DS direct to power amp vs. a preamp in the path


#1

Hi all,

In the past, I have experimented with a few pre-amplifiers in my system, including some highly regarded passive, tube and SS ones. The clear winner for my system so far was a passive pre-amplifier, a ~$1K, with upgraded parts including a $400 P&G volume pot.

A few days ago, I decided to try and bypass everything, and hooked up the DS DAC directly to my amp. The result was such a mind-blowing improvement in all aspects of sound, that I now seriously question how can adding anything in the signal path improve things.

I started a thread on Audiogon in which one of your dealers mentioned that Paul McGowan said that the new BHK pre-amp will sound better than hooking up the DS direct to amp.

Since I will be using the same output from the DSD, I would like to understand how come adding an active component, more cables, RCA connectors, solder points, etc to the signal path can make things ‘better’, in the true “High Fidelity” sense.

The only thing I can think of is matching gain / impedance, but if that is not an issue with my setup, why would I want to add anything in between?

Thanks for your thoughts.

Ami


#2

In reality all that adding additional components into the signal path (if the output stage in the DAC is already competent enough to drive the amp) will achieve is simply a different coloration profile. For some people this can be subjectively preferred.

If the sound is more beautiful from the analog outs of the preamp, than was it was at the inputs, I can assure you this wasn’t from the original recording :). However there’s nothing wrong with this. After all this hobby is subjective. Whatever sounds best to your ears is the only thing that matters.


#3
ami said I would like to understand how come adding an active component, more cables, RCA connectors, solder points, etc to the signal path can make things 'better', in the true "High Fidelity" sense.
This is the $64,000 question. Many experienced listeners -- including Paul himself in Music Room 1 -- have found improved sonics when a preamp is added. Others prefer the DS straight in their amps. The topic has been discussed at length here and the consensus is that nobody really understands why adding the additional components improves the sound; logically it shouldn't. All you can do is try it in your own system.

#4

It’s simply due to a different “voicing” that can easily be preferred subjectively. With DAC’s most of the voicing is done in the digital domain with filters. In preamp’s, this is done in the analog domain with transistors and tubes. If you want to engineer a preamp that people enjoy listening with a wide variety of sources, and you want a wide audience to like how it sounds in their systems, it usually pay off to purposely “sweeten” the sound a bit. This is how 95% of all “audiophile” gear is engineered.

Studio gear is a different story. Since the job of studio gear is to get the sound from point A to point A leaving as little sonic signature as possible on the audio. However when used at home, and compared with purpose “voiced” audiophile gear, one can easily mistaken this transparency as “dry” or "cold.


#5

Thanks for your thoughts.

A subjective preference can’t really be challenged.

I’m now very happy with my DS direct to amp setup, and will just connect my phono stage (a modded GCPH) when I listen to Vinyl.

Maybe in the future I’ll experiment some more with the BHK or others.

Have a wonderful weekend,

Ami


#6

I feel comfortable with this reply from Ted Smith…

http://www.psaudio.com/forum/directstream-all-about-it/directstream-as-pre-amp/

"There are two issues that come to mind: gain (which has already been mentioned) and the other is cable capacitance.

With respect to gain, there’s a “best” sensitivity of amp to use with the DS direct: you need enough headroom to have dynamic music (even on your louder tracks) but also enough sensitivity that you aren’t using the volume control far from 100 a lot of the time. Obviously if your music collection has tracks that are significantly different in loudness or dynamic range or if the amp isn’t sensitive enough or is way too sensitive you’ll probably want a preamp.
With cables that have too high of a capacitance there are FR response issues with almost any source. With most sources high capacitance implies a high frequency rolloff, but at times the transformer output of the DS can interact with cable capacitance to add a little high frequency boost. In an already existent system that already has high capacitance cables but is otherwise balanced changing from some other DAC to a DS may make quite a difference in the very top of the audio band. Either a rolloff or a boost of the highs could be beneficial in some setups, but in general, average to lower capacitance cables will be better with the DS or you’ll need a preamp to drive/buffer a higher capacitance or long run cables after the DS.
My counter argument to the minimalist point of view is that “Why should you expect a $6000 preamp in a $6000 DAC for free?” We don’t always build our systems from whole cloth where we might have the opportunity to find a set of components with no interface issues: a preamp is a good thing to have on hand for the cases where other factors like gain mismatch or cable length or… get in the way of a well balanced system.
Given a particular amp the DS could be designed so that you probably wouldn’t want a preamp – and similarly given the DS an amp could be designed so you probably don’t want a preamp, but in real life, as all things in audiophile land, you’ll need to listen for yourself to different setups and make up your own mind."


