Hi all.
 
First off, sorry but my four questions below aren't all dedicated source question. As they relate to source equipment I still wanted to ask about the non-DAC parts as anyone with experience from the models can likely answer those also. Q1 - which is a source question - is my main question after all. 
 
Problem
I've been trying to grasp the differences between some of the interesting new NuForce equipment, but their website is not very informative as to the overlap between the models. As I know they are a sponsor of this forum, I'd love to hear from them or anyone else with experience of the different models where the expected differences lie (in terms of performance). 
 
Need
My need is for a new pre-amp and DAC to my main speaker system, as the Nuforce HDP that I am using now will move to the library and only serve my headphones and (active) studio monitors. I previously - after stubbornly refusing to admit it for a long time - accepted that I liked the HDP pre-amp more than my ~5 times more expensive Copland CTA303 (with new and upgraded tubes), so I'm clearly appreciative of what NuForce have been doing lately. Down the chain, I will likely be using the STA-100 as power amp to drive my Mirage M3si speakers. I understand that the UDH-100 (and HAP-100, although it is not a source component) is likely to be a headphone amp upgrade over my HDP. However, that's not my goal with the upgrade as I pretty much only listen to headphones when I'm sitting by the computer in the library, and we are soon moving to a house where the library and living room (main listening room) are in different locations.
 
Questions
Q1: What is the difference in terms of DAC between the UDH-100 and the DAC-80? Are they the same, or what? Both are listed with the asynch 192 kHz, and I believe I've read (or did I dream this?) that the UDH and DAC-100 had the same DAC, and that the DAC-80 is pretty much a DAC-100 without the headphone amp. 
 
Q2: What is the difference in terms of pre-amp between UDH-100 and the DAC-80? Is there a difference, or is the reduced price of the UDH only a result of the much more limited inputs (a single USB)? 
 
Q3: What is the story between UDH-100 and HAP-100? Do they have the same headphone amp?
 
Q4: I know the HAP has a different pre-amp than the UDH already: How much of a difference is there really between them? I have failed to find any form of even early impressions to compare them. Well... I suppose that Totally Wired in NZ have some comments on all parts in the series, including the pre-amp differences, but they sell the equipment also so it would be odd to see them say anything else than that the HAP is a clear step up from the UDH/DAC pre-amps.
 
My hopes
Overall, I obviously aim for bang-for-the-bucks but I'm not silly enough to let a small margin of cash decide if there would be a clear upgrade in sound. It's the first 500 bucks that hurt the most, not the final few after all.
 
Best case: I can safely go with only the UDH (which is cheaper than the DAC-80) as I only need one input (from an iMac). Granted, I'd have an extra headphone amp but it wouldn't hurt, just in case I 'have to' pick up a pair of HD800 at a later point, or want to sit in the living room and listen to my current cans rather than by the computer. Only a UDH assumes that the DAC (Q1) and pre-amp (Q2) are equally strong between the UDH and DAC-80. 
Decent case: I can go only with the DAC-80. I'd have an array of extra digital inputs that I have zero use for, but whatever. This option assumes that the DAC (Q1) or pre-amp (Q2) is stronger in the DAC-80 than in the UDH.
Worst case: The DAC-80 is superior in DAC to the UDH, and the HAP-100 is clearly superior to the DAC-80 as pre-amp. I would thus end up with both a DAC-80 and a HAP-100, despite not needing a headphone amp. That would be a great headphone amp setup that would be barely used in that capacity, which seems like a waste. Yeah, sure, I could get some HD800 here also, but I already spent twice the money than on just a UDH so I'm not sure I want to splash out more on a second set of headphones (well... a fourth really, but the first three really just count as one, don't they?).

The UDH-100 & the Dac-80 have the same dac but the Dac-80 has more inputs and has twice the pre-amp output. They don't recommend using the UDH-100 & Dac-100 (i own) for preamp use. I am considering selling my Dac-100 to get the Dac-80 or Dac-9/CDP as I run studio monitors off my Dac-100 at the moment.

Is it for the limited inputs (just one) they don't recommend the UDH-100 for pre-amp or is it the output voltage? I earlier read a review saying that the DAC-80 had 1.97 Vrms just as the UDH, but I see now when I double check their specs that you are correct.
 
