[bcwang]

Quote:

Originally Posted by jasonl /img/forum/go_quote.gif We have spent the past 3 days to look over HDP (more testing before a big production), and also to determine if there is any way to optimize it both for IEM and high impedance headphones so that people like bcwang with very sensitive ears can avoid hearing the noise floor with IEM. The conclusion is that HDP has to be optimized for headphones as our original design goal. We think IEM will still sound awesome if you can not hear the noise floor being detected by sensitive IEMs. We have published this technical note about the noise floor: Nuforce.com | Guides It is not due to the SMPS so there's not much we can do about it unless we compromise our design goal to lower the gain of HDP to suit IEM. We will start taking orders for HDP starting 2/26.

I think keeping the design goal for driving hard to drive headphones is the right decision. I've seen examples already where the HDP full volume range is utilized. Lowering the power would be a mistake if this is to compete with the big boys.

Also, since many (if not most) people cannot hear the noise floor with IEMs, it is probably not a big issue at all. In fact, as HPA pointed out, it is quieter than many other high performance headphone amps already.

It is great that nuforce discloses this possible issue so potential buyers are aware of what to expect. That is a responsive company and not one that hides/denies controversy and hopes it simply goes away.

 

[woodibly]

Hello Head-fi'ers! I like to do thorough research on all things I ever plan on purchasing. And I must say, deciding on phones, dac, and amp may be the most frustrating research I've done! However, thanks to Larry and everyone, I think I'm ready to jump on this HDP!

 

[HeadphoneAddict]

Quote:

Originally Posted by bcwang /img/forum/go_quote.gif Take your time, don't rush the comparison. The more thorough the better. And funnily, as we all talk about hiss, it seems to be all relative to the listener. -Your comment: "Amphora also has much more hiss than HDP with IEM" -A review on the amphora I was just reading: " What I also cannot talk about is noise. Because here again, there simply isn’t any. It just isn’t possible to ask an amp to be quieter, or have a blacker background, than the Amphora. In this regard, it is, I believe, the best I have ever heard. Tubes always involve at least a little bit of hiss at the very top of the amp’s volume range. There is nothing of the sort here, and it’s also quieter than any of the SS amps I have around. This may well be due to the battery operation – not sure. But it sure is one silent runner." Haha, I think agreement on the noise level of an amp is hard to achieve.

Actually, the ALO Amphora only has hiss for me with very sensitive IEM, not with full size phones. When Skylab did his review it was with full size headphones, and many of them were 600 ohm Beyer headphones. I can't hear any hiss with full size headphones with most amps, including the Amphora. In that respect it does have a black background.

Quote:

Originally Posted by jasonl /img/forum/go_quote.gif We have spent the past 3 days to look over HDP (more testing before a big production), and also to determine if there is any way to optimize it both for IEM and high impedance headphones so that people like bcwang with very sensitive ears can avoid hearing the noise floor with IEM. The conclusion is that HDP has to be optimized for headphones as our original design goal. We think IEM will still sound awesome if you can not hear the noise floor being detected by sensitive IEMs. We have published this technical note about the noise floor: Nuforce.com | Guides It is not due to the SMPS so there's not much we can do about it unless we compromise our design goal to lower the gain of HDP to suit IEM. We will start taking orders for HDP starting 2/26.

I think the production HDP that I have now is very well suited for IEM and full size phones. I think it will only be the rare individual who will be able to hear hiss with the HDP when using IEM.

Quote:

Originally Posted by Hygienist /img/forum/go_quote.gif HPA, Thanks for taking the time to be so thorough! I'd just like to ask, in your review of the DACport you said using that as a DAC/Amp, compared to the HDP used as a DAC/Amp, the DACport was only of slightly less quality. Do you still stand by this assertion (especially when used with IEMs, such as JH13), or has the revised unit changed your opinion?

I still stand by my position that the HDP as a DAC/amp is better than the DACport by a small but noticeable degree in detail and depth of stage. What has changed in the final production HDP is that the DACport is no longer warmer sounding than the HDP, and they are more similar in that area now. Also the bass now has a little stronger foundation on the HDP than on the DACport. The DACport is very good, and if I didn't have the HDP I would be using the DACport the most with my Macbook Pro, especially out on the back deck while listening to music while "off the grid".

Quote:

Originally Posted by bcwang /img/forum/go_quote.gif I think keeping the design goal for driving hard to drive headphones is the right decision. I've seen examples already where the HDP full volume range is utilized. Lowering the power would be a mistake if this is to compete with the big boys. Also, since many (if not most) people cannot hear the noise floor with IEMs, it is probably not a big issue at all. In fact, as HPA pointed out, it is quieter than many other high performance headphone amps already. It is great that nuforce discloses this possible issue so potential buyers are aware of what to expect. That is a responsive company and not one that hides/denies controversy and hopes it simply goes away.

