REVIEW (in progress) - Nuforce HDP 24/96 USB-Optical 24/192 Coax DAC Preamp and Headphone Amp - Page 6

I don't know how long it takes to incorporate a simple change like the one they decided on before production, but that news came to me on 2/3/10 and I forgot to post it right away. It's a simple resistor value change if I recall.

I just moved my Apogee mini-DAC up to my bedroom rig so that I will be able to compare them more easily soon, but I might wait for the production HDP for more than casual comparisons.

I only had a Duet here for about a month last February, and did comparisons with Blutarsky at a mini-meet summer 2008 without my Sigma 11 PSU for the Apogee. Apogee mini-DAC single ended line-out sounds very similar to the Duet, if not slightly better than the Duet in terms of fullness or presence and realism. The mini-DAC's headphone jack's soundstage was wider but not as deep as the duet, and it had less hiss and slightly crisper highs. I wouldn't call the Duet recessed, but the mids were a little deeper like the Pico, and the mini-DAC was very slightly more forward.

I'm sure you would also like to see it properly vetted and be the best that it can be for the price. My understanding is that the most recent changes implemented should not delay the product much, and that they have made a significant improvement to the already nice sound. This should be good news. I really don't think it will be much longer at all.

I can't speak for Nuforce, but I am guessing that they have a production line set up which can start producing them in quantity as soon they give the approval with the final resistor values. There is nothing wrong with the HDP prototype I have here, but I suggested a couple of improvements and they tried something on their end and found that it made a nice improvement to an already good product. They don't want to release a rev 1 product simply to ship on time, and then have to release a rev 2 shortly after that to address a couple of minor changes that could have been made from the start. They are perfectionists, but not to the degree that they would delay this longer than they have to.

They have other people who test their prototypes from the earliest stages, and they have many high end headphones for their designers to listen with (HD800, Editon 8). I have some earphones/headphones or amps that they don't have, and visa versa. So I help them by giving feedback, and if it sounds like my suggestions will further improve or refine the product, then they try it on their end - and if they agree that the product is better then they will implement the changes quickly into the final product in time for shipping if possible.

However, I can only get stuff to try 2-3 weeks before they turn on the assembly line, because the gear needs to be close to a finished product in order to ship it out to me and other testers. They are not going to send out a breadboard DAC and amp with no case for me or my peers to try out. So, they take the product to 98% of final version, and then let me and others have a go at it. At that point they are comfortable that if any issues are found that it can be quickly fixed in time to implement before production begins.

With the uDAC we found an improvement that could be implemented with no delays in production, mainly eliminating hiss with my Westone 3 and ES3X using the built-in headphone amp. In the HDP it will be an improvement in power across the board, and better performance with low impedance IEM from the built-in headphone amp (I had no concerns with line-out to be addressed). This issue was discussed around 2/3/10 and a new prototype was completed by 2/5/10 and shipped from Taiwan. Once Nuforce USA receives them and they test fine, I will get one to try. If they test fine, I don't see them holding up production just for me, especially since the engineer on the project and I hear things similarly and agree on our impressions.

Now, with the UF-30 headphone they did delay production for several weeks (months?) in order to tweak and implement the improvements that I and others suggested, but tweaking drivers to tune the sound is an order of magnitude harder than trying a new resistor or capacitor. The final UF-30 was noticeably better than the prototype, which I have compared side by side in my review. But, those kind of delays will NOT happen with the HDP. It really should be final at this point, and go into production as soon as the main engineer gives the okay.