Is there any DAC compatible with FreeBSD?

Cannot recall the manufacturer and model, but a "stick" DAC cannot drive my Fostex T40RP mk3n nor FiiO E7 (aux input, wants line level), while all earphones I had were OK.
 
There appear to be two basic grades of 'stick' or 'dongle' dacs, 1V output and 2V output, depending on the module they have used internally. The low voltage versions - the CX31993, NICE-HCK and JM20 are really intended to drive IEM's, and low impedance IEM's at that. For higher impedance headphones, I recommend get the 2V versions which are the 'MAX' variants I tested, those typically have an additional audio op-amp buffer driving the output rather than relying on the dac chip's built-in audio amp; typically an SGM8262 from SG micro (also used in the Fiio K11 R2R). The exception to the rule being the TRN Black Pearl which contains 2 x CS43131 dac chips, so that each chip only has to drive one headphone drive unit (one CS43131 chip per side).

In any case, when driving better quality headphones like the HD650 and DT990, I recommend using a proper headphone amplifier to get the best possible sound quality. In my case I have the Firestone Audio 'cute beyond' class-A, which is very nice, and the Musical Fidelity V-cans, that is also pretty good. And if you have $3000 Focal headphones... I guess you already have a good amp to use with them, and you can ignore everything I say! 😁

1778940727837.png



1778998941584.png


Of course you can get much better headphone amps than the two above. If you want something really good, get the Musical Fidelity X-cans V3...
1778940848055.png

Or if you can afford it... the Graham Slee SOLO is very nice, really, you can't get much better than this no matter how much you spend. Well, something even more expensive might measure better, but I will bet 10 dollars that you won't be able to hear it! 😁
1778940911667.png

With the exception of the Firestone which comes from Taiwan these are all British designs.. I'm sure there are very good Japanese and US designs as well, I remember Audio Technica AT-HA5000 is another good class-A headphone amp, using the famous Hitachi power mosfets. This one, I wish I could get some day... :-)
1778942922415.png


Remember, whichever amp you have, one secret is to use a good quality linear regulated power supply, not a switch-mode wall-wart. A good linear PSU will give you a big upgrade to the sound quality.

Anyone can spend $10000 and get a good sound, that's the easy way. It's more interesting to think "how can I get good sound from $200".
 
I don't like Mr Behringher, because of what he did to the famous Tannoy loudspeakers company here in the UK, so sad. I still have my Tannoys of course, they were really some of the best speakers made. But this is politics... maybe the dac product is ok of itself.
 
I try to find out the platform a given app was written for, then run that platform.

I am not a gamer but I dearly loved win7 as an operating system. It is FAR more responsive than win10+ even with the bloat stripped out.

I’m forced to win10 due to planned obsolescence with my dailies that no longer launch on win7.

This means dedicated hardware and win7 OS for my DAW and others that are not forced into eternal OS upgrades.
 
I don't know about using FreeBSD as a DAW... but there is a very nice series here from Alien BOB about making a DAW based on slackware. Hopefully the moderators won't mind me posting it. It would probably give a lot of useful pointers to anyone who wanted to make a DAW based on FreeBSD. Eric has done a great job writing this series of articles, it is very comprehensive. I think if you browse around his site you will find some more recent updates to the DAW series as well.
blog.slackware.nl

Configuring Slackware for use as a DAW

Welcome, music-making (Slackware) Linux-using friends. This article will be an interactive work and probably never finished. I am looking for the best possible setup of my Slackware system for maki…
blog.slackware.nl blog.slackware.nl

Well... there is a thread here https://forums.freebsd.org/threads/using-freebsd-to-build-recording-studio.79617/
and something here https://github.com/marcelbonnet/freebsd-ports/blob/master/FBSD-DAW.md
.. although the second one is a little old.
 
In the spirit of "what can I do for a little money", I tried the following system out.

1. thinkpad X220 running freebsd 14.4
2. CX31993 DA06 dac
3. Douk audio U3 headphone amp https://www.hifireport.com/douk-audio-u3-review/
4. Beyerdynamic DT-990 PRO headphones
5. 2-RCA to 3.5 mm jack cable (free, had one lying around)

If we ignore the price of the thinkpad, checking the current prices gives:-
CX31993 - 5 pounds (aliexpress)
Douk U3 amp - 25 pounds (aliexpress)
DT-990's - 135 pounds (amazon)
total - 165 pounds

Substituting HD560S headphones for the DT990's reduces the total price to 130 pounds.
Substituting a JM20 for the CX31339 adds 10 pounds to the total.

How does it sound? Not too bad. The amplifier has plenty of power to drive these headphones, it's plenty loud enough. However after listening for half an hour, I think the weak point is the U3 headphone amp, which gets a bit harsh and fatiguing after a while, depending on the type of music being listened to. So I would choose a better headphone amp if possible, if going this route, and spend a little more on the headphone amp itself. Perhaps the HD560S would sound a little more relaxing, the DT990's do tend to be quite revealing.

