Head-Fi.org › Forums › Equipment Forums › Dedicated Source Components › REVIEW (in progress) - Nuforce HDP 24/96 USB-Optical 24/192 Coax DAC Preamp and Headphone Amp
New Posts  All Forums:Forum Nav:

REVIEW (in progress) - Nuforce HDP 24/96 USB-Optical 24/192 Coax DAC Preamp and Headphone Amp

post #1 of 1670
Thread Starter 
I have the New Nuforce HDP DAC prototype here which I am evaluating, and I have some "sneak-peak" impressions.

The first or second post of this thread will be updated or replaced with a full review when I have completed burn-in and my assessment. Total listening time has been only two hours last night, and tonight I have been listening for two hours, after a 24 hour break. The HDP did open up a noticeable amount with just the 24 hours of burn-in, and I will be running it for 10 days straight to complete burn-in.

I can't post photos of the prototype right now, but I will post pictures of the final version as soon as possible. Barring unforeseen circumstances, Nuforce expects to start shipping these on 2/10/10. If it helps at all, I can say the chassis looks exactly same as the Icon and Icon Amp.

FEATURES: Like the Icon 12-watt integrated amp it has a volume knob on top, a selector switch below that, and a headphone jack below that. There is also a faint blue power-on LED in front just above the headphone jack. Unlike the uDAC, this LED turns off when the headphone amp is turned off, while the uDAC uses the light to indicate USB is connected since it acts as an S/PDIF converter when the volume knob is turned off.

The HDP runs on a 45 watt 15v 1.6A PSU like the Icon Amp with 24 watt/ch speaker out. It accepts digital and analog inputs, so you can connect several of your digital sources and something like a CD player or an iPod via line out dock. The USB DAC operates at a native 24/96 resolution, with no extra drivers, and it runs on my Mac just fine at 24/96 via USB type-B port. It also appears to have a 3.5 mm optical input jack running at 24/96, which doubles as a 3.5 mm analog input like on a Macbook. I didn't know the HDP would have this feature, and I am pleasantly surprised. I will be testing this and the RCA Coax digital input later in my review. Finally there is a pair of RCA inputs and outputs, and the RCA outputs look to be very high quality jacks.

So, to summarize:


* USB type-B
* 3.5 mm mini optical digital / doubles as 3.5 mm analog in (like Macbook)
* RCA coax digital
* RCA pair for L/R input


* 1/4" headphone in front
* RCA pair for L/R output - tied to volume attenuator as a pre-amp

ASSOCIATED GEAR: So far I have tried it as a 24/96 USB DAC with some 24/96 hi-res music from HDTracks.com (Nancy Bryan, Ottmar Liebert, Ry Cooder) out of my Macbook. I used Audio Midi Setup on the Macbook to choose 24/96, as it defaulted to 16/44 when I plugged it in the first time. After that one time, I unplugged it and plugged it back in, and the USB output defaulted to 24/96 automatically.

AS A HEADPHONE AMP: I started with my Westone 3, which are very sensitive custom IEM, and there was NO hiss or noise at all with the built-in headphone amp. With these very sensitive IEM, when the volume is turned down close to zero there is only a very slight channel imbalance, but one can easily turn it down low enough to go to sleep with music and IEM and not feel like it was too loud in one channel or both. The sound with the Westone 3 was very good. Tonight I have have been listening with my custom IEM (UE11 Pro, JH13Pro, and ES3X). It works well with all of them, but I am especially pleased with the synergy with my UE11 Pro, which are often quite picky about the amp I use with them. So, as with the uDAC, WA6 and Square Wave XL amps, the HDP is an excellent match for the UE11 Pro and controls the bass well and fills in the mids. Yet it's not adding any extra forwardness with my ES3X or JH13 Pro, and it's not a bass-lite amp that would only get along with UE11 Pro, which is great. Right now it's the ES3X that I am enjoying with it.

I have also been using very hard to drive 25 ohm 87 dB/mw head-direct HE-5, 300 ohm 102 dB/mw Sennheiser HD600, and 32 ohm Grado HF-2 (don't know sensitivity). I have enjoyed the HDP with all of them. The HDP manages to drive the inefficient HE-5 better than I would have expected, since these phones usually demand an amp with 2 watt output at 32 ohms. Still, my maxed Woo WA6 can drive the HE-5 decently, and the HDP's power output is at least as good with HE-5. Volume levels with HE-5 will not be earsplitting like with a 2 watt amp, but as with the WA6 it does play louder than I like to listen to my music. As good as it sounds with the HE-5, with my re-cabled HD600 it seems to be an even better match, as well as with the Grado HF-2, since these phones are much more efficient.

I did feel like the HDP needs to burn in a little to open up and become more refined when I got it, but fortunately it is NOT bad sounding in any way at all out of the box. And, in 24 hours it has opened up considerably (like the Icon did before). It seems to be tuned for strong tight bass to my ears, which never seems to be overdone, which makes me happy. So, the built-in headphone amp seems to do well with low impedance inefficient phones, and high impedance phones. The only specs I have for power is 80mw at 600 ohms.

PENDING phones: In addition to the above phones, I plan to try it with my HD800, Denon LA7000, ATH-A900, ESW10, HFI-700, and 600 ohm AKG K240M in the final review. I will also compare it to my Apogee mini-DAC headphone out, ZDT, WA6, Sq Wave XL, SAC KH1000, EF5, and uDAC.

AS A DAC/PREAMP: I also tried it as a USB DAC preamp with the RCA analog out feeding a homebuilt eXStatA electrostatic headphone amplifier and some HE Audio Jade electrostatic headphones (used Anti-Cables RCA IC). It appears to be a very detailed source, and didn't seem to need a lot of burn-in as a preamp, offering good depth into the music. It's a great choice to drive this particular "stat" amp because the person who built the amp made it with separate left and right volume knobs (he's building me the same amp with a single volume attenuator). So, I could use the HDP's single volume knob to adjust the volume, instead of twiddling with two knobs on the amp.

