pre-amp vs dac straight to amps

IME, going direct is not a cake walk - it takes work to get right. This configuration is going to reveal flaws upstream. The simple choice of the power cable or interconnect you use on a component will become critical since any anomaly will become very evident and very annoying.

I'd try swapping out cables until I find a configuration that works. At the very least you are going to learn more about your system and the capabilities of your components.

Cm - Based on your observations, it is likely that the current drive from the Alpha is not as good as the preamp. The enabler for DAC direct to amps is the DAC output drive.

This is the reason why most passive resistor-based linestages kill dynamics. They reduce drive current.

Steve N.
Empirical Audio

I have been going back and forth using a Jeff Rowland Capri PM in line with a Berkeley alpha 2 DAC feeding a Modwright KWA 150 SE and the Berkeley direct has greater transparency, detail, air and lower distortion BUT the center fill is oddly thin and the sound is slightly less meaty. To my ears the preamp contributes a subtle layer of fine grain and less clearly defined instrument outlines. It is odd but the straight up alpha 2 is objectively superior at revealing music information yet I still miss aspects of the added noise the Rowland contributes a warm, human character that is compelling. I am truly conflicted.

I have a PerfectWave DAC and a VAC Renaissance 30/30 amp and much prefer it with my VAC Standard preamp in the middle. That being said, there is additional detail without the preamp that works for some music and recordings, but there is also added stridency and edginess that makes it much more unpleasant for others. All in all, I find it more musical with the preamp; also a little bit of forgiveness in a system makes for pleasant listening across a much wider variety of source material.

"for me, it's through the preamp that has lots of bass punch and impact!"

This is because your DAC has a high-impedance output stage. Going direct is superior only if the DAC has strong drive on the output stage. OP-amp outputs usually dont cut-it.

Steve N.
Empirical Audio

mlapenta,

I had to smile when I saw your post.

My experience is exactly the opposite of yours: DAC direct to amps is more "transparent," has better detail, and smoothness—but, for me, it's through the preamp that has lots of bass punch and impact! (Isn't audio—or is that the human mind?— wonderful?)

I suppose, though, that this could be explained by the particular combinations of components used.

[My experience is based, most recently, on the following set-up: DAC is Bel Canto DAC 3.5VB/VBS1; preamps are Bryston BP-26, Allnic L3000A, BAT VK-51SE; power amps are McCormack DNA-500 and DNA-1 SMc Audio Revision Gold; speakers are Tannoy System 15 DMT II and TAD Exclusive TSM-2402 clones.]

No experience—yet—in computer-based audio, but I prefer using a preamp.

First reason is a practical one: I have four source components, one each for CD, SACD, LP, and FM, so I need quick 'n' easy switching from one to the other.

Second reason is that, in my limited experience, it always sounds more "alive" through a preamp (and for me, that means an active preamp).

Now, with audioengr's explanation of the problem—shortage of DACs "with a decent volume control technology"—I understand why.

My expirence has been running my Benchmark HDR 1 feed directly to my Kharma MP150 amps for 6 months, then added a Modwright LS 36.5 Pre. The difference was astounding soundstage, warmth, voices came alive. The Benchmark was cold and thin in comparison not to knock the Benchmark but I'll keep mine as a Dac.

ok, i tried a/b on pre-amp vs direct. I was kinda stunned at the sound direct from DAC to amps. It was so big and in your face, lots of bass punch and overall more "impact" I was glad to hear that human voices did not suffer in this.

However, I do feel there was a slight loss of detail and smoothness in upper mid range so.... still preplexed on which way to commit. new per-amp or passive pre-amp.

anyone try this channel island VPC-3 Passive controller for volume out of DAC? I am concerned that going from a DAC to class D amps (also Channel Islands) will sound to digital? I had liked to believe my tube pre-amp was warming sound?

I'm using my DB audiolab Tranquility DAC direct into my tube power amp. Using the dithering control in pure music serves as volume control. I haven't put my Quicksilver preamp back in my system. Works great.

I'm running my Wadia 121 DAC direct into a Bel Canto amp and it sounds great. Granted, the only preamp I tried in this system was a Rotel RC 995, so I can't comment on how it would sound with a seriously high-end preamp. I do know that Wadia makes a big pitch in the manual not to use a preamp. I posted the exact language in another thread. As always, YMMV.

Greater than 10dB degadation is only with software controlled volume.

Often digital volume circuits in DACs are actually digitally controlled analog circuits. There are many off-the-shelf chips that do this.

Steve N.
Empirical Audio

I have owned and checked out quite a few DAC's and tried them all direct and via a pre-amp. Which is better varies on the DAC and I can find no commonality to give a definite answer - you need to suck it and see.

I personally haven't noticed on the DAC's that are better direct connected greater than 10db volume reduction led to an degradation in quality. I well recall checking this out on a very transparent reference system (using the reference DAC of that system - a PDX which does sound better direct connected) with some very experienced audiophiles and none of us could detect a difference with any amount of volume reduction.

Again my suggestion is to check it out for yourself.

Thanks
Bill

I have used Perfectwave DAC digital volume controls and bel canto, and both are excellent. I took out a 10K tube preamp myself. Waste of money.

I don't know the technical reasons for my own preferences but my pre amp adds a lot to the overall sound I get. I find that the tubes my pre uses are very good at giving my sound big Tone as I call it a certain full rich and lush at times quality that I like. I have owned an ARC pre and found it to be fairly transparent not adding or limiting much. AS always it coimes down to system synergy and personal preferences.

Aside from jitter, preamp distortion noise and compression is the MOST detrimental thing is most systems IME. Elimination of the pre is a huge win.

Depending on how you do this, however, the results can vary widely. I do not recommend using a standard DAC line-out and then using digital volume to reduce the volume. This will degrade the SQ significantly. I have found that more than about -10dB starts to degrade the SQ. Less than that is okay, but this is not enough to use ONLY digital volume. A combination of manual analog volume and digital volume is fine.

So, the next challenge is finding a DAC with a decent volume control technology. In my book there are only two that are decent: Transformer-based attenuation and D/A reference voltage control. Active gain-control and resistive attenuation dont cut-it.

Steve N.

i really wanted to go without a pre and tried hard to make sense of it. in the end....i couldn't. my system sounded better with a well matched pre.

it also sounded worse with a not so well matched pre (i tried a few).

no way around trying it for yourself.....but don't be a one and done. try a few a see what happens. it's all about synergy and working well together....or sometimes not.

Ummmm, may I suggest that you try out the DAC -> Amp setup and see for yourself how it sounds? I connected my Oppo BDP-93 straight into my Butler amp when my pre-pro was being updated at the factory and I found the sound to be surprisingly good.

I no longer have an analog source, so this setup works out quite well for me in a pinch...

-RW-