[nicooo]

To all Mac users with the internal USB-DAC card installed:
 
Starting with Yosemite (Mac OS X 10.10) Apple requires all kernel extensions (i.e. your DAC driver) to be signed. Unfortunately, Lake People / Violectric have not updated their driver with the right signature yet. As a consequence the driver will not be loaded by the OS and your music will sound funny to say the least. If you already updated to Yosemite and have no way to roll back to the old OS version you can circumvent the problem by disabling the signature check with the following procedure:
 
- Open a terminal (open Spotlight and type "terminal", a text console will appear)
 
- Type the following: sudo nvram boot-args="kext-dev-mode=1"
 
- Press enter
 
- Type in your admin/root password and press enter.
 
The next time you plug in your Vio the driver should be correctly loaded (maybe reboot if not). You have to repeat this procedure after resetting the PRAM of the Mac.
 
HTH,
nicooo
 
PS: When you look around the internet you will notice that Violectric isn't the only company without up to date drivers. Apparantly a lot of USB DACs suffer from the same problem since the drivers are usually supplied by the chip manufacturers (Tenor in this case) who can't be bothered to sign their drivers. If you haven't updated to Yosemite yet I suggest you hold off until the situation has cleared.

 

[xaval]

I'm still on Mountain Lion and Snow Leopard. Not by chance... for quite a few bit of things.
To make it safe on any SO, I ordered the Toslink input! 

 

 

[plakat]

  To all Mac users with the internal USB-DAC card installed:
 
Starting with Yosemite (Mac OS X 10.10) Apple requires all kernel extensions (i.e. your DAC driver) to be signed. Unfortunately, Lake People / Violectric have not updated their driver with the right signature yet. As a consequence the driver will not be loaded by the OS and your music will sound funny to say the least. If you already updated to Yosemite and have no way to roll back to the old OS version you can circumvent the problem by disabling the signature check with the following procedure:
 
- Open a terminal (open Spotlight and type "terminal", a text console will appear)
 
- Type the following: sudo nvram boot-args="-v kext-dev-mode=1"
 
- Press enter
 
- Type in your admin/root password and press enter.
 
The next time you plug in your Vio the driver should be correctly loaded (maybe reboot if not). You have to repeat this procedure after resetting the PRAM of the Mac.
 
HTH,
nicooo
 
PS: When you look around the internet you will notice that Violectric isn't the only company without up to date drivers. Apparantly a lot of USB DACs suffer from the same problem since the drivers are usually supplied by the chip manufacturers (Tenor in this case) who can't be bothered to sign their drivers. If you haven't updated to Yosemite yet I suggest you hold off until the situation has cleared.

Thanks for your effort, that seems to work (i.e. the driver does indeed load and no distortion after 10+ sec.). Two things: It seems to be necessary to write the nvram value *after* installing the driver and I'd leave out the '-v', i.e.:
 
# sudo nvram boot-args="kext-dev-mode=1"

 

[nicooo]

You are right, the "-v" is not needed. It causes a verbose boot of Mac OS, i.e. the whole boot process it's printed out on screen. I updated my post accordingly. From my understanding the order of driver installation and nvram configuration shouldn't matter but whatever works...

 

[mulder01]

I habitually follow the same pattern of always warming up my equipment for 30-60 minutes prior to listening - by playing a CD at a lower listening volume.

Jeff.

 
Wow really?  That's the first time I've ever heard of anyone waiting for solid state amps to warm up.  Do you have an explanation of what this achieves?  I was under the impression that electronics worked better cooler.

 

[xaval]

I've had dozens of audio equipment for 2 decades and irrespective of tubes or solid state with very few exceptions they sound better once settled down. Some achieve this faster than others. This is ime...

 

[plakat]

You are right, the "-v" is not needed. It causes a verbose boot of Mac OS, i.e. the whole boot process it's printed out on screen. I updated my post accordingly. From my understanding the order of driver installation and nvram configuration shouldn't matter but whatever works...

I did not expect that either, but I did set boot-args... after reboot following the driver installation the setting as gone however. Surprising. Setting it again worked and after the next reboot the driver did in fact load (verified by trying it out and looking at the output of kextstat).
 
Thanks again!

 

[roskodan]

 

I habitually follow the same pattern of always warming up my equipment for 30-60 minutes prior to listening - by playing a CD at a lower listening volume.

Jeff.

 
Wow really?  That's the first time I've ever heard of anyone waiting for solid state amps to warm up.  Do you have an explanation of what this achieves?  I was under the impression that electronics worked better cooler.

lol, common misconception that the 'better' working must be the 'better' sounding, we are talking about listening not measuring performance, there is plenty of scientific literature meticulous explaining every potential effect of temperature on electronic component's performance
 
what's important for us here is knowing that the temperature of the component will change the sound, then everybody can decide for themselves what sound 'better', cold or warm

 

[Xenophon]

   
Wow really?  That's the first time I've ever heard of anyone waiting for solid state amps to warm up.  Do you have an explanation of what this achieves?  I was under the impression that electronics worked better cooler.

