Hi Rob

I also have a similar set up with DAC magic and beoport. The improvement in the sound of digital music is fantastic.

I have had to reduce the volume to about 2/3 on itunes itself as with the volume on full a dreadful crackling sound is heard, particularly on net radio.

Im curious as to why you can have the volume on full as in my case I cant...

Any advice appreciated.

David Coyne

Sydney, Australia

Nice to see people sharing their experiences with the DacMagic. There are DACs with volume control, but they tend to be a bit steeper in price than those without, due to the design challenges of creating a transparent volume control (that doesn't degrade the sound.)

The Arcam would probably do fine, you would be introducing an additional step in your signal chain. But why not use the volume control in the Mac, or use an iPod Touch/iPhone?

Or - you might want to consider purchasing a used Benchmark DAC, with volume control. A number are coming on the market now, as people are upgrading to the latest version HDR with remote control.
The early versions without remote control are excellent, and have the same interior DAC. Look for a DAC1 or DAC1 USB unit, though I agree with the poster above about the toslink connection instead of the USB. (With the optical connection, you get galvanic isolation between the computer or airport express, and the DAC - reduced chance of any ground hum or noise being transferred between the units.)
I see Benchmark DACs going at very good prices, for used units.

This is the latest trend - to use asynchronous USB, where the computer is slaved to the DAC, and where various apodising filters are used to remove so-called pre-ringing in the digital signal.
The manufacturers have to think of something ... Today, dCS, Wavelength and Ayre offer apodising filter solutions, as well as Meridian, which has put this in their updated CD-player, which Stereophile drooled over as delivering "the best measured performance ever."

It's then a question of whether you can hear the added performance, or whether this is a measured benchmark that is irrelevant. And there are issues with removing pre-ringing (an artefact of anticipating the incoming digital signal), you can risk enhancing post-ringing, but that is often masked by the signal proper.

Modern electronics have jitter-performance down to picoseconds. A picosecond is 1 TRILLIONTH of a second.

0.000 000 000 001 seconds.

Desperately looking for reasons to get audiophiles to spend money on digital circuits, the industry is turning jitter into a major problem, when it isn't. What is the problem? Well, you could risk your digital circuitry either not reading the 1 or 0 right - chances of that happening are non-existent with today's equipment, unless you have actual hardware failure.
So then it's down to whether jitter can introduce timing errors in the playback of the signal - i.e. that you get good old vinyl wow and flutter, but in the digital domain, and whether this can contribute to "listening fatigue" and a sense of "digital harshness."

So let's try to get this number in perspective. A Redbook CD-signal has 44.100 samples per second, with a data-depth of 16 bits.

If we divide the circumference of the Earth at the Equator by 44.100, we end up with segments that are about 900 metres long. Let's say that you want each segment to be exactly the same length, and that there is something called jitter that is making this difficult. Even with the worst jitter performance shown above (with the power supply creating jitter of 2800 picoseconds), the individual segments would vary by at most a couple of millimetres. That's pretty good for something that is 900 meters long. And with jitter down to where we usually see it, in good (not extraordinary) components, the variation would be around 1/10 of a millimetre for a 900 metres long segment, of which there are 44.100 produced every second.

If one thinks that's a significant factor affecting listening enjoyment, then do choose extravagant jitter suppression. The greatest jitter problem in audio is the nervousness of the traditional audio industry, as the consequences of the digital music shift become clear.

The CASH page of Computeraudiophile.com is a good reference of value for money in digital audio:

soundproof wrote:

The Arcam would probably do fine, you would be introducing an additional step in your signal chain. But why not use the volume control in the Mac, or use an iPod Touch/iPhone?

Hi Soundproof!

you seem to know everything about audio! When you mentioned above about using Volume Control in Mac for DACMagic. So will that work fine? I seem to understand from one of the posts that if you use DACMagic I will not be able to control the volume from Mac, that's why I put arcam into the equation...

wowmix wrote:

I seem to understand from one of the posts that if you use DACMagic I will not be able to control the volume from Mac, that's why I put arcam into the equation...

The default output format for digital audio from Macs is full volume, but you can control this, either using the volume control on the Mac or using your iPod Touch or iPhone. I'm doing this right now, with playback from a Mac mini to my soundcard.

However - I have BL5s, which make it possible for me to set a working volume for them, and I have set it so that whatever source they are fed, they do not blow out my ears or windows (which they could probably do if set at max.)

BL3 doesn't have that option, and you therefore risk feeding them unlimited volume, and that can be a loud experience. So you either have to get into the habit of making sure that you have set the volume where you find it comfortable, before sending them a signal; or have a volume control (your Arcam or a DAC with a volume control option). I'd personally prefer not going through the Arcam, so maybe you should look for a DAC with volume control, and have that set at a level where you never risk blasting the speakers, and then just leave the volume in the Mac at max.

If you trust yourself to always check the volume setting on the Mac before hitting play, then you're OK using a Touch or iPhone to control playback volume.

DACMagic vs Edirol UA-25EX

How about Edirol UA-25EX by Roland. I've read the spec but I don't understand everything. The price is similar between the two. Can anyone give me a comment on these 2 please. Which will be a better companion to my MacBook?

http://www.rolandus.com/products/productdetails.php?ProductId=970&ParentId=114

Thanks in advance.

Hi David,

Not sure I can offer any wisdom on why you cannot take iTunes volume above 2/3 when feeding the DACmagic without getting crackling. I read in a number of places that early versions of iTunes didn't control the volume at low settings particularly well from a quality perspective so you should always run it at full volume. I understand this was fixed from iTunes 7 onwards, but when I set up my system I thought it was logical to run a full volume so as not to risk any potential degradation through the software trying to manage the volume.

I'm using a TOSlink cable rather than USB (as I did find a difference) are you? Perhaps there's a difference here in the way the DACmagic handles the input. Otherwise I'll leave it to others who have greater knowledge of the D to A world than me (I'm relatively new to this).

Best,

Rob

If you're getting crackling at some volumes but not others when using the iTunes volume control, then it's a sign that either the 'Sound Enhancer', or iTunes 'Equalizer' are on, both of which are useless RE gain structure, and usually result in crackling volume (due to clipping - the signal reaching it's maximum volume and 'flattening' off at the top).

Always ensure the iTunes Equalizer and Sound Enhancer are switched off. Both do nothing other than introduce masses of distortion into the signal. If you really need to EQ the sound, use a good external equalizer, like the Klark-Teknik digital EQs (which are brilliant). The iTunes Sound Enhancer does nothing other than switch a portion of the signal out-of-phase and boost the bass - an absolute joke!

Actually, there's also a problem with the USB ports. Always use the front USB ports, the one closest to you, not the one in the rear on laptops. A number of people using USB are getting crackling and pops with the rear USB port on Macs.