Adding a pre amp

[diecaster]

7 minutes ago, barrows said:

What you are telling me is that either your amp sounds bad, or your DACs sound bad.  And you are covering up the bad sound by adding more (euphonic in this case) distortions from your preamp.  Do you really think this is the best way to getting the best possible sound?  Would not a better approach be driving an amplifier direct with good sounding DAC, or replacing your bad sounding amp (whichever the culprit may be).

 

Always talking in absolutes you are....everyone else is wrong and you are right. Your position is the only way an active preamp could improve sound quality is if the DAC has a crappy output stage. You are being unreasonable as other industry professionals with more lofty reputations (actually, with reputations) don't agree with you.

 

 

[fas42]

46 minutes ago, Blake said:

My only fear is exactly as you described above.  I have no doubt that if I end up preferring the direct method, one of these days I will forget to attenuate the volume via software, hit play and blow my speakers.  

 

Ummm, I've used software control of volume for decades, and have never had an incident - devices remember your last setting, in general; if you have a party, and leave the hardware volume right up there from that, the same situation could arise. Also, speakers in a good system can take "a bit of abuse", without falling off the perch.

[sandyk]

16 minutes ago, barrows said:

I am curious who these designers are.  most amplifiers I see have higher input impedances.  Although it does not take that robust an output stage to properly drive a 10K input impedance either.  Anything <~100ohms should be fine.  As mentioned there are many DACs which fit that bill (Chord, Weiss, etc)

 I am not across recent designs  from the USA, but many designers will now have taken on board the very worthwhile lessons and improvements detailed by highly respected Audio designers such as Douglas Self from the U.K. and Bob Cordell.

Many recent Power Amplifier designs published by Silicon Chip magazine, where they sometimes boast of the lowest distortion  amplifier designs ever published, are based to quite an extent on  the work of Douglas Self.

Have you seen any of the Douglas Self Audio Power Amplifier handbooks ?

[esldude]

7 minutes ago, diecaster said:

 

Always talking in absolutes you are....everyone else is wrong and you are right. Your position is the only way an active preamp could improve sound quality is if the DAC has a crappy output stage. You are being unreasonable as other industry professionals with more lofty reputations (actually, with reputations) don't agree with you.

 

 

So can you explain how a DAC with a good output stage is improved by a preamp? 

 

You do realize the output stage of a good preamp has the same job as the good output stage of a DAC.  That they often use the same kind of circuitry.  That a preamp may need to compromise on gain or other factors to work with multiple sources in ways a DAC/pre need not do.  

[fas42]

15 minutes ago, diecaster said:

 

I would argue that "analog flavor" can deliver a bigger hit of realism since it often sounds more like what you would hear at real life venues. Every concert and event I have been to that uses amps/transducers (99% of them) presents more color/distortion than I will ever have in my home setup. Heck, our speakers at home have more distortion than a high quality tube preamp/amp combination will produce. Also, high quality tube preamps and amps don't necessarily give up much in detail and even harmonics sound much better than odd. 

 

Well, I hate real life venues like that - in particular, rock music and similar is usually terrible because it goes through PA rigs at the bottom of the food chain in terms of quality. But those sort of recordings can sound magnificent if replayed by a high SQ system ... many people would be flabbergasted by how impressive old recordings can be, when done right ...

[diecaster]

3 minutes ago, fas42 said:

 

Well, I hate real life venues like that - in particular, rock music and similar is usually terrible because it goes through PA rigs at the bottom of the food chain in terms of quality. But those sort of recordings can sound magnificent if replayed by a high SQ system ... many people would be flabbergasted by how impressive old recordings can be, when done right ...

 

I wasn't talking about huge venue events.......that's just noise.

[fas42]

3 minutes ago, diecaster said:

 

I wasn't talking about huge venue events.......that's just noise.

 

Fair enough ... but it's extremely rare  for even the smallest establishments to get it right. In Sydney we have a famous, small spot for live acts, The Basement - plenty of clips on YouTube featuring artists performing there - and the sound reinforcement there is just as awful as all the rest of them ... OK for an evening, to pick up the excitement, and vibe; but falls a long way short of what the artist or group can really sound like.

