Adding a pre amp

[barrows]

9 hours 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?

Hmmm, while I believe one should pay attention to this possibility, I am not worried myself.  In 8 years of going DAC direct I have never experienced this.  A well designed DAC should never allow this to happen.  Think of all those portable headphone amps out there (Hugo, Mojo, etc) which use digital volume controls, ever hear of one failing this way and blowing up someones expensive headphone, or eardrums?

Indeed, if a manufacturer sells a DAC designed to go amp direct, and it fails and then blows up some tweeters, i would hold that manufacturer responsible and demand they pay for repairs.  (same thing for amps going DC on their outputs).

My experience with the (excellent) digital volume control in the ESS chips has proven to me, that it, for one, is bombproof and does not experience this kind of problem.

Additionally, note that many preamps use digitally controlled (analog) volume controls, it seems to me that they would be just as vulnerable to this kind of problem: as a digital glitch could set them to 0 dB (and I actually have seen that happen with a commercial product), so this risk would also exist with many analog volume controls.

[firedog]

On 3/2/2018 at 5:55 AM, diecaster said:

You need to look at this part of the Nelson Pass quote more closely:

 

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

 

I file these under "How About That".

 

BHK says something similar in the video of his thoughts on active preamps. 

 

The bottom line here is that guys with a ton more experience than you think active preamps sound better than passive/none. I am not telling you that you have to like active preamps. But crapping them makes no sense. My 40 years of experience is audio sides with Pass and BHK. 

First, you appeal to authority instead of actually making a point. There are other manufacturers who recommend running their DAC with VC directly into a (their) power amp. Every side in the argument can bring an authority to back up his point of view - and has - so the experts all cancel each other out. 

Second, you do realize that it could be understood that all NP and BHK are saying is that they like the coloring a good preamp brings, which just reinforces what Barrows is saying. 

[mansr]

"For every expert there is an equal and opposite expert." -- Arthur C. Clarke

[Ralf11]

suppose I have an Oppo Sonica DAC ($600) - will SQ improve if I connect it to a pre-amp??

 

for the pre-amp we could pick an older used one for $1,000 - $2,000 

 

let's get out of generalities and post something specific

[Ajax]

Hi All,

 

If this thread has demonstrated anything to me it is the amazing willingness and good grace of technically competent people such as mansr, esldude and barrows (et all) to help those less knowledgable understand what is, and is not, important to obtain good audio. We are incredibly lucky to have them here as members.

 

CA therefore provides an incredible opportunity to learn, so please stop this insane elitist bullshit about being an audiophile for 40 years and listen to these guys. Take of your blinkers, open your mind and appreciate the opportunity to grow your knowledge base. How many different ways do you think they can word basic audio concepts?

 

The nonsense posted by the "you can't have a DAC and a pre amp in the same box" crowd is fast approaching beer and music's farcical "Sample Rate" thread. Comments in this thread mimic his refusal to accept the validity of the Nyguist theorem (whilst at the same time admitting to being a layman). I was one of those who initially blogged under his Apology thread for him not to leave, because he was asking some good questions, however, I was very disappointed with his lack of empathy and respect for others when he played "the victim card" citing abuse AFTER attacking both Barrows and BigBob. He did not call them names but he sure as hell questioned their integrity, while all they were trying to do was provide members with technical information and sources of inexpensive DACs, respectively.

 

For those of you who still think they can't have their pre amp and DAC in the same box, without paying $10k+, please remember all you are doing is providing a bridge between a source (digital file) and a power amp. As pointed out previously all this bridge needs to do is select the source, attenuate the file (digital volume control), convert the bits to an electrical pulse (DAC) and then boost the signal to "line level" ready for the power amp.

 

The point that mansr, esldude and barrows have been trying to get across is that the less complicated and simple you make this path (bridge) the less chance of generating unwanted noise - LESS is MORE. They are also saying that if you prefer the sound that results from adding a pre amp into the path then go right ahead, just know that the sound you are enjoying is most likely additional noise, and the resulting signal will most likely be less transparent (accurate) with the pre amp than without it.

 

Before responding to this email at the very least please check out the DAC3 is not designed to add "euphonic" coloration to the audio , which emphasises the point these gentlemen are trying to make. Benchmark make devices for use in studios where it is essential the mastering engineer has an accurate version of the original signal. He can then "flavour" to suit.

