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New HLLY SMK-III Digital Audio Decoder - Page 8

post #106 of 138



i received some ad823 two weeks ago and had a lot of time to test them. Beside the already mentioned op275 + opa2134 combination a combination of op275 + ad823 as well as a combination of opa2134 + ad823 is worth a try (the first mentioned combination is more lively, but somewhat too bright, the latter is laid back and deeper, but lacks datail grade and livelyness, in comparison to the first one. In my opinion both are better than the op275 + opa2134 combination). I already receiceved some 8066, however they are not attached to the adapters yet...

post #107 of 138

i tested a lot of different opamp combinations with the line outs the last weeks (I'm using the smk-iii as a dac). The opamps i tested were the op 275, opa2604, opa2134, ad823, and ad8066.


First of all, the hlly smk-iii (mod) already provides a good sound out of the box and is quite worth its money ... However, replacing the opamps improves the sound quality noticeably:


Out of the box, the smk-iii is equipped with op 275 as filters (from the front, the two opamps on the left side) and I/Vs, which provids a lively and moderate detailed but also a somewhat un-harmonic, bright, "electrostatic" and aggressive sound (especially the bass, wich is quite interesting for the first hours but becomes annoying as time passes); completely lacking a "soundstage" in comparison to the following combinations.


Here are the highlights:


filter: op 275 & I/V: opa2134: The opa2134s make the sound a little bit darker and laid back and also broaden the soundstage.


filter: op 275 & I/V: ad 823: The sound is somewhat bright (but not too bright) and has a "electrostatic" quality, gains a wide soundstage and is much more detailed. The bass is very punchy. In all, the sound is lively but the bass feels a little bit out of place. However, a very enjoyable but analytic combination. If you like electronic music, this might be your choice.


filter: opa2134 & I/V: ad 823: Same as before but less aggressiv and less refined (the bass is less punchy), somewhat laid back, and a bit darker (just a bit). Seems to be better for long listening sessions than the previous combination (might be a bit less detailed, but almost not worth to be mentioned).


filter: ad 823 & I/V: ad 8066: Excellent soundstage and detail grade, the bass is punchy but not as dominant as with the op275, the sound feels somewhat "electrostatic" and is lively but also a bit bright and "un-harmonic". Gets the second place award.


filter: ad 8066 & I/V: ad 8066: WOW! My absolute favorit! Excellent detail grade, very lively and harmonic sound and an unbelievable broad soundstage (also the best locatability) but not the typical burr brown "laid back" or op275/ad823 "electrostatic" sound. Some songs gave me the impression the singer stands in front of me playing his guitar (jack johnson) and others let me believe the singer stands 10 meters away framed by a orchestra (celine dion). The ad 8066s provide excellent mids and highs (really impressiv), not bright but also not dark, just perfect. The sound is very harmonic neither the highs nor the bass, nor mids feel out of place. A very very easy "to-listen-to" combination. The only deficit might be the bass: The bass is goes deeper than with the previous combinations and feels therefor less "tangible" and punchy (in fact it isn't - it is still as good as with the others). I first switched back to the previous mentioned combination because of this - i thought using the ad 8066s as filters would lack bass. This is definitely not the case. The bass is still very good but is more in the background and not as dominant as with the previous mentioned combinations, which, in all, allows for the great harmonic sound. You should go with this combination if you have speakers/headphones that deliver a deep bass (not necessary a dark sound). Otherwise i recommend one of the previous combinations. Also a pa2227 & ad 8066 combination should be worth a try...(let me know if you did try it;-)


With the last two mentioned combinations the hlly smk-III (mod) as a dac provides an excellent sound!

post #108 of 138
Thread Starter 

AD8066 you say, I think I have one but will check and get more if needed.

post #109 of 138

Actually, you will need four of these (two for filtering - the two on the left- and two more for the I/V conversion - the two on the right). Let us know, if you can confirm my impression about the sound with these opamps (you should give them about 30- 50 hours "burn-In" or "becoming-accustomed-to-the-new-sound", whatever your hifi-religion is ;-))

post #110 of 138


I recently got my SMK-III mod and have a question concerning sample rate indicator behaviour.

The device is connected to a laptop with WinXP SP3 via USB interface. I'm using XMPlay player without any ASIO drivers, default DirectSound only.

