Do preamps enhance (beautify or improve) sound quality?

Does putting a preamp between a DAC and a power amplifier improve the sound?

I know one firm who sells preamps that insists it's so (...really good at talking to camera, but why put an old signal generator on top of a bookshelf speaker?)

If the DAC and amp match within IEC61938, and the interconnect isn't pants (or snake oil), then you're getting the best sound quality from that pairing you're ever going to get.

Unfortunately, people who say that today are burned in the wicker man or at the stake of hi-fi-fo-fum... etc.

All audio circuits except for the simplest - a piece of suitable wire - inflict their own character on the sound...

It's called distortion, noise, frequency response and phase lag or lead at sensitive frequencies.

What you can do (as a designer) is manipulate the sound using these destructive characteristics, to give the sound what the reviewers love to write about, which is nouvelle cuisine and wine tasting. And that's what shifts carloads of boxes, and makes you rich - provided you know what the reviewer's sweet spot is, and that's often more to do with anything but the truth.

But, you can also do that with tone-controls, but then the customer is in charge of the results, and that brings in unwanted variables - each will sound different due to taste and will not work well for social media thumbs up(YouTube).

And that's what killed off real high fidelity - shtum.

Hey guys! It's dead. You can stop killing it now. What? You're not listening. OK then, you guys win. Enjoy the moolah.

I recalled a designer introducing valve or other into the CD player to offset the electronic tone and some now use " plug In " software capsule to return the tonal effect to a more palatable natural sound.

Then there is the high output of CD /DAC  players that accentuate the "bright glare ".  I see from my less than knowledgeable perspective, that even the new generation brought up on Digital electronic computer generated sound who have lived to hear a Saxophone or Contre -bass or Violin in a live set Up and then return to their CD player to be dismayed, the " feeling or emotional content' is not there in it's vivid content. 

I see a Pre -Amp necessary to attenuate the CD ' output and yes Music is Created in a medium of Communication and it's authenticity and originality is the value of the ' Art" . But , the artist and his " piece of creation ' is under the spell the Sound Engineer and electronic  Mixing Console among much hardware and Software before it reaches the Listener in appreciation of the Creation. But listening to a specific piece of music on different " audio system" provide a different take or taste and the Listener consume according to the " Perception" he chose or has develop in his Psychy and if as mIne in Acoustic instrument tone and wooden timbre enclosure instruments ....would accept a Pre-Amp that returns the natural tone or relieve the digital tone. But there are " Pre Amp" and today's world know it as " tone re - Processors" 

I did a phase filter about 20 years ago using "all pass" filters, because all pass filters are for shifting phase.

They sometimes get used to shift phase by 90 degrees between two channels for low leakage hearing aid loops. Another novel feature is the true mono converter, which I believe was used by some AM mono broadcasters, which made the centre information 3dB less powerful, and sounded more "natural" than the commercial stations with their a+b/2.

Anyway, because of the large phase shifts of elliptical filters in early DACs and CD players, the highs would lag by upwards of 270 degrees or double that.

If the turnover frequency could be identified, then the all pass turnover could be tuned to the same frequency, and at some point would equate to 90 degrees, and if you add that to 270 degrees, you get 360 degrees (or 720 degrees), which is also zero degrees. Instead you get a time lag instead of a phase lag.

It seemed to "improve" the sound by reducing harshness, but with alterations to analogue filters, there was no mileage in it, so ended up down the memory hole.

Anyway, this is my opinion of the hi-fi industry giants...

Hi-fi-fo-fum,

I smell the wallet of an audiophile,

Be he alive, or be he deaf

My library of music is some 40  audio cassettes tapes, 100 Vinyl records and 200 Cd's and over byte full of 24 Bit download and apple music. 

The industry has established the " RIAA " equalisation for Vinyl replay in Pre-Amp and is well accepted and refined. CD''s was Philipps Data storage medium and tentatively to introduce in audio replay. It took over domestic home audio set up. But I kept my Record player and Cassette heads and successive generation of  new develop electronic Filters to the Digital to Analogue Conversion left me with a software or "app " to apply more analogue to the CD DAC output.

I could not do much to the Industry mandate CD' /DAC Red Book implications but I can to the AMP and it must be ANALOGUE and Transistor derived from Valve genetic. Now, if I can attenuate the CD output with a Transistor Pre amp ....the digital glare is dead and Music restore i n it's authenticity and creativity and emotionality. My Proprious and 70's design was not read in a glossy Invitation pamphlet to AUDIO Fair in London or Birmingham or Cologne but my distinct assessment of the components and design to hear Music.

