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.

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.

New Earsonics Headphone Amp

I just learned (from Earsonics) that there will be a new headphone amp being released by Earsonics, in 'a few days', designed for their IEM. With my EM4 coming, I will eagerly awaiting this product!

Headphone Amp Ordered

After some quick research, I settled on a pre-built version of the O2 amp, purchased from JDS Labs, an open source headphone amp project. The main reason that I went for this headphone amp initially was:

1. Cheap.
2. Low noise.
3. High measured performance.
4. No time to DIY or try our more expensive options.

According to the shipping information, the amp should arrive in about a week, before my Earsonics EM4 arrive. But, I will still have an opportunity to test this with my HF5 and see how they stack up. I am keen to further explore again the Vioelectric V200, and it would be great that once the EM4 arrive, that I take the O2 amp and the phones to demo and compare it against the V200.

Custom IEM and Updates

Well, it has been some time since the last post, but it has been very busy and hectic lately. We have finally moved our family and settled in Hong Kong. Quite a big adventure for us, but just settling in. All my plans for the C3g headphone amp went to bits after my last post. The Yamamoto teflon sockets just arrived last week (obviously I was gone) and the luggage left no room for anything audio. The only exception was my Calyx Coffee and the Etymotic HF5.

Well, with that change of plans, and me settling in Hong Kong, I realised that full sized headphones wasn't going to work. I spend about 2 hours on the MTR system to and from work, and to date, have been using the Ety. Small, easy to fit in the pocket, and gives a decent sound with the iPhone 4. What I can say, is that the music isn't very engaging, warm and lacks a top end sparkle. But given the current situation, I'll have to make do. Or so I thought!

From setting up a full sized headphone rig with tube amp, I have now moved my focus to highest quality IEM with small solid state amps. My search for the right IEM started with the Etymotic ER4S/P. Many describe their sound as 'bland', but accurate and surgical. Probably not what I was looking for. If anything, I am trying as best to find something that has a similar sonic signature to my well used (and loved) HD650. That warm and engaging sound. Moving on from standard (or universal fit) IEM, as I did not really like the fit and feel of any of the universals that I had, I decided on a custom fit. Having read around, it seems that custom fit gives two very important advantages; better isolation and higher comfort.

Doing a quick search on Google, I found a place in Hong Kong that does custom ear mold; Phonak. After finding this, and getting my impressions for HK$800, I also found a few others that are more focused towards the audiophile custom IEM. Phonak is more a general audiologist. Having got my custom ear mold and my list down to high end custom IEM, I started to look for shops and brands. A real benefit of Hong Kong is its abundance of audio hi-fi stores. From a quick search, I found the following; Jaben, Mingo, Kingsound and Audiophysics. Audiophysics does not sell headphones, but headphone amps.

I went to Mingo after work and had a quick sessions with the iQube V1 and the Westone ES3. A few quick notes. The iQube has background noise with the ES3. Irrespective of sound, that is off the list. The ES3 has a nice balanced sound, the mids were balanced, not too forward or recessed. The bass is quite good, firm, not flabby, but not too fat. It doesn't have a huge amount of treble sparkle, but much better than the HF5.

After this visit, I did some research and narrowed my choice down to Earsonic EM4/EM3Pro and Westone ES5. This was primarily based on various Internet reviews and commentary. Doing further research, confirms that these two brands would probably be better suited to my taste then the JH or Ultimate Ears.

So long story short, I went to Jaben a few days ago, had a quick session with the Earsonics SM3, and placed an order for the EM4. Have been told up to 4 weeks for delivery of the EM4, but was suggested that this would be a lot shorter in duration. I didn't order anything special, smoke grey for the housing with black cables. Well, I am not anticipating their arrival.

The next step, a good headphone amp.

C3g Headphone Amp Progress

  

Here are some photos of the progress build of the C3g Headphone amp. As you can see, the TubeCAD Regulator PSU unit is assembled, and the various major components laid out. The key components: Acoustic Dimension 41 step attenuator, Lundahl LL1689 Amorphous core output transformer, TubeCAD PS-1 heater and HV regulator, two Hammond mains transformers, and massive IEC Inlet with filter, fuse and switch. All of this in a 16x8x3 Hammond aluminium case.

