Do I need a preamp?

[deaddog]

Sorry for being dense but I'm a bit confused by the threads I've read. I am building a 2 channel system that will solely be for digital music - either via Sonos or usb from the computer. I am looking at an integrated amp (Bryston B100) and a decent quality DAC. But, if all the preamp portion does is add a volume control, I can get the Bryston amp alone, use the DAC's volume control, and save $1500 over the integrated.

 

But will the two setups sound the same - assuming same source and same amp and same speakers? And you can assume that my ears are decent but not superhuman as I'm now 50+.

 

If the answer is "skip the preamp and buy a good dac" feel free to recommend one that plays well with Bryston and has a volume control

 

thanks

 

[esldude]

Nope, you do not need a pre-amp. I'll let others suggest a DAC with volume control.

 

Will they sound the same? Probably.

 

If they don't it likely is because the pre-amp is not fully transparent.

 

So leaving the pre-amp out might improve sound, and won't hurt sound quality.

 

 

[ringenesherre]

The answer depends on how the volume control is implemented in the DAC. If it is in the digital domain, you loose bit depth at lower volumes (because essentially you scale down the integer values).

 

If it is in the analogue domain, a good stepped attenuator or something similar will sound better. A less-than-optimal potentiometer might be less desirable than the digital-domain solution, though.

 

So in the end it comes down to what your DAC is using and what kind of preamp we are talking about. Depending on the setup, adding a passive volume control instead of a preamp is an option, too. Depending on your budget, Goldpoint SA2 or SA2X would be a start.

 

[barrows]

You do not need a preamp. Just make sure that the output of your DAC is well matched to the input sensitivity of your amp: in most cases this means using a DAC with 2V-3V output level. By having these levels matched, you will not have to use excessive attenuation (important for DACs with digital volume controls). Note that DACs using ESS Sabre 9018 DACs (like the Wyred 4 Sound DAC2) have volume controls which operate at 48 bits: essentially this means the digital volume control is going to be the least compromised way to adjust the volume.

Go ahead and spend the money you just saved on buying better speakers!

 

[Mark Powell]

I am new to computer audio too, but you have an advantage over me. You are starting 'clean' whereas I had lots of already paid for parts that cost-effectiveness meant I had to continue to use. I also made a serious mistake by buying a DAC with no volume control. I live in England where prices can be very different so 'your mileage may vary'. Here goes -

 

Don't try and save money by using the volume control on your player (J Rivers Media Center, Windows Media Player and so on). Not only is the result awful, I guarantee that sooner or later you will blow up your loudspeakers by starting at full volume. Turn these up to maximum and use your proper volume control.

 

Buy a DAC with a volume control. Ensure it is proper analogue one, not digital. Not even a hi res digital. My choice would be a Benchmark. I do not have the specs to hand but there are several different sorts that all look the same. Pay slightly extra and go for the full preamp version. It has at least one analogue input and sooner or later you will need this for any other front end you might buy. CHECK that the Benchmark's volume control is indeed analogue - I am not sure. They have a headphone output too. Also check that the volume control does not apply only to this. I think they have a switch at the back so you can turn the volume control on and off.

 

A Bryston power amp will be fine, though they can be somewhat expensive. Remember that YOU are paying for their famous 20-year warranty, not them. Bryston come from the professional end of the market so they can be rather cold and lacking in excitement. Also they tend to a rather dull top end. However, that's just my opinion.

 

Assuming you are using Windows, start by using Windows Media Player. Its ripping engine is the equal of any provided you tick 'Use error correction' in the organise>options>devices>dvd-drive>properties box. It can be rather slow with this turned on, however.

 

Use Windows Media Center for playback. It is only a front end for Windows Media Player and actually does nothing physically, but it has the best user interface on the planet.

 

These come included in Windows 7 Home Premium and up.

 

If you are interested in Internet Radio, download the free Windows version of iTunes from Apple. It installs problem-free in seconds and is straightforward to use. DON'T, whatever you do, use it for anything other than radio. I only use it because I have the deep misfortune of enjoying Country music.

