R2R DACs - Is it normal to hear hum??

[Bernardo_G]

Hello guys.

I fell into temptation of an R2R DAC so bought a Ladder Czerny that was on a discounted price some weeks ago https://shenzhenaudio.com/products/ladder-czerny-r2r-digital-to-analog-convertor-dac

I have had great experience with their Bach preamp, so I bit the bullet with their entry-level R2R DAC; I'm highly satisfied with the performance and sound I get, however when I listed through my headphone amp, I notice that the DAC has a humming sound that can be faint on annoyingly loud depending on how hard I push the headphone amp. My previous DAC (Schiit Modi+) was dead silent even when reproducing music at extreme volumes. I did A-B tests using the same gear and the result was the same... the hum comes from the DAC.

I truly want to keep this DAC but this humming sound is a no-no; is this normal of R2R DACs or is there something wrong with my unit? Someone told me that this DAC is most probably the same as a Denafrips Ares12th under the hood, so I'd appreciate any feedback from Denafrips' users. I'm a newbie to R2R DACs.

Thanks!

 

[DVDdoug]

No it's not "normal" for any DAC to have audible noise. But if you have a ground loop it could be caused by something else.

There will always be SOME noise from the analog output (or from any active analog electronics), and any amplification will amplify the signal and the noise. And some headphones are more sensitive (louder) than others and that makes any background noise easier to hear.

I'm highly satisfied with the performance and sound

Apparently not...

My previous DAC (Schiit Modi+) was dead silent even when reproducing music at extreme volumes. I did A-B tests using the same gear and the result was the same... the hum comes from the DAC.

If the other DAC works, use it. Most DACs are better than human hearing so if it didn't die, or unless it's missing some features you want, you didn't need to change it.

 

[MaxwellsEq]

I truly want to keep this DAC but this humming sound is a no-no; is this normal of R2R DACs or is there something wrong with my unit

No, there's no reason why an R2R DAC should have hum. There are some R2R Dacs on here that have measured in the same ballpark as the Sigma-Delta designs.

 

[Bernardo_G]

No it's not "normal" for any DAC to have audible noise. But if you have a ground loop it could be caused by something else.

There will always be SOME noise from the analog output (or from any active analog electronics), and any amplification will amplify the signal and the noise. And some headphones are more sensitive (louder) than others and that makes any background noise easier to hear.


Apparently not...


If the other DAC works, use it. Most DACs are better than human hearing so if it didn't die, or unless it's missing some features you want, you didn't need to change it.

Hello @DVDdoug. Yes I'm satisfied with the type of sound this DAC delivers. I've noticed a pleasant difference in how the cymbals sound and overall how the drums feel in the mix in certain albums; also the vocals sound smoother and the bass is a little bit less focused but weightier and meatier. This effect can be felt equally through speakers and through headphones.

I compared it to the Modi+, back-to-back and while that one is also a good DAC, when I listen through headphones it sounds louder but a bit harsher or "shouty"; the Czerny sounds mellower and more relaxed, but... the hum!!! It cannot be detected through speakers but through headphones is audible; hence my original question.

 

[Bernardo_G]

No, there's no reason why an R2R DAC should have hum. There are some R2R Dacs on here that have measured in the same ballpark as the Sigma-Delta designs.

Any examples please??

 

[MaxwellsEq]

Any examples please??

Sure, Amir reviewed the Topping Centaurus R2R DAC. It was pretty good. Intermodulation Distortion is not state of the art, but probably inaudible:

Topping Centaurus R2R DAC Review

This is a review, detailed measurements and listening test of the Topping Centaurus R2R stereo balanced DAC with PEQ filter support. It was sent to me by the company and costs US $999. The unit has the elegant look of the new Topping DACs with high resolution, high contrast screen, nicely...

audiosciencereview.com

 

[DVDdoug]

I've noticed a pleasant difference in how the cymbals sound and overall how the drums feel in the mix in certain albums; also the vocals sound smoother and the bass is a little bit less focused but weightier and meatier. This effect can be felt equally through speakers and through headphones.

Ummm... Take a look at my "signature" below. Proper scientific, level-matched, blind listening tests can be surprising!

Most of those words aren't really defined... SOME of that COULD be explained by frequency response variations but most electronics have flat frequence throughout the audio range (but not speakers or headphones). For example a lack of bass, or boosted bass is a change in frequency response. That would be unlikely in a DAC and you didn't say "more bass", "less bass" or "no bass"... You said "less focused bass". I don't know what that means and I doubt it would show-up in a measurement or in a blind listening test.