There are some time restrictions as I will be leaving shortly, and need to complete this within a few days, otherwise it will have to go in the post. Note that I am missing still the Yamamoto Loctal teflon sockets. Still, a lot of chassis work to be done, as well as testing, etc. 

Some equipment Audition

Had the opportunity to go to a local Hifi shop and demo some equipment this afternoon. The gentleman assisting me was very helpful and friendly. The equipment that I had the chance to audition was:

1. HD800 with Duson HA160D, Violectric V200 and Sugden Masterclass HA4.
2. Sugden Masterclass HA4 with the T1, Ultrasone Edition 10 and Audeze LCD-2.

The session last just under an hour and the majority of time was spent with the Sugden as the amp. The source was an old Luxman tube CD player and the CD was Coldplay's Viva La Vida.
The easy ones first. I found both the Burson and the Violectric to be not as good as my HD650 and Elekit. The difference was in engagement and 'musicality'. The Burson had wider soundstage than the Violectric, one being beyond my ears and the latter being between my ears. The V200 sounded actually a little boring, nice sound, a little less bass than the Burson. The Burson had a very heavy stepped attenuator, which was great, except that it may clicking noises through the headphones every time I changed volume. This was quite annoying. So after around 5 minutes with each of the Burson and Violectric, I moved onto the Sugden.
Never have heard of the Sugden, but was told this was a hand-made amp in the UK. This amp is class A, and having a look through the brochure, it appears to be discrete Class A with a very laid out PCB. Anyway, the amp was cold initially and was initially connected to the HD800. This was a very nice combination. The voices and vocals were very well focused, the bass tight and the overall sonic balance and presentation was very good. I started to warm to this amp. Compare with the other two, this amp felt like it had more control over the headphones.
Over the course of the next half and hour or so, I swapped to different headphones. The first being the T1. Less bass than the HD800, different sonic presentation, a little on the neutral (maybe sterile) side. Similar to the differences I found between the HD650 and the DT880. I then tried the Edition 10. Wow, they certainly are a different sound to the rest! Light weight, well built and quite comfortable on the ear. The Edition 10 had almost overwhelming bass for me on the Sugden. It dominated the sonic presentation. The vocals had a distinct clarity/sparkle to it, that I was not used to, and perhaps I could call it 'edgy', whilst the T1 and HD800 was 'smooth'. I don't think its' a bad paid of headphones, but definitely not my cup of tea. Finally, I tried on the LCD2. Again, what a difference. Massive and heavy; quite the contrast to the Edition 10. I found that it wasn't a great match. The sound was a little flat and one dimensional. It also seemed far away, even though the soundstage was in my head. Nice balance, but probably a little weak in the bass regions.
Finally, I put the HD800 back on, and I was immediately smitten with the combo. Perhaps it was the fact that I am so used to the HD650, that the sound was so much more easy on my ears. Good balance between the lower and upper ranges. Also, the vocals didn't seem as focused or coming from a smaller source than either the T1 or the Edition 10 (which sound like a small point source). Perhaps sonically the Edition 10 and LCD-2 are very good, but for my own ears, through the Sudgen, I'd rate the HD800 the best, with the T1 second, followed by Edition 10 and LCD-2.
Coming home, I immediately turned on my current setup and listened to the same music. Though it was through a completely difference source (Mac and Calyx Coffee) into the Elekit. I'd have to say that I still prefer this setup! Even with the hum, which in contrast to the other amps, which were all dead silent. Even though this was an exercise in testing headphone amps, it appears that it may have turned out to be more of a headphone selection, and it might be worthwhile to bring my own setup to the same place and try out the HD800 and the other headphones to see how it all goes.

Hi Resolution Audio

Just a few more notes about my research into higher resolution audio than the standard 'Red Book' CD of 44.1 kHz at 16 bit. Reading a little about SACD/DSD, implies that the maximum possible with that format is around 20 bits, 96 kHz. But given my desire to run everything from the computer, means it is not really part of my audio landscape. Looking at a few HD audio websites, primarily HD Tracks, appears that 96 kHz at 24 bit is readily available. There was limited offerings at 24 bit 192 kHz. However, the range of music available is still limited, and only a few of the artists that I like to listen to are available. It would be interesting to see if the 192/24 becomes more readily available with a larger selection of artists, otherwise, it would seem moot at this point in time, to invest in hardware and tracks in this much higher resolution.