It's the same with lots of gear.  For instance the FirstWatt speaker amps (using MOSFET/JFETs) sound better after 10 minutes of warmup (and they draw 200 W in pure class A but so no need to buy a room heater but that's another matter).
 
I once auditioned a Burson Conductor and at the time the official recommendation in the manual was to just leave it on permanently iirc, the reason being that 'warming up' took a REALLY long time and the sound was simply crappy if it hadn't warmed up.  Felt like bad design as it wasn't just a matter of a subtle sound coloration there.  With other amps I don't feel warmup makes a difference (e.g. my V200).

 

[mulder01]

 
lol, common misconception that the 'better' working must be the 'better' sounding, we are talking about listening not measuring performance, there is plenty of scientific literature meticulous explaining every potential effect of temperature on electronic component's performance
 
what's important for us here is knowing that the temperature of the component will change the sound, then everybody can decide for themselves what sound 'better', cold or warm

Too bad if you prefer the cold sound.  You can only listen to one song, then back in the fridge it goes

 

[roskodan]

Originally Posted by mulder01 /img/forum/go_quote.gif
Too bad if you prefer the cold sound.  You can only listen to one song, then back in the fridge it goes

yeah, wouldn't want to be that guy tho XD
 
anyway as previously mentioned by others in various threads, nevertheless of electronics performing better/worse when colder/warmer, there is the issue of thermal balance/coupling inside the equipment, especially when components (pre op amp, power regulator, power stage etc.) are made from discrete elements (not integrated inside one or more silicon chips so to speak), there is difference in temperature among the various parts of the discrete components themselves (since components closer to something that get hot fast will warm up faster) not to talk about difference between various components inside the piece of gear, also between channels, before the piece of gear reaches a more or less homogeneous working temperature back to front, it doesn't matter if it's cold or hot but that everything inside is thermally coupled, in that regard it's easier to let it warm evenly by itself than to keep it in liquid nitrogen XD, especially when it sounds better that way

 
also thermal coupling was one of the reasons violectric preferred using integrated opamps rather than discrete ones
 
basically thermal discrepancies inside the gear makes more of an audible difference that electronic elements (semiconductors, caps, resistors etc.) working better at a certain temperature than other, the linear (as specified) working temperature range of electronic components is far greater than the oscillation in temperature the gear is subject to when operating, at least for audio equipment, when there is no problem with heat dissipation

 

[Megalomaniak]

 
It's the same with lots of gear.  For instance the FirstWatt speaker amps (using MOSFET/JFETs) sound better after 10 minutes of warmup (and they draw 200 W in pure class A but so no need to buy a room heater but that's another matter).
 
I once auditioned a Burson Conductor and at the time the official recommendation in the manual was to just leave it on permanently iirc, the reason being that 'warming up' took a REALLY long time and the sound was simply crappy if it hadn't warmed up.  Felt like bad design as it wasn't just a matter of a subtle sound coloration there.  With other amps I don't feel warmup makes a difference (e.g. my V200).

 
Well, in every piece of hi-fi equipment Ive had at home, and Ive had a bunch of them (my father used to repair them), Ive rarely seen improvement in sound after warming up, only in true vintage stuff for speakers with tubes, but just for a few minutes. And the main difference was the distorsion and background noise.
 
Where Ive seen most improvement is in speaker PA systems, for live performances and that stuff I usually set up, the amplifiers operate at high wattage, delivering like 3000-4000 Watts per amplifier so they have to warm up, and the speakers, usually 450-1200W per speaker and 1000-3000W subs too.
 
Even, some PA amplifiers do warm up before they "start working".

 

[plakat]

While I personally never came across a PA amp that actually has a warm up phase, many do have a current limitation when switching on to avoid peak current killing any fuses. Acoustically relevant properties of speakers do change with temperature however, that effect *can* be relevant on large PA systems where magnets do get really hot and the temperature in a compression chamber does change over the evening.
 
Out of habit I never run a PA at full load within the first 10-15min. I don't think its really relevant nowadays with switching power supplies and so-called digital amps that raun fairly cold due to better efficiency. Letting the speakers warm up a bit may on the other hand extend their life span though.
 
At home I never run equipment anywhere near its limit, so any precautions regarding operating temperature etc. do not apply (I don't own tube amps).

 

[alvinmate]

Hey Guys,
 
I am super excited today and wanted to share with everyone some photos of my new headphone rig..delivery was done today and I still have to tweak few things and potentially upgrade some components..did a quick test run and simply put this amp is amazing...

 

 

[project86]

Looking good! I dig the Apollo-R player, nice match with the V281 in terms of size.