 

I have strong opinions which, as often as not, turn out to be wrong. But here is one. Don't install extraneous clutter such as J Rivers Media Centre or Exact Audio Copy. What comes out of your USB port will, configured correctly, be the same whatever you use. Keep it simple.

 

Hope this helps.

 

[PeterSt]

Hi Mark,

 

I'm sure your advices *have* to be appreciated, because they look genuine. The effort of writing alone ...

 

But I don't see even one line I would concur with. Ok, the clutter from JR, yes.

 

Of course all of your reasoning springs from one little error :

 

What comes out of your USB port will, configured correctly, be the same whatever you use.

 

... which is totally not true. The "configured correctly" is subject to some gray area of course, but who was the one new to computer audio ?

So at least practically this won't hold, and besides that I have yet to see the first situation where all is arranged for in such fashion that players don't matter.

 

Just some counterweight !

Regards,

Peter

 

[Mark Powell]

Hi Peter

 

I don't disagree, but my main premise was 'keep it simple'. For example, my DAC has a choice of three filters, so I spent a long time agonising over which was 'best', and checking which filter gave the most enjoyable result from a particular short guitar piece, which I was using as a general reference. I don't want to do this simply because the manufacturer can't make up his mind.

 

I am being generous here, one could say he is doing as a marketing point and can provide lots of meaningless graphs in his literature.

 

Similarly with rippers and players. They all give errors, but only small errors. The errors from the various suppliers will of course be marginally different, but again, only marginally. The bad ones simply won't last.

 

I spent days faffing around with J Rivers, EAC, and so on before I thought 'What did I actually buy all this stuff for?'

The actual reason was so that I could rip hundreds of CDs that are available for free from my local public library. I am not cheating the artists by doing this, no more or less than I am when I take out a book. Copying is not really cheating either, it is no different from taking out the book again, which we all perhaps do. Don't know if it's different in the USA, but authors and musicians here have to agree before the state authorities can place their material in the public libraries.

 

Om my being new do it, I am not new to hi-fi in general, and computer audio is just another source. And being in the software industry for years makes it fairly quick to get the basics right. After all, configuration is just setup, not programming.

 

Mark

 

[lightminer]

I haven't investigated this in recent years, but I have a Supratek pre-amp and everything sounds better with it in the system. 5 or 6 years ago when I bought it I compared it to some DACs with pre's as well as compared to truly nothing (which was a bit loud, but I could still do some comparisons).

 

No question at all, sound was much more 'dead' without the pre, and imaging was much worse.

 

If you can get a truly outstanding pre in there, like a Supratek, an Audio Research, or even an older Mark Levinson 380s, there will be a huge difference, but if we are talking about a transistor $500 pre, you're better off sticking with digital.

 

You could also, for now, go with the digital pre, and in 1 or 2 years, sample some really high-end pre's and you'll know for sure if its an improvement.

 

Go to a stereo store with a Joule-Electra pre and hear what that can do (possibly the best pre made, of course very arguable/subjective, but I think there is no argument that it is in the running for best under 50k). Ask them about running straight from a DAC with a pre in it, and I'm pretty sure they will just squint at you .

 

 

Now - that said - the 'full digital' boxes are very interesting, right now represented I think by the NAD M3 and the Wadia 150 PowerDAC. These have a whole other approach, and may eventually be the way to go. There is still a long way, however, until they can even get into the same room as a JE pre and OTL amp.

 

[Elprior]

Barrows said :

in most cases this means using a DAC with 2V-3V output level. By having these levels matched, you will not have to use excessive attenuation (important for DACs with digital volume controls)

 

On theory, I would agree, but the ability to change the output level might be an issue. With my dac set to 2V, with maximum (digital) attenuation of -60dB, 'the recordings from the loudness war' are far from being quiet. And this is the minimum output I can set.

