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NuForce DDA-100 impressions thread (computer, but not headphone, DAC/amp)

post #1 of 69
Thread Starter 

The NuForce DDA-100 DAC/amp (sort of, see below) has just hit the market.  It handles digital audio for speaker systems, but not headphones, so it won't be of interest to everybody here.  For others, it will I think be very interesting. 

 

The DDA-100 is a Class D "direct digital amplifier."  It's not in fact a DAC/amp, with a DAC section handling D/A conversion and feeding an analog signal to an amp section.  All signal processing, including volume control, is handled digitally and then applied to modulate the amp output.  The D/A conversion is thus, as NuForce puts it, accomplished "at the speaker posts."  So it's in fact a "power DAC" or a "digital amp" or something along those lines.  That's why there's no headphone section or output - the audio signal begins with the full amp output. Advantages, in principle, are simplicity, short signal paths and the like, and efficiency. 6Moons breaks it down further and shows some internals:

 

http://www.6moons.com/audioreviews/nuforce17/1.html

 

This digital Class D technology has been around for a while, but not widely, and as I understand it only in much more expensive applications (I believe the lowest cost unit after the NuForce is the NAD C 390 DD, at about $2500.00).  The DDA-100 is $549.00  It has one USB, one coax, and two optical inputs.  The USB handles up to 96/24, the coax up to 192/24.  Output is 50wpc.  NuForce has said elsewhere in on-line discussions that this power level allowed them to hit a sweet spot in the design that permitted high-quality implementation at a relatively low cost. 

 

It's small and simple, with on/off, source, and volume all handled by one knob.  The source and volume are displayed on the front in red.  Here it is in my living room:

 

700

 

I've had it burning in for about a day now.  I'm not an audiophile, but I'm very sensitive to sound quality: I like clean, with lots of detail and separation.  My normal home system is Red Wine Audio gear, the latest vesions of the Isabellina DAC and Signature 30 amp, with some careful tube rolling to get the sound where I want it, feeding Omega speakers.  Source is usally a PC running JRiver via an AR-T Legato SPDIF converter.  It's by no means the highest-end or fanciest setup, but it sounds great: I've had guests stop dead in their tracks when the music comes on.

 

The DDA-100 absolutely plays in this league.  It's not as warm as the RWA setup, but in every other way it's as good or better (and that may be better, if you don't like the tube sound).  Soundstage, placement, separation, tone, and clarity are all outstanding.  I've never heard anything this good out of anything remotely near this price.  By any standard this is very high-quality sound; at the price, it's fantastic.  I got this unit to audition as part of a system I'm building for a family member, but I'm not sure I'm going to let it go.  I'll be very interested in what others hear, but I'm really impressed.

 

A few other points.  I don't have much high-res material, but the USB input handled some HD Tracks files without any trouble, and they sounded even better.  It's happy with the Legato - it's hooked up but out of sight in the picture above - but I can't say yet how much difference it makes in this configuration.  The USB input works with the iPad and camera connection kit, which is nice.

 

My one issue so far is a substantial speaker thump at power-on and power-off.  NuForce says it's normal and OK, but my own personal jury is out for a bit.

 

EDIT: After living with this unit for a while, I withdraw my concerns about the thump (which is power-off only unless you cycle the amp quickly).  It's there but it's not going to hurt anything.


Edited by barbes - 8/21/12 at 4:51pm
post #2 of 69

Sounds like a nice setup you have there. I'd be a little worried about the thumping though. But other than that, a good buy for the price. 

post #3 of 69
Thanks Barbes, for your impressions. I've no doubt these 'amplified dacs' will have the future; the combine dac, pre amp and power amp into a much simpler, cleaner one box solution that will provide better price/quality then the classic solutions; at last this is what I constantly read in every NAD M2/C390DD review.
post #4 of 69
Thread Starter 

Anybody else heard this yet?  I'm curious about others' impressions.

post #5 of 69
Mine just arrived today. Haven't had a chance to plug it in yet, but the appearance is quite nice. The pics make it look competent yet boring, but in real life it has this sort of hip, minimalist Ikea style look to it. Very cool. I can see why Nuforce likes to pair this with the Amphion speakers because they have similar appeal.
post #6 of 69

would be interesting to hear it drive Ortho headphones....:)

post #7 of 69
Thread Starter 
Quote:
Originally Posted by project86 View Post

Mine just arrived today. Haven't had a chance to plug it in yet, but the appearance is quite nice. The pics make it look competent yet boring, but in real life it has this sort of hip, minimalist Ikea style look to it. Very cool. I can see why Nuforce likes to pair this with the Amphion speakers because they have similar appeal.