Hmm... that changes things. I suppose a relatively ok option would go for the UDH strictly as a DAC and the HAP as pre-amp then. That adds up, doesn't it? Oddly, I'd have two headphone amps that I didn't really need, but the price-performance of the DAC and pre-amp is very nice for speaker use. When I finally pick up a pair of HD800, I'll be all set in terms of amplification already I guess. 
 
Cheers, Kazsud. Much appreciated.

output voltage

Ok - a good reason then
 
Thanks again.

In the DAC-80 User's Guide it states: 
"The analog RCA output should be connected to your preamp using high quality interconnect
cables. Please note: It is not recommended to directly drive a power amplifier from the RCA
outputs."
 
On the contrary, in the UDH-100 User's Guide you can find a section "Transparent Preamp".

chowyeung said:

  In the DAC-80 User's Guide it states: 
"The analog RCA output should be connected to your preamp using high quality interconnect
cables. Please note: It is not recommended to directly drive a power amplifier from the RCA
outputs."
 
On the contrary, in the UDH-100 User's Guide you can find a section "Transparent Preamp".

Click to expand...

 
I haven't read the user's guide of either one of them, so I have to ask if it isn't the preamp of the UDH itself that they talk about under 'transparent preamp'?
 
In terms of the DAC-80 and the wording in its user's guide, that should be because many power amps expect more than 2 Vrms. There are several that are ok with 2 Vrms also, though, so they're just trying to cover their behinds with that wording. As far as I understand, their own STA-100 would be no problems to run as power amplifier directly connected to the DAC-80. Sure, the HAP-100 as pre-amp is even better, but the DAC-80 to the STA-100 wouldn't be a problem and not harmful.

trasselkalle said:

  In terms of the DAC-80 and the wording in its user's guide, that should be because many power amps expect more than 2 Vrms. There are several that are ok with 2 Vrms also, though, so they're just trying to cover their behinds with that wording. As far as I understand, their own STA-100 would be no problems to run as power amplifier directly connected to the DAC-80. Sure, the HAP-100 as pre-amp is even better, but the DAC-80 to the STA-100 wouldn't be a problem and not harmful.

Click to expand...

 
In my (albeit not extensive) experience with power amps, most do not need more than 2Vrms. Most in fact reach full output with less than 1Vrms. The STA-100 only needs 0.89V itself.

I would like to revive this topic as I recently purchased a DAC-80.
 
The DAC-80 was supposed to replace my Nuforce iDo in my bedside rig. I was using the iDo connecting it to a Little Dot MKIII tube preamp driving my HD800's. When using the DAC-80, there was an improvement, but actually not so much that I want to sell the iDo. It confirmed me that the iDo is actually a great little device that adds the convenience of using my iPad (to access FLAC from my NAS).
 
So, not really needing the DAC-80 in my bedside rig, I decided to give the DAC-80 a try in my hifi setup in the living room.
 
My living room set-up is a Nuforce AVP-18 as preamp connected (bi-wired) to two good old Quad 405 power amps driving my self-built hifi speakers, four-way speakers of the Danish brand VIFA.
 
I have been using the DAC-80 to directly drive the Quad 405's. As my speakers are bi-wired, I have a RCA Y-splitter connected to the DAC-80, with two interlinks going to the right Quad and two interlinks going to the left Quad, each Quad having one channel driving the bass and one channel driving the mid/highs.
 
I have an AVP-18 as I used to have a 5.0 set-up, but I recently moved and noticed that I don't care enough about 5.0 DD/DTS enough to go through the hassle of pulling cables. It's stereo that I really care about.
 
Enough about my set-up, back to the DAC-80.
 
As soon as I disconnected the AVP-18 and connected the DAC-80, I was truly AMAZED by the improvement.
The DAC-80 is far better than the AVP-18 both as pre-amp and certainly as DAC.
Better controlled bass, deeper bass, excellent separation, beautiful mids (voices are fantastic) and the sound stage was truly amazing.
 
The sound stage actually changed from being two dimensional (on the plane through the speakers) to three dimensional (really having instruments and voices come forward or move to the background).
 
So, the AVP-18, which I liked so far, is to be retired soon.
 
My questions:
- Is it a problem to keep using the DAC-80 as a preamp as well as a DAC, directly connecting my Quad 405's? Will my Quad 405's eventually run into technical problems because of this voltage problem?
- Otherwise, should I consider buying a pre-amp? I see no direct need, because I don't have any analog sources anyhow. What would be the advantage?
- If having a pre-amp would be a must, would the HAP-100 be a good option, or should I consider something else?
- I was also considering selling both the DAC-80 and the AVP-18 to then purchase a NAD M51 instead, replacing all of it. Anyone have any experience comparing NAD M51 versus DAC-80/HAP-100 combination?