And, with this stat amp's two volume knobs turned up to maximum, the HDP and amp were totally silent of any background noise (at least in my noisy house). This is normally a balanced headphone amp, but it can be driven single ended with a simple RCA to 3-pin XLR adapter, without the need for my input transformer box to convert from SE to balanced. When driven single ended this way, the amp's volume will be about 3 dB lower, while gain remains at 1000. The HDP did not have a problem driving the eXStatA amp to be as loud as it would have been with a higher level XLR balanced input.

PENDING DAC comparisons: I plan to comparing the DAC's via analog output vs the outputs of the PS Audio Digital Link III and and Apogee mini-DAC. I may also have a CEntrance DACport 24/96 USB DAC/amp to compare, as a headphone amp and preamp (using ALO Audio 1/4" > RCA cable).

NOTE: I hadn't planned to post much more until burned in. This a sneak peak to let people get a glimpse of what's ahead. I am testing the prototype as Jason stated elsewhere, so I can't post photos because the layout does not match that of the final product. If I find anything at all that I think that needs to be corrected I will be notifying Nuforce to have changes incorporated into the final product. So far I have no concerns like that.

NOTE: I have been continuing with my impressions in post #2 as I become more familiar with the HDP. Please continue reading there. Thanks! Made this red since a few people missed this note.
post #2 of 1670
Thread Starter 


Reserved Post #2

UPDATE 01/31/10:

Originally Posted by kostalex View Post
Is it possible to feed HDP DAC output to external amp (WooAudio 3 in my case) and then back to HDP audio input (from WooAudio 3 preamp output in my case)? If I plug headphones to HDP then, I would have kind of hybrid amp.
No, you can't do this because only one input can be active at one time.

Originally Posted by eneloquent View Post
Not to add to much to the clamoring horde, but I wanted to second this with a more specific angle.

I'm curious as to a comparison of its driving abilities. If the uDac didn't have quite enough muscle to really push some of the more inefficent cans (i.e. 300ohm Senns), is the HDP enough of a step up to make an audible difference, to act as an adequate substitute for a dedicated SS amp (like a Caliente?) I'm assuming so, but I'd like your opinion on this gap specifically, if you have the time to do so.

Power output: 80mW x 2 @ 16-Ohm

Headphone Output: 6.3mm headphone output jack drives headphones up to 600-Ohm (80 mW@600-Ohm)
As far as the driving ability specs, I think they were stressing or implying that the intended market for the uDAC is the computer-source/IEM people (or with easy to drive phones); whereas the HDP is aimed at the stand alone source/computer/full size phone market which demands more power. So far it seems both DAC/amps are suited for the typical or most commonly used IEM and full size phones, at least among those I posted that I have tried). I don't believe that phones like the HE-5, K1000 and 600 ohm AKG K240M (or highly dampened modded orthodynamic phones) are in the uDAC's target market.

Thus, the uDAC is considerably less powerful than the HDP with the very inefficient 25 ohm HE-5 that require large current reserves and power, and the uDAC barely gets by driving the HE-5 while the HDP actually drives them to levels similar to the WA6 (which is very adequate but still not enough for blasting).

The uDAC will play the more efficient 32 ohm HF-2 louder than it can the HE-5, but it will still clip much sooner with the HF-2 than the HDP will. I can actually max out the volume with the HDP with HF-2 and instead of it getting fuzzy and distorted at max, the bass just goes a little flatter as it runs out of current. Like many desktop amps the HDP is better behaved as you reach the power limits.

The uDAC is also less powerful with the HD600, but it has adequate power levels for most people to still really enjoy these 300 ohm cans (similar to the most power portable amps). However, with infected Mushroom "Dancing with the Kadafi" the HDP can drive the HD600 to very loud levels, make my ear lobes start to vibrate, and do it at max volume right at the edge of clipping. This is desktop amp power, not a 5v portable amp.

Getting off topic of the power specs, but while I'm talking about HF-2 - The sound signature of the HF-2 is also better suited to the HDP than the uDAC - the uDAC is more forward sounding than the HDP with HF-2, while the HDP is more open and unfettered sounding with them. This is one of those times when I really wish I hadn't sold my re-cabled RS-1 which are more detailed and open than the HF-2, as they would come in handy with my reviews. I am also noticing the HDP sound signature changing a little with burn-in and the highs are a little less present at 36 hours, but this is less of a problem with HF-2 than HD600. I expect more sound changes with time, so I would like to avoid commenting a lot about the sound until my 10-day burn-in is done.

Note - I have not compared the HDP to other desktop amps yet, nor it's 300 ohm performance to my other desktop amps yet, and I have not tried the 600 ohm AKG or the K1000 yet. I'm still very early in the evaluation process.

Originally Posted by Blackwheel View Post
Could you also compare this to the uDac please and let us know whether or not you believe the price difference is equivalent to the performance boost? I understand that this has more ins/outs, but purely from an audio quality frame of reference, is the HDP worth the extra $$$. Thanks.
I expect that I will compare HDP to more DACs than just my two more expensive desktop DACs.

Originally Posted by A_Dying_Wren View Post
Gah... $399 I can possibly budget for but $499 puts it way over the top.

Any chance of a head-fi introductory discount?
They said they will try to shoot for $449 if possible, but I agree that an introductory $399 price for the first 10 or 20 head-fi members sounds like a good way to get more people to listen to the HDP and post their thoughts.

Originally Posted by Blackwheel View Post
I'm actually more interested in the opposite scenario . How do the HDP and uDac compare as a preamp when using a dedicated amp?

Please address both situations. Thanks
See above.