The little U3 actually looks quite well made, it has an all metal case and the volume pot and connectors all seem fine, you even get a power button on the back. I haven't taken mine apart but there are plenty of photos of the PCB online if you search for them. Certainly the exterior build of this small amplifier impressed me much more than that of the Fiio K11 R2R dac. I noticed on aliexpress that there is a 'pro' version of this amplifier for a bit more money, so that may be worth investigating. The sound quality is obviously not as good as a better grade amp like the Firestone, but really its pretty good for the price. Just don't pay too much, I noticed some online sites are selling these for a lot more than the aliexpress price.

U3.jpeg

Alternatively, you could just buy a JM20-MAX or JM98-MAX dongle and drive the headphones directly, and it will probably sound at least as good, for about the same money; although you lose the analog volume control and the flexibility of having a separate headphone amp.

Still, this exercise gives you an idea of what is achievable for not a lot of money. Personally I would not skimp on the headphones themselves, cheap headphones are a waste of money. The HD560S is another good choice, for a bit less than the DT990's, but I wouldn't go much lower down the range than that.

For a cost comparison, buying the DT-990's and the Fiio K11 R2R will cost 135 for the headphones and 150 for the Fiio, so 285 pounds total. That's using the K11's built-in headphone amp. If you then want to buy a better amp and power supply and use the K11 purely as a dac, you can probably raise that to 500 or more. Of course that's if you are buying new kit, ebay is always worth a look.
 
I tried out an Aiyima DAC-A2 this afternoon. Surprisingly good. It identifies as a C-MEDIA usb device.

$ cat /dev/sndstat
Installed devices:
pcm0: <Conexant CX20590 (Analog 2.0+HP/2.0)> (play/rec)
pcm1: <Intel Cougar Point (HDMI/DP 8ch)> (play)
pcm2: <Intel Cougar Point (HDMI/DP 8ch)> (play)
pcm3: <Intel Cougar Point (HDMI/DP 8ch)> (play)
pcm4: <C-Media Electronics Inc. USB HIFI AUDIO> (play/rec) default

No problem driving my 250 ohm DT-990's with this, it has plenty enough power. Nice build quality, all metal case construction, aluminum control knobs, 4 rubber feet on the base. Shame there is no way to switch the tone control pots out of circuit, but they can be set to their midpoints to obtain a flat frequency response. The two tone pots have detents while the volume pot is smooth. The volume pot includes a power on switch and a red led lights when it's on (I'm so pleased it's not blue for once). The tone controls boost and cut do actually work.

It needs a usb mains adapter to supply 5V power, they do not provide one in the box but they do include a cable. Alternatively you can plug the power cable into a second usb socket on the laptop, that worked fine with the thinkpad, though it's a bit messy having two cables running to it from the laptop. Plus the power cable they provide is about 0.5m long while the usb 'signal' cable they provide is 1m long. Meh. Unfortunately it does not appear to be able to take power from the cable providing the music signal, I tried it out of curiosity but it will not switch on.

www.aiyima.com

AIYIMA DAC A2 | Headphone Amplifier | Digital Audio Decoder | Hifi Stereo Bass Amplifier

AIYIMA Focus on Audio. DAC Amplifier | Headphone Amplifier | Digital Audio Decoder | Hifi Stereo Bass Amplifier - AIYIMA DAC A2
www.aiyima.com www.aiyima.com
I paid 24 GBP for mine which included shipping from Guangdong. It's kind of crazy that as the value of the currency has shrunk with inflation, so has the physical size of the electronics you can buy with it.

Mugshot.
dac-a2.jpg


Typical high density SMD board. The dac is an MS8412 https://www.scribd.com/document/766212494/MS8412 seen at centre-left and audio is buffered by a NE5532 dual opamp, upper left, which is not socketed. The c-media USB interface chip https://www.cmedia.com.tw/applications/headset/CM6542 is seen at center right. The headphones are then driven by an AD 97220 dual audio opamp https://www.analog.com/media/en/technical-documentation/data-sheets/MAX97220A-MAX97220E.pdf at upper right.

The board has coax and optical spdif inputs as well as usb, and dual RCA audio output. However there is no audio input, so it cannot be used as a standalone headphone amp. Still, they have crammed a lot in to a small case. This is another board you won't be repairing in a hurry, however the case is reassuringly sturdy, no plastic, so it should have a reasonable chance of lasting a while so long as you don't spill a cup of coffee over it.

So this is yet another low-cost option. Sound quality is ok, it worked straight away with freebsd 14.4 as soon as I plugged it in. It's nice to have the volume and tone controls too.

My Burr-Brown dac sounds much better than this one, however. In fact I prefer the sound of the CX31993 and the ESS to this one.
 
You must log in or register to reply here.
Back
Top