 

I still find the sound to be good at this level, but this is so much system dependent !

 

Deaddog, I'm afraid you'll have to go out and listen to combos before deciding if it suits your tastes or not

 

Elp

 

[deaddog]

Guys

 

This is incredibly helpful - thanks. Assuming I get a DAC with decent volume control, will that give me as good of control over the volume as found in a decent preamp (for example a bryston 6). I want to be able to change the volume in very slight increments AND I will want to be able to turn the volume extremely low at times - and I will want to do this easily, in a single step, preferably using a remote control. I know I can do that with a good pream (or good integrated) - but will I have the same control using a good DAC?

 

Thanks

 

[Priaptor]

I would never disagree with those who claim no need for a preamp and who find sonic improvement. Much of this is subjective.

 

My own experience is jaded as I prefer, subjectively, a preamp, but I am using what I consider a fantastic unit, the Audio Research Ref 5 with the Audio Research DAC 8, which has no digital volume.

 

Having said the above, I did use a PS Audio with and without the Ref 5 and preferred the preamp.

 

My advice, is look at your budget. Start with what you are and you can always try at some future point as I did, a preamp and make up your own mind.

 

[Mark Powell]

Deaddog

 

I just looked up Benchmark as in my earler append I did not have complete information.

 

The model I was looking at is the HDR. It has a motorised analogue volume control, remote control, headphone socket, and one analogue input in addition to the digital inputs. It is 1895 dollars.

 

Personally, had I not recently purchased a DAC I would be at the dealers buying one of those this afternoon.

 

Regards,

Mark

 

 

 

 

 

 

 

[Elprior]

From my dac with digital volume control :

I want to be able to change the volume in very slight increments

 

No problem, mine is using 0.5dB ones.

 

AND I will want to be able to turn the volume extremely low at times

 

This is down to matching correctly the dac output with the amplifier(s) input sensitivity.

My amplifiers are rated as follows : Input sensitivity = 252mV, 1W @ 8 Ohm; 2.57V, 100W @ 8 Ohm; 1.81V, 100W @ 4 Ohm

Obviously, with 'records from hell/loudness war' this is not a perfect match to my 2V output setting.

For most taken care records, this is close to muting the outputs - which is an option for the former ones

 

Even if sensitivity is well matched, you still have to decide if you like the sound that comes out of it.

 

in a single step, preferably using a remote control

 

Ok, no problem with my dac.

I guess that's a feature on the shop list for you

 

Elp

 

[ted_b]

I have always been a "you must use a preamp" guy, and have owned several great preamps. Of course, if you have multiple sources, some analog, then its a moot point. But even when faced with one main digital source (DAC) I had always preached preamp. it seemed to always add weight and heft and tonality that I required. Furthermore, i tried several DACs (I auditioned over a dozen in the past 2 years) that allowed a direct-to-amp setup, and universally hated the sound. It was usually quite analytical and flat.

 

My latest preamp is the Concert Fidelity CF-080. It is a world-class pre that is well-reviewed. I love its sound, or lack thereof. However, on a dare, I tried my Antelope Zodiac Gold DAC in direct-to-amp mode (after hundreds of hours of break-in) and found that I lost very little (especially in the deal breaker areas of imaging and timbre/tonality) and gained a slight improvement in micro-detail. Yes, there are tradeoffs, but at the price of the Concert Fidelity it became my easiest no-brainer in my audiophile life. Note: the Antelope has an analog volume control, remote managed.

 

If the volume control is digital there may be more to investigate, but in many cases the digital attenuation has been designed to minimize any resolution loss (by providing enough headroom or by doing it above 24 bits thus allowing enough bits to drop off and still have full bit depth of the recording). And even if a few bits drop off at very low volume, one doesn't listen seriously at very low volume.

 

Net/net, try these in your home! It is the only way you'll know. When I bought my Gold DAC I would have bet big bucks that it would not replace my preamp. Go figure.

P.S Some DACs even have analog inputs to further add to the preamp function within.