Originally Posted by estreeter View Post
Larry, you clearly have your work cut out for you with this one - you need to make it all things to all men AND convince Jason that cheapskate Head-Fiers cant possibly afford a $499 amp. As one of those cheapskates, I accept that Jason has to make a profit on this thing - I just want him to make the shipping date. The 499 price might actually improve my chances of getting one before the dreaded 'Out of Stock' icon appears on the product page.

Thanks in advance for the review. As I posted elsewhere, my decision will largely be based on your review, and I suspect that many others feel the same way - no pressure, dude
Sorry, I don't have that much influence on them, but if there is ever a problem with the sound then they confirm it and don't argue about correcting things.

UPDATE 02/04/10:

Originally Posted by .Sup View Post
no pics yet?
Originally Posted by eneloquent View Post
I think this has been stated by Larry a couple times;
He's not going to take pics of the unit he has, as it's going to look nothing like the final product. It's a reference model thrown together so he could test/validate the sound.

The final product will be in the same case as the Icon Amp, and if anyone drops pics of it, it'll probably be Jason. Making a buying decision - or even informing your buying decision - on any pics Larry could provide would be flawed.

Trust me, I want to see the damn thing too, but I don't want to see pics of Larry's because it's not what one I would buy is going to look like. Go harass Jason in the sponsor forum for pictures. ¬_¬

Originally Posted by Sgt_Strider View Post

When you say HD600, I'm assuming you're referring to the Sennheiser HD600 right?
Yes, Sennheiser.

Originally Posted by Sgt_Strider View Post
Are you saying the new Nuforce HDP doesn't pair up well with the HD600? If that's the case, I'm assuming it'll be the same for the Sennheiser HD650?
I never said it doesn't pair up well with HD600 ?!?!? I gave some positive comments initially and reported that the HDP sound signature fluctuates slightly with burn-in and that I don't want to post more impressions until the sound stabilizes. I don't have HD650 and don't like them as they are harder to pair with an amp than HD600, so maybe I should not speculate on the 650's right now.

Originally Posted by Sgt_Strider View Post
You are satisfied with the Westone 3's performance with the Nuforce HDP 24/96 right?
Yes, I am. However the sound is fluctuating as the HDP burns in and I don't know where it will end up at 200-250 hours. I hit about 125 hours last night, halfway there.

Originally Posted by transient orca View Post
I think what has been said is that uDac could use more power to drive HD600 better.
The uDAC is not bad with the HF-2 and HD600, but is very underpowered with HE-5 and slightly underpowered with HD600. But, the uDAC does better with HD600 than many of my 5v portable amps do, and falls between those and my 9v amps. When using the uDAC, I actually like the synergy with HD600 on uDAC more than the HF-2 on uDAC, because the HF-2's strong bass and mids become even more prominent with the uDAC (RS-1 were better with uDAC than HF-2 as well).

So, the HF-2 and HD600 sound nice on the uDAC but they both make a noticeable gain moving to the HDP in detail, soundstage, transparency and power levels. The HDP clearly has more power than the uDAC (16v 42-45 watt PSU), and with full size phones like HE-5, HF-2 and HD600 the HDP sounds better.

REGULARLY SCHEDULED UPDATE 02/04/10, typed up last night after listening but forgot to post:

I am listening with some 24/96 hi-res albums that I downloaded from HDtracks.com (one example Nancy Bryan "Neon Angel") to listen to the HDP. I have between 120 and 130 hours on the HDP. Some of my listening is done by over-focusing on one area or aspect, and so I may not be familiar with all the differences between compared products. If I don't volunteer a piece of info then I wasn't ready to. Such are the failings of posting these snippets of impressions before I am done.

The HDP is opening up nicely with burn-in -> with better detail, depth and ambience/space than the uDAC, which is less detailed but warmer and more forward or intimate sounding. The uDAC when listened to by itself is very detailed, warm and euphonic sounding (pleasant), and the DAC is even more detailed and spacious via RCA out. However, the uDAC, when compared to the greater detail of the HDP, is almost like listening to a nice but lower cost tube amp that very slightly smoothes out the details and makes the sound a little more romantic and musical.

The uDAC is not embarrassed by the HDP, but it's performance is clearly not on the same level. It's in direct comparison with the HDP where you can best hear the slightly less treble presence and less detail and depth in the uDAC headphone out. The gap between the two lessens slightly when using RCA out into my eXStatA and Jade electrostatic rig, but it's definitely there - I am still only using the HDP in USB 24/96 with native 24/96 tracks and only half-way through burn-in. The HDP headphone out sounds crystal clear like my Apogee mini-DAC, while retaining a slight warm tint so it doesn't sound cold and sterile either. The Apogee headphone out may actually not portray quite as deep of a soundstage (Iron-Dreamer felt that way about the Apogee as well, before he sold it to me).

The HDP is also better at driving high impedance loads than uDAC -> if I match the HDP volume against the uDAC volume while using a low impedance Westone 2 or 3 IEM, and then switch to 300 ohm HD600 without touching the volume knob, the HDP is playing noticeably louder than the uDAC with the HD600. The sound signature of the Westone 2 IEM pairs up with the warmer UDAC a little better than with the HDP; but the Westone 3 and ES3X, UE 11Pro and JH 13Pro IEM all sound better with the HDP, as does the HD600, Grado HF-2 and head-direct HE-5.

In regards to volume after switching from Westone 2 to the HD600, in comparison the $500 24/96 USB CEntrance DACport review sample seems to fall in between the HDP and uDAC; and it is louder than the uDAC and quieter than the HDP when not touching the volume after the phone swap. But the detail and depth and ambience/space seems more similar to the HDP. The DACport is maybe very slightly more forward than HDP but not as forward as the uDAC. And the HDP maybe has slightly more treble energy than the DACport (which is still ahead of uDAC in treble presence). But otherwise they are similar in performance (not identical, but close, and I haven't had enough time with either of these DAC/amps to be accurately compare, so please don't ask for more till I am ready to volunteer it).

