Đánh giá dac fostex hp a3 năm 2024

The new Fostex HP-A3 is the perfect DAC for Computer Audio. This high quality unit features 32bit D/A Conversion with an integrated headphone amplifier exclusively designed to get the most from and PC audio set-up.

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Fostex HP-A3 là một DAC hoàn hảo cho nguồn phát từ máy tính. Chiếc AMP này có chức năng hỗ trợ chuyển đổi 32 bit và được tích hợp một với một bộ khuếch đại tai nghe được thiết kế đặc biệt cho nguồn phát từ PC.

Sau khi máy tính được kết nối với AMP fostex HP-A3, âm thanh phát ra sẽ trở nên cực kì trong trẻo, âm trường rất rộng và sâu. Độ trong trẻo của bản nhạc rất tự nhiên , có một chút ấm áp, hơi ấm hơn so với CEntrance Dacmini hoặc Meier Stagedac, và khá gần với DACport CEntrance. Mid rất tốt và hoàn chỉnh. Độ cân bằng âm khá giống với DACport, nhưng Fostex HP-A3 có một âm trường rộng hơn và sâu hơn.

This is a review and detailed measurements of Fostex HP-A3 DAC and headphone amplifier. Even though the product is current and listed on both Amazon and Fostex websites, I also found reviews dating back to 2011. So unless there have been some revisions, this is an "older" unit. It is on kind loan from a member and lists for USD $299 with prime shipping from Amazon.

Any memory of Fostex's long history and Japanese lineage goes out the window the moment you gaze at the ordinary and DIY-like packaging of the HP-A3:

What is the deal with the huge washer on the headphone jack showing?

Functionality is not bad with USB and Toslink inputs but is missing S/PDIF. I liked seeing the RCA/Phones switch allowing me to test the RCAs as the DAC output. Note that the volume control changes the RCA levels so you can use it to drive active speakers and such, avoiding a pre-amp.

No gain switch is included which I like to see as mandatory feature given the wild variation in headphone sensitivity and impedance.

No driver was needed as the unit only supports up to 96 kHz sampling and hence is UAC1 compliant.

Let's get into measurements and see how she does.

Measurements As usual, I start with my Dashboard measurements using USB input:

View attachment 15900

You see what I am seeing? Two rather massive spikes at roughly 15 and 16 kHz severely degrade performance to a distortion that is at whopping 0.2%. SINAD (signal above power of noise and distortion) as a result takes a massive nosedive to very poor 54 dB.

I switched inputs to Toslink and they vanished:

View attachment 15901

While not great, at least nothing is badly broken as it is with USB.

I expect no-name companies to release such faulty products, not Fostex. Surely they have professional measurement gear to measure such obvious fault with the USB implementation.

Given how poor the performance of USB is, I am going to truncate the rest of the test and just show one power vs distortion curve using 300 ohm load:

16-24 bit/ 96kHz (Khi sử dụng đầu vào USB, tần số lấy mẫu sẽ được cố định ở tốc độ 96kHz. Những file audio tần số lấy mẫu nhỏ hơn như 32k/44.1k/48kHz sẽ được tự động được nâng lên 96kHz và đầu ra S/PDIF Out cũng được cố định ở tốc độ 96kHz).

I’ve had the Fostex HP-A3 DAC/Amp box for quite a while now but haven’t had the chance to write about it. I spent some time with it when I have just received it from Fostex and my initial impression was very positive. The sound is very clean with zero grain, soundstage was wide and deep. Tonality was very natural with a slight touch of warmth, slightly warmer than the CEntrance Dacmini or the Meier Stagedac, not as warm as the HRT Music Streamers, and quite close to the CEntrance DACport. The mids nice and full bodied. The tonal balance is quite similar to the DACport, except that the Fostex had a wider and deeper soundstage. At roughly the same dimension of the Audinst HUD-MX1, I thought of the Fostex HP-A3 as a high end Audinst. Not in the sense that they share a similar sound (the Audinst is darker and grainier), but in the sense that they are both fairly compact units that run off directly off the USB port. Personally, I love simple set ups like these.

And then a few weeks ago the Schiit amps arrived, as well as the CEntrance, Meier and Graham Slee stuff. I decided to leave the Fostex alone for now and do the Schiit and CEntrance stuff first, since people have been asking for them for quite some time. After I got out the Schiit and the CEntrance articles out of the way, I started receiving shipments of the high end DACs which includes the Audio-Gd Reference 7.1 and Bryston BDA-1. Surrounded by these high end DACs, I told myself, “I better get the Fostex review out, otherwise it’ll be postponed for another month.” And so here it is: my attempt to finish the Fostex HP-A3 review.

At the moment my powerbook is connected to three DACs: the Fostex HP-A3, the Audio Gd Reference 7.1 and the Bryston BDA-1. I have been listening to the $2,000 Bryston for a few days now and when switched to the Fostex HP-A3, I was prepared to hear some serious drop in source quality. Sure enough I was hearing less definition on the instruments, ambiance was less defined, percussion not as impactful, the separation not as distinct, but as a whole, I was quite surprised on how similar the two DACs sounded. Yes, the Fostex HP-A3 and the Bryston BDA-1 is similar in their tonality.