  

Thanks Graham. Sadly it is right on the money!

If I was a you-tuber, which I'm not, I could sit with the £25K APx525 audio analyser behind me (the one with the BW52 and AG52 where "power amp designers have the best analyser in the world for testing overshoot, undershoot, and ringing in the device under test" according to AP).

I could have my laptop running (the old V3.4) software, and show you all the BS you'll see on ARSE.

But no. I'd show you reality, because if you'd used audio analysers since 34 years ago (including Lindos and Neutrik), your mindset isn't set up to cheat.

I could set the APx525 into loopback and show you how wonderful a piece of wire is!

Then, if I had a selection of those so called wonder preamps, I could show you how every single one is inferior to a piece of wire.

If I had the time, money, and inclination, I could clone what some of the "great designers" (in their own opinion) say is perfect, and show the high frequency triangular waveforms which show the poor slew rates, which they equate to the best hi-fi sound.

Under the video you would see lots of dislikes, and in the comments you would see lots of trolling. The reason being that all those wannabes who are earning the big money out of YOU, would want the YouTube search engine to relegate my video so it wouldn't come up in search results...

...very similar to the way this entire website doesn't show up on page 1, 2, 3, 4 etc, in organic search, unless you use my name as your search term.

The truth died many years ago. The rot started in the 1970's, and if you don't believe me, then search for Jim Lesurf of Armstrong in your favourite search engine.

 But there is an inherent technical electric Output value that distort in CD and offering a Menu to suit music taste is recognition of that CD's  deficient sound. I attend north and south London musical venues to refresh my experience of true music and convince that Home music replay is distortion BUT feel to be wise enough to seek Genera/GOld V for the RIAA equalisation I enjoy with my Thorens turntable as other with different would sound very different and I chose Proprius and 70's to replay my acoustic base Music library of CD's because other sound very different and Not to taste .....I would accept the change of tone if my Music Psychic perception or actual experience from my ears to my brain provide the emotional experience i seek in Music.  

CD's has an Inherent difficulty in it's Electric output value and it's Tone. I will accept any "wire" that rectify this to a moire natural acoustic in better musicality. 

At this point I am absolutely convinced that the big manufacturers sometimes trawl the high traffic forums for ideas and buzzwords to imitate and regurgitate. On these high traffic forums, certain fads come and go as anyone who has looked at them for years will notice.

A certain fad was emerging maybe three years ago. You'd have forum members repeat certain buzzwords for this fad and sure enough, a very large manufacturer starts making something right in line with the fad complete with the same buzzwords.

I found out about it because the large online/catalog shop I buy record cleaning fluid from stocks products from this company and uses their cut and paste ad copy. In that the same catalog there are number of dubious claims about totally different products as well. I usually thumb through the catalogs quickly before throwing them in the trash.

Phase and loudness go together. It seems like very few know this. They should know it if they understood speaker basics. At high frequencies if you are off-axis the volume is lower, yes?

So what is the phase? If the power is -3dB, you should be off-axis by 45 degrees.

Now, here I'm talking about a natural situation. Some speaker manufacturers may manipulate things so the above doesn't happen.

But, basically the 45 degree thing produces a halving of power, and that's how stereo images work, and lots of things in the recording studio work that way. One example being the constant power pan circuit.

I'm sure in nature too, if your head is turned 45 degrees, the sound that was head on or side on will be + or - 3dB to what it was.

So, if the digital cut frequency that turns over at -3dB is not 45 degrees out of phase, then it isn't natural.

And most DAC (or CD) outputs cut steeper such that -3dB is far higher than 45 degrees.

If we dare to make a DAC that doesn't start to cut before 20kHz, and then its rate is gradual enough that -3dB is going to be 45 degrees or very close to it, then it might sort out that unnatural digital sound?

Well, the only way to do that is to use the highest oversampling possible, to shove the sampling frequency much higher than it usually would be.

And then once we're well past the human hearing range, we can then cut hard, such that the phase displacement doesn't make the -3dB point steeper than 45 degrees.

So, that's how the Majestic and Bitzie analogue filters work, and I think that most users have noticed how natural they sound.