 

[barrows]

Audiophile myths debunked:

 

1. analog volume control is better than digital:

 

OK, the above is patently untrue. The real answer is: it depends on the implementation. Besides variable gain preamps (Ayre KX-R) which are very rare, analog volume controls use resistive attenuation to control volume, either via a pot, or a resistor ladder of some type-even the very best resistors (Texas Components TX-2575s at $10 each) add noise/distortion to the signal which is measurable. Additionally, adding an analog preamp to the system also adds noise and distortion from its active gain/buffer stages, and from the additional interconnect and connections needed.

A well implemented digital volume control (as in the ESS DAC chip which operates at 48 bits) will do less damage to the signal than any analog volume control. Period, note, that this does not mean that all digital volume controls will outperform all analog ones. It is important to understand that analog volume controls are not benign when considering this, they add distortions of their own.

 

2. A really good preamp will always sound better than going DAC direct.

 

Also patently untrue. This gets a little tricky, and one needs to audition different set ups to be sure, but once again we are talking about the implementation here. If a DAC has an output stage which can properly drive the input stage of the partnering amplifier, then there will be only a disadvantage in adding a preamp to the system, as the preamp can only add distortion and noise. Many DACs, though, are not capable of properly driving an amplifier input stage, so one has to try out the setup in question and listen to know if it will work well.

Additionally, some people prefer having a preamp in the system because they like the "color" it might add to the sound: note that this "color" is an additional distortion, and while it may be pleasant (and their is nothing wrong with that) it is a distortion, and not present in the original music. I, personally, would add, that if a system needs added distortion to sound good: there is a problem in that system which would be better addressed at its source.

 

3. Do not use software based volume controls as they are terrible.

 

Another myth which is patently untrue. Again, it comes down to implementation. Some software volume controls may be terrible, but my experience with the volume control in Pure Music (with dithering) shows it to be a very good volume control.

 

conclusion: I would ignore anyone here who answers your question using absolute language and speaking audiophile myths: the real answer is: it depends, and one must investigate the options in their system via testing to find a set up which works best.

It took me a lot of testing to get to the point where I could ditch my preamp (Ayre K-5xeMP) and get better sound by going DAC direct to amp (PASS LABS X150.5) but I am there now and the sound is better without the preamp in the chain.

 

[sandyk]

"A well implemented digital volume control (as in the ESS DAC chip which operates at 48 bits) will do less damage to the signal than any analog volume control. Period, note, that this does not mean that all digital volume controls will outperform all analog ones. It is important to understand that analog volume controls are not benign when considering this, they add distortions of their own."

 

Damn. That rules out a Lightspeed Attenuator then ! (heh,heh!)

 

 

[barrows]

Is it your assertion that the Lightspeed is benign? Another volume control I did not mention is the transformer based approach: of course, any additional transformer in the signal path will add distortion.

I am not familiar with how the light based attenuators operate. I do believe the variable gain approach as used by Ayre in the KX-R is as benign a volume control as possible, but one still has the additional signal degradation caused by the preamp itself. The gain of the circuit is changed to change the volume, rather than attenuating the signal itself: this approach has the additional benefit of keeping the S/N ratio intact at all volumes.

But I do not intend to add an $18K preamp (Ayre KX-R) to my system just to add some distortion/noise of an additional gain stage, interconnect, and connections.

 

 

[SteveChicago]

... I started one called 'Resurrecting the Preamp' for example.

 

I found in my system that I like the preamp added in, although the DAC I have is good and has vol. control

 

You might read the other threads to get a wider range of experiences.

 

[SteveChicago]

... I started one called 'Resurrecting the Preamp' for example.

 

I found in my system that I like the preamp added in, although the DAC I have is good and has vol. control

 

You might read the other threads to get a wider range of experiences.