Unfortunately, the DACport only has one USB input and one 1/4" output for the same price as HDP with multiple inputs and outputs. DACport uses the headphone out as the pre-amp out if you want to drive an amp with it, but it is powered via the USB bus like the uDAC. I don't see see the DACport as a competitor to the HDP because it's geared for the portable laptop market like the uDAC, even though it's a 24/96 USB DAC like the HDP. DACport sounds as good as a $400-500 DAC/amp should sound (Apogee Duet 24/96 Firewire also comes to mind), but it lacks the additional features of the HDP or Duet, or the power of a desktop amp.

UPDATE 02/09/10:

Originally Posted by bcwang View Post

Hopefully with your suggestions this thing will ship perfect. Meaning, the amp can drive high impedance cans like the HD650 and low sensitivity cans like the K701 as good as the best amps out there. While still having zero hiss with the most sensitive IEMs and having balanced channel volume driving them at low listening volumes. It's a lot to ask for but nuforce claims amazing performance from the HDP.

And if the DAC section is as good as their CDP-8 for 44.1_16, and beat things 10x the price...this thing could really be a winner. Of course we'll have to see.

One thing that maybe you could answer now as it probably won't change. In your testing, did you feel there was any quality difference between using usb, toslink, or coaxial digital?
I have not finished evaluating it, but the 24/96 USB is probably up to the quality of the optical at 24/96 from Macbook, from the limited testing I have done so far. And it does a great job with 16/44.1 files too.

They finalized and overnighted the production version to me today (2/9), but it was late enough that I don't know if I'll have it Wednesday or Thursday. I'll send back the burned-in prototype overnight to be modded to final version, and that will be sent back to me for the review. In the meantime I will be testing out the production model as soon as it arrives, with them expecting to be ready to ship around Friday.

Originally Posted by Rdr. Seraphim View Post
Per the ESS site (see ESS Products - DAC), the ES9022 has an integrated 2Vrms driver, which is standard line out. However, it seems like my DNA Sonett is sensitive to input, so I rarely run the µDAC or my Pico at max volume.
Just be careful and don't assume the HDP also uses an ESS SABRE DAC like the uDAC.


Front - volume knob top, selector for USB, Digital, or Analog. USB selects the 24/96 USB input. Digital will select the RCA coax as default unless a 3.5mm optical cable is plugged in then that over-rides the RCA coax. Analog will select the RCA input as default unless a 3.5mm analog connector is plugged in, then it will use that. These were choices made in order to keep costs down. I am using the USB for Macbook, Coax for Marantz CD5001, and an iMod Vcap dock into the RCA analog inputs.


UPDATE 02 11 2010:

I am heading out to my UPS Store mailbox to pick up what I think is the production HDP sample (the only fed ex I was expecting).

Here is a list of more of the 'goodies' revealed that they built inside the HDP.

1. Digital input has no capacitor along the signal path.

2. Analog input has a single DC decoupling caps. Signal path has minimal components.

3. USB interface is host powered and fully isolated from HDP with optical isolators.

4. The 24/96 USB interface outputs I2S signal to high quality DAC.

5. The digital circuit is on a separate daughter board.

6. The DAC chip consists of 4 internal 24/192kHz DACs to provide full differential and balanced output. The differential signal [eliminates] DC offset without the need for decoupling caps. [note - word left out above, I inserted what I think it was. I will ask if that means the signal at the RCA is balanced +/- and not a +/gnd]

7. Five separately isolated internal power regulations for each of the required digital and analog voltage.

UPDATE 02 11 2010- Changes heard in revised-final production HDP:

This afternoon I received a final production HDP to evaluate the changes made from the prototype. It only has about 2 hours on it. There is a noticeable improvement in performance with low impedance headphones, especially with the Westone 2 IEM. Previously the prototype HDP was good with a wide variety of IEM, including the Westone 3, Westone ES3X, JH13Pro, UE 11Pro, Triple.fi 10 Pro, and Monster Turbine Pro. But I did have concerns with the Westone 2 which via the original HDP sounded thinner, brighter and more bass-lite than usual. The synergy just wasn't there (with universal or custom tips), unlike with the other IEM in my collection.

The W2 was the only IEM listed above that sounded considerably better on the uDAC than prototype HDP. There was a more level and warm enjoyable frequency response when the two were mated together, while the ES3X was also slightly better with uDAC. The others I still preferred on the prototype HDP for it's more expansive soundstage and detail. But with W2 the sound was almost like what you get when trying to use a P-to-S adapter or extra resistor on an IEM that didn't need one (eg W2). The production version of the HDP now sounds much better with Westone 2, being it's fuller and warmer sounding with stronger bass; yet the bassy phones like Westone 3 and UE 11Pro did NOT become bass heavy in the process. So this is a very good change all around, by improving synergy with a wider variety of IEM. I am still listening with W2/UM56 tips a couple of hours later and enjoying it.

Before I shipped the prototype back this evening to be brought up to spec, I switched back and forth between the two units for an hour and could not believe how dramatic the improvements are with Westone 2 and HE-5. The Westone ES3X also picked up a nice boost in bass performance, although though it sounded good before. I also noticed that even the usually forward sounding ES3X do indeed have a deeper soundstage now with the final HDP vs the prototype. The changes with the W3 and UE11Pro are not as great as they already synergized well with the HDP before, but they retain their synergy. Same with the HD600 which sounded good before but now can play a little bit louder too. The bump in power is noticeable, and with Westone 2 and the prototype HDP I would set volume at 12-1 o'clock for normal listening, but now with the production HDP I can turn it down to 10 o'clock for similar volumes.