When there is only one sound source running (e.g., XMPlay) the switching between output sample rates for 44100 and 96000 recorded files works just fine. Indicator on the front panel switches from 96 kHz downto 44,1 and back as it should be. But when I add yet another sound source playing content, e.g. Flash Player on the youtube.com web page, the samlpe rate indicator gets stuck at 96 kHz position. Then it doesn't react to any switching between 96->44,1->96->44,1 music files played in XMPlay. It still indicates 96 kHz.

Has anyone encountered such problem? How do I make this set work properly?



Carried out some research today. Аfter booting-up and WinXP complete loading device was connected to USB. WinXP found new hardware and installed drivers. Device was switched on after that. Front panel indicator showed 44,1 kHz. Ok.

Then the set was left alone in this state for a while. No music was playing, no user activity at all.

After some period of time (in different cases - from 3 to 8 minutes) the indicator switched and stuck to 96 kHz on its own. Subsequent playing files with different sample rates does nothig to change it's state (foobar & xmplay were used).



I think I've solved the problem! Changing the sample rate in the Foobar's Resampler (PPHS) DSP plugin (or XMplay's "Sample rate" option along with "Apply sample rate to all file formats" checked) makes the indicator to change its state correctly in accordance with manual sample rate selection. Sound changes respectively. That's great! :-)



Yet another fact. WinXP stops playing music via USB after resuming from hibernation. Rescanning devices in the device manager window resolves this trouble.

Edited by Maks - 8/14/11 at 12:23am
post #111 of 138
Thread Starter 

Thanks for the hint, glad you solved the problem.

post #112 of 138



May I know which 8066 version you opted for? AD8066ARMZ or AD8066ARZ?


My unit would sometimes go into silence a couple of seconds before halfway playing music and this could sometimes happen a few times in a row. Connecting it to a better power adapter improves the situation but it's still there. Would replacing the Caps with bigger ones solve this problem?



post #113 of 138



I'm using the 8066ARZ. I had this problem too (independent of the opamps i were using). I changed the crappy power cable to overcome this. The dac still needs one or two seconds for recognizing the source. However there are no problems afterwards. Maybe the stream you are feeding to the dac is interrupted here and there ( 1- 3 sec gaps between the songs) which makes the dac searching for a source?
I'm using the mod version with better caps and i'm also using it in europe... but i don't think this matters.



post #114 of 138
Hi, are you using them in combination with the 8066? If not you should give them a try as i/v converters. Its amazing how the 8066 improve the performance over all the other opamps i have tested so far.
post #115 of 138


Will OPA637 work fine in phone section? Concern is that OPA637 prone to oscillation if gain is less than 5. Will this trouble pop-up with this dac?

post #116 of 138



I'm now using it with 8 x OPA627 (filters and I/V conversion). Sounds excellent (the bass is much better) ! The soundstage is smaller than with AD 8066s and the detail grade might be somewhat reduced. However, the best combination I have tried. This upgrade was worth the investment (about $ 140).

post #117 of 138

Can you post an FOTO with marked places where you changed the OpAmp's ?
For both AD 8066s  and  8 x OPA627 options.

post #118 of 138
Originally Posted by EarlyBird View Post



I'm now using it with 8 x OPA627 (filters and I/V conversion). Sounds excellent (the bass is much better) ! The soundstage is smaller than with AD 8066s and the detail grade might be somewhat reduced. However, the best combination I have tried. This upgrade was worth the investment (about $ 140).

Using opa627 in filter is not a good idea. Good combinations

ad8066 i/v, ad8620 filter

ad8620 i/v, ad8620 filter

ad8066 i/v, op2132 filter

ad8620 i/v, op2132 filter

opa627 i/v, ad8620 filter

opa627 i/v, op2132 filter

post #119 of 138

Hello Head-fi community!


I've read this thread and have not found an answer to my question.


I have a recording studio, and use Metric Halo ULN8s for my audio interfaces. These are always being taken up by my DAW software so I needed a DAC with a balanced out to interface with my ULNs. I use this DAC for all computer playback, which includes playback from itunes, Safari, and my SFX auditioning software. I was REALLY hoping that my OS (Lion 10.7) would be able to control the volume of the output. That bar remains grey as of now, which is a major disappointment. I'm confused because I was under the impression that if the device was a core audio device, and didn't have it's own control panel, that tyhis would work.


Does anyone else have their volume bar greyed out when using this interface with OSX? 


Thanks in advance,


post #120 of 138
Does anyone else have their volume bar greyed out when using this interface with OSX?

i think OSX correctly set output level to 100% to avoid degradation of signal quality

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