 

 

[GUTB]

1 minute ago, Ajax said:

Hi All,

 

If this thread has demonstrated anything to me it is the amazing willingness and good grace of technically competent people such as mansr, esldude and barrows (et all) to help those less knowledgable understand what is, and is not, important to obtain good audio. We are incredibly lucky to have them here as members.

 

Rather it demonstrates the effects of willful ignorance on those users' part. It's quite striking actually.

[mav52]

13 minutes ago, GUTB said:

 

Rather it demonstrates the effects of willful ignorance on those users' part. It's quite striking actually.

So you are basically noting that anyone that uses a pre-amp and not a dac in the role as a pre-amp is ignorant, is that how I read what you wrote. 

[One and a half]

5 hours ago, barrows said:

Hmmm, while I believe one should pay attention to this possibility, I am not worried myself.  In 8 years of going DAC direct I have never experienced this.  A well designed DAC should never allow this to happen.  Think of all those portable headphone amps out there (Hugo, Mojo, etc) which use digital volume controls, ever hear of one failing this way and blowing up someones expensive headphone, or eardrums?

Indeed, if a manufacturer sells a DAC designed to go amp direct, and it fails and then blows up some tweeters, i would hold that manufacturer responsible and demand they pay for repairs.  (same thing for amps going DC on their outputs).

My experience with the (excellent) digital volume control in the ESS chips has proven to me, that it, for one, is bombproof and does not experience this kind of problem.

Additionally, note that many preamps use digitally controlled (analog) volume controls, it seems to me that they would be just as vulnerable to this kind of problem: as a digital glitch could set them to 0 dB (and I actually have seen that happen with a commercial product), so this risk would also exist with many analog volume controls.

When the white noise did happen, it was very worrying. I rather not test that stress level. Besides, the pre-amp has other inputs which are used, so a DAC is another input.

[sandyk]

9 hours ago, mansr said:

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

 

I normally don't use suppliers such as UK Farnell . 

As a pensioner I try to get most of my stuff locally or from ebay surplus stock where items like this had dried up last time I checked. I try to get surplus items in reasonable quantities for matching purposes. 

It's often too expensive for me to use sources like Farnell these days, where many items need to be sent out from the U.K. anyway.

[mansr]

1 hour ago, sandyk said:

I normally don't use suppliers such as UK Farnell . 

As a pensioner I try to get most of my stuff locally or from ebay surplus stock where items like this had dried up last time I checked. I try to get surplus items in reasonable quantities for matching purposes. 

It's often too expensive for me to use sources like Farnell these days, where many items need to be sent out from the U.K. anyway.

Farnell was just an example. Surely there are component distributors in Australia too.

[sandyk]

A quick summary of some of the features of the better Preamplifiers, as published by Stereophile.

This may give some idea of why they may be more expensive

Mostly using discrete circuitry. Separate Power Supplies.
Some may even be battery operated, with a "Recharge Mode" and a total Isolation Mode, where the Total Isolation Mode usually sounds a little better.
Additional filtering of the main output stage as well as a local lower noise supply to the input differential amplifier.
The preamp's line stage may have no capacitors in the signal path and is flat to DC.
With some. a balance control is also provided, as well as balanced operation, and extensive Moving Coil Cartridge Preamp section options.
The advantage it presents over a passive control is its more powerful cable-driving ability, even over long runs.
Dual-mono, and ultimately direct-coupled signal path, intended to achieve high gain, low noise, wide bandwidth, and excellent linearity.
R-2R ladder volume control—instead of a traditional potentiometer, where sometimes relays select different combinations of resistors so that the volume can be adjusted in precise increments of 0.1dB from 0 to –70dB.

 

 

https://www.stereophile.com/category/solid-state-preamp-reviews

[sandyk]

1 hour ago, mansr said:

Farnell was just an example. Surely there are component distributors in Australia too.

We have Farnell and others, but in many cases the components need to be sent out from the parent company, perhaps UK Farnell which has happened to me, resulting in several weeks delay, or from an Asian warehouse. They rarely carry the extensive ranges of the U.K. and U.S. parent companies due to Australia being a much smaller market,and there are often extensive lead times with many components. Quite often, there are large shipping costs, especially from the U.S.A.  unless you exceed a specified order amount. An E.E. friend has offered on a couple of occasions to include my smaller requirements with his much larger order, but I don't like doing that.