With the very inefficient 25 ohm HiFiMan HE-5 orthodynamic headphones, what used to be a moderate but not "too loud" volume with the knob maxed at 5 o'clock is now just as loud at 3 o'clock on the new amp, while normal listening is around 1-2 o'clock on the volume knob. The HDP now seems to max out a good 3-4 dB louder at 5 o'clock with the HE-5, which is much louder than I would listen normally. The HF-2 will clip or distort at around 2 o'clock on the volume knob now (too loud for me), but normal listening volumes are at just 11-12 o'clock. Normal listening with the HD600 would be 1-2 o'clock, with clipping between 4-5 o'clock. I estimate that power is more than doubled with low impedance phones, and at least 25% more powerful with 300 ohm HD600.

Because the volume at a particular knob position is now louder, at extremely low volume levels for sleeping with IEM it is easier to get down into the region of channel imbalance. As the volume knob approaches zero/off (below 9 o'clock) the left channel gets quieter than the right, where 8 o'clock is zero volume but not off. For me this 9 o'clock is quiet enough to fall asleep to the music, but for others they might want to go a little quieter. If I am using USB as the source, I can turn the Macintosh system volume down and the HDP will get quieter, so I can then turn up the amp's volume knob above 9 o'clock and the issue is resolved. All of my listening is with the volume knob above 9 o'clock anyways, and I usually don't use software or system volume attenuation (or EQ).

The background is totally black. With the music paused while using very sensitive IEM (like Westone 2 or 3 and ES3X, or UE 11Pro and JH13Pro) I hear no hiss at zero volume. With the volume all the way up there is only a subtle suggestion of noise in the background. Same thing if I play a music file containing only digital silence.

I haven't been able to focus on much more than power levels and frequency response with the new production HDP, so more listening is in order, as is more burn-in. I will be trying it out as a DAC/preamp tomorrow and the weekend, via RCA out as well. I do prefer the new HDP with 2 hours of burn-in over the older one with 300 hours, but the 300+ hour HDP did sound smoother and more refined than when it was new or vs the new one. I believe that is the primary change with burn-in, and it is an important one. At very high volumes before burn-in the sound can be slightly strident in the upper mids and highs, and this seemed to have been much better after the 300 hours of burn-in. Nevertheless, that is at volumes higher than I would ever sit back to listen to music.

So, I shipped the first prototype HDP back tonight for the modifications to the final revision. I could not think of any good reason to leave it the way it was, knowing what it can sound like when brought up to spec. They will get it Friday, and I will have it back next week when the production HDP will only have about 100 - 125 hours.

UPDATE 02 17 2010 - Changes heard in revised-final production HDP:

Originally Posted by pekingduck View Post
Hi Larry,
It's probably not a fair comparison... but I'd really like to ask if the amp part of the HDP rivals the Amphora?
No, but it's close. After just 100 hours the final rev HDP beats all my other portable DAC/amps, although the best ones come close to the HDP, just as the HDP comes close behind the Amphora (with either Pico DAC or HDP DAC as source). Once you get to a certain level of performance, the improvements in sound are often subtle, but sometimes more noticeable than others. The D4 with upgraded opamps can sound fantastic with my IEM, but I can switch to the HDP and feel like the sound is a little more refined and I can hear deeper into the music - yet it wont make the D4 sound bad, just not as good.

The differences in power, or hiss, or synergy with some pieces of gear will stand out more than the differences sound signature or soundstage. For example, the Amphora sounds good with HE-5 but it cannot match the power levels of the HDP with those phones, so that is one area where the HDP stands out above the Amphora. The Amphora does his with my ES3X and the HDP doesn't, plus it gives them a nice bump in the bass, so that is another area where the HDP excels over the Amphora.

I believe I like HDP just a little more than the 24/96 DACport and Apogee mini-DAC headphone out as well, which are also slightly better than the Pico and D4 and others. The depth and refinement I hear as the final revision HDP burns-in is taking it to another level over the 1st prototype I tested. Still, I think the DACport would be my next favorite next to the HDP, even over the Apogee headphone out (whether using 24/48 USB or 24/96 optical). It was my comparison of the DACport side by side with Pico amp w/DAC that convinced me the Pico could be sold (Pico's DAC is better than it's amp). Then again, I also liked the opamp rolled D4 more than the Pico amp w/DAC. The Pico DAC-only > Amphora or P-51 is another story, and it comes very close to the HDP, except in power - but that costs $900 including the jumbo cryo silver x mini IC ($800 with a cheap cable).

With the final rev HDP here since Thursday night I have been neglecting my main rig, bedroom rig, laptop rig, stat rig, and everything else as I continue to enjoy the HDP with all my IEM, HD600 and HE-5. I'm thinking these 100 hours of burn-in are enough to get an idea of what it can do, but I'm still going for my standard 300 hours for consistency.

Originally Posted by kostalex View Post
Do you mean USB > DACport > Headphones perform better than USB > Pico amp w/DAC > Headphones? Where may I find the details of this comparison? What headphones were used?
You have all the details I have written anywhere on that subject - it was my first post about it.

The DACport and HDP are set for 24/96 USB and I'm listening to Nancy Bryan "Neon Angel" in 24/96 hi-res download, and they both sound better to me via USB DAC than the Pico amp w/DAC. I switch to Diana Krall "Live in Paris" 16/44.1 CD rip and I still feel that way. The sound just seems more complete and present and natural, letting me hear deeper into the music - whether with Westone 2, Monster Turbine Pro Gold, Westone 3, Westone ES3X, UE11Pro or JH13Pro. In my previous reviews of the Pico amp I felt that it was slightly lacking in lower midrange warmth vs other amps, although detail, transparency and soundstage is great. With already warm phones like Denon, Ultrasone and some Grados or HD600 the Pico was good.

