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Topic: DAC (Read 9269 times) previous topic - next topic
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DAC

Hi, I hope I'm posting in the right section.
I would like to ask forum members for your recommendations for a good quality dac for 2 track recording.
I'm mostly archiving vinyl but I already have a high quality phono pre-amp already, so no RIAA eq required.
I have been using an EMU 0202 for a number of years, but suspect things have moved on since then.
I have done the normal research around the web for recommendations, but found most reviews not based on straight 2 track line level recording.
My ideal budget would be around £150. Any recommendations would be very much appreciated.
Thanks

Re: DAC

Reply #1
Quote
but suspect things have moved on since then

The thing have not moved on is vinyl. ADC/DAC quality (especially a known model with excellent published measurements like EMU0202) is never a bottleneck in vinyl archiving and vinyl rip playback.

https://www.ixbt.com/proaudio/emu/0202/emu-0202usb-2444-lineout.shtml
https://www.ixbt.com/proaudio/emu/0202/line-in-24-44.shtml

I'd suggest spend the money elsewhere, like buying some vinyl records and so on.


Re: DAC

Reply #3
Folks: what are the input level/volume considerations?
Interfaces with input level equal to or higher than the preamp's output level are fine. Usually written in the specs (dBV/dBu/Vrms).

No such limitation if the interface and/or the preamp have adjustable analog gain.

Re: DAC

Reply #4
Quote
have been using an EMU 0202 for a number of years, but suspect things have moved on since then.
As long as the drivers still work with your current operating system, you're fine.

As a rule, the only "spec" to be concerned with is noise.    Frequency response and distortion are usually better than human hearing, even with the line-input on a consumer soundcard.  (The mic input on a regular soundcard or laptop is generally useless for quality recording).    With an analog record, the record noise plus the analog hum and hiss from the preamp usually dominate so a "better" interface is unlikely to give you better results.  

Sometimes you can get (excessive) noise in USB-powered interfaces that comes from the computer's power supply.   It's usually a high-pitched whine.     Some interfaces are more sensitive to power supply noise than others and a different computer can make it better, or worse.  An interface with it's own separate power supply will avoid that issue.

Quote
I'd suggest spend the money elsewhere, like buying some vinyl records and so on.
Or CDs or MP3s.   :D




Re: DAC

Reply #5
Many thanks for your replies to my post. Looks like the consensus is to carry on with my 0202 Dac. It has always given me good results, I was just wondering if there had been any new dacs released that would give me better results, as I've been using this dac for about 7, 8 years or so.

Re: DAC

Reply #6
Hi Porcus, Noted, although I have posted as Dac, it is an ADC question I've raised. I only use it for recording, as I have a standalone Dac for playback. No hum or hiss from my phono set up, apart from any that may be on vinyl itself.


Re: DAC

Reply #8
Even without considering vinyl's limitation and transparency, those old EMU interfaces still have godlike specs at their price point. Find some random Behringer, Tascam, Focusrite, M-Audio interfaces at £150, their measurements are not necessarily better than the EMUs. The better spec'd ones like RME Babyface Pro are well over £150 with features like digital I/O and FPGA mixer which are irrelevant to ADC quality.

Re: DAC

Reply #9
Ok, good to know it can still compete.
The ADCs mentioned in previous post are the ones I've been reading about, but as you've suggested they tend to come with facilities that I'd never use.

Many Thanks

Re: DAC

Reply #10
This is interesting for me too since I'm about to digitalize my vinyls. I hope the OP doesn't mind me asking a question here.

As a rule, the only "spec" to be concerned with is noise.    Frequency response and distortion are usually better than human hearing, even with the line-input on a consumer soundcard.  (The mic input on a regular soundcard or laptop is generally useless for quality recording).    With an analog record, the record noise plus the analog hum and hiss from the preamp usually dominate so a "better" interface is unlikely to give you better results.  
Does this mean that I might as well use the line-in on a PC soundcard for the recording instead of chasing down a higher quality ADC?

What I have are a couple of 10-year old desktops from ca 2008 with onboard sound and a 3-year old laptop. I think I've heard that desktops have much better soundcards than laptops - is this (still) true?