[sandyk]

18 minutes ago, esldude said:

So can you explain how a DAC with a good output stage is improved by a preamp? 

 

 Perhaps your definition of a good output stage doesn't even come close to that of many other members ?

Very few affordable DACs even use low impedance buffers at their output, and are susceptible to the usual Interconnect vagaries. A friend found that even a well respected Bricasti M1 DAC was capable of a further worthwhile improvement by biasing the output I.C.s into Class A operation.

Barrows though, is usually referring to much higher priced units that many members can't  justify the expenditure on , unless they are either well heeled, or still single without any children to put through College etc.

[barrows]

30 minutes ago, diecaster said:

You are being unreasonable

I am entirely reasonable...  Please apply some reason and explain to me how a preamp can "improve" sound by adding something additional which is not present in the recording (as that is all a preamp can do to change the sound)?

 

Additionally.  I never said a preamp could only improve the sound if a DAC has a crappy output stage.  What I am saying is that if you have a bad sounding DAC (for example what many in this thread have described as "clinical" or "digital" sounding) you may end up with "better" sound by adding a preamp, but what you are doing is adding distortions which cover up the bad sound of the DAC.  this approach, while it may make your system more listenable, is also losing resolution and real musical information.

What I ma saying is, if one has a bad sounding DAC, the solution which will result in the best performance of the system, is to get a better DAC, not add distortions which add color to the sound which was never in the recording in the first place.

 

[barrows]

32 minutes ago, sandyk said:

 I am not across recent designs  from the USA, but many designers will now have taken on board the very worthwhile lessons and improvements detailed by highly respected Audio designers such as Douglas Self from the U.K. and Bob Cordell.

Many recent Power Amplifier designs published by Silicon Chip magazine, where they sometimes boast of the lowest distortion  amplifier designs ever published, are based to quite an extent on  the work of Douglas Self.

Have you seen any of the Douglas Self Audio Power Amplifier handbooks ?

So you are only referring to theoretical designs which do not exist as commercially available products, seems quite far off topic here?

I was talking about actual high end amplifiers which audiophiles can purchase, ones which might be used with a DAC audiophiles can purchase.

[barrows]

8 minutes ago, sandyk said:

 

 Perhaps your definition of a good output stage doesn't even come close to that of many other members ?

Very few affordable DACs even use low impedance buffers at their output, and are susceptible to the usual Interconnect vagaries. A friend found that even a well respected Bricasti M1 DAC was capable of a further worthwhile improvement by biasing the output I.C.s into Class A operation.

Barrows though, is usually referring to much higher priced units that many members can't  justify the expenditure on , unless they are either well heeled, or still single without any children to put through College etc.

Well, if they did not need to purchase a very expensive preamp they could afford a much better DAC...

[sandyk]

2 minutes ago, barrows said:

Well, if they did not need to purchase a very expensive preamp they could afford a much better DAC...

 

 It all depends on how many Input sources they have.

 Many members still have high quality Vinyl setups too.

[sandyk]

10 minutes ago, barrows said:

So you are only referring to theoretical designs which do not exist as commercially available products, seems quite far off topic here?

I was talking about actual high end amplifiers which audiophiles can purchase, ones which might be used with a DAC audiophiles can purchase.

 No, they are also commercial products , such as from The Signal Transfer Company .

https://www.google.com.au/search?source=hp&ei=5SaaWtXPOYqM8wXo146QAw&q=the+Signal+Transfer+Company&oq=the+Signal+Transfer+Company&gs_l=psy-ab.13..0.1440.10725.0.12872.28.20.0.7.7.0.307.4445.2-17j1.18.0....0...1c.1.64.psy-ab..3.25.4560.0..35i39k1j0i131i67k1j0i131k1j0i67k1j0i22i30k1.0.hdJr1eFS4-4

[barrows]

7 minutes ago, sandyk said:

 

 It all depends on how many Input sources they have.

 Many members still have high quality Vinyl setups too.

Of course, and usually, in that case they will need a preamp anyway, i have only advocated for DAC direct in the case of those who do not have analog sources.  There are now a handful of DAC-Preamps (like Mola Mola) which could be a good option for these folks and would help to keep the box count (and distortions) lower.