But, with a wide variety of other portable DAC/amps to pick from I usually preferred to use the Pico as a DAC/preamp feeding an already warm sounding amplifier (like Woo GES or Woo WA6). The Pico Slim vs Pico Amp at CanJam rectified all of my concerns about the original Pico sound, matching my P-51 in sheer portable performance, and possibly being a little more refined sounding while doing it (at least with my ES3X). Since I have the Pico DAC-only it made sense to sell the original Pico and add the Slim. This way I can separate the DAC and amp and have a smaller amp to take with me for iPod, and leave the DAC portion with the Macbook.

The HDP target audience is different than the DACport or Pico amp w/DAC target audience - since HDP plugs into the wall and has more power for full size phones. But, it still handles all my IEM with finesse. If I wanted the best portable DAC/amp that could run entirely off USB power for mobile laptop use, I'd pick the DACport over the other portable DAC/amps I have reviewed (including Duet, Pico, and all the others). It's also a little more powerful than the uDAC with HD600. If I wanted the best bang-for-the-buck USB DAC/amp that could plug into the wall, to feed full size amps and drive full size phones, it would be the HDP. The Apogee mini-DAC headphone out comes close, but it's not quite as refined and sounds a little more aggressive like a P-51, and the mini-DAC headphone soundstage is not as deep although it is very wide. Others have complained about the mini-DAC's built-in amp sounding more 2D than others too. And, I got one of the last USB versions of Apogee, as they are all now firewire.

Hopefully sometime this week or the next I will try comparing the HDP vs Apogee mini-DAC while feeding the full size amps in my bedroom, like the WA6, SAC KH1000, and ALO Amphora. I'll be able to switch between the external amp and built-in amp as well. Then I plan to take the HDP downstairs to my main rig to compare to the PS Audio Digital Link III feeding my EC ZDT amp. I can use my Jensen balanced input transformers to feed the HDP into my balanced WES (no SE inputs). And, as a bonus I can feed my phono preamp into the HDP, not just digital. A final bonus is I can also try my 12v Sigma 11 PSU that I use for the Apogee and see if that helps performance.

UPDATE 02/23/10 (late night):

Originally Posted by bcwang View Post
Your 300 hour mark should be coming up soon. Can't wait to get your full impressions.
I have been posting my listening updates often in post #2, so be sure to take a look there. Basically the HDP headphone amp is great and at less than 10 hours it was clearly better than the prototype which I returned to be updated. The HDP headphone amp is probably on the level of (and reminds me of) the $690 Grahm Slee Solo SRG II that I borrowed and reviewed just a month ago; and it's only slightly below my $1250 maxed Woo WA6 with RCA 6DE7 and Sophia Princess 274B, or my $995 ALO Amphora headphone amps.

The WA6 and Amphora have a little more depth of stage and soundstage size, and a touch more refinement and transparency, among other things; but the HDP headphone out is surprisingly close for a much lower price. This is whether using my HD800, HD600, HF-2, HE-5, or IEMs. I actually prefer the HDP for the HE-5 because it seems to have more power than WA6 and Amphora now, rather than less like the prototype had with these phones.

And, while the Solo SRG II was not a good choice for IEM because of noise and high gain, the HDP is perfect for all of my IEM, universal or custom. My UE11Pro are very picky about what amp I use with them in order to control the bass and fill in the mids, and the WA6 has always been my best amp for them. But the HDP headphone amp is almost as good as the WA6 with the UE11Pro, and it actually beats the Amphora when using the UE11Pro (Amphora also has much more hiss than HDP with IEM).

The HDP as a desktop amp beats all of the portable DAC/amps that have come through here now or in the past, including the DACport which comes close, or my opamp rolled iBasso D4 and D10 which are slightly farther back but also quite good. It almost seems like the HDP's $449 price is reasonable for the DAC, and the $449 price is also reasonable for the headphone amp, and somehow we get both for the same low price. In my book that makes it a best-bang-for-the-buck purchase.

What I am focusing on right now is the HDP as a DAC feeding my other amps, and comparing it to my Apogee mini-DAC, and then my PS Audio DLIII. That is taking me more time than I had planned.

UPDATE 3/6/10:

Originally Posted by bcwang View Post
I wonder how the HDP sound quality compares with the PS Audio Perfectwave......hint hint
I unpacked the PWD tonight but it isn't hooked up yet. I want to bring the HDP down to the main rig soon to compare to the PS Audio DLIII, and then I'll hook up the PWD and try that. At least I'm hoping I have time to get that done soon.

So far The HDP as a DAC/preamp feeding the Woo WA6 comes close to the single ended output of the Apogee mini-DAC, but I'm also using a 12v Sigma 11 PSU on the Apogee that makes it better than using the stock PSU. I think the Apogee just sounds a little more refined and organic when using the Sigma 11 with it, with a slight glare and less meaty bass when used with the stock PSU. One of my friends had thought the Apogee was a little aggressive sounding as well. After spending my first week or so with the Apogee and stock PSU, once I got the Sigma 11 working I haven't looked back (it arrived damaged). Before I bring the HDP downstairs to my main rig, I might want to try the Sigma 11 PSU on the Apogee, if the plug fits.

UPDATE 3/11/10, and partly in response to http://www.head-fi.org/forums/6468536-post378.html

Thanks for your thoughts K_19. I've also said the HDP > maxed WA6 is better than the HDP alone. The HDP amp once it is burned-in is more on the level of the $700 Grahm Slee Solo SRG II that I reviewed a month before the HDP. You will hear the HDP headphone amp become more refined and open as it burns in, so i think you will be more pleased later. I also agree the HDP DAC is better than the Pico DAC or DACport, and as a DAC it comes in very slightly below my Apogee mini-DAC with S11 PSU (but beats the Apogee headphone out for sure). As for K701, I never liked them and sold them after one week back in 2007.