Terrific. Let us know what you think. (I agree on the design, it's wonderfully streamlined.)
post #8 of 69
Quote:
Originally Posted by dw1narso View Post

would be interesting to hear it drive Ortho headphones....:)

 

 I'd like to see how well the DDA-100 handles the HE-6. I'm currently running mine off the Icon2, but there's still a little bit of clipping at the very highest volumes (sounds fantastic otherwise). I think the extra headroom of the DDA-100 might give it the extra edge.

post #9 of 69
Quote:
Originally Posted by Armaegis View Post

 

 I'd like to see how well the DDA-100 handles the HE-6. I'm currently running mine off the Icon2, but there's still a little bit of clipping at the very highest volumes (sounds fantastic otherwise). I think the extra headroom of the DDA-100 might give it the extra edge.

I'm not so sure it would work. Digital amplifiers have a problem with high impedance speakers, because the (required) output filter is usually designed for 4-8 ohm loads. If the load is 50 ohm there will be a lot of ringing in the high frequencies, which is certainly not something the HE-6 will tolerate. There are potentially some ways around this, but I'm not sure if it will ever quite be ideal.

 

I'll ask Nuforce about it for my InnerFidelity review. 

 

Not quite the same, but I am successfully using the DDA-100 to drive a Woo Audio WEE electrostatic transformer box. I have that powering some Stax SR-404 Limited and it sounds pretty darn good. 

post #10 of 69
Quote:
Originally Posted by project86 View Post

I'm not so sure it would work. Digital amplifiers have a problem with high impedance speakers, because the (required) output filter is usually designed for 4-8 ohm loads. If the load is 50 ohm there will be a lot of ringing in the high frequencies, which is certainly not something the HE-6 will tolerate. There are potentially some ways around this, but I'm not sure if it will ever quite be ideal.

 

I'll ask Nuforce about it for my InnerFidelity review. 

 

 

Hmm that's too bad. I'm quite liking the sound from the Icon2, but wish it had a tad more headroom. 

 

A speaker tap with a 10 ohm resistor in parallel might work though wouldn't it? (plus maybe another resistor in series to attenuate for safety sake)


Edited by Armaegis - 9/2/12 at 10:22am
post #11 of 69
Quote:
Originally Posted by project86 View Post

I'm not so sure it would work. Digital amplifiers have a problem with high impedance speakers, because the (required) output filter is usually designed for 4-8 ohm loads. If the load is 50 ohm there will be a lot of ringing in the high frequencies, which is certainly not something the HE-6 will tolerate. There are potentially some ways around this, but I'm not sure if it will ever quite be ideal.

 

I'll ask Nuforce about it for my InnerFidelity review. 

 

Not quite the same, but I am successfully using the DDA-100 to drive a Woo Audio WEE electrostatic transformer box. I have that powering some Stax SR-404 Limited and it sounds pretty darn good. 

 

Yes please get the information from Nuforce... because I currently use a tripath based digital amp working fine with my HE5LE.

post #12 of 69
Quote:
Originally Posted by Armaegis View Post

 

Hmm that's too bad. I'm quite liking the sound from the Icon2, but wish it had a tad more headroom. 

 

A speaker tap with a 10 ohm resistor in parallel might work though wouldn't it? (plus maybe another resistor in series to attenuate for safety sake)

 

Adding a series RC network (8 ohm - 10uF) across each output would eliminate the problem. Parallel resistor would probably do the trick too. 

 

 

Quote:
Originally Posted by dw1narso View Post

 

Yes please get the information from Nuforce... because I currently use a tripath based digital amp working fine with my HE5LE.

 

Nuforce didn't actually mention this, but it's something I've learned from other designers of similar devices. I'm not sure if the same applies to a Tripath based design but I would think it would. Tripath uses a spread spectrum PWM technique for amplification, often paired with a simple 2nd order low pass passive filter to remove ultrasonic switching residue. That sort of design wouldn't really be equipped to optimally pair with a 50 ohm load. But as long as it sounds good to you, I guess it's not a big issue for your particular amp. 

post #13 of 69
Quote:
Originally Posted by project86 View Post

 

Adding a series RC network (8 ohm - 10uF) across each output would eliminate the problem. Parallel resistor would probably do the trick too. 

 

 

 

Do you mean the resistor in series and capacitor in parallel with the load? or both in parallel?


Edited by Armaegis - 9/3/12 at 7:23pm
post #14 of 69
Up.
I would like to buy this DDA 100 to drive my eltax monitor III, but i can't find a lot of review. What s your feeling or your own test concerning this product?

christophe
post #15 of 69
Quote:
Originally Posted by sadan123 View Post

Up.
I would like to buy this DDA 100 to drive my eltax monitor III, but i can't find a lot of review. What s your feeling or your own test concerning this product?
christophe

 

I'm still listening for my review, but so far so good. It's got an unbelievable amount of drive for the small size and weight of the box, and it seems really transparent which indicates the "DAC" aspect is well done. 

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