Re: DAC

Reply #11
10-year old desktops from ca 2008 with onboard sound
I guess a 2008 desktop motherboard may have an AC97 or a newer HD Audio codec. The main problem is such codecs usually have a rather low and fixed analog input level like 1Vrms which may clip some phono preamps with fixed output level.

If you still want to try, record at 16-bit 48kHz rather than 44.1kHz in order to avoid the potentially low quality resampling from typical AC97 codecs. 24-bit is pointless as the ADC in a 2008 codec is usually something like 80-90dB SNR.

Re: DAC

Reply #12
I guess a 2008 desktop motherboard may have an AC97 or a newer HD Audio codec. The main problem is such codecs usually have a rather low and fixed analog input level like 1Vrms which may clip some phono preamps with fixed output level.
The desktops I have from ca 2008 have Intel HD Audio. It seems that this is still the standard today? Or do newer desktops have better onboard sound?

If you still want to try, record at 16-bit 48kHz rather than 44.1kHz in order to avoid the potentially low quality resampling from typical AC97 codecs. 24-bit is pointless as the ADC in a 2008 codec is usually something like 80-90dB SNR.
Is low quality resampling and 80-90dB SNR still the case with the newer Intel HD Audio codecs?

Re: DAC

Reply #13
There are premium HD Audio codecs like ALC1150/1220 on "gaming" grade and usually full sized ATX motherboards, they are $100-200 more expensive than mainstream motherboards with ALC892 which is not too different from a 2008 HD Audio chip like ALC888. However this $100-200 premium also includes irrelevant features like fancy RGB LEDs, more PCIE lanes for multiple GPUs, NVMe SSD and so on.

Yet the codec model is not a reliable indication of quality. Loopback test (line out -> line in) reveals the weakest link and depends on different motherboard design, the same codec can perform very differently in real world situation:

http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/74183-gigabyte-aorus-z270x-gaming-5-motherboard-review-12.html

...and a 7 years old discrete soundcard still blow them away, and with a 2Vrms input.
https://hydrogenaud.io/index.php/topic,100481.0.html

If one can spend additional $100-200 for a motherboard, I would say spend on a discrete soundcard or USB interface which has a more consistent performance, and can be reused on another computer. The motherboard I am using is only $62 (2015) with an ALC892, about 90dB ADC performance and no AC97 low quality resampling issue.

Re: DAC

Reply #14
Thank you, well explained.

So maybe my old PCs could be up to the task, but I would need to do loopback testing to determine. Since I tend to put too much time into testing stuff once I get started, I think I'll take the easy way this time and just grab an external ADC instead.

If one can spend additional $100-200 for a motherboard, I would say spend on a discrete soundcard or USB interface which has a more consistent performance, and can be reused on another computer.
Is $100-200 also the price range required for a good external ADC? Or would it be possible to get a good/excellent one under $100?

Re: DAC

Reply #15
90dB ADC performance is not a limitation as long as there is no clipping, it can be identified by finding squashed peaks in the recorded waveform. As an example I attached some files here, can you tell which one sounds best or worst by listening?

Is $100-200 also the price range required for a good external ADC? Or would it be possible to get a good/excellent one under $100?
Possible but you need to do some research, google keywords like "[product name] + rmaa" or "[product name] + rightmark" to find some reports, and don't forget to read reviews and forum posts to find complains about driver stablity/compatibility and so on.

Re: DAC

Reply #16
I couldn't hear any differences between the files. But I could hear the same kind of very small imperfection in all three files at 0:18-0:19 though.

Is this example of clipping as "bad" as it gets with 90dB ADC performance, or did you give me a tough one to detect?

Re: DAC

Reply #17
If I decide to use an external ADC, I could use an optical input (toslink) on one of my desktops. Is this preferable over USB?

Re: DAC

Reply #18
I couldn't hear any differences between the files. But I could hear the same kind of very small imperfection in all three files at 0:18-0:19 though.

Is this example of clipping as "bad" as it gets with 90dB ADC performance, or did you give me a tough one to detect?
(a) Recorded by my ALC892's line-in
(b) Recorded by my ALC892's mic-in
(c) Original file (CD)

So if there are any artifacts, they are in the original file rather than additional audible distortion. I've attached the RMAA report of (a) vs (b).

The result is clear, 90dB is good enough even for CD quality loopback, no way it would be inadequate for vinyl. Toslink/internal/external is irrelevant.