Tonight I did something controversial - it's what I'm known for. I compared the HDP with lossless music via Macbook Pro USB, to my iMod > ALO Jumbo Cryo Silver X mini-mini > portable Vcap dock > Soloz 12 strand litz-braid mini-RCA > HDP. I listened via the HDP headphone amp with my JH13Pro and UE11Pro. Both sources are extremely close in sound signature, and with quick A/B switching they sounded pretty much the same, and even the volume levels of the two sources matched. It took a long time listening to both sources (most of the evening) to hear a very slight edge in favor of the HDP DAC for some extra air and ambience and micro-detail, with maybe a slightly more open sound (iMod very slightly more forward). Not bad for less than half the cost of the iMod rig ($1,100 with cables and iPod).

In previous comparisons I've posted that the Apogee mini-DAC had also slightly beaten my iMod/Vcap dock. The point is, the iMod/Vcaps and Pico DAC are very good performers, but I prefer the HDP and Apogee. I also prefer the Apogee mini-DAC slightly over my Digital Link III, and I think the HDP and DLIII are closer in performance to where I can't decide which I like better feeding the WA6. While the HDP may not be an absolute giant killer, it holds it's own very well against these $700-$1000 DACs. I don't want to start a FOTM here, but you have to spend 2x the cost of the HDP to only slightly beat it, and probably a lot more to decisively beat it.

As a matter of fact, if I already owned the HDP and I was looking for an upgrade, I would probably not "upgrade" to the more expensive Apogee or DLIII. The step up in sound may not be a big enough to make the extra cost worth it, unless you have a balanced amplifier you want to feed. For example, the Woo WA22 is a completely different animal when fed balanced input vs SE input, and there the improvements were very audible. I can say that the PS Audio Perfectwave DAC (PWD) is a step-up worth taking, but unfortunately I haven't heard a lot of DACs between the $3000 PWD and the $700-1000 DLIII and Apogee mini-DAC.

UPDATE 3/15/10:

Originally Posted by MysticWizard View Post
Hi everyone!


So, what do you think I am doing wrong? Do I need a much better system to hear these differances? Should I be plugging it in to different parts of the computer? Do I need to set specific settings in the computer or playback software that I am not doing? Do you think there is a problem with the unit itself?

I'm sorry, but I don't know why you don't hear the increased micro-detail, transparency, soundstage or power, unless it's because the HDP really does need the 100-300 hours of burn-in more than I recall.

I don't want to say your headphones are not resolving enough because I haven't heard the Klipsch, and don't know what Senns you are using. I don't think changing audio midi setup to 24/96 will make a difference when playing 16/44 files, but I do keep mine set for 24/96 all the time. I am also not familiar with the audio player you are using, as I use iTunes with lossless ALAC and AIFF files. With a PC you may need to install ASIO4ALL or some other app that helps get windows mixer out of the way.

I wish I could help more, but there is always the return period if burn in doesn't help or you can't get the improvement you are looking for. I wouldn't just do quick A/B comparisons though; I would listen to entire performances and see if the HDP impacts your enjoyment more, because sometimes the sound signature and volume levels being similar will mask the actual improvements in transparency, micro-detail and depth of stage when doing quick A/B comparisons.

I had that issue when comparing the iMod/Vcap dock to the HDP which was compared to the Apogee mini-DAC as well, where everything was very close and I had to do extended listening periods to hear the very slight improvement over my $1,100 iMod rig. Most people agree the Macbook audio out is about as good as the iPod's and not all that bad, but that the iMod/Vcap dock is an improvement over the stock iPod; so even if the HDP and iMod were equivalent I'd call the HDP a noticeable upgrade over stock Macbook audio. The Apogee mini-DAC with Sigma 11 PSU has a very slight improvement in air and ambience and treble extension over the HDP and iMod/Vcaps, but with the stock PSU the Apogee is not quite as refined sounding as a 300 hour HDP or iMod due to a slight sheen over the highs and slightly reduced bass impact. So, the differences can be subtle.

UPDATE 3/16/10: How it compares when used as a DAC/preamp.

Originally Posted by Nachkebia View Post
I wonder why is this review in dac section and not amp?
Originally Posted by K_19 View Post
Well, it's a combo and it can really go in either forum. I'm guessing that Larry put it here as he reviewed the uDAC here (which is also a combo, but more DAC oriented as name indicates) and just did it for the sake of consistency. Also, HDP seems to target not just the headphone amp market but also the preamp market for speakers and such, and is more versatile as a source than your typical headphone amp/DAC combo.
Yes, I look at the HDP primarily as a very nice DAC/preamp, which happens to have a very nice headphone amp built in that competes with amps under $700. Since it's also preamp with analog input, and has one of the few affordable 24/96 USB DACs out there, I put it in the source reviews section; just as I would the Apogee mini-DAC which has a nice headphone out that competes with $250-400 amps. The fact that the HDP feeding my Woo WA6 or ALO Amphora is an improvement over the HDP alone supports the placement here in Source Forum. However, I'm finding that it takes a $700-1200 amp to pass up the built-in amp, and I was enjoying it so much that I keep going on about it.

Right now the HDP as a DAC seems to be very close to the level of my iMod/Vcap dock, PS Audio DLIII, and Apogee mini-DAC. It's close enough that I put the DLIII up for sale because the HDP is more versatile by having the amp and smaller size. The DLIII can feed balanced amps via XLR out and has a little better separation and soundstage via balanced out; and if I didn't have the PS Audio Perfectwave DAC I might still be keeping the DLIII, mainly because my WES was the demo unit and doesn't have single ended inputs. I'd have to use input transformers and two sets of interconnects and an XLR gender changer to feed the HDP into my WES, and after all that the sound could suffer just a little bit.

