Monday, 5 December 2011

Q&A on Violectric V200 and V800

Another Q&A on the Violectric V200 and the V800 DAC for use on IEMs. 

1. For the USB input on the V800, is limited to 24/96kHz. It appears to be an add-on daughter card. In the future will you be releasing a 24/192kHz USB reciever card, and thus, can that be installed as an upgrade to the V800?
[VE] You are right, the USB input is sdituated on a daughter board and may be upgraded.
We intend to refurbish this PCB when a working 24/192 solution is deliverable. Currently it is not.
This new card will also be offered as an upgrade for existing systems.

2. Is the volume control in the V800 using the attenuation within the DAC chip? Or does it attenuate the signal after it has been processed? Where would be the best place to use the volume control? If the V800 is indeed a digital volume, then I'd assum that it'd be best to apply it there at the V800 and leave the V200 fully open?
[VE] It seems that you do not share the common often reported issues on digital volume control.
For my opinion digital volume control is better than most analog solutions.
Best would be to position the volume from V200 fully open as here no channel missmatch/crosstalk issues have to be feared.
You can adjust the max. volume by  operation the Pre-Gain adjstments from V200 or the max-gain adjustment from V800. 

3. Using the EM4, which are 124 dB headphones, I am very concerned about noise, is this combo dead quiet?

[VE] It is !! We have several customers using In-Ears who proved that.

4. Ultimately, is it better, since my source will be a computer, to get the V200 with the 24/96 option instead? Are the DAC different? Will you be releasing a 24/192 USB module forthe V200 later?
[VE] Although the USB transceivers inside the HPAs and the DAC are equal, the overall circuitry differs much.
The USB PCB inside the HPAs offer a DAC called PCM 1793, inside V800 there is a resampling unit to completely remove jitter and a better DAC called PCM 1792.
Together with the daughter board for the DAC we will make a 24/192 board for the HPAs

Q&A for Justaudio AHA-120

Here are some questions and answers from Justin of Justaudio regarding their AHA-120 and its use with high sensitivity IEM. 

1. How is the background noise issue? I am very concerned and sensitive to background noise, and was wondering what are the dB levels or noise?
[JA] Measurements are better than specification - in practice with 6dB maximum gain preset and using sensitive IEM (25ohm, 114dB/mW) noise (hiss) is only just slightly (barely) audible at 80-100% volume control position; So dominant noise will be source/mp3 player. 
2. I saw that you do offer a lower gain version for IEM, are there any cost differences?
[JA] Gain jumpers are fitted as standard now, so there is no difference in cost any more if using standard presets (6dB or 12dB).
3. With the pot on the AHA-120, what is the channel tracking like? 
[JA] Very good - with new process it is possible to track within 0.5dB by grading the pots.
4. I read somewhere that you were going to release an IEM specific amp, is there a time frame for that, and will it be a Class A design?
[JA] No plans at present.

Thursday, 1 December 2011

iBasso D-zero

Out of impulse today, I laid down some cash for an iBasso D-zero. I really wanted to test out how an amp and USB would perform on the iPhone and iPad, an this seemed to be one of the cheapest solutions. At the same time I got a Fiio line out I connect.

The unit itself seems to be a standard decent construction, nothin terrible or excellent. Good fit and finish. Straight up I plugged her into the iPhone with the line out and started playing music. The phones were the Ety HF5, 105 dB balanced armatures. The gain was set to low. No noise or hiss. That was a great start.

Then I proceeded to play some very familiar tracks through them. The volume control was probably set around 50% or so. First thoughts were better midrange vocals and better extension an control on the bass. That was all I had time for. Now I await the unit to be fully charged and some burning in. But I look forward to more use and integration with the iPad USB. The O2 should also arrive next week, so something to compare.