With electronics there are ONLY 3 characteristics of "sound quality" - Noise , distortion, and frequency response. With acoustics and speakers in a room there are other complications. See Audiophoolery. Usually (with electronics) frequency response and distortion are better than human hearing unless you over-drive an amplifier into clipping (distortion). Sometimes you can get noise (like your hum problem) but that's easy to identify and describe, as you did clearly.

 

[LTig]

If the DAC feeds a headphone directly, a high output impedance changes the frequency response according to the changes of the impedance of the headphone over frequency - usually resulting in more bass around the resonance frequency of the driver. This is actually a problem of the internal headphone amp though, not of the DAC itsself.

 

[Roland68]

Hello guys.

I fell into temptation of an R2R DAC so bought a Ladder Czerny that was on a discounted price some weeks ago https://shenzhenaudio.com/products/ladder-czerny-r2r-digital-to-analog-convertor-dac

I have had great experience with their Bach preamp, so I bit the bullet with their entry-level R2R DAC; I'm highly satisfied with the performance and sound I get, however when I listed through my headphone amp, I notice that the DAC has a humming sound that can be faint on annoyingly loud depending on how hard I push the headphone amp. My previous DAC (Schiit Modi+) was dead silent even when reproducing music at extreme volumes. I did A-B tests using the same gear and the result was the same... the hum comes from the DAC.

I truly want to keep this DAC but this humming sound is a no-no; is this normal of R2R DACs or is there something wrong with my unit? Someone told me that this DAC is most probably the same as a Denafrips Ares12th under the hood, so I'd appreciate any feedback from Denafrips' users. I'm a newbie to R2R DACs.

Thanks!

You could first test where the hum is coming from.
How did you connect the DAC to the source? USB?
Then you could test the DAC via SPDIF or Toslink on another source, without USB.

 

[bigpilot]

So it's an entry level Chinese DAC that costs $700?!

I'll pass.

 

[Bernardo_G]

Hello everybody!

As a follow-up from my previous post... I found the cause of the problem. The DAC was set from the factory for 220V and here in Colombia our electrical grid is 110V so I adjusted the settings and voilá... the humming noise is gone and now the DAC is dead silent (as it should be)!!

The sound is really really good now; I know that many people say that all DACs sound the same but compared to my old Schiit Modi+, the Czerny sounds a bit fuller and bolder, and the high frequencies sound a bit more "refined". The Schiit sounds a bit "shouty" when I turn up the volume really loud, in both cases, with speakers and with headphones.

I'm done (for now, LOL)) with my setup.

 

[Bernardo_G]

...you didn't say "more bass", "less bass" or "no bass"... You said "less focused bass". I don't know what that means and I doubt it would show-up in a measurement or in a blind listening test.

The best way I could explain is with an example: when listening to the intro of MJ's Billie Jean with the Modi+ in my setup, the bass line sounds really defined and punchy as if the bass player was using a pick to play the bass through a solid state bass amp; with the Czerny this same intro of the song sounds as if the bass player used his fingers instead of a pick, making the sound less clanky but meatier.

Also, in the same song, the "tsh tsh tsh tsh" sound (at 0:13) sounds more subtle and airy with the Czerny; with other DACs (Modi+ and Fiio K11 R2R) it sounds more pronounced and even as if it was being compressed.

Yes, I know that It can be my imagination, but I did this same tests with several songs I know well and I get the same feeling; another example would be the intro drum part of RHCP's Danny California. BTW I know how some of these instruments and rigs sound because I've been playing in a band for 20+ years and have become used to those sounds (the bass, the cymbals, the bass drums, etc) in a live and rehearsal context.

 

[xanalog]

As a follow-up from my previous post... I found the cause of the problem.

Thanx for letting us know and putting a closure to your problem.
I think a similar problem (220/110V) was previously mentioned elsewhere at ASR.

 

[maudio]

Yes thats the part of analog sound. Or did you hear a vinyl ever without a hum?

 

[Bernardo_G]

@maudio I don't get it; so that means that if a DAC's purpose is to tur digital to analog, ALL DACs should present this problem?

When I had the issue, the humming noise from the DAC was far louder than my phono preamp (which is very very quiet, BTW). I was considering returning the DAC but luckily I found the cause and fixed it really easy.

 

[xanalog]

i was joking there shouldnt be no hum even less than for delta/sigma but this depends on the psu and ground..
that’s why i galvanically isolated USB power to my SMSL SU-1 ChiFi DAC and couldn’t get even better sound.

You should go back and revise or add a smilie at the end of that previous post.

...Or did you hear a vinyl ever without a hum?

When I read it, I got cross-eyed but lacked will to contest your statement.

 

[maudio]

You should go back and revise or add a smilie at the end of that previous post.

When I read it, I got cross-eyed but lacked will to contest your statement.

you should go back to common sense.