I was the one who asked them for more power with full size phones.

 

[feverfive]

I asked about this in the uDAC thread, and sorry if it was already addressed here (don't think so as I did skim the whole thread), but will the HDP work o.k. by connecting into a POWERED USB hub? My Macbook Pro has only 2 USB inputs; one is used for connecting to my hub, & the other I need to reserve for syncing my iPhone/touch/classic...

 

[kite7]

The HDP does not get power from the USB connection since it uses its own power adapter, the uDAC on the otherhand does. You should get a usb hub if you need more usb ports.

 

[HeadphoneAddict]

I am using the HDP on a USB hub that is powered by my Macbook and it's working fine with 3 other DAC's.

 

[Poetik]

Just ordered one, looks like they're now up for sale again.

 

[SleazyC]

Having a hard time figuring out whether or not I want to pick up one of these. I was hoping to grab a tube amp for the office but this thing is so small and the review makes it sound like it really is a great sounding amp. Wondering if I should pick this up now and use it as a DAC for my eventual tube amp.

 

[CountChoculaBot]

Going off what this guy said, would you be able to recommend a tube lover this thing used as a DAC/Amp? Tube lover as in I prefer a more romantic sound than a razer accurate one.

 

[HeadphoneAddict]

Quote:

Originally Posted by SleazyC /img/forum/go_quote.gif Having a hard time figuring out whether or not I want to pick up one of these. I was hoping to grab a tube amp for the office but this thing is so small and the review makes it sound like it really is a great sounding amp. Wondering if I should pick this up now and use it as a DAC for my eventual tube amp.

Looking at the gear in your sig line, I think the HDP would work well for you until you can get a tube amp to feed it into. It's warm sounding but at the same time crisp and present in the highs, so there is more treble than your uDAC, but it works well as a DAC feeding my Woo WA6.

Quote:

Originally Posted by CountChoculaBot /img/forum/go_quote.gif Going off what this guy said, would you be able to recommend a tube lover this thing used as a DAC/Amp? Tube lover as in I prefer a more romantic sound than a razer accurate one.

If you are a tube lover who wants a romantic tube flavor over accuracy, then you might like something like the HiFiMan EF2 DAC/Amp a little more if you have Grados or HD800 or AKG-K701. Iif you have something like HD600, HE-5, Denons, ATH-ESW10 or ATH-A900 then the HDP will still make a tube lover happy. I like tubes and SS personally, and HDP sounds razer accurate with HD800 and HF-2, but maybe not what someone who only likes tubes would like (i.e. WA6) when combined with the wrong headphone.

 

[kite7]

I think my HDP may be defective. Sometimes there would be no sound for a few seconds through the headphone jack and RCA output when I start to play something right when I finish loading up the operating system. Also, at very random times the sound would either cut off or crackle for no reason and this is very bothersome. Tried both my usb pci card and motherboard usb ports, same thing. The worst case scenerio I ran into was no sound coming out at all for a few minutes after I turn on the HDP before I turn on my computer and I tried turning the HDP on and off and plugging AC adapter but I can't determine the cause.

 

[TheDuke990]

Quote:

Originally Posted by kite7 /img/forum/go_quote.gif Also, at very random times the sound would either cut off or crackle for no reason and this is very bothersome. Tried both my usb pci card and motherboard usb ports, same thing.

I think this has nothing to do with the HDP. USB ports have a low priority and when the cpu runs on nearly 100% sometimes the music starts crackling. This happens also to my system (aune Mini USB DAC).

 

[kite7]

Quote:

Originally Posted by TheDuke990 /img/forum/go_quote.gif I think this has nothing to do with the HDP. USB ports have a low priority and when the cpu runs on nearly 100% sometimes the music starts crackling. This happens also to my system (aune Mini USB DAC).

This has never ever happened with my Musiland 02US DAC. I have a quad core cpu and never does the cpu run at 100%.

 

[TheDuke990]

Sorry but my explanation was not 100% correct. This happens to me also when the cpu runs with 10% load and this has to do with the priority how the PC handle USB ports. I read this in another forum. Unfortunately I'm not able to find the post.

 

[woof37]

Quote:

Originally Posted by TheDuke990 /img/forum/go_quote.gif I think this has nothing to do with the HDP. USB ports have a low priority and when the cpu runs on nearly 100% sometimes the music starts crackling. This happens also to my system (aune Mini USB DAC).

My thoughts as well. You should install ASIO4ALL and increase the buffer size. If your system has high CPU utilization, you won't get great performance out of a USB DAC.