DAC straight to amp

[svtcontour]

Hi all, so for years I've used Jriver to drive a dac connected to a power amp but I'm often told that I'd get better results using a preamp. To me it seems the less stuff in the chain, the clearer - in theory, the sound. If I dont need any additional gain of a pre or have no need for more inputs, is there any reason a dac to a preamp then power amp might be a better option?

 

[jasonhanjk]

If the dac can drive 10k ohm with THD+N 0.0005% and below. Don't use a pre amp.

 

[JSmith]

If I dont need any additional gain of a pre or have no need for more inputs, is there any reason a dac to a preamp then power amp might be a better option?

Not really, especially since you don't require additional gain or further inputs. One needs to ensure the pre-amp is not adding further noise and distortion to the chain though, otherwise that will be added to the signal and amplified.


JSmith

 

[Blumlein 88]

Nope you don't need one. A good preamp might be transparent, but it won't improve the signal. If you don't have any other sources, then a pre-amp isn't doing anything for your sound quality.

 

[svtcontour]

Awesome, thank you all. Its confirming what I'm already thinking. Maybe people are just used to having preamps with power amps and see it weird without it

I flip between two DACs - the Gustard X16 and the Denafrips Ares II (which has a high output impedence) and I drive a Ramsa WP9220 power amp then to a pair of DIY open baffle speakers. Love it so

 

[Kijanki]

Less is more I agree, but preamp often drives power amp better (lower output impedance), while preamp's volume control is likely better quality.
I use Benchmark DAC3 directly to AHB2, but somebody with exactly the same setup inserted high quality Benchmark's preamp and reported better sound.

 

[JSmith]

reported better sound

What comparison controls were used... sighted or blind? Generally this is attributed to a slightly differing volume and when level matched those differences may disappear.


JSmith

 

[Kijanki]

What comparison controls were used... sighted or blind?

I don't remember. It was on Audiogon forum a while ago. I remember only that he was very satisfied with the change. Benchmark DAC3 with digital source has digital gain control, but with analog source it uses tiny ceramic pot. Benchmark LA4 has 256 0.5dB step relay gain control (40 relays + precision metal film resistors).

 

[JSmith]

I don't remember.

Fair enough, sorry I misread and though that was your experience.

It was on Audiogon forum

I see...

I remember only that he was very satisfied with the change.

Sure, however this isn't really anything helpful for the OP is it?


JSmith

 

[Holmz]

Less is more I agree, but preamp often drives power amp better (lower output impedance), while preamp's volume control is likely better quality.
I use Benchmark DAC3 directly to AHB2, but somebody with exactly the same setup inserted high quality Benchmark's preamp and reported better sound.

True, so we need to know the output impedance of the DAC and the input impedance of the pre.

If the DAC is adjusting gain by chopping off bits, then a pre may also be better.
So we are blind without some further details.

 

[Kijanki]

Sure, however this isn't really anything helpful for the OP is it?

It is. It shows example of inserted component that made positive sound difference, even if only for one person, not to mention that inserted component might add pleasant coloration - not my cup of tea, but many people like it (for instance, "warm" sound). As for blind tests - I don't find them useful. While switching between different speakers in store I found them different but couldn't make decision, since they sounded different with different music. For me the best would be to take them home for long listening session to determine how I feel overall about them - hard to do with blind test. Constant switching between them is just confusing to me. YMMV.

 

[Kijanki]

So we are blind without some further details.

Agree. There so much gear available that we need to know/expect something to make educated decision even for the trial only.

 

[JSmith]

It is.

Sorry I disagree that one persons random subjective comment holds any weight whatsoever... YMMV.


JSmith

 

[Holmz]

Agree. There so much gear available that we need to know/expect something to make educated decision even for the trial only.

I am talking about specs like output impedance, not some expectation bias.

 

[Blumlein 88]

The Gustard has 120 ohms output impedance for RCA and 350 ohms for XLR. Should be fine if cables are kept reasonably short. Certainly 2 meters or less is perfectly fine. The input impedance on your amp is 40 kohm so not a problem.

The Ares II however has 1250 ohms output impedance on RCA and 2500 ohms output impedance on XLR. You probably are okay here to 2 meters, but ideally want it less or perhaps this is one that might benefit slightly from a preamp. I'd keep it to no more than 2 meters on the interconnects.

SoundStageNetwork.com | SoundStage.com - Denafrips Ares II Digital-to-Analog Converter Measurements

www.soundstagenetwork.com

 

[Kijanki]

I am talking about specs like output impedance, not some expectation bias.

You could go by specifications first, but bias also plays some role here. Many people purposely inserted warm sounding tube pre into cold/flat sounding system to make it sound more to their liking.

 

[Loathecliff]

As for blind tests - I don't find them useful.

Gasp..Uttered on ASR

://m.youtube.com/watch?v=FQ5YU_spBw0

 

[JSmith]

As for blind tests - I don't find them useful.

Well sighted tests are generally useless for many reasons;

The Dishonesty of Sighted Listening Tests

An ongoing controversy within the high-end audio community is the efficacy of blind versus sighted audio product listening tests. In a blind...

seanolive.blogspot.com

JSmith

 

[Kijanki]

Well sighted tests are generally useless for many reasons;

May be useless if you have strong bias. Otherwise I find longer listening sessions more useful. Even double blind study, that supposed to reject null hypothesis, can be flawed if you test biased people. For instance, you test different speaker cables on people who believe that wire is wire and there should be no difference (negative placebo effect).

 

[Holmz]

You could go by specifications first, but bias also plays some role here. Many people purposely inserted warm sounding tube pre into cold/flat sounding system to make it sound more to their liking.

Yeah bias plays a bit role… and a somewhat large role.
That does not make a distorting system a higher fidelity system though.

And adults are somewhat able to own some tube gear, and understand it may be altering the fidelity. It doesn’t require a full black-n-white melt down of cognitive dissonance.

- One can look at a tube preamp and see high 2nd harmonics. And decide to get it.
- And they can also look at one with a high 3rd harmonic and decide against it.
- And they can look at 19 and 20 kHz tones and select a preamp with a graph of stuff poking up at 1 kHz.

However we were talking about if a DAC can serve as a preamp technically.
So we have:
1) Output impedance of the pre
2) Input impedance of the amp
3) Whether the volume is a method of chucking out bits (bit depth) on the least significant digit end.

Technically:
- If #3 is happening, then run a preamp.
- If #1 is abnormally high and #2 is abnormally low, then run a preamp.

Subjectively:
- If likes a preamp, then run a preamp.
- If one wants to spice up the sound, then run a distorting preamp.

I like most of my gear to be neutral, and limit the use of spice to flavour it.
But I do have tube equipment, and likely will be having some Class-D amp relatively soon.