Who is using their DAC as a preamp?


Just curious the results people are hearing using Dac as line stage. Some dacs even have Analog inputs.  
aberyclark

Showing 23 responses by georgehifi

You really need a good preamp to have incredible midrange, depth and texture, resolution, etc.
Sorry but it must be coloration’s your hearing, and if you like that that’s fine it suits your system, some like to color the sound of their source if not happy with it.
But it’s impossible for a preamp to make up (midrange, depth and texture, resolution) itself, and then add it to the music that comes from the source information. Better off getting the sound of the source right.
  
Classic Ivor Tifenbrun (Linn) saying,
"It all starts at the source, get that right and your 1/3rd of the way home, get it wrong and your forever chasing your tail changing things to make up for it".

Cheers George
aberyclark
Who is using their DAC as a preamp?
Using dacs or cdp’s that most have digital domain volume control, is the most transparent/dynamic, least colored way of hearing the source.

But only if the volume is at or above 75% of full volume. Any lower because it’s too loud than 75% and you run the risk of "bit stripping" eg: 14bit resolution instead of 16bit, and 12 bit if you go even lower.

All is not lost if this is happening and it’s too loud over 75%, you simply use a good passive volume control between the dac and amp, and pre-set the level on it so your dac is used above 75% for the level you need.

Cheers George

George,
Linn also makes some great preamps.
I believe you like the coloration/distortion, it brings, but it impossible for it to make (midrange, depth and texture, resolution) itself
Pass Labs as well they all need to make money for the company, and this is what Nelson Pass says.

Nelson Pass,

We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.


Cheers George
These would be two different animals

A dac with volume ability "generally" has no preamp in it, it has a low output impedance buffer stage, and a "digital domain volume control".
That buffer is usually as good as most solid state preamps output, low impedance and has enough voltage  to send most amps to give full wattage (clipping)

There are one or two dacs with "analog domain volume" just before the output buffer, that have analog inputs and can switched from the dac chip output to these analog inputs, and the output buffer as above could have "extra gain" put on it via it’s feedback and "said" to be a preamp.

Cheers George.
I was watching a PS Audio video where the owner was saying digital volume controls , like many dacs and PS Audio preamps have, are better.

Source digital domain volume controls are the best, but! You need to be careful that if you attenuate too much with them you start to "bit strip", that is you get 14 bit or 12bit music resolution, instead of 16bit. Don't go below 75% of full with them it's said, and you don't run that risk of "bit striping" the music.
 
If you have to go lower than 75% because it's too loud, then your better off leaving it up full (100%), and using a passive preamp to attenuate to a good loud level, then use the digital volume to change the volume between 100% and 75%.

Cheers George  
The only thing it seems to lack is coloration.
So true, but many seem to like it (preamp) colouring their source because they "maybe" don’t have the right one (source) yet, so prefer the bandaid fix it instead.

Cheres George


Yes +1 pdreher if you like the sound of your source, a lot of money is saved this way, as all preamps have their own colourations, and you need to go through a few before getting the right one you like, why not just do the same with the source and forget the preamp.

Chers George
Suppose, if you want or need a preamp?

Cheers George
For late night listening, I currently have a Schiit EQ (Loki) in the effects/tape loop connection of the Rogue. I just boost the lower frequencies a little...basically I use it as a loudness switch. Since the EQ has "true" bypass, I can just use it in line between dac and amp if I decide to ditch preamp.
An excellent choice for late night low volume listening, and the Schiit Loki at $149 is a bargain, does all what you said and more,   https://www.schiit.com/products/loki   just put it between any of these configurations: 
1: Between source and poweramp (if you have source volume control)
2: Between source and preamp
3: Between your preamp and poweramp.
4: Or in the tape loop on an integrated amp.

Cheers George 



Cleaner than the Sys...Ebay item # 253818627052...HiFi version. $40 or less, shipped. About what you would pay to build one. Promise..


Trouble is the minimum 1:10 impedance ratio.
It shows a 100kohm Alps passive!!!! and that will be a problem not for the source but with many poweramps
They should have made it 10kohm, that way all is good, except for <33kohm poweramps, which thank god there are not too many of.