[GUTB]

When was the last time one of you guys has been to a live music venue? Last time for me was a jazz club in Chicago (Andy's). Live music is NOT transparent. It's warm, rich in harmonics, and very dynamic. The creation of that harmonic fabric, the creation of a believable soundstage, and powerful dynamic expression are vastly more important than transparency.

[barrows]

59 minutes ago, diecaster said:

industry professionals with more lofty reputations

As an audiophile since the late 70s, I have a great deal of respect for some of the more well known figures/designers/engineers in the high end.  Such as John Curl, Nelson Pass, etc.  but I do not worship every opinion which they may have.  i also have a great deal of respect for a few of the next generation, guys like Bruno Putzeys, who have very different ideas about how to get great sound (and if one heard Mr. Putzeys' Mola Mola system driving Vivid Audio Giya speakers at RMAF a few years back they would find it hard to argue with his approach).  I am open minded about getting great sound, and with some considerable effort I have learned that clinging to audiophile myths from the past (feedback is bad, only circuits with discrete components can sound good, class A amplifiers are best, etc) curtails development of better sounding gear (and often at lower costs).  There is a very strong air of elitism in high end audio, and this air of elitism is killing the industry.

Advances in technology have made better sound possible, often at lower costs, but audiophiles are sometimes trapped by their devotion to mythic beliefs which are no longer valid.  

[barrows]

10 minutes ago, GUTB said:

When was the last time one of you guys has been to a live music venue? Last time for me was a jazz club in Chicago (Andy's). Live music is NOT transparent. It's warm, rich in harmonics, and very dynamic. The creation of that harmonic fabric, the creation of a believable soundstage, and powerful dynamic expression are vastly more important than transparency.

I think you do not understand the meaning of transparent in this context?  My Girlfriend is a musician, I hear live unamplified music often of her rehearsing.  When I say "transparent" in the context of this discussion i mean transparent to the source (recording): that it, the recording is reproduced without the additional of artifacts.  So if the the recording captured everything which you describe above, then that would be present in a transparent playback system: the system is transparent, that is the system is not adding anything of its own.

[diecaster]

53 minutes ago, barrows said:

As an audiophile since the late 70s, I have a great deal of respect for some of the more well known figures/designers/engineers in the high end.  Such as John Curl, Nelson Pass, etc.  but I do not worship every opinion which they may have.

 

I don't worship them....and I am not asking your to worship them. Just don't discount their opinions or mine!

[One and a half]

When, not if, the DAC decides to send white noise instead of a signal, the volume of the pre amp remains the same. If the DAC creates white noise, it will be at 0db, and that signal directly into a power amplifier will most certainly fry tweeters. So why is there a discussion on using a pre amp with a DAC again?

[TubeLover]

On 3/2/2018 at 12:47 AM, sandyk said:

 

 A good quality preamp usually has a far better output stage than most affordable DACs, often using a discrete output stage, and quite often also uses higher voltage .+ and - supply rails (> + and -20V) than most  DACs. They often use Class A topology as well.

Exactly!

 

JC

[sandyk]

1 hour ago, One and a half said:

When, not if, the DAC decides to send white noise instead of a signal, the volume of the pre amp remains the same. If the DAC creates white noise, it will be at 0db, and that signal directly into a power amplifier will most certainly fry tweeters. So why is there a discussion on using a pre amp with a DAC again?

 Imagine what could happen with an event like this into a typical high quality amplifier such as the attached Silicon Chip ULD3 with specifications as shown, with a full power sensitivity of a tiny fraction over 1V into 4 ohm speakers. (200 Watts)

Momentarily, the amplifier would possibly deliver quite a bit higher than the rated 200W into 4 ohm speakers before blowing a fuse . (if you were lucky !)

Being white noise, the tweeters would most likely be destroyed.

Note also the fairly low input impedance of 12Kohms, which is quite a bit lower than many DACs would prefer.

Click on the image for a larger image.