(a) and (b) are played by the same source, ALC892's DAC, with carefully adjusted output level to avoid clipping. Therefore the key point is whether your phono preamp is capable of output level adjustment or not. The Realtek's input level are adjustable, but only within a rather narrow range.

Re: DAC

Reply #19
If I decide to use an external ADC, I could use an optical input (toslink) on one of my desktops. Is this preferable over USB?
toslink is relevant only if you have ground loop problems, in such cases there will be obvious and distracting hum. You also need to have a turntable/preamp with toslink output and a soundcard with toslink input to use it. If you don't have all of these already it will surely cost more than $100-200 with potentially no improvement if you don't have ground loop problem in the first place.

To avoid misunderstanding, all toslink jacks you can find on desktop motherboards are for output, not input.

Re: DAC

Reply #20
(a) Recorded by my ALC892's line-in
(b) Recorded by my ALC892's mic-in
(c) Original file (CD)

I could visibly see that (c) differs from (a) and (b) in Cool Edit (yes, I still use that old program...), but it was inaudible to my ears.

Yes, the result is clear to me. And my "best" motherboard for audio (Abit QuadGT) has HD Audio and should be of decent quality of its time, but I still need to do loopback testing I guess.

/.../ the key point is whether your phono preamp is capable of output level adjustment or not. The Realtek's input level are adjustable, but only within a rather narrow range.

My phono preamp is a Cambridge 651P which has fixed output, so a potentional matching problem there.

Re: DAC

Reply #21
If I decide to use an external ADC, I could use an optical input (toslink) on one of my desktops. Is this preferable over USB?
toslink is relevant only if you have ground loop problems, in such cases there will be obvious and distracting hum. You also need to have a turntable/preamp with toslink output and a soundcard with toslink input to use it. If you don't have all of these already it will surely cost more than $100-200 with potentially no improvement if you don't have ground loop problem in the first place.

To avoid misunderstanding, all toslink jacks you can find on desktop motherboards are for output, not input.

I have toslink in and out on one of my motherboards (Abit QuadGT), so it's an option and I would only need to buy an external ADC with toslink output, eg. this one: http://www.cypeurope.com/store/store/app/product/AU-D4/Analogue-Audio-Converter

So price-wise it probably doesn't matter compared to an external ADC with USB output.

But I don't know if I have ground loop problems, I haven't checked this.

Re: DAC

Reply #22
I have toslink in and out on one of my motherboards (Abit QuadGT), so it's an option and I would only need to buy an external ADC with toslink output, eg. this one: http://www.cypeurope.com/store/store/app/product/AU-D4/Analogue-Audio-Converter

So price-wise it probably doesn't matter compared to an external ADC with USB output.

But I don't know if I have ground loop problems, I haven't checked this.
Motherboards with toslink input are really rare and I am surprised.

That means the conversion quality depends on the AU-D4 itself. It is 48kHz fixed, input voltage level is unspecified so there is no guarantee of clip-free operation, noise and distortion level is also unspecified and therefore not necessarily better than the Realtek.

To identify ground loop and clipping you can attach some 30-second recordings with loudly recorded vinyls and empty preamp noise here, speculation is not needed.

Re: DAC

Reply #23
Quote
But I don't know if I have ground loop problems, I haven't checked this.
If you are not hearing "excessive" power-line hum, don't worry about it.    

If the hum is bad, you might have a ground loop or a missing/broken ground.

There are other sources of hum...   There is almost always some AC hum picked-up by the cartridge and amplified by the preamp, and sometimes hum can get-in through the preamp's power supply.   If you're not hearing it at normal listening volume, you're OK.  


Re: DAC

Reply #24
Thank you both for helping out. So the clipping issue is probably my only concern.

I'm not at my home location right now, but I have checked that I have the ALC888 chip and the previously mentioned Cambridge 651P with fixed output. If this combo creates clipping, would it be a bad idea to use my stereo preamp in the chain to adjust the levels?

record player > phono preamp > ALC888
vs
record player > phono preamp > stereo preamp > ALC888

On the stereo preamp, I can either use the volume control normally or I can fix the output at a desired level separately for each input so that the volume control is disabled (but I don't think it's bypassed, I think it's just fixed).

But this would also mean to introduce an additional amp in the chain, is this a bad idea?