There should be no issue using the DAC-80 as a defacto preamp in this case. The notion of preamps is only important in cases where you specifically need the volume control, or multiple inputs, or where you have a low stability margin power amp with unusually low input impedance matched with a source of unusually high output impedance. As you do not fall into any of these cases, don't worry about it.

Thanks a lot @Armaegis for your fast response. In fact, I do mind that the volume control of the DAC-80 is not perfect, it seems to move in steps that are quite large. Going from the lowest volume to silent is actually quite a big step, in the late evening even the lowest volume is somewhat too loud. Maybe the gain of the Quad 405's is too high. But then again, to buy a HAP-100 just for that is maybe a bit overdone.
 
At least now I know I am not going to ruin my Quad 405's which have been loyal to me since the ninety's (and before that to their previous owner since the seventy's .
 
Question that remains then is: how would the DAC-80 as pre-amp compare to the NAD M51 as pre-amp?
Considering I only have one digital source in my speaker rig, using optical SPDIF, the DAC-80 has sufficient inputs.

arcee said:

  I would like to revive this topic as I recently purchased a DAC-80.
 
The DAC-80 was supposed to replace my Nuforce iDo in my bedside rig. I was using the iDo connecting it to a Little Dot MKIII tube preamp driving my HD800's. When using the DAC-80, there was an improvement, but actually not so much that I want to sell the iDo. It confirmed me that the iDo is actually a great little device that adds the convenience of using my iPad (to access FLAC from my NAS).
 
So, not really needing the DAC-80 in my bedside rig, I decided to give the DAC-80 a try in my hifi setup in the living room.
 
My living room set-up is a Nuforce AVP-18 as preamp connected (bi-wired) to two good old Quad 405 power amps driving my self-built hifi speakers, four-way speakers of the Danish brand VIFA.
 
I have been using the DAC-80 to directly drive the Quad 405's. As my speakers are bi-wired, I have a RCA Y-splitter connected to the DAC-80, with two interlinks going to the right Quad and two interlinks going to the left Quad, each Quad having one channel driving the bass and one channel driving the mid/highs.
 
I have an AVP-18 as I used to have a 5.0 set-up, but I recently moved and noticed that I don't care enough about 5.0 DD/DTS enough to go through the hassle of pulling cables. It's stereo that I really care about.
 
Enough about my set-up, back to the DAC-80.
 
As soon as I disconnected the AVP-18 and connected the DAC-80, I was truly AMAZED by the improvement.
The DAC-80 is far better than the AVP-18 both as pre-amp and certainly as DAC.
Better controlled bass, deeper bass, excellent separation, beautiful mids (voices are fantastic) and the sound stage was truly amazing.
 
The sound stage actually changed from being two dimensional (on the plane through the speakers) to three dimensional (really having instruments and voices come forward or move to the background).
 
So, the AVP-18, which I liked so far, is to be retired soon.
 
My questions:
- Is it a problem to keep using the DAC-80 as a preamp as well as a DAC, directly connecting my Quad 405's? Will my Quad 405's eventually run into technical problems because of this voltage problem?
- Otherwise, should I consider buying a pre-amp? I see no direct need, because I don't have any analog sources anyhow. What would be the advantage?
- If having a pre-amp would be a must, would the HAP-100 be a good option, or should I consider something else?
- I was also considering selling both the DAC-80 and the AVP-18 to then purchase a NAD M51 instead, replacing all of it. Anyone have any experience comparing NAD M51 versus DAC-80/HAP-100 combination?

Click to expand...

 
 
You should feed the Dac-80 Coax from the iDo.

The NAD master series is generally well regarded, but unfortunately I do not have any experience with those products.

Just to let you know, I have in the meantime received my NAD M51 and it is a substantial upgrade over the AVP-18 for stereo sound. In a 2.0 setup the M51 has deeper, more controlled bass and more detail.

But, I must admit that the M51 is not on par with the DAC-80. The inconveniences of the DAC-80 set aside, the DAC-80 sounds better, more detail than the M51 and this amazing 3D soundstage that both the AVP-18 and the M51 do not produce.

It showed me what a fantastic DAC the DAC-80 really is!


Sent from my iPad using Tapatalk

Very interesting... I would have expected the M51 to be a step up.