 

[esldude]

Didn't do the exact Lightspeed Attenuator thing, but 10 years ago I did mess with something very similar. I much preferred my DAC's to feed my amp directly with passive volume control until good digital volume controls were available. I mostly used 12 position switches with good resistors and matched gain on everything carefully. I experimented with using some light sensitive resistors, and some opto-couplers in various arrangements. They showed promise and with more effort could work well. But you had to have very clean power supplies.

 

I ended up with an odd switched resistor array instead. Used one series resistor and 7 different value shunt resistors in parallel each switched in or out by quality switches. They combined something like the ladder arrays in DAC's did. So it worked like a binary volume control. Had 128 quite small volume steps. Input and output impedance was well handled at all positions this way. After not so much time I even was able to flip the switches to change volume without much thinking about it. Seemed very inconvenient to someone not used to it however. Allowed me to have lots of small steps without needing many resistors and without microprocessor or relay logic to control them. Also allowed me to use Vishays without breaking the bank.

 

Best passive I have gotten to use, but when consumer gear with good digital volume control was available the passive solution was no longer needed.

 

[sandyk]

Hi Barrows.

I was being mischievous.

I would never even consider using a Lightspeed Attenuator with a Preamp that has close to 4 Zeroes in it's distortion figures.I like to hear recordings the way Record Producer intended, not with lashings of added warmth. Unfortunately, my DAC is only good for no more than 10dB of digital volume control before deterioration becomes quite marked with 16/44.1 , but not quite so bad with 24/96, as it is with many other affordable DACs.So until I can afford to construct a B2 or B3, or purchase an Oppo 95, then I will continue to use a very high quality DIY Class A preamplifier.

Regards

Alex

 

[sandyk]

eslduse.

Like you, I have been there done that too, but not as far as 128 volume steps.I did play around with compressors and expandors using LEDs and Opto couplers many years ago.

I agree that the later digital volume controls as implemented in the Sabre DAC chip and others, is the way to go. But, until then...

Regards

Alex

 

[harmonica2]

I am sure there are situations where a preamp included with a DAC outperforms some analogue pre-amps or integrated amplifiers.

 

However, one thing to consider is how quickly DACs are getting better and cheaper, whereas analogue integrated amplifiers are a mature technology.

 

By combining the DAC and the pre-amp, you are making it more difficult to upgrade your DAC, something you are likely to do given the speed at which they are improving.

 

In the other hand, a quality integrated amp is likely to be considered a quality piece of gear for many years.

 

My advice is to keep the DAC separate for now until the technology settles down.

 

[Mark Powell]

Why do so many people say you need a preamp? Some manufacturers call their DAC with a volume control a 'Digital Preamp', such as Benchmarks HDR. Because that is precisely what it is.

 

Do the 'separate preamp' guys believe that putting some digital circuitry in front of a regular preamp (all in the same case) automatically makes the Benchmark guys and the others less competent at designing a preamp than anyone else?

 

Then we have the 'analogue versus digital' volume control wars. The problem then is that we get into such stuff about how much bit depth of a digital volume control is needed to equal or be better than analogue. Why bother?

 

Remember KISS (For those very few who don't know - Keep It Simple, Stupid). The less active components in a system the better. Ask Nelson Pass. Do the digital volume control boys have the remotest idea just how many active components there are in a digital volume control chip? Lots of passive ones too, almost all of them resistors.

 

The noise in an analogue volume control is extremely low, especially so at the very low currents involved. One made up of rotary switches is probably best, as then you dont get a worn track. Digital volume controls are an insanely complicated solution to a non-existent problem, though they probably don't do any actual harm.

 

Sorry Deaddog, you asked a simple question and hoped for a simple answer. You didn't get it, and you won't. I am just as guilty as everyone else.

 

[Mark Powell]

It's a different track, I know, but related. We get guys talking about buying laser beams to measure speaker distances to fractions of an inch - must be more accurate than a tape measure, it's got a digital display!

 

If they go to a live concert do they ever move their head?

 

Do they go to concerts? Maybe not. It's not about music, it's about 'stuff'.