benchmark, but decided that would be like my cat rolling in the dirt after a bath.

I've done some tube rolling in my power amps and XO tweaking with my subs to to reemphasize some of the tonal colors I like.  Another option I've been playing with is a tube saturation plug-in in Jriver.  When used subtly it adds a nice touch of tube bloom to the sound and can be turned on and off as I please.

The new combo gives me all the advantages of a super clean and resolving source with a few hints of tonal color to give me what I like.

Russ