Cheers George
There is the even better, the Alps "Back Beauty", but they cost a lot more.

https://i.ebayimg.com/images/g/O1kAAOSwQolbFS19/s-l300.jpg

https://www.picclickimg.com/00/s/MTA3MVgxNjAw/z/W~QAAOSwYGFUv3Ah/$/1pcs-ALPS-RK40-50KA-Black-Beauty-...

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSrMqGsGmwCWfSPDB1Y9O6LrTsKEfybIOqvEkwLGaCSU4Li...


I am sorry Georgi, but this device is an EXCELLENT passive unit
As for the sound, I don’t doubt you like it,. and what you get is a bargain, I’m just pointing out the confusion of their ad in what actual value Blue Velvet is used and you get, all values will work as I pointed out, some better than others, because of proper >1:10 impedance matching input and output.

We just have to wait for someone to have a look at what’s inside them.

Cheers George
Yes typo "Black Beauty" if you came through Audio 70's/80's you know all about the Alps Black Beauty and Blue Velvet.
https://www.google.com/search?q=Alps+%22Black+Beauty%22&rlz=1C1CHZL_enAU820AU820&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjZ5Lv4n-_hAhVYWysKHWNkD_UQ_AUIDigB&biw=1408&bih=869

https://www.google.com/search?rlz=1C1CHZL_enAU820AU820&biw=1408&bih=869&tbm=isch&sa=1&ei=fcHDXNK9ONmR9QPNn73ICw&q=Alps+%22Blue+Velvet%22&oq=Alps+%22Blue+Velvet%22&gs_l=img.12..0i30j0i24l6.25691.35942..38034...0.0..0.207.1739.0j11j1......0....1..gws-wiz-img.......0i7i30j0i8i7i30.28dFrooeV2A

As for using a separate pot, same value, for each channel, there is no EE reason that it should be better or worse.
  
But I get the same thing with owners of two Lightspeed Attenuators, the  Stereo version and the Dual Mono version, they swear the Dual Mono sounds better.
I think it's because they can dial in an exact central stereo image with the left and right level controls, regardless of room/equipment/ music source influences, and this has an slight influence on the sound to them.


Cheers George
It all over the place, they say 50k input but don’t say which one, which means a 50k pot. Could be the cheap 24mm they have, as you can’t see the value on it.
But the pic if you zoom on the Alps (Blue Velvet) says 100kohm A taper (log) pot and it would be a 100kohm input impedance.

Whatever it is (50k or 100k), 10kohm is the best value to have, as all decent sources can handle 10kohm load (save for a couple of silly tube output ones)

A 10kohm pot has "at worse" 2.5kohm output impedance which is fine for any poweramp with >33kohm or higher input impedance.

Would be nice if you open it and find an Alps 10kohm A-taper (log) Blue Velvet for $40 with box and decent rca’s and free shipping.

Cheers George
T+A DAC 8 DSD
 We have again further improved the unit’s outstanding pre-amplifier, and incorporated a volume control of fully analogue construction based on High-End Melf resistors. The “State of the Art” output stage is of fully symmetrical design and discrete construction. Its impedance is very low, and it is equipped with symmetrical(XLR) and asymmetrical (RCA) outputs. These features make the DAC 8 DSD more than just a High-End converter: it is also a High-End pre-amplifier of supreme quality.
T+A DAC 8 DSD Different ladder resistors they are Melf not Visay. But it is a full discrete preamp output stage with more than enough output.
 
Perla Audio MAESTRO PRE-AMPLIFIER
It doesn't say anything about the Perla Audio Maestro being anything but a passive preamp. 
It uses power, but that's just for remote receiver and volume control movement duties, it's still a passive looking at the website.
  https://www.perlaaudio.com/pre-amplifiers

Cheers George 
I call it correcting wrongs, "looking for a fight" doubt that very much.
"Relax there fella" Really!!!

My preamp is the Perla Audio Maestro which has both active and passive inputs.
There are no active inputs. What emcdade was stating is simply wrong, and I corrected it.
  
And please!! don't call me Georgie, that's only reserved for my blonde Russian mini skirted music teacher, when we play "teacher and student" and I've been a bad boy!    

Cheers George


Seems like they’re claiming that actives are better than passives
They must make preamps. And quite a few.

https://benchmarkmedia.com/collections/preamplifiers

Cheers George
George,
First of all, Perla’s new preamp has both active and passive inputs.
Considering I own it I SHOULD KNOW.