Again, my choice in the Calyx Coffee, which is limited to 96/24 would be a good choice for the short and perhaps medium term. The next step is to make available some of this high resolution tracks, and compare that against the standard Red Book versions.

The other question of over sampling is coming up. I am pretty sure that the Calyx oversamples 44.1/16 into its native resolution, due to the Block diagram with a component "Oversampling Filter". This would suggest that whatever sampling frequency is fed into the DAC, is samples it into its native frequency. Which I would presum is 96 kHZ. Again, going back to various historical threads, people seem to say a lot of positive things about Non oversampled DAC. Perhaps this is an area to do some more reading on.

Another reason why I chose the Calyx is because it used an ESS chip. As I have a full Twisted Pear Audio kit for the Buffalo II (using the ESS9018) along with the Legato and relevant PSU, I'd like to sample the audio signature of the ESS chips before I embark on the build. Given my limited time and space, I'd like to know whether this is something that I can live with, or live without. Hopefully, I can get a decent session tonight, and provide some more thoughts.

Updates and Digital Audio

It has been an awful long time since my last post; but things have been pretty hectic of late. Primarily is our decision to relocate our family to another country, which will be taking place within a few months. This event, along side other life things, has meant very little, if any, time to blog. At the moment, I barely get any good audio sessions in...

In light of the relocation, this has spurred me to look into portable solutions. Having a good assortment of headphones already is a good start, but this has forced me to look into the weakest part of the chain. At present, all my music is run through iTunes (AAC Lossless) and played to the headphone amps via the standard audio out on my Mac Pro or Macbook Pro. Note an ideal solution. This then started to get me looking into improving the digital connection between the computer and the amp.

Welcome to the world of USB Audio... Initially, there were a catch up in the USB Audio technology. The way I understand it is, there is USB Audio 1 and USB Audio 2. USBA-1 only allows for 48kHz/16 bit. But the newer standard of USBA-2, can support high sampling and bit depth. The highest I have seen so far is 384kHz/32 bit. However USB1.1 can support stereo 96kHz/24 bit in terms of its band width, and USB2 can obviously go higher. On top of this limitation are the limitations in drivers in the various OS. Add further to this is whether or not the USB device is asynchronous or not. More technical terms and more technical information to digest.

The long and short of it, I decided that the best place to start would be a USB device that had RCA outputs that can handle up to 96kHz/24 bit. And in this market, there was plenty of choice. Being able to handle the higher resolution allows me to explore HD audio tracks, which would not be possible had I stuck with something simplier with only 44/48kHz at 16 bit. Through the various web pages, etc, I was able to gleem that there was an awful lot of South Korean and Scandanvian companies making USB audio devices. Alongside that, the standard Chinese offerings and others from US and Germany. Some of the companies that I came across includes: Calyx, Bel Canto, M2Tech, Lead Audio, Lindemann, HRT, April Music, Anedio, Bladeius, CEntrance, SoTM, Halide Design and a few otherse. Where possible, I tried to avoid the Chinese companies. When I get the change, I hope to write some notes about the various units that I looked at over the last few weeks.

Again, without boring everyone, I settled on a Calyx Coffee. An asynchronous 96kHz/24 bit USD DAC using a lower version of the ESS DAC Chips the ESS9023. I chose this because it was relatively good price (middle of the pack), had the ESS DAC chip, looked good and has external control buttons. This was brought from Wicked Digital and the unit arrived yesterday, and has started the burning in process. The main difference I can see from this chip and the top of the line ESS9018 is that it only has 1 DAC circuit for each channel (whereas the 9018 has 8 circuits that can be customised in various configurations) and it also has voltage output (as opposed to current output).

Well, hopefully, I can provide more insight into this DAC, which is currently hooked up to the Elekit and HD650.