VV,
I have owned my DEQX HDP3 for almost 2 years now. I set it up myself. Since I have been a speaker designer builder hobbyist for about 25 years, I found it a lot of fun (work too) to get the setup to where I like it.
You should know that you cannot add a DAC outside of the DEQX because no matter what you do - you will end up going thru the ADC and then DAC of the DEQX. In other words the last DAC you hear will be the DEQX.
The overall sound quality is stunning on my system. I am not using the speaker correction/eq and have manually tweaked room eq. (using up all the memories) and I have sub delay correct. I did not like at all what the auto settings for driver eq and group delay created for me. I may take another crack at them in the future. But for now I am enjoying the music too much to bother wringing the last 5% out of the DEQX.
I am running Carver 60" ribbons (35W tubed Cary) into 11" Etons in custom cabinets (200W transistors). Crossing over at 200 Hz low pass and 190 Hz high pass, 48 db/octave. It goes stunningly loud. I can almost not hear the kevlar woofer cone mode at 800Hz.
I have set up the memories for 4 eq settings and use them constantly for variable bass lift/cut. The parametric eq I have set up for more judicious tayloring. Specifically I have the mid eq set at 3.5khz, 1 octave wide - to handle sibilance on those CDs where the recording engineers forgot to replace their hearing aid batteries before mixing.
I vary eq for each and every track I play (as required, many do not require any action). A far cry from the no eq audiophile days of yesteryear. Now I don't have to suffer thin recordings followed by bloated ones, screachy vocals followed by distant singers. I used to think that was what accurate was supposed to sound like. What a maroon. As if any recoding engineer knew what my playback system was going to be... Now I can enjoy all my early transitor mixed 70s music with early digital 80s music as well as 1960s tube mixed RIAA compromised tunes. Even today's fully compressed pop music can sound amazing. The DEQX has allowed me to make them all listenable and tuneful. This has been a significant improvement to my music enjoyment. Pure serendipity. The feature that I most like and use was never a purchasing point.
So from an eq perspective I can make my speakers sound like almost anything I want to (freq balance wise). I can't change their normal harmonic character, or the room modes that come with my house. Don't let eq experts tell you otherwise. If you have a peak or null at 60 hz - you can eq it a bit but the mode or null is structural - you needs traps etc to truly manage those.
I have concerns with my DEQX and Bryston BDP-1 integration and handling for 24/96 files (clicks and pops on startup). But if it would play 24/96 pop free and maybe play 24/192 I would be 100% pleased. As it stands it plays 16/44 flawlessly and all of my FLAC converted CDs sound way better than from any CD drive I have tried.
I haven't bothered with chasing upgrades because this is as good as it gets for me. I have not heard its equal at any price, anywhere. I think I can give the credit to the DEQX and BDP-1. I think you have a setup issue if you do not like the sound quality of the DAC. Because frankly I can't hear the DAC.
