• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Are pre-amps necessary

Joined
Oct 1, 2019
Messages
14
Likes
5
#1
Firstly thank you for this site. I get tired of being led around by peoples opinion and its nice to just see the numbers and decide your own path on what you want to upgrade next.
I was hoping to replace my preamp and my dac this year and after finding this site I thought maybe I can just skip the pre-amp and go directly from my dac to my power amp and use the volume control on the dac.

However upon more reading I found that using a DAC as a preamp is not always the best idea. Basically a dac with the built in volute control is actually using a digital attenuator and this can be lossy. I was actually interested in the Matrix Audio X-SABRE Pro and came across a review on 6moons that stated this. Upon more reading I came across the same information about using digital attenuation.

Is this true? are there some dac's with built in volume control that are better than others? or using a digital volume control is just never a good idea.
I was always under the impression that you set the volume control on whatever media player your PC uses as highest. Also are the dac's out there that use a better method to control volume if I skip the preamp path.
I like the less is more approach to things. and would rather concentrate my budget into one piece if I can.

Should i just upgrade my dac and continue using my old preamp instead? I would appreciate some insight.
For reference I have a
Lite Audio 68 dac using spdif (i set the volume control on this to max)
Parasound P3 preamp
Parasound HCA3500 power amp
and some heavily modded polk sda 1.2TL's speakers

I have no plans to replace the power amp and the speakers I just wanted to do something different with the dac and pre. to do something new and different as well as get a dac that was cleaner and had some newer tech's from my old one. should I just keep the p3 and replace the dac and use the p3 for volume control.

ALL my source is digitally stored in lossless format.
 

RayDunzl

Major Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
7,223
Likes
3,741
Location
Riverview, FL
#2

RayDunzl

Major Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
7,223
Likes
3,741
Location
Riverview, FL
#4

garbulky

Addicted to Fun and Learning
Joined
Feb 14, 2018
Messages
980
Likes
316
#5
How many kinds are there?
Some will upsample it or convert it to a higher bit depth and then reduce the volume. Some will reduce the volume without doing all that (more lossy). My Emotiva XDA-1 had the latter type. Foobar I believe has some sort of 64 bit digital volume control of the first type.
 
Joined
Oct 1, 2019
Messages
14
Likes
5
#6
so basically that is false. digital attenuation performed by a dac is not lossy?
or is the implementation in some dac's not as good? what ration feature would I look at in a dac to make sure it is done correctly?

some more reading leads me to believe that if you upscale say 16 bits to 24 bits and then perform digital attenuation you dont loose anything. some of this is over my head I must admit.

I also seem to be reading that analog volume control is still worse than any kind of digital volume control
 

anmpr1

Addicted to Fun and Learning
Patreon Donor
Joined
Oct 11, 2018
Messages
624
Likes
854
#7
I was hoping to replace my preamp and my dac this year and after finding this site I thought maybe I can just skip the pre-amp and go directly from my dac to my power amp and use the volume control on the dac.
Your current DAC has tubes in the audio stage? Is that correct? In that case I'd study the DAC reviews here, and then buy something in Tier 1 that's within your budget. Getting rid of the antique glass will do more to make your system accurate than worrying about a preamp volume control.

Matrix is an excellent, albeit pricey, choice. At least from the one's reviewed here. And it does offer output gain.
 

Fluffy

Active Member
Joined
Sep 14, 2019
Messages
269
Likes
345
#8
Digital attenuation is less about loss and more about noise floor. A 16 bit stream can represent a dynamic range of 96 db, hence it has a noise floor of -96 db. If you would keep the stream at 16 bit and lower the amplitude of the signal, with each 1db of lowering you will get 1db closer to the noise floor, until at -96db your signal will be lost in the noise floor. Of course, you will hear a rise in noise way before that.

But digital volume control doesn't usually work like that. If you take a 16 bit file and stream it over a 24 bit stream, which has 120 db SNR, you can potentially lower the amplitude of the 16 bit audio by 24 db before any loss of SNR will take place. And it gets better as you improve your bit depth. At 32 bit you have potentially 192 db of SNR, so you can almost lower the 16 bit audio by its full 96 db SNR and just barely scratch the noise floor of the 32 bit stream.

You need also to consider two other factors. First is the practical SNR of your entire system, and of your own hearing. CDs were made with 16 bit because that’s way more than you realistically need to play any sort of music in any setting other than maybe an anechoic chamber. Since your base noise floor in whatever room you're are listening in is probably higher than 30 db, you don't really need even 96 db of SNR. And most systems will have less SNR, where amplifiers and mostly speakers are the limiting factor.

Dacs are usually the least limiting piece in the chain, and well-engineered dacs can easily have SNR of 100 db and more. And that’s the second factor to consider – you can only realistically use the bit depth whose SNR is lower than the SNR of your dac (called linearity sometimes). Say, if your dac has 110 SNR, you can't even use the full potential of 24 bit audio, let alone 32 bit. But that is not really a problem.

Think of it like this – say you have a base noise of 30 db SPL in your listening room (which is really low). If you set up your system to play 16 bit audio such that the quietest possible bit is at 30 db SPL, that would make the loudest possible bit (0dbFS) at 126 db SPL! Which is higher than the threshold of pain for humans, and is as loud as a jackhammer close by. You'll probably never listen to music at that volume, and I doubt most speakers can play at that volume without distorting terribly.

That means that most dacs has more than enough SNR to digitally control the volume without any perceptual noise floor. If a dac has that option built in, make sure it's converting the stream to 24 bits at least. 32 bits is the professional industry standard for audio editing, so anything beyond that is completely overkill. Nothing in the world has more than 192 db SNR anyway.