[One and a half]

16 minutes ago, sandyk said:

 Imagine what could happen with an event like this into a typical high quality amplifier such as the attached Silicon Chip ULD3 with specifications as shown, with a full power sensitivity of a tiny fraction over 1V into 4 ohm speakers. (200 Watts)

Momentarily, the amplifier would possibly deliver quite a bit higher than the rated 200W into 4 ohm speakers before blowing a fuse . (if you were lucky !)

Being white noise, the tweeters would most likely be destroyed.

Note also the fairly low input impedance of 12Kohms, which is quite a bit lower than many DACs would prefer.

Click on the image for a larger image.

There's no need to imagine, just be ready to fork out $ and wait for tweeters to arrive. The subject of white noise out of a DAC occurred 'a few times' mind you with Audirvana + and HQ Player, both not configured as expected with DSD as the file source. Bang to white noise, if it wasn't for the pre amp, a different story. 

[mansr]

11 hours ago, sandyk said:

As far as FETs go, they aren't so easy to obtain these days

What are you talking about? Farnell stocks over 10,000 different models:

http://uk.farnell.com/c/semiconductors-discretes/transistors/mosfet-transistors/single-mosfet-transistors

[davide256]

8 hours ago, GUTB said:

When was the last time one of you guys has been to a live music venue? Last time for me was a jazz club in Chicago (Andy's). Live music is NOT transparent. It's warm, rich in harmonics, and very dynamic. The creation of that harmonic fabric, the creation of a believable soundstage, and powerful dynamic expression are vastly more important than transparency.

hmm. You just described the starting points for transparency. Full transparency requires more... the ability to easily focus on the playing of accompanying lines in the music by individual instruments. And yes this happens where the hall is good. I hate having to settle for a bad hall where accompanying instrument voices get blurred behind the main melodic theme... I want to hear clearly everything that the composer and artists intended the audience to hear.

[Summit]

The main task for an amplifier is to take a weak audio signal and boost it to generate a signal that is powerful enough to drive speakers or headphones. This is an oversimplification there the whole amplifying process is seen as one process, but the processes inside most DAC, amplifier and audio systems is more complex and also depend greatly on audio design.

 

A preamp can both be a preamplifier circuit within a device (like a DAC or integrated amp) or it can be dedicated external preamp. A preamplifier is an electronic circuits that converts a weak electrical signal into an output signal that’s is (hopefully) strong enough to be noise-tolerant and strong enough to be sent to a power amplifier.

 

An amplifier is NOT amplifying by adding to an already exciting signal as many seems to believe. In reality an amplifier generates a completely new output signal that is BASED on the input signal. To understand how an amp works one need to see the signals as two separate circuits, there the output circuit is generated by the amplifier's power supply. That means that the power supply and power circuit is of great importance then it comes to amplify a weak audio signal, no matter if the preamp is placed in an external or internal box.

 

Let go one step deeper, every transistor or tube pair can represents one amplifying stage of an amplifier. Most amplifier have several amplifying/boosting stages there the final output stage of the power amp is driving the speaker.

 

So then someone are saying that a bit of transparency is lost with every amplifying stage it can be true because every transistor or tube will add its own noise, but not because different gear is double amplifying an existing signal or because all the noise from the source automatically will be added to the new signal. A good preamp is acting like a purifier that smooths the signal, not by adding coloration, but by make a new signal from (hopefully) cleaner power. Extra IC between components are always degrading the signal thou and it’s true that what’s lost is lost and cannot be added back later by an amp.

 

If we take a Chord DAVE for example and examine the difference between using headphones direct out of DAVE DAC/pre too DAVE + dedicated headphone amp, the difference in loss of perceived transparency is probably bigger than with speakers there also a power amp is used in the system that will add its noise (the noise from the preamp is masked by the noise from the power amp).

 

If a SOTA DAC sounds better with or without a preamp depends not only on DAC and preamp but on the rest of the system, and on preference. IMO a really good dedicated preamplifier doesn’t add more noise and coloration than say a power amp, probable a lot less. A really good dedicated preamplifier normally have batter impedance matching, staging, bass, tonality and drive than most DAC. A few exceptions may exist. Unfortunately a really good dedicated preamplifier cost a lot and therefore maybe not always the best bang for the buck in many modern audio system that only have one digital source.  

 

As always, best to test in your own system and see if a standalone preamp gives superior SQ or not.