[srserl]

Just what I was thinking. I was staring at the bantam dac wondering if it would fit...I think I'll do one even if I have to get a slightly thicker or longer version of the case. I'll just have to order a couple boards when I order my mini-max pcb.

Scott

 

[royewest]

I almost ordered a "slightly thicker or longer version of the case" from Mouser but really, there wasn't an obvious choice. I'd be interested in what you pick. Or course, I'd like to add a switch so I can bypass the Bantam if needed...

 

[srserl]

1455C1202 is 4.72 inches long. I used one of these to case a Twisted Pear Opus USB receiver module which was too long for the 1455C802. I just used a carbide blade in a 10" chop saw to cut it down to the exact length I needed. I'll have to wait and see if there will be room on the back panel to wire an alternate power jack and a switch for bypassing the dac.

Scott

 

[TzeYang]

hey guys, when using the PCM2702, do you need to put some digital attenuation (lowering the volume on your foobar) to avoid clipping like most sound card do?

 

[jERiCOh]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif hey guys, when using the PCM2702, do you need to put some digital attenuation (lowering the volume on your foobar) to avoid clipping like most sound card do?

I finished my first out of 4 last night and tested on Ubuntu and MacOS. I did not experience any clipping by not lowering the volume. The only clipping I got was on Windows running in my virtual machine and it was only caused by an overload of the cpu. It is amazingly well sounding for the size and the price ...

 

[royewest]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif hey guys, when using the PCM2702, do you need to put some digital attenuation (lowering the volume on your foobar) to avoid clipping like most sound card do?

I'm connected to a Macbook Pro using iTunes, set to max volume. I get no clipping. I gather that in the most current iTunes/MacOS systems you can use the iTunes volume control without degrading the digital signal, but I'm not inclined to mess with it if I don't have to.

On a related topic, I'm one of those folks who find most amps impossibly loud, so I do have my Mini^3 volume set very low.

 

[TzeYang]

Hearing it is hard since dynamic peaks vary too often and they are often forgiving to the ears.

I've never heard of any good soundcard that does not clip when set to 0dB (highest output). I own an EMU1212M and EMU0404 myself and I understand how it's necessary to do some digital attenuation for DACs.


The PCM2702 does not have a peak meter like the EMU does, so it's quite impossible to "measure" whether the dynamic peaks are clipping.

Any suggestions?

 

[error401]

0dB, by definition should imply that no clipping is being introduced by that device. I don't trust the clip indicators on my e-mu 1212m. I'm pretty sure they're triggered whenever a sample hits 0dB, which doesn't mean clipping is being introduced by the card. It's either in the source material (lots of modern music) or a valid 0dB sample.

I'm fairly sure that no digital amplification is occurring inside the chip.

 

[tomb]

I'm fairly certain that unless you run the Bantam (or Alien and other similar DAC's) at full volume, the S/N Ratio will suffer greatly.

Someone correct me if I'm wrong, but I could swear I read somewhere that we should operate the BantamDAC {AlienDAC} with full volume set in the OS. Use your amp to adjust the volume.

 

[Citizen86]

How I understood it was that you are not running an analog signal at all, it's a digital one (obviously), so unless you are running it at full volume, like tomb mentions, then you are altering the signal and changing it from it's original form. You want the DAC to work with an unaltered signal for cleanest and most original sound.

Isn't that why people use things like ASIO4ALL? I've read in some threads that if it is truly working then in many programs you shouldn't be able to change the volume at all via the computer...

Don't quote me on any of this though, I don't know for certain...

 

[TzeYang]

I think my question was based on the "demands" of the digital signal being too high for the chip's output voltage swing.

Yeah that's probably what i meant, but thanks I'll run it at 0dB and try to get a scope to test the output.

 

[pinkfloyd4ever]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif I'm fairly certain that unless you run the Bantam (or Alien and other similar DAC's) at full volume, the S/N Ratio will suffer greatly. Someone correct me if I'm wrong, but I could swear I read somewhere that we should operate the BantamDAC {AlienDAC} with full volume set in the OS. Use your amp to adjust the volume.

Oh crap, really? I always use the volume knob on my keyboard as well as on my amp. I've actually wondered about this alot, but had never really looked into it since I'd never heard anything either way, and I can't tell a difference.

Quote:

Originally Posted by Citizen86 /img/forum/go_quote.gif How I understood it was that you are not running an analog signal at all, it's a digital one (obviously), so unless you are running it at full volume, like tomb mentions, then you are altering the signal and changing it from it's original form. You want the DAC to work with an unaltered signal for cleanest and most original sound. Isn't that why people use things like ASIO4ALL? I've read in some threads that if it is truly working then in many programs you shouldn't be able to change the volume at all via the computer... Don't quote me on any of this though, I don't know for certain...

I use ASIO4all and I can still adjust the volume with my keyboard. To switch between my alien and my soundcard (which I use for speakers right now) I have to switch it in both ASIO4all and in the Windows Sounds and Audio Devices Properties...Am I throwing away signal quality

Anyone an expert in these issues or know of any good reads on the topic?

 

[Citizen86]

Well I was reading in a thread quite a while ago that ASIO should disable volume control... but then some people are still able to. If you don't hear any audible difference, then I wouldn't worry about it too much. But I would also say, that if you are able to set your DAC to receive 100% volume while still giving your amp enough space to use the volume control, I would do that preferably.

 

[TzeYang]

You can still control the volume using foobar because the volume affects the "gain" of the digital file.

That's why I pondered if digital attenuation was necessary to avoid clipping.

 

[tomb]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif You can still control the volume using foobar because the volume affects the "gain" of the digital file. That's why I pondered if digital attenuation was necessary to avoid clipping.

Here again, whenever I tried the attenuation feature in foobar, it sounded very bad.