Please show us a link?
Sorry, you need to look at what the manufacture says you own, it has a cd input and two auxiliary inputs, there are no active inputs.
The only reason it’s powered is because it needs power for the volume control motor and for the remote control receiver circuit and for the blue light on the front.
https://www.perlaaudio.com/pre-amplifiers


Secondly as you put it, it’s the T+A Dac 8 that I mentioned about Vishay and Melf. As many manufacturers make Melf resistors as it stands for "Metal Electrode Leadless Face" This had nothing to do with your Perla passive preamp and what resistors are in it.

Cheers George
Looks like I have to eat my words emcdade and say sorry, it does seem that there is/was a Perla Audio Maestro preamp "active" looking at this used one for sale (already??), but why it wasn’t on the Perla Audio website is still to be fathomed out.
https://www.ukaudiomart.com/details/649409751-perla-audio-maestro-pre-amplifier-active-and-passive-in-a-single-chassis/images/1768798/

Cheers George

George, if you look further down on the Douk page of the device, in the specification section, it states that the Alps 27 pot is 50K ohms. I have not taken mine apart, which would be easy, but I am telling you, it sounds quite invisible.
https://www.ebay.com.au/itm/Douk-Audio-High-Precision-Passive-Preamp-Volume-Controller-HiFi-Pre-Amplifiers/253818627052?hash=item3b18c4e3ec:m:mFApKB2238-vYIZZSg26Ehg&frcectupt=true

This one actually shows a 50kohm motorized pot not 100kohm, but a 10kohm would still be the best to match up with a lot more amps and sources.
But this one is motorized but no remote or power input or receiver, I have no idea what these guys are into, and I don't think they do either.
https://www.ebay.com.au/itm/FV3-passive-preamp-HIFI-volume-controller-ALPS-RK168-FOR-amplifier-NEW-VERSION-/143178261198?_trksid=p2385738.m4383.l4275.c10

Cheers George


However if someone felt that their solid state amp was a little to harsh they might want to mellow it out with a preamplifier.

Yes this is what they’re good for, a tube pre "maybe" to mellow, and many solid state ones that can add some "etching" (focusing).

A passive is about as close to neutral you can get so long as impedance matched.

And direct (no preamp) is the ultimate in transparency, like a straight wire, but if you don’t like it, you don’t like the sound of your source. And need one or the other active preamps to colour it.

BTW "impedance matching", goes for actives "almost’ as much as passives do.

Cheers George
Disagree George

It’s your right to, but fact is digital domain volume controls in dac and cdp’s are the most transparent way of controlling the volume. But like with anything there are proviso’s.

To make sure they don’t go into "bit stipping" (resolution reduction from 16bit to 14bit to12bit the lower they go ) they should be use at or above 75% of full level.
Wadia and Mark Levinson and Bricasti ect ect in their flagship dac/cdp’s models, know this and is why they give a user option of pre-setting the analog output buffer gain/level reduction or increase, to then enable the digital domain volume control to be used at or above 75% of full.
EG: Wadia’s way of doing this. https://ibb.co/VQpdGHz. Mark Levinson was similar and Bricasti was a different way, from memory via the back panel.

Cheers George
ahofer
  I've tried a variety of preamps and the only real difference I noticed was an increased noise floor (that was with a Spectral preamp, not a tube unit, interestingly enough) and some tube bloat.

So true ahofer, that's all they can do, increase noise/distortion/colouration and give tube bloat, against going direct if it's a match, and 99% of the time it is a match.
Many tube preamps aren't a match with low input impedance amps also. 

Cheers George 
Or a preamp with built in DAC
??? The whole point is using a dac’s (digital domain) volume control with no preamp after it, as a dac’s output buffer stage in 99% of cases has enough output and drive to drive just about any poweramp well over it’s full power.

Why as Nelson Pass says:
"Reduce the dacs output greatly with a preamps volume control just so then preamps output "gain stage" can make it back up again."
Your loosing signal to nose ration big time by not utilizing all the dac’s output which keeps the noise down. (Your robbing Peter (the dac) to pay Paul (the preamp)
It’s like driving a car with the handbrake on, and having the engine rev harder to keep the speed up.
Or if that analogy doesn’t do it for you.
It’s like turn on a garden tap full wanting max water pressure at the end of the garden hose, but the hose has got a kink in it.

Cheers George