To save money I tend to use ebay quite a bit for surplus items, or https://www.utsource.net/

Neither do I like to use my Credit card for orders unless there is no other alternative, and prefer to use Paypal which companies like Farnell and RS Components do not normally accept.

[diecaster]

4 hours ago, Ajax said:

Hi All,

 

If this thread has demonstrated anything to me it is the amazing willingness and good grace of technically competent people such as mansr, esldude and barrows (et all) to help those less knowledgable understand what is, and is not, important to obtain good audio. We are incredibly lucky to have them here as members.

 

CA therefore provides an incredible opportunity to learn, so please stop this insane elitist bullshit about being an audiophile for 40 years and listen to these guys. Take of your blinkers, open your mind and appreciate the opportunity to grow your knowledge base. How many different ways do you think they can word basic audio concepts?

 

The nonsense posted by the "you can't have a DAC and a pre amp in the same box" crowd is fast approaching beer and music's farcical "Sample Rate" thread. Comments in this thread mimic his refusal to accept the validity of the Nyguist theorem (whilst at the same time admitting to being a layman). I was one of those who initially blogged under his Apology thread for him not to leave, because he was asking some good questions, however, I was very disappointed with his lack of empathy and respect for others when he played "the victim card" citing abuse AFTER attacking both Barrows and BigBob. He did not call them names but he sure as hell questioned their integrity, while all they were trying to do was provide members with technical information and sources of inexpensive DACs, respectively.

 

For those of you who still think they can't have their pre amp and DAC in the same box, without paying $10k+, please remember all you are doing is providing a bridge between a source (digital file) and a power amp. As pointed out previously all this bridge needs to do is select the source, attenuate the file (digital volume control), convert the bits to an electrical pulse (DAC) and then boost the signal to "line level" ready for the power amp.

 

The point that mansr, esldude and barrows have been trying to get across is that the less complicated and simple you make this path (bridge) the less chance of generating unwanted noise - LESS is MORE. They are also saying that if you prefer the sound that results from adding a pre amp into the path then go right ahead, just know that the sound you are enjoying is most likely additional noise, and the resulting signal will most likely be less transparent (accurate) with the pre amp than without it.

 

Before responding to this email at the very least please check out the DAC3 is not designed to add "euphonic" coloration to the audio , which emphasises the point these gentlemen are trying to make. Benchmark make devices for use in studios where it is essential the mastering engineer has an accurate version of the original signal. He can then "flavour" to suit.

 

 

 

But less often isn't more.......this is absolutely true in regards to active preamps.

[cjf]

21 hours 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).

For being such an "expert" your responses make me scratch my head.

 

So what your saying is that your DIY DAC and DIY Hypex NC400 Amps are soo revealing that well heeled brands like Pass Labs, Meitner, Lynx and Benchmark all pale in comparison and sound worse in a DAC Direct scenario? That crap only fly's with those who dont know any better, sorry. I currently own the same DIY Amps you do among others and have owned the Mola Mola stuff you have given high praise to in a previous reply. Guess what, I sold it and its not all its cracked up to be.

 

I've already mentioned that I've tried your approach and feel it doesnt sound better despite your theories, but I guess we should all keep in mind that this was using low brow equipment compared to the stuff you have so gracefully pieced together. Just imagine where these other brands would be if they had you around to show them the error of their ways in DAC/AMP/PREAMP/VOL CNTRL design.

 

Give me break!

[pkane2001]

18 minutes ago, cjf said:

For being such an "expert" your responses make me scratch my head.

 

So what your saying is that your DIY DAC and DIY Hypex NC400 Amps are soo revealing that well heeled brands like Pass Labs, Meitner, Lynx and Benchmark all pale in comparison and sound worse in a DAC Direct scenario? That crap only fly's with those who dont know any better, sorry. I currently own the same DIY Amps you do among others and have owned the Mola Mola stuff you have given high praise to in a previous reply. Guess what, I sold it and its not all its cracked up to be.

 

I've already mentioned that I've tried your approach and feel it doesnt sound better despite your theories, but I guess we should all keep in mind that this was using low brow equipment compared to the stuff you have so gracefully pieced together. Just imagine where these other brands would be if they had you around to show them the error of their ways in DAC/AMP/PREAMP/VOL CNTRL design.