But in my testing, for feeding the WA6, Amphora, eXStatA electrostatic amp, or SAC KH1000 amp for my K1000, the HDP does a very good job via RCA output, and I don't see a benefit to using the larger DLIII. I like that the HDP and Apogee mini-DAC both act as preamps and let me control the amplifier volume levels.

UPDATE: April 4 2010 (Happy Easter!)

Originally Posted by K_19 View Post
I think one of the biggest upsides with the HDP is that it's very transportable, for sure. It's very small, and the included power supply is on the small side as well... it's definitely very travel friendly. I probably couldn't think of another transportable all-in solution that would match HDP in terms of performance and functionality... perhaps a few portable DAC/amp solutions (D10, D4, Pico, etc), but if you have harder to drive headphones then I have no doubts that HDP would easily outperform those.
The HDP is definitely travel friendly, and I can grab mine and move it around anywhere in the house to use with my Macbook, but it would be even better if it had an option to run just off USB power when not needing a lot of power.

UPGRADED 45 WATT PSU NEWS - I've spent a while with the larger 45 watt PSU and I have to say the smaller stock PSU seems to be a little more neutral sounding and more properly balanced in frequency response, while the larger more powerful PSU adds a noticeable bump in the treble and a maybe small bump in the bass or a small dip in the mids relative to the bass. Combine that with the TWag cable on my JH13Pro and it becomes brighter than I like. It sounded really good with the HD600 though. And, I have to add that the HDP is quite good with JH13Pro with stock PSU, and sounds very close to my Protector balanced amp with them.

I switched back to the stock PSU today and I clearly prefer the stock PSU, especially with my HE-5 or JH13Pro and the built-in headphone amp, or when feeding my Protector balanced portable amp. I would imagine the larger PSU is just what the HD650 would need, but I don't have one to test with it. I think I might need to get an HD650 just to have around when testing gear for synergy.
post #3 of 1670
Could you give us a price range like 200 to 1000000000000?
post #4 of 1670
Thread Starter 
Originally Posted by jonhapimp View Post
Could you give us a price range like 200 to 1000000000000?
post #5 of 1670
post #6 of 1670
Subscribed! Eagerly waiting for further impressions! Too bad you don't have the HD 650 or AKG 701 to test with. I am guessing you will get a lot of questions about these two phones!
post #7 of 1670
Looking forward for more impressions.
Thank you Larry.
post #8 of 1670
I'm really looking for the dimensions of the unit.
post #9 of 1670
Since HDP hasn't been shipped yet, we initially set the price to be $399 but final production cost came out higher than estimate. $499 is what we like to have, but now we are considering $449 . So stay tune, we hope to have good news about the final price soon. Comparing to the competition and the performance, $499 is already a great price. But we like to set aggressive price/performance benchmark so we continue to crunch the numbers.

Disclosure: This is already mentioned in the uDAC thread but I would like to disclose again. Larry received the pilot production unit free of charge as we are impressed with his extensive knowledge and fairness with his review. In a public forum, there is no need to hype a review since it will quickly be exposed by others. Typically beta testers will receive final production unit free of charge in appreciation of participating in the evaluation.
post #10 of 1670
Waiting for the DAC performance comparisons, especially to either Pico/D10/D4.
post #11 of 1670
well if 399$ is no longer possible,then 449$ would be a perfect price.
499$ feels so much more than 449$,it's a psychological thing i guess.
it feels like paying 400 instead of 500
post #12 of 1670
Originally Posted by jasonl View Post
Since HDP hasn't been shipped yet, we initially set the price to be $399 but final production cost came out higher than estimate. $499 is what we like to have, but now we are considering $449 . So stay tune, we hope to have good news about the final price soon. Comparing to the competition and the performance, $499 is already a great price. But we like to set aggressive price/performance benchmark so we continue to crunch the numbers.

Disclosure: This is already mentioned in the uDAC thread but I would like to disclose again. Larry received the pilot production unit free of charge as we are impressed with his extensive knowledge and fairness with his review. In a public forum, there is no need to hype a review since it will quickly be exposed by others. Typically beta testers will receive final production unit free of charge in appreciation of participating in the evaluation.
Gah... $399 I can possibly budget for but $499 puts it way over the top.

Any chance of a head-fi introductory discount?
post #13 of 1670
Is it possible to feed HDP DAC output to external amp (WooAudio 3 in my case) and then back to HDP audio input (from WooAudio 3 preamp output in my case)? If I plug headphones to HDP then, I would have kind of hybrid amp.
post #14 of 1670
Could you also compare this to the uDac please and let us know whether or not you believe the price difference is equivalent to the performance boost? I understand that this has more ins/outs, but purely from an audio quality frame of reference, is the HDP worth the extra $$$. Thanks.
post #15 of 1670
Originally Posted by Blackwheel View Post
Could you also compare this to the uDac please <SNIP>
Not to add to much to the clamoring horde, but I wanted to second this with a more specific angle.

I'm curious as to a comparison of its driving abilities. If the uDac didn't have quite enough muscle to really push some of the more inefficent cans (i.e. 300ohm Senns), is the HDP enough of a step up to make an audible difference, to act as an adequate substitute for a dedicated SS amp (like a Caliente?) I'm assuming so, but I'd like your opinion on this gap specifically, if you have the time to do so.

Power output: 80mW x 2 @ 16-Ohm

Headphone Output: 6.3mm headphone output jack drives headphones up to 600-Ohm (80 mW@600-Ohm)
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Dedicated Source Components
Head-Fi.org › Forums › Equipment Forums › Dedicated Source Components › REVIEW (in progress) - Nuforce HDP 24/96 USB-Optical 24/192 Coax DAC Preamp and Headphone Amp