Well, I received package with N900 boards so its time to be a bit more active on the forum

At the start some background:
Creative Audigy 2 ZS Platinum Pro from 2004. Last produced soundcard with the hardware MIDI synthesizer. In the sound quality this 24bit/192Khz soundcard is an absolute killer and for me it sounds better than most newer constructions, even USB and audiophile ones. In the November 2019 I changed PC and I had no more PCI slots, simple PCI->PCIe adapter make it work like a charm again. That card had its studio twin - E-MU interface with exactly same DSP and all of the ICs inside; to make Creative card for use for the civils they designed headphone opamp with very low gain.

Because I'm using Fostex T40rp as my daily headphones for many years, now MK3 (much sturdier MK2 has been stolen a month ago) I was living with a fact this great soundcard can't drive better headphones. Until now.
At the Friday, right before midnight, I was listening the music and I've got the idea - what if I can make this card compatible with more demanding headphones?

I was looking for the pictures of the board of SB0290 unit (frontpanel) but there was no pictures at all so I think mine are first ever sent. Opening is simple, just unscrew everything, remove potentiometers caps and remove screws also from there. There is also one screw under the casing in the middle.

On the top is a huge shield soldered to the bottom of the PCB


After removing it we can finally see the top side


Okay, now zoom on the headphone amp


Yes, that's Japanese NJM4556A opamp which amplifies signal from CS4392 24bit/192kHz DAC. It's DAMN good, but to secure users with 32Ohm and less headphones, and of course, separate this construction from proper E-MU solution, opamp gain has been set to less than 2. Just by adding 1kOhm resistors parallel to the R151 and R121 I set the gain to almost 8, because opamp is powered from the 9V regulator and maximum output voltage from DAC is 1.05V that's highest safe value for opamp, and I think my ears too.


With those two guys there I made this soundcard compatible with almost any pair of headphones. The last thing to do is to replace encoder which change volume in the windows to the standard potentiometer right after opamp. Also encoder can be pressed and it will act as mute button, I found ALPS potentiometer with a proper switch so I will still have mute functionality.


If you can see, its already lying with the knob inserted but I'm still waiting for second potentiometer, microphone one because it becomes not enough reliable. That's everything