E-MU 0404 USB 2.0 and some "artifacts peaks" on left channel

[regiregi22]

It shouldn't change, as the only mod has been re-routing the cables, not any change in components.

Regarding pots, I have the same problems. Even after some years of intensive use, output volume pot is starting to crack and make funny noises when turned up/down. The main downside I can see is how to fit a physically bigger pot in that cramped space.

 

[soundchaser]

Fixed it....

Just bought two units on Kijiji and modded them. Worked great. Thanks sidiy and everyone else who contributed.

In order:

Left 1 Before Left 1 After left 2 Before Left 2 After

Thanks again

Matt

 

[Telstar]

Just bought two units on Kijiji and modded them.

What mods did you do? The one posted above by sidy?

 

[soundchaser]

What mods did you do? The one posted above by sidy?

Yes, I used twisted wire wrap wire for the mod. I'd say this mod's a winner.

Matt

 

[31697B]

This looks great... clean with no residual freqs all over the place. Just ordered one to modify.

Thx-RNMarsh

 

[31697B]

Has there been any similar products which use the better AK5388? That one is being sold for about $10 in singles at DigiKey so I wonder if it is inside anything we would want to use/modify.

Thx-RNMarsh

 

[gazzagazza]

Someone has tried to list these...

Audio interfaces and their AD/DA chips LISTED - Gearslutz.com

Has there been any similar products which use the better AK5388? That one is being sold for about $10 in singles at DigiKey so I wonder if it is inside anything we would want to use/modify.

Thx-RNMarsh

 

[31697B]

Has anyone tried paralleling ADC in some way for improved performance?
Seems this could be done with multiple ADC IC's or with multiple channel products.

Thx-RNMarsh

 

[31697B]

I just did the sidiy rewiring mod. Thx a lot. -Richard

 

[mbandiera]

Do you have any suggestion against THD in E-MU 0404usb?
Thanks.

 

[31697B]

The measurement accuracy below -100dB is a problem. It cant be trusted. To get accurate harmonic measurements below -100dB, you need a notch filter on the front end.


THx-RNMarsh

 

[lemon]

Is there any news about development of this card?

I am thinking some multiturn pots for inputs and output for precise handling and opamps like LME49720.
Member "1audio" changed the opamps with LME49720 at the EMU 1212m with 10dB THD improvement.

 

[lemon]

If someone see at the photo:
DSCF1963

There are 3 JRC2068 (same with NMJ2068) opamps near the inputs before ADC. They are chip opamps but have very low noise (see here).

Any related info will be appreciated. My goal is to improve the ADC Capture at the ARTA FFT.

 

[DEHiCKA]

I'm planning to try NE5532 -> AD8599 and NJM2068 -> LME49720 on input to improve THD.
Is there any schematics for the input stage?

 

[lemon]

From what I know, no!
At the following link NwAvGuy: Op Amp Measurements
there is a test to various opamps (the test done for O2 Headphone Amp).
At least to Noise Floor, the JRC2068 internal opamps of emu have very low noise equal to OPA227/2227.
The Author says at gains less to 4X, nothing overall could be the NJM2068 (same to JRC2068).

I don't know about THD level !

 

[Bonsai]

Is this the EMU 404 USB 2.0 that is referred to earlier in this thread (the one sidily modified so well)

E MU 0404 USB 2 0 Audio MIDI Recording Interface | eBay

Thanks

(Amazingly low noise floor by the way!)

 

[lemon]

Yes.

 

[Bonsai]

Thanks- appreciate it!

 

[DEHiCKA]

From what I know, no!
At the following link NwAvGuy: Op Amp Measurements
there is a test to various opamps (the test done for O2 Headphone Amp).
At least to Noise Floor, the JRC2068 internal opamps of emu have very low noise equal to OPA227/2227.
The Author says at gains less to 4X, nothing overall could be the NJM2068 (same to JRC2068).

I don't know about THD level !

He didn't measured AD8599 nor LME49720 though.
AD8599 have better noise per datasheet, and both AD8599 and LME49720 have much better THD+N: 110-120dB vs. 100dB. Not shure if ADC itself will not mask it. It's 15 minutes for me to change four opamps on the left channel, so it's not a big deal. I need it for measurement purposes, so I don't bother for musiality.

 

[1audio]

The EMU 0404 (and all the other USB thingies with numbers from EMU) use the AK5385 level ADC. Its quite good but has a rising noise floor starting at about 30 KHz. The only fix is a better ADC. Unfortunately the only better option is the AK5394A which is about twice the footprint so its not a drop in at all.

Some really enterprising soul could figure out an airplane board with the better ADC and associated stuff but what a task.

Upgrading the opamps to LME49720's etc. will lower the distortion some.

I do wish these boxes were easier to open and work with.