E-MU 0404 USB Modification?

lumanauw

diyAudio Moderator Emeritus
2002-10-04 1:27 am
Bandung
www.facebook.com
I just buy E-MU0404 USB, for measurement purpose. In standard form, this sound card is quite good, all noise are below 120dB.

What modification can be done to this unit, to get better measurement properties? In loop back FFT, there seems some frequencies are rising.

The opamps are NE5532 and NJM2068. Is it OK to replace those dual opamps with OPA2134?
 
lumanauw said:
I just buy E-MU0404 USB, for measurement purpose. In standard form, this sound card is quite good, all noise are below 120dB.

What modification can be done to this unit, to get better measurement properties? In loop back FFT, there seems some frequencies are rising.

The opamps are NE5532 and NJM2068. Is it OK to replace those dual opamps with OPA2134?

I've heard using a linear 5v PSU insead of the bundled wall wart gives notable improvements, and I've also heard that replacing some of the op-amps with 4562's improves things even further. I only ordered a 0404usb today, so I may try this out when it arrrives. :)
 
The 0404 usb has some of the lowest noise floors and distortion figures of any soundcard - like -110dB to -120dB. I can't imagine why anyone would need quieter? My guess is that the ground paths are probably as important or more than different opamps, and very difficult to change. A linear PSU might help too, but once again, this thing is already very very clean - that's why I've got one too. ;)

The only change I'd like to see is the damb SPDIF be made available to all applications!
 
cuibono said:
The 0404 usb has some of the lowest noise floors and distortion figures of any soundcard - like -110dB to -120dB. I can't imagine why anyone would need quieter? My guess is that the ground paths are probably as important or more than different opamps, and very difficult to change. A linear PSU might help too, but once again, this thing is already very very clean - that's why I've got one too. ;)

The only change I'd like to see is the damb SPDIF be made available to all applications!
Well mine still hasn't arrived, but by the sounds of it, changing the op-amps isn't really worth the hassle.

Some people over at head-fi have said that the headphone out has more gain when using a different (higher current) PSU, which may mean the existing PSU is a little underspecced... It does seem a little optimistic that the whole unit can use less than 5W so much in there like DAC, ADC, pre-amp, headphone amp, etc... So I think the first thing I'm going to try is another PSU.

As for the SPDIF, so you mean not all applications can output SPDIF?
 
MikeHunt79 said:

Well mine still hasn't arrived, but by the sounds of it, changing the op-amps isn't really worth the hassle.

Some people over at head-fi have said that the headphone out has more gain when using a different (higher current) PSU, which may mean the existing PSU is a little underspecced... It does seem a little optimistic that the whole unit can use less than 5W so much in there like DAC, ADC, pre-amp, headphone amp, etc... So I think the first thing I'm going to try is another PSU.

As for the SPDIF, so you mean not all applications can output SPDIF?


If the gain depends on the supply current capacity (or the supply voltage for that matter) this is a spectacularly incompetent unit. Which it isn't, far from that. I would completely disregard that supply comment as Full Of It.

Do you realize that 5W at +5V (or less) is 1 Amp? Sounds like overkill already to me.

jd
 
janneman said:
Do you realize that 5W at +5V (or less) is 1 Amp? Sounds like overkill already to me.

jd
Apparently the stock PSU is around 800mA, I'm not really sure how much power these things use but it's just something I've seen on another forum... I guess there's no beating personal experience, so when mine arrives I'm going to see for myself if a PSU makes a difference as I have more than 1 5v PSU, especially to the headphone output. :)
 
MikeHunt79 said:

Apparently the stock PSU is around 800mA, I'm not really sure how much power these things use but it's just something I've seen on another forum... I guess there's no beating personal experience, so when mine arrives I'm going to see for myself if a PSU makes a difference as I have more than 1 5v PSU, especially to the headphone output. :)


I have an 0404, I'll see if I can measure current consumption, just for the heck of it...;)

jd
 
janneman said:



I have an 0404, I'll see if I can measure current consumption, just for the heck of it...;)

jd
Thanks, if possible could you measure if it uses any extra power with headphones plugged in... I imagine it will make very little difference, but I'd be interested nonetheless. :)
Tolu said:
One guy recommended an old Zip drive PS. It should audibly superior to the standard one.
I actually have a Zip drive PS somewhere, I cut the plug off but if I can find another I'll give it a go. :cool:
 

Crassus

Member
2009-01-11 2:38 pm
Quick introduction: I recently sold my Emu 1212M (modded: I bridged the coupling caps, replaced others in the analog section with blackgates) and now have the Emu 0404 USB. It sounds ok for the price (or compared to decent CD players like Marantz CD67), but I don't like it as much as the modded 1212M. The 0404 can sound a bit harsh at times (especially symbals on drums and vocals sometimes have a bit too much energy in the "s" region and have a bit of a "sharp" quality). I know this sounds weird because the frequency response and other specs are quite flawless but to my ears, this sort of sounds like the original 1212M. The modding brought "life" to the sound and maybe the 0404 is just an unpolished diamond...

I'm hoping you guys can help me out a bit in trying to squeeze more out of this little gem. The 0404 uses AK4396 as the da-converter and I'm sure many of you have heard the buzz around this one (many regard the AK chips as the best converters and the 4396 is definately from the higher end of AK chips).

So, let me give you a short tour.