#7

A great analogy is, I consider myself a real purist when it comes to fine AAA Prime, dry aged New York Striploin steaks. Some real purists would say steaks of this caliber should be eaten without even a dash of salt and pepper on them, let alone steak spice and BBQ sauce. Others might marinate them in beer, wine and BBQ sauce and like them even better. Me personally like just a dash of salt, pepper and garlic.

Who’s right or wrong? Nobody, we’re all right. Because we’re all human :slight_smile:


#8

I can’t personally speak to the purity of the BHK preamp, but the BHK monoblocks sound quite similar to my sand amps that I purposefully chose just because of their neutrality. I suspect that Bascom went for the same neutrality in his preamp. FWIW there’s no voicing in the filter design of the DS. There are choices guided by experience and theory but not tailored for any particular sound.


#9
Ted Smith said I can't personally speak to the purity of the BHK preamp, but the BHK monoblocks sound quite similar to my sand amps that I purposefully chose just because of their neutrality. I suspect that Bascom went for the same neutrality in his preamp. FWIW there's no voicing in the filter design of the DS. There are choices guided by experience and theory but not tailored for any particular sound.
Yes this is why some prefer going though a preamp. Because you built the output stage in the DS to be as transparent to the source as possible. However some prefer to view life through rose colored glasses :)

But this is fine! No different than pressing the magic wand to enhance photos on the iPhone. If the end result is more pleasing for you, then it’s the best choice for you :slight_smile:


#10

Agreed.

But now I need to talk to someone with an iPhone and obtain a demonstration of the magic wand.


#11
Mivera A said A great analogy is, I consider myself a real purist when it comes to fine AAA Prime, dry aged New York Striploin steaks. Some real purists would say steaks of this caliber should be eaten without even a dash of salt and pepper on them, let alone steak spice and BBQ sauce. Others might marinate them in beer, wine and BBQ sauce and like them even better. Me personally like just a dash of salt, pepper and garlic.

Who’s right or wrong? Nobody, we’re all right. Because we’re all human :slight_smile:


That analogy doesn’t really work for me, I’m a long time vegetarian. :slight_smile:

#12

I vastly prefer fresh tofu to fried. Perhaps this is akin to the purist view.


#13
ami said
Mivera A said A great analogy is, I consider myself a real purist when it comes to fine AAA Prime, dry aged New York Striploin steaks. Some real purists would say steaks of this caliber should be eaten without even a dash of salt and pepper on them, let alone steak spice and BBQ sauce. Others might marinate them in beer, wine and BBQ sauce and like them even better. Me personally like just a dash of salt, pepper and garlic.

Who’s right or wrong? Nobody, we’re all right. Because we’re all human :slight_smile:

That analogy doesn’t really work for me, I’m a long time vegetarian. :slight_smile:


Okay perhaps organic vs laced full of chemicals would be less euphemistic than my prior analogies? :slight_smile:

#14
ami said Hi all,

In the past, I have experimented with a few pre-amplifiers in my system, including some highly regarded passive, tube and SS ones. The clear winner for my system so far was a passive pre-amplifier, a ~$1K, with upgraded parts including a $400 P&G volume pot.

A few days ago, I decided to try and bypass everything, and hooked up the DS DAC directly to my amp. The result was such a mind-blowing improvement in all aspects of sound, that I now seriously question how can adding anything in the signal path improve things.

I started a thread on Audiogon in which one of your dealers mentioned that Paul McGowan said that the new BHK pre-amp will sound better than hooking up the DS direct to amp.

Since I will be using the same output from the DSD, I would like to understand how come adding an active component, more cables, RCA connectors, solder points, etc to the signal path can make things ‘better’, in the true “High Fidelity” sense.

The only thing I can think of is matching gain / impedance, but if that is not an issue with my setup, why would I want to add anything in between?

Thanks for your thoughts.

Ami


Thanks Ami and it’s a great question. In my experience, most preamps get in the way of the music and DirectStream direct into the amp is by far the preferred method. I’ve done this and preached this for years.