I am not saying that the $2,000 BDA-1 has been outclassed by the $400 Fostex. With high end gear, sometimes the difference may seem little on paper, but when you are hearing it, it’s obvious that the two gears belong to a different class. More definition on the instruments, better ambiance, better percussion, all of these combined translate to a big difference in how real the music sounds on your ear. It’s like reviewing the 3-series BMW and comparing it to the 7-series. I would write something along the line of: “the leather is softer, the ride more comfortable, steering lighter on the 7-series” — surely doesn’t sound like much on text, but the moment you take a sit on the cars, you know that there is no way the 3-series can be compared to the 7-series. However, if I were to look at it from the Fostex HP-A3’s point of view as a $400 piece of DAC/Amp box, the comparison surely is flattering and indeed it brings my appreciation of the Fostex to a different level. Previously it was just a nice sounding DAC/Amp box. But now it’s the DAC/Amp box that sounds like the $2,000 Bryston. Oh, and the Fostex happens to add 24/96 over USB and a built in headphone amplifier, all of these while running directly off the USB port’s power. Now that’s awesome.

The Fostex HP-A3 front and back. Notice that the HP-A3 is still made in Japan — hence the very high build quality.

The HP-A3 uses Japan’s Asahi Kasei’s AKM AK4390 D/A chip which supports a 32 bit input data and up to a 216kHz sampling rate. Digital input is available in the form of USB and Toslink, the USB fixed at 24/96 while the Toslink can also be used up to 24/96 (I haven’t been able to find a source that transmits higher data rates through Toslink). At first I was confused by the 32-bit branding, as obviously the digital inputs only support up to 24 bit data lengths. I talked to Hiroaki @ Fostex about this, and his reasoning is that the Digital to Analog processing would be smoother and better through the 32-bit D/A chip. I really don’t have the technical knowledge to engage in an in-depth discussion about this, and so I prefer to leave it at that.

Build quality is all around excellent and definitely better build than say the Audinst HUD-MX1 that is priced much lower at $180. If you have seen the Cambridge Audio Dacmagic, then the build quality of the Fostex is about the same. It would have been nice if Fostex also included a 1/8″ output together with the 1/4″, like what you get with the Audinst. Not a big deal, just makes operational a bit more convenient.

AK4390 “Audio4pro” D/A chip.

The Tenor TE7022L USB receiver is a very popular USB receiver chip used in many 24/96 USB DACs.

TPA6120 based headphone amp with a Burr Brown OPA2134 op-amp on a socket.

Despite the headphone amp being based on the TPA6120 chip and the Burr Brown OPA2134 opamps (both are very popular headphone amplifier chips), the sound of the Fostex HP-A3 headphone out sounds nothing like the other amplifiers based on either of these two chips. The TPA6120, for instance, though a very potent chip, normally has a noticeable amount of grain in the sound, though in quite low levels. The OPA2134 is usually not known for a smooth or refined sound. Somehow, with the design of the circuit on the HP-A3, and perhaps the choice of components as well (ie: all the electrolytic capacitors are Nichicon Gold), the sound of the HP-A3 is totally smooth and grain free, and definitely very similar to the sound of the Fostex HP-P1 portable DAC/Amp. The amp is not the punchiest amp around, but it definitely is a fine sounding amp and I didn’t have any complaints listening to the HD800 straight from the headphone amp out.

A product that begs an obvious comparison with the Fostex HP-A3 is the CEntrance DACport. Roughly the same price point, the same 24/96 over USB capability, both runs directly from the USB bus, and both comes with a built in headphone out. The DAC section is definitely better on the Fostex. Cleaner sound, more spacious sound, better separation et cetera. The Fostex is sort of in between the CEntrance DACport and DACmini. The Fostex being more spacious, warmer, smoother, and more laid back, where the DACmini is more lively, more forward and has a better articulation, bass control, and detail extraction.

Overall the HP-A3 is a very strong performing product backed with the Fostex brand name. The tonality is very likable, similar to the HP-P1 and/or the Bryston BDA-1 that I’ve made references to. I suppose the point of discussion will mostly be around the price tag of the Fostex HP-A3. Street price of the Fostex HP-A3 is supposed to be around $400, according to Hiroaki at Fostex. Like the HP-P1, however, the Fostex DACs seem to lack a proper distribution channel outside of Japan. I found that the online retailer joynetmall has it for $479.85. Rakuten has it for $413.28. The best price I was able to find is from Amazon.jp which lists it for ￥ 30,520 or roughly $386.54. So at the moment the price is quite all over the place, but I think it’s safe to assume that the HP-A3 will be priced slightly above the $400 mark (I think $415-$425 is a good price for it).

For $400 I’ve been making recommendations for the Schiit Asgard and the HRT Music Streamer II. That combination will give you a more potent amplifier section, though the HP-A3 DAC is quite better than the HRT Music Streamer II (it’s more of a match with the HRT MS II+ and the Cambridge Dacmagic). Obviously this is a strong performing product, and one that is designed to be very easy and very convenient to use. The necessity to use a USB power supply may be odd at first (for instance if you decide to use a CD player as a transport, you still need to hook up the Fostex’s USB port to a USB power supply. I use the Ipad’s adapter), but it’s really not a big issue. Anyway roughly for $400, the Fostex earns a very strong recommendation as it gives you a more potent DAC section than the CEntrance DACport.