[avexdevil]

argh completely forgot i posted on this thread. the crackling issue has been resolved, all i needed was a reboot . I chanced upon a helpful post but i can't remember where, it advised for audinst users to connect the unit via usb before powering it on via AC to avoid any stuttering/crackling issues.
 
i've added a matrix m-stage to couple with my audinst since then, I have to say it's a whole new beast altogether (especially if you're using a k701/702 with the audinst).

 

[borez]

I just got this to pair with my AE5s, and they are indeed a significant difference compared to the old Audigy 2 card I was using. However, some quirks, and wonder if you guys could advise:
 
1) There are instances where the MX-1 can't sap enough power from the USB bus (i.e. faint indicator light, crackling, distorting sound). I've to pull out the USB cable, wait for 1/2 mins, and plug it back. Don't think it's the problem with my PSU (am using a Seasonic X650), and it's plugged direct to the motherboard.
 
2) It's not fully burned in yet, but I do feel the sound's slightly biased towards the cold side. As I listen to more vocals/jazz, am thinking of doing some opamp rolling. Saw that a suggestion was to look at the OPA2227, but there're a couple of variants. (i.e. OPA2227, OPA2227AD, etc).
 
3) Is there any sonic difference between plugging in the 3.5mm jack, or the RCA connectors? Understand that there are different opamps driving the 2 sections.
 
Thanks!
 
EDIT: Problem 1 seems to be solved when I swapped the stock USB cable to another one (24AWG + 28AWG, similar to the monoprice cables here: http://www.monoprice.com/products/product.asp?c_id=103&cp_id=10303&cs_id=1030301&p_id=5437&seq=1&format=3#specification)

 

[chrisc0]

Hi, I just now registered to this forum even though I read a lot about the mx1 here. I'd like to share some impressions on my audinst:
It sounded good straight out of the box, but restless as I am, I had to change/add some things. At first I noticed that the analog part of the wm8740 is powered via USB. Thats very bad, because the USB power usually has a lot of ripple. To solve this I put a ADuM4160 and a regulated 5V PSU in the USB line. Next I swapped the DAC output opamp for a pair of OPA827s. Then I did the same with the line out buffer, because I mainly use the line out. Finally I swapped the opamp caps for Silmics, because I didn't trust the Sam Youngs.
Here is a photo of the result:

 
Was it worth it? Yes. The ADuM4160 enhances clarity and reduces some sqeeling noises from the computer's PSU. The new DAC out OPA827s enhance the sound in every aspect: dynamics, precision, linearity, soundstage, ... The new line out buffer OPA827s haven't got the HF harshness of the original OPA2134 and add even more soundstage and precision. With the new caps the sound gets cleaner and has a much better dynamic range.
 
PS: I use the original external PSU from Audinst. I don't think a better PSU would enhance the sound quality, but I will try when i get a chance.
 
 
@borez: I tried the OPA2227. It sounds much better than the LME, but won't give it much more warmth. I had the OPA2227P and it worked fine. There is a sonic difference between the HP and the RCA out. The headphone out has more bass.

 

[audiofil]

Very interesting mods.
There is one thing I want to point out:
The DAC chip, WM8740, has the I/V conversion and low pass filtering built in.
Therefore the opamp (originally the LME49860) serves for a different purpose , probably voltage gain.

 

[chrisc0]

I just checked out the Wolfson homepage and you are absolutely right. Thanks for the correction. I'm going to edit my previous post a little, it's really embarrassing...

 

[darknessproz]

I got an interesting question with regards to the Audinst. 'm planning to get either the Westone ES5 or the UM Miracle by the end of the year. My question is, how does the DAC in the Audinst compared with the iPhone 4? I can get the Audinst for about S$200. Would its sound quality trump a transportable rig like iPhone4->LOD->S$200 amp?

