[Sardonyx]

Quote:

I have experienced a fluctuation in gain from the headphone out. Sometimes I need 20% volume to reach full volume and sometimes it's 70% with the same track. The quality of the audio is still the same. Anybody experienced this? Where is this gain switch on the board and how does it look like?

Gain is set by 2 sets of jumper pins, location is shown in the manual.   You can't miss them, there are no other pins nearby.  It is supposed to ship in low gain mode, with the jumper blocks off both sets.  I don't know what would happen if someone goofed and put one block on & one block off.  Does the volume change within a track, or is it more like low one time, then next time it's loud?  If you are sure nothing is changed in the computer settings, I would suspect an intermittent loose connection.

 

[maxiak]

Hi guys.
I own Audinst too. Could anyone conclude which opamps may I put to Audinst without necessity of soldering anything and without taking risk of damagind the device? I mean opamps which are in DIP8 and their datasheets would let them be put into audinst (voltages and all the other data are comparable with the stock opamp)
I want to try a few opamps to make this DAC sound more like i want it to, but i don't have any electrical knowledge. Can anyone help me???
Cheers

 

[Yangorang]

So here's how I'm currently using my Audinst HUD-MX1:
 

 
Sounding pretty good I think...
The USB Isolator and 12V LRPS are DIY.
 
Also just one interesting thing that I haven't seen anyone else comment on yet - Audinst actually put up RMAA measurements in their forums here.  Useful for people that like to look at specs like me I guess.

 

[kingoftown1]

I really enjoyed the Audinst with the O2 as well.

 

[skyline315]

Just ordered the Audinst this past weekend.  We'll see how long shipping takes.  I'm a bit irritated with Obama since I found out he's in South Korea.  Why on earth didn't he just bring my amp back with him so I could avoid this shipping hassle?  
 
I plan to pick up on Asgard in a couple of months to pair with it.  Here's hoping that's a good combo...

 

[maxiak]

UPDATE:
 
Could anyone conclude which opamps may I put to Audinst without necessity of soldering anything and without taking risk of damagind the device? I mean opamps which are in DIP8 and their datasheets would let them be put into audinst (voltages and all the other data are comparable with the stock opamp)
I want to try a few opamps to make this DAC sound more like i want it to, but i don't have any electrical knowledge. I mean i want to change the LME49860 opamp. and i would like to see a list of opamps I can safely use.
 
Can anyone help me???
Cheers

 

[Yangorang]

Quote:

UPDATE:
 
Could anyone conclude which opamps may I put to Audinst without necessity of soldering anything and without taking risk of damagind the device? I mean opamps which are in DIP8 and their datasheets would let them be put into audinst (voltages and all the other data are comparable with the stock opamp)
I want to try a few opamps to make this DAC sound more like i want it to, but i don't have any electrical knowledge. I mean i want to change the LME49860 opamp. and i would like to see a list of opamps I can safely use.
 
Can anyone help me???
Cheers

A lot of the really high performance opamps seem to be single SO-8 parts so you'll need to use an adapter of sorts like the ones from BrownDog.
For dual DIP-8 opamps the stock LME49860 is already one of the highest spec'ed around as far as I know.  Perhaps you can browse eBay for some listings of presoldered SO-8 opamps to adapters like the one I linked to.  As for single SO-8 opamps the AD797 and LME49990 seems like good options.

 

[Sweden]

Quote:

Gain is set by 2 sets of jumper pins, location is shown in the manual.   You can't miss them, there are no other pins nearby.  It is supposed to ship in low gain mode, with the jumper blocks off both sets.  I don't know what would happen if someone goofed and put one block on & one block off.  Does the volume change within a track, or is it more like low one time, then next time it's loud?  If you are sure nothing is changed in the computer settings, I would suspect an intermittent loose connection.

It's never a case of changing audio within one session. Only after the unit have been turned off and then on again have I experienced this. I'm not closed to the possibility that it could be software related. I can't find the manual right now and have opened up the case before, but I was too unsure to what was necessary to change gain. Where on the board are these pins? Thank you for your answer.

 

[Yangorang]

Quote:

I really enjoyed the Audinst with the O2 as well.