But it has been pointed out to me that the addition of SOME preamps, very few of them, actually improves the sound - like the Aesthetix Calypso, like the BHK Signature. The opinions on why this might be true run the gamut. I can’t say I fully understand it. Heck, I can’t say I even partially understand it, though I have some ideas.

My friend Arnie puts forth the notion that despite DirectStream’s bit perfect volume control, it still sounds different when used as a level adjust - a claim I have never verified and up until the discovery of a few preamp’s that made such a wonderful improvement, I can’t say I would have ever even given it a second thought. To be honest, I can’t hear the difference on DS when the level’s changed, at least in the top registers of its range. But, it’s a theory.

Still others suggest some DACs benefit from short interconnects - and if the preamp’s transparent enough, its active addition is less harmful than the added length of cable usually needed - or the interaction of the cable and DAC - though one can sure poke a bunch of logic holes in that argument. A preamp’s input looks remarkable identical to an amp’s input.

Truth is, I don’t know. What I do know is what I have said. DirectStream into the power amplifier directly is always preferred - unless you have one of a very small handful of preamps.


#15

“Truth is, I don’t know. What I do know is what I have said.” -PMcG

Refreshing, in this business.smile


#16

Hi Paul,

You said, “DirectStream into the power amplifier directly is always preferred”. Could you list a couple of examples of amps you used this way? I really want to try this. However, when I connected my DirectStream Junior directly to the amp section of my Luxman L-505u int amp (bypassing the preamp section), the noise floor was much higher. Not sure why.


#17

In this case you want to engage the attenuator and reduce the gain of the DSJ. This can be done through the setup menu.

DSJ has a lot of gain and going direct into some amplifiers, speaker systems, can raise the noise floor - which is why we added the output attenuator.

I have gone direct into our own amplifiers for years - and that of Audio Research and Sonic Frontiers too. I don’t have an opportunity to experiment too much with different amplifiers, but most are about the right sensitivity that I have. I also have the experience of many customers who have different setups than me.


#18

I too have recently experimented with the DS direct to my amps, and have determined that my preamp was definitely masking stuff

Thinking back, the primary purpose of the preamp (tube) was to take the edge off earlier iterations of digital reproduction, as well as provide an analog path for my vinyl and tape collections.

Although I’m loathe to admit it, I rarely listen to vinyl or tape these days – Tidal provides access to stream able versions of much of my analog collection, and Roon makes the stuff easier to locate – so, I’m looking at simplifying my system. I’ve ordered a Nu Wave preamp, which will replace $10k worth of phono preamp / main preamp.

Lets hope Nu Wave is up to the challenge!


#19
Paul McGowan said In this case you want to engage the attenuator and reduce the gain of the DSJ. This can be done through the setup menu.

DSJ has a lot of gain and going direct into some amplifiers, speaker systems, can raise the noise floor - which is why we added the output attenuator.

Paul – I run the DSJ straight to my power amp (Peachtree 220) via balanced XLR cables, if I “engage” the attenuator, I don’t get enough volume, therefore, I have it set to “off.” I just want to confirm I understand your suggestion above…am I doing something wrong, or is my lack of volume when the attenuator is “on” due to the type of amp I’m using? Thanks…

Todd Harris


#20
Paul McGowan said

I have gone direct into our own amplifiers for years - and that of Audio Research and Sonic Frontiers too. I don’t have an opportunity to experiment too much with different amplifiers, but most are about the right sensitivity that I have. I also have the experience of many customers who have different setups than me.


Hi Paul,

What kind of sensitivity spec I should look for in an amp if I want to run it directly with DSJ?

Apparently, my Luxman int amp L-505u when used as an amp only is not a good candidate since the higher noise level does not go away even with DSJ attenuator on and/or ground lift. The L-505u spec is copied below. I am using Focal Sopra No 2 speakers which has a sensitivity of 91dB and minimum impedance of 3.1 ohm.

Power output: 100 watts per channel into 8Ω (stereo)

Damping factor: 110

Input sensitivity: 0.3mV (MC), 2.5mV (MM), 180mV (line)

Signal to noise ratio: 75dB (MC), 91dB (MM), 105dB (line)

Output: 180mV (line), 1V (Pre out)

Speaker load impedance: 4Ω (minimum)