 

[dw1narso]

the LME49860 serve to convert differential output from the 8740 into single ended signal... similar to what Gamma2 do...
 
chrisc0, try SLA battery for external PSU. I used Hitachi 12V7Ah SLA and happily surprised with the improvement I got... that without doing any moding inside..

 

[chrisc0]

darknessprotz, my brother just bought himself an iphone. I'll compare it to the audinst soon, but I don't think it'll match the sound quality of the audinst. The iphone is more practical though.
dw1narso, I didn't think of a battery before. It's a good idea. I'll try that out. Thanks

 

[chrisc0]

I'm listening to my Audinst at the moment, this time with a good regulated power supply. Contrary to my previous opinion, it makes a major difference. More dynamics, "punchier" bass, crisper highs and overall cleaner. The headphone out benefits the most. The psu doesn't even have to be very powerfull. Mine has 5W @ 14,6V and enough power from what I can hear.

 

[darknessproz]

That would be helpful. Be sure to use a LOD with the iphone!
 
Quote:

darknessprotz, my brother just bought himself an iphone. I'll compare it to the audinst soon, but I don't think it'll match the sound quality of the audinst. The iphone is more practical though.
dw1narso, I didn't think of a battery before. It's a good idea. I'll try that out. Thanks

 

[dw1narso]

Quote:

I'm listening to my Audinst at the moment, this time with a good regulated power supply. Contrary to my previous opinion, it makes a major difference. More dynamics, "punchier" bass, crisper highs and overall cleaner. The headphone out benefits the most. The psu doesn't even have to be very powerfull. Mine has 5W @ 14,6V and enough power from what I can hear.

I'm also surprised that Audinst respond very well withe a good and clean supply. When I open and look inside, I saw regulators on many places so I originally thought: how can I improve the the supply with external regulator with such regulators on many places. But then I know later that I'm wrong.
 

 

[amigastar]

hello,
 
very nice review audiofil. but one thing bothers me. i have the Audinst Hud-mx1 and AKG K240DF combo but i've noticed after using both for about 6 weeks that the highs on the DF are little harsh and sibilantly. how could i reduce this phenomenon? since i am listening very loud to music this problem occurs even clearer. i was thinking about getting the matrix m-stage additionally maybe that would smooth the sound? i've read here on the forum that the AKG DF's produce harsh highs with not so good amplifiers. any advice would be nice, Thanks.

 

[chrisc0]

The HF harshness was one of the main reasons I did all the tinkering on my audinst. It's not easy to get it out completely. Exchanging the DAC out opamp would be the first thing to do. The new opamp should be of high quality because in my experience most of the low cost ones have problems with the highs. The next thing is very easy. Use a software resampler like sox on your computer to upsample to 96kHz because the audinst doesn't do that very well. After that it becomes a little bit more complicated. As i recently learned, the PSU plays a crucial role on a dac. I built a replacement psu for my audinst which works wonders. Getting a ready to use psu of such quality might be quite expensive.
 
edit: I don't know about the k240. On my k701 the harshness was annoying but not severe. In my case the excessive modifications removed all problems and improved the sound quality a lot. However this doesn't have to work for you.

 

[nb_41]

Hey,
 
I recently got an Audinst, used, and it's definitely improvement in all area's compared to my laptop out. However, I feel that the treble now has more detail/resolving compared to the laptop out which is good, but the treble seems to be at a lower volume now compared to the rest of the frequency range.
 
I guess my findings are opposite to some of the people who say it has a "cool" sound. I would say mine is slightly on the warm, laid back side.
 
Would switching out the opamp help make the treble a bit more present? If so which ones?

 

[chrisc0]

You can alter the sound changing the opamp. But the warm bassy sound on the headphone out comes from the second opamp in the headphone amplifier (which is very difficult to exchange). You would have to find a very treble sided opamp to cancel that out. Something like the OPA2134 or the OPA2227 perhaps. But these are more neutral and linear sounding, not exactly HF weighted.