 

Give me break!

 

Relax, I don’t think Barrows is coming to take your preamp away. All he’s done is explain his reasons for why he believes in not using a one. This is a harmless discussion, not a fight for world domination. If folks would only engage on a level of reason and logic, perhaps we could all learn something from each other.

[barrows]

40 minutes ago, cjf said:

So what your saying is that your DIY DAC and DIY Hypex NC400 Amps are soo revealing that well heeled brands like Pass Labs, Meitner, Lynx and Benchmark all pale in comparison and sound worse in a DAC Direct scenario? That crap only fly's with those who dont know any better, sorry. I currently own the same DIY Amps you do among others and have owned the Mola Mola stuff you have given high praise to in a previous reply. Guess what, I sold it and its not all its cracked up to be.

My DAC outperforms Benchmark by a mile, Meitner, I would not be so sure (I have not heard the latest Meitner/EMM stuff).  In direct comparisons here in my system it outperforms the highly regarded PS Audio DirectStream as well.  My reference amplifier for a few years here was a Pass Labs X150.5.  While there were some aspects of the sonics of the Pass I preferred, ultimately my Ncore 400 based stereo amplifier build outperformed the Pass in both noise floor and detail retrieval, and with a few tweaks I preferred it to the Pass, although I am still a great admirer of Mr. Pass' designs.  Without the tweaks made to my Ncore amp the Pass would have stayed here.

I have heard most of the high end amplifiers on the market (Constellation, Soulution, VTL, AR, etc, etc) in various systems, and most of the highest rated DACs as well (Chord DAVE, dCS Vivaldi, various MSB, TotalDAC, etc, etc).  To be fair, if a commercial DAC were built to the same level of sophistication as my current DAC, it would have to be a 5 figure product at retail.  An experienced DIYer can actually build very, very competent audio components at a fraction of the price of purchasing the best commercial high end gear, but it takes developing some years of experience and countless hours of experimentation and testing and building.

I have no experience of your system, but if you did not like Mola Mola I suspect there was a system incompatibility, system matching is always going to matter and not all components will sound their best together.

 

I do not recall suggesting that my gear sounds better than anything else, whether connected DAC direct or not, not sure where you got this ides, but I am not sure what you are trying to accomplish by denigrating my choice of components.

 

I believe right now we are experiencing a bit of a Renaissance in audio component design and this Renaissance is facing a fair amount of opposition from audiophiles who believe the myths of the past.  An example of this is the change of paradigm in the approach of some designers:

The old school way of designing was often based on the following philosophy: the designer accepts that the finished product will have some (audible) level of distortions, so the designer chooses to make these distortions of the type which are less subjectively annoying to the listener, like choosing to have lower order distortions rather than higher order distortions, and sometimes choosing to favor even order distortions over odd.  While this approach has validity there is now a new approach.

The new school way of designing is illustrated by what Mr. Putzeys does with his designs:  Instead of accepting that there will be some level of (audible) distortions, Mr. Putzeys just reduces ALL distortions to levels where they cannot be perceived at all.  As long as the distortions are non perceivable, it matters not a bit what order they may be, or whether they are even or odd.

 

This Renaissance in design has been allowed by both very, very clever designers, such as Mr. Putzeys, but also by an increase in understanding about how things work, and by technological advances in the actual parts used to build audio components.

 

If high end audio is to survive as an industry, we as audiophiles would do well to embrace this new approach, as it promises both better sound quality AND more affordable products.  (Although unfortunately I see no such evolution happening yet in speaker design, the needs of the cabinet still require very expensive constructions, and good physical driver assemblies are still rather expensive to produce-transducers, whether speaker or microphone are always going to be the biggest stumbling block to the best possible sound quality). 

[sandyk]

1 hour ago, barrows said:

The new school way of designing is illustrated by what Mr. Putzeys does with his designs:  Instead of accepting that there will be some level of (audible) distortions, Mr. Putzeys just reduces ALL distortions to levels where they cannot be perceived at all.  As long as the distortions are non perceivable, it matters not a bit what order they may be, or whether they are even or odd.

 

Which is exactly what Douglas Self is doing, and is thoroughly discussed in his Audio Handbooks.