This sounds like it's in the past tense...so what are you enjoying now that's better heh?

 

[Gang]

There's great.
 
Would you tell me which USB Isolator and 12V LRPS diy kit you are using? 
I am also planning to have a try.
 

 

[kingoftown1]

Quote:

This sounds like it's in the past tense...so what are you enjoying now that's better heh?

The D18's slightly on a different level

.  I did continue to use the Audinst for iem use while I was sorting out all the kinks in that new system, though.
 

 

[Yangorang]

 

The D18's slightly on a different level 

.  I did continue to use the Audinst for iem use while I was sorting out all the kinks in that new system, though.
 

Ahh you mean this thing right?  http://tamaudio.com/store/index.php?route=product/product&path=35&product_id=106
Definitely looks quite nice....I'm just waiting around for the ODAC to pair with my O2 and I'll probably just keep the Audinst around for mobile use.
 
 
 
Quote:

There's great.
 
Would you tell me which USB Isolator and 12V LRPS diy kit you are using? 
I am also planning to have a try.
 

These are actually both DIY parts of mine that I'm prototyping at the moment.  I am logging my progress here but it probably won't be finalized for a while since they're just side projects of mine and I'm using cheapo PCB services that take forever to make anything.
You don't actually need the 12V LRPS to power the USB Isolator as it has an onboard 5V linear regulator; it's meant to be powered by a 7.5V wall wart - I was just using it in such a configuration so I could test both of my projects at once.  I tested the 12V LRPS plugged into the Audinst directly as well and it worked fine.  
I actually found that conveniently, you could turn the HUD-MX1 on/off by switching the power to the isolator on/off - I switch between my speakers and headphones at times and was finding it annoying to either unplug the USB cable to the Audinst or switch audio devices within Windows.
 
If you want a prebuilt/kit USB isolator that is available right now look towards Circuits@Home.  As for a 12-15V LRPS to power the Audinst you have quite a few options available from AMB and others.

 

[Yangorang]

I took out my DMM today and checked on a few random things out of curiosity.
 
First of all a little bit about the parts:
REG5 - KIA278R12 - 12V LDO linear regulator part
REG2 - 33063 DC-DC Converter Part - I'm guessing this is configured in some sort of voltage inverting configuration to generate the negative power rail
REG3 - PHJ1 Marking - I believe this is a TPS793475DBVRQ1 part from TI which is a 4.75V LDO regulator
REG1 - 17-33 Marking - seems to be a 3.3V regulator in SOT-223 form factor from what I've measured
 
Now for a little analysis of the circuit:
Ground is unified across the board and is connected to chassis, USB ground, DC jack ground, etc.
 
REG3 and REG1 take power directly from the USB bus and are undoubtedly there to clean up the 5V from USB.  REG3 feeds into the analogue supply of the WM8740 DAC while REG1 feeds into the digital supply.  One or both of these are probably powering the TENOR USB receiver IC as well but I didn't check.
 
REG5 does not seem to play any active role unless a power adapter is plugged in.
Under USB only power conditions the power rails of the LME49860 opamp measured: +8.35V/-8.86V
With the 15V stock adapter plugged in the power rails of the LME49860 opamp measured:  +11.76V/-12.91V
With a 12V LRPS adapter plugged in the power rails of the LME49860 opamp measured:  +11.44V/-12.61V
 
With the 15V stock adapter plugged in pin1 of REG5 measured 14.67V and pin2 measured 12.00V.  Here it's just operating as a 12V linear regulator should.
With a 12V LRPS adapter plugged in pin1 of REG5 measured 11.71V and pin2 measured 11.69V.  In this case it seems to be doing nothing essentially.
 
Hope this information may prove useful to someone.

 

[skyline315]

Alright, guys.  Need some help.
 
Got the mx1 today and LOVE it.  Works perfectly for music.
 
However, as soon as I tried to play a blu-ray (WinDVD), it caused the software to freak out.  The video stuttered and I was unable to get any sound.  The output in WinDVD was set to "Digital (S/PDIF) to external processor".  Any ideas?
 
Thanks!

 

[kingoftown1]

Is it something the Audinst can't handle like DSD?