You have also clever solutions like the one in the RME ADI-2-DAC that uses digital volume control. In the default mode it has more than enough SNR to control the volume seamlessly, but if you are still concerned, you can optimize its noise floor by setting the base reference level to your liking using actual analog circuitry, to get the best SNR possible. It even has a mode in which it blends together digital and analog control to automatically achieve the lowest possible noise floor. But this is a massive overkill in most cases.

So to conclude, fear not from digital volume control. If the dac is decent and you resample your stream to 24 bit at least, it will be completely transparent.

Edit: I made a mistake actually. 24 bit depth gives you SNR of 144 db, not 120 db.
 
Last edited:
Joined
Oct 1, 2019
Messages
14
Likes
5
#9
Your current DAC has tubes in the audio stage? Is that correct? In that case I'd study the DAC reviews here, and then buy something in Tier 1 that's within your budget. Getting rid of the antique glass will do more to make your system accurate than worrying about a preamp volume control.

Matrix is an excellent, albeit pricey, choice. At least from the one's reviewed here. And it does offer output gain.
yes it does have tubes. based on some advice I had in the past I thought it was the cool thing to do. I had also been looking for tube preamps a few weeks ago.
hence finding this site and reading more about the "tube" effect. I decided to scrap that idea. So thank you.

I had some money to spend so I was looking at the matrix x-sabre. Call it a delayed present. I just cant decide if i need the MQA version and yeah I have read multiple opinions on mqa already.

I was also looking at the RME ADI-2 that was mentioned in the next post. Which is much cheaper. And cant decide between the 2. I presume they would both work well as a combined pre/dac option.

Paying less is obviously better but I am just trying to decide if an extra 500 bucks will get me something worth that extra coin. My budget range seems to be in the 1k-2k range. and skipping the preamp upgrade now free's up more money for a better dac.
 

Sparky

Active Member
Patreon Donor
Joined
Jun 9, 2019
Messages
143
Likes
52
Location
Manchester
#10
@Fluffy wow mate... You just blew my tiny mind. :D

I was going to suggest the RME ADI-2 DAC but you beat me to the punch. Bravo...
 
Joined
Oct 1, 2019
Messages
14
Likes
5
#11
Thanks for the long write up on Digital attenuation .
My source has always been foobar on my PC due to its simplicity and I believe it can be re sampled to 24. but i was always been a purest and kept things the same at 16 so I need to do some reading on this.
Additonally i have been reading about roon since i seen it mentioned on here a few times. and I have played with jriver in the past.

i presume any of these players can be setup to do this re sampling properly?
 
Joined
Oct 1, 2019
Messages
14
Likes
5
#13
Always a dangerous way to make decisions. I'd slow down, read some more, and see if an good solution presents itself.

What's wrong with what you have?
The main thing I wanted to replace was the DAC. i wanted to swtich to using USB and getting rid of the tubes in my old dac. if i am going to buy one I was thinking of getting something with some of the latest bells and whistles like DSD etc..
The preamp replacement is not necessary but if I am going to go with a quality DAC and can just bypass the preamp that is a plus.
You dont know what you are missing until you know. I have read some positive and negative's about my preamp so I thought about upgrading it as well. But it would be nice if I can just bypass it and focus on a dac with built in preamp.

I have been reading about the next DAC i want for about 4-5 years now lol. I keep talking myself out of it. Hence it feels like my upgrade budget grew a bit since I sat on what i was wanting to spend 5 years ago and never spend it.
 
Joined
Oct 1, 2019
Messages
14
Likes
5
#15
If I go with that and decide later on MQA is something I want to include. Am I SOL? or is there a way to add a external device that can do the MQA filters and pass it though to your DAC for the second unfolding.

I am looking at Amir's list of blue dac's and then going though the threads to see if there is something on concern. Is there anything of importance I should pay attention too?
I know I want balanced output's and volume control. Other than that and the cleanest signal.. Do I just need to decide what bells and whistles I want? and how much I want to spend?
 
Joined
Aug 21, 2019
Messages
29
Likes
51
Location
Toronto
#16
I know I want balanced output's and volume control. Other than that and the cleanest signal.. Do I just need to decide what bells and whistles I want? and how much I want to spend?[/QUOTE
I think that you are right to want those two features in a DAC that also has very good SINAD. There are now quite a few that Amir has reviewed that meet these criteria and cost much less than the the RME. The RME's headphone amp is a nice feature; it might be worth considering if you also want that. Otherwise, many reviewed SMSL, Topping or Sabaj options would meet those criteria for much less.
 

restorer-john

Major Contributor
Joined
Mar 1, 2018
Messages
2,581
Likes
4,300
Location
Gold Coast, Queensland, Australia
#17
If you have a tuner, a turntable and maybe a few other random line level sources, use a quality preamplifier. Like your P3. It's a quality piece of gear- personally, I don't know why you'd consider replacing it.

If it's just you and your one digital source, a D/A may be sufficient, but digital volume controls are generally horrible. Personally, I can't stand them.
 
Last edited:

Fluffy

Active Member
Joined
Sep 14, 2019
Messages
269
Likes
345
#19

restorer-john

Major Contributor
Joined
Mar 1, 2018
Messages
2,581
Likes
4,300
Location
Gold Coast, Queensland, Australia
#20
The digital control on my Devialet feels luxurious to me, being able to set precise volume, from very low to very high, with perfect channel matching is really nice.
Generally horrible. In my experience. Of course there are some awesome ones (most likely like your Devialet).

Most of them jump, are slow and unresponsive, too fast, their range switching is awkward, or they make clicking/stepping noises. Others "forget" levels after a few short hours unplugged or turned off, and/or need standby power to keep a setting. All absolutely disastrous if you have a big power amp strapped on the end.

Give me an Alps RK-27 or die...

1570701100857.png


(kidding) :)
 

Similar threads

Top Bottom