On the left side of the potentiometer is the da-chip (half visible). On the right side of the chip are the R+, R-, L+, L- rails going in to the 4 capacitors. After the capacitors are two JRC 2068 opamps. On the left side of the caps is the headphone stuff (let's not go there).


On the right side of the potentiometer the output stage continues. Two 5532 opamps next. The big plastic thingies are the balanced outputs.


So what I've done so far? I replaced the four caps (coupling?) with Elna Silnic II as I had some in my drawer. Did the sound change? Don't know. At first I couldn't hear a difference but after keeping the unit on for 24h I got the feeling that maybe the sound is not as harsh but then again, maybe it's just my brain playing tricks on me.

What would you guys/gals suggest I could try next? Can you find muting transistors I could remove or any idea if I could bridge the coupling caps etc? I have Auricaps in the input of my amp so DC is not a big concern.

For reference:
AK4396 datasheet (last pages include reference circuitry and I believe it's very close to what the Emu has)
Some nice photos of the Emu 0404 USB PCB
Lots of PCB pics
 
There is not much you can “hack” or “tweak” with the 0404-USB. It is full if tiny SMD’s, even some BGA’s. The PSU consist of several DC-DC converters and it is hard to track the routing on the boards. Besides that it is of a stacked board construction that makes modding not easy.

Regarding performance: My M-Audio Audiophile192 does better for the same money. And that is a PCI card inside my main PC.

However for general audio measurement the 0404 is fine with a laptop.
 

Crassus

Member
2009-01-11 2:38 pm
Pjotr, I sort of disagree. The AK chip is suberb and I would imagine that taking the signal out from the DAC legs via a transformer would be a great "hack" but that's something that I'm not going to do.

I was interested in smaller scale experimentation. Coupling cap shorting, mute transistor removal etc but I'm afraid my skills in tracing the PCB or even understanding what the SMD components in the analog output section do is what's stopping me. In other words I have very little knowledge of these sort of things (knowing which SMD thingies are filter/coupling caps and what I could short/bridge) but that hasn't stopped me from previously following advice and soldering different tweaks with good results.

So, if someone who can read schematics (AK reference board I linked previously) wants to give me a hand I would appreciate it very much. The difference the cap shorting alone did on the 1212M was something I liked very much and have a feeling that the 0404 would benefit a lot from similar tweaks. I just don't know what to do just by looking at the PCB so I can't unleash the full potential of the 0404 :)
 

Crassus

Member
2009-01-11 2:38 pm
I've seen comments like these:

"I have modified the 0404 by shorting out the output buffer and output caps which increased the bass and lifted a slight veil - worth doing IMO" around the internet but I haven't been able to find any pics about exactly what to jumper. The description matches what I experienced on the 1212M when tweaking it.

(For admin/moderator: I joined DIyaudio in January. When can I post freely without a moderator checking each message?)
 

Salas

diyAudio Chief Moderator
Paid Member
2002-10-08 11:31 am
Athens-Greece
Can't modify my previous message and the forum image zoom broke the links. Here are the full sized ones:[/url]

Uploaded them for you. Will let administrators know about your still newbie issue.
 

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iko

diyAudio Moderator Emeritus
2008-05-29 2:41 am
Toronto
I just got an 0404 usb as well, and might try to improve some little things. At the very least I'll build a low noise shunt regulated 5V psu to replace the original one. I ran some tests last night using RMAA and the lowest self loop thd was about 0.00032 (48Khz/24bit). The thd seemed to vary wildly on the input and output volume setting (even when making sure there is no clipping). I'm not sure how much these numbers can be trusted anyway. Different software gives different results.

FWIW, I also bought it for measurement purposes, but maybe it was a mistake.
 
It's funny - I also have an 0404 usb that I use solely for measuring purposes with a laptop.

I don't know that I have listened to actual music out of it through USB - they are supposed to sound much better than their price range.

I bought it with the intent of using it for measuring and as a test preamp/dac for projects - but never got anywhere with the DAC portion due to not being able to easily use the spdif in/outs without soundforge or some other ASIO app - and even then it's not very smooth compared to the m-audio patchpanel/mixer on the 1010. As a small preamp it works pretty well - it is nice to have the LED level indicators on the inputs.

I don't like that it doesn't automatically sync to different sample rates - another plus for my 10 year old M-audio set.
 

Salas

diyAudio Chief Moderator
Paid Member
2002-10-08 11:31 am
Athens-Greece
I don't see a low bias voltage minijack mic input for electret at its pictures on the web. My tracker pre has it, and I don't use my dedicated pre for the Panasonic capsule speaker mics now. Less kit and cable and it was eating its battery fast enough that mic pre. Plus it relies on laptop's usb power also if I wanna take it somewhere to measure.
 
I just buy E-MU0404 USB, for measurement purpose. In standard form, this sound card is quite good, all noise are below 120dB.

What modification can be done to this unit, to get better measurement properties? In loop back FFT, there seems some frequencies are rising.

The opamps are NE5532 and NJM2068. Is it OK to replace those dual opamps with OPA2134?

There is no point in modding this unit unless one can get rid of the 110kHz generated by the switching power supply inside.

Even on spdif output with an exteranal dc supply, the unit is far inferior sounding to a $75Musiland US 01 which is capable of 192k output.

The software on the 0404 also sucks and this is typical of Creative who supplies hundreds of MB of Junk Software which is not necessary.