Even then, there can be further improvements made in the PSU area , such as independently powering the front end with separate very low noise power. DC coupling is another area of audible improvement if properly implemented. It gives a "preciseness" to the LF area especially , but is not normally done with Power Amplifiers, as it also needs good associated Speaker Protection circuitry in the event of anything more than several hundred mV of DC appearing at the Speaker output. .

[diecaster]

First you say this:

 

1 hour ago, barrows said:

My DAC outperforms Benchmark by a mile, Meitner, I would not be so sure (I have not heard the latest Meitner/EMM stuff).  In direct comparisons here in my system it outperforms the highly regarded PS Audio DirectStream as well.  My reference amplifier for a few years here was a Pass Labs X150.5.  While there were some aspects of the sonics of the Pass I preferred, ultimately my Ncore 400 based stereo amplifier build outperformed the Pass in both noise floor and detail retrieval, and with a few tweaks I preferred it to the Pass, although I am still a great admirer of Mr. Pass' designs.  Without the tweaks made to my Ncore amp the Pass would have stayed here.

 

Then you say this:

 

1 hour ago, barrows said:

I do not recall suggesting that my gear sounds better than anything else, whether connected DAC direct or not, not sure where you got this ides, but I am not sure what you are trying to accomplish by denigrating my choice of components.

 

Well, which is it.

 

Also, if you think the Ncore 400 based amps sound better than the Pass stuff or quality tube amps, I don't care what you have to say about anything because we are clearly from different universes when it comes to what sounds good to us.

[barrows]

17 minutes ago, diecaster said:

First you say this:

 

 

Then you say this:

 

 

Well, which is it.

 

Also, if you think the Ncore 400 based amps sound better than the Pass stuff or quality tube amps, I don't care what you have to say about anything because we are clearly from different universes when it comes to what sounds good to us.

Dude, do you understand grammar?  Tenses?  Only in this response did I make any such comparisons in response to your ill informed (you have not heard it) denigration of my gear.  Previous to this post I made no such comparisons.

[Fluffytime]

6 hours ago, GUTB said:

 

Rather it demonstrates the effects of willful ignorance on those users' part. It's quite striking actually.

 

No, it demonstrates that you have no idea what you are talking about. Again.

 

And yes, your utter ignorance is quite striking. Indeed.

[barrows]

38 minutes ago, diecaster said:

Also, if you think the Ncore 400 based amps sound better than the Pass stuff or quality tube amps, I don't care what you have to say about anything because we are clearly from different universes when it comes to what sounds good to us.

Fair enough.  The comparison was very close, and only after some tweaks to my NC-400 amp did I prefer it to the Pass overall.  I will advise that you have not heard my NC-400 amp, and I have directly compared it to the Pass.  Of course now Mr. Pass is on to the .8 version and it is probably bit better.  But all these differences are so small as to be easily changed by a change of speaker cable or interconnect.

Because I am putting  a lot of effort into developing my DIY DAC(s), it is very important for me to have an amplifier which is as neutral and transparent to the source as possible.  By having a transparent and neutral amplifier, I can be sure of what the sound of my DAC is.

What sounds good to me is music, and I want to hear the recording as it is, not as it is colored and smeared by system.

You appear to have very strong opinions about what sounds good to you, perhaps you should consider posting your system details so all can see what your choices and experiences in components are.

[sandyk]

Given  Barrows much earlier posted reports (several years ago) on the audible effects of Jitter etc. which closely corresponded to that of my own and John Kenny's reports, I will admit that Barrows does have finely tuned hearing abilities, although personally, I would be surprised to hear an NC -400 amplifier equal one of Nelson Pass's best Class A Power Amplifiers. 

I do agree with him however, that an  experienced DIY person can extract much more from many commercial designs, quite likely a little more from some of Nelson Pass's designs too.

[Fluffytime]

Does anyone actually take John Kenny seriously anymore?

[sandyk]

4 minutes ago, Fluffytime said:

Does anyone actually take John Kenny seriously anymore?

 

 I would expect that John Kenny is far more experienced and knowledgeable in this area than you are, although perhaps a little full of himself since he became a manufacturer.

[fas42]

23 minutes ago, Fluffytime said:

Does anyone actually take John Kenny seriously anymore?

 

Some do ... http://www.tnt-audio.com/sorgenti/ciunas_isodac_e.html