Chordate anatomy photos

Creative x-fi surround 5.1 sb1090 mod

This mod aims to improve the overall performance of this soundcard.  Capacitors are added in parallel to existing ones.  This helps improve linearity because film caps were used and transient response due to higher capacitances.

Before:

 

Suddenly, capacitors:

Caps are added at the V+ of the L/R opamp, Cirrus 4361 DAC, and Cirrus CS5345 ADC.

Listening to it, I can say that it sounds "faster" if that makes any sense.

Next, I might try to replace the current L/R opamp (TD1308) to the OPA2365 or completely bypass it and use it solely as a DAC.

EDIT: I don't know if it's all in my mind, but I dare say it's handing bass better now.  Before, it would start distorting a little before I had my amp at a good loud volume.  Now the bass is being handled better with no detectable distortion.

It's mostly done now.  What's left is figuring out how to deal with a small ground issue.  Maybe the power supply design was insufficient.

Here it is almost done.  There were too many wires going from the amplifier board to the power board, so I  reduced the number by daisy chaining power and ground cables.  Hopefully this doesn't affect the sound negatively.
I have made changes to this since this picture, but this will be the general layout.
Now I have to finish drill holes in the front panel for the headphone jack, power switch, and LED, and in the back, I need to cut out the rectangle for the IEC.

Completed the AC->DC section.

The power section consists of 2 rectifiers, one each for the +15V and -15V rails.
The filter capacitors are Panasonic FM 1500µF 35V metal foil caps and a 1µF Epcos Polyester film cap.
The linear regulators are the 7815 for the positive rail and the 7915 for the negative rail.
The reservoir caps are Panasonic FM 3300µF 16V metal foil caps and a 1.2µF Vishay-Dale polyester cap.
The dual TO-220 heatsink is soldered to the board, and the regulators are stuck to it by pressure and Arctic Silver Ceramique thermal paste.

The 1/4" headphone jack is not part of the power section, but it is there because of it's location on the front panel and so it can support the board while mounted to the front panel.

Construction on the amp has begun.

The amplifier section was completed today,  I'm going home for the weekend, so this won't be dont till monday maybe.

The amp is still coming.   Right now I'm still designing it and getting input on it.  I'll be ordering the parts sunday night.  I bought a drill to do case work.
Here's a schematic of it that looks like it was drawn by a retarded Dr. Frankenstein.

     Here are the two Alps 50K "Blue Velvet" potentiometers I plan on using in my amp.  One will be used as the input volume control, and one will be for the bass boost control.

      I'm really excited about these because all my previous potentiometers have been Panasonic EVJs, so this will be a step up in tracking accuracy and hopefully sound quality as well.

 

     Here's a close-up picture of the Brown Dog 021001 Dual 8-DIP to 8-DIP adapter.  I'll be using it to mount (hopefully) dual OPA627 opamps.

Feedback resistors

So for the headphone amp, you should choose lower resistor values for the R3 & R4 feedback resistors. "First, high values will increase your circuit’s suspectibility to stray RF and electromagnetic noise. Second, higher resistor values are inherently nosier." 
However, lower values (<1K) will increase the wasted current to significant levels.  I guess this doesn't matter if running off wall power.

Well, I guess it was bound to happen.
I bricked my phone today trying to flash it between the 111.040.0704 firmware back to the 111.030.0609 firmware.
I was worried at first, but then I remembered that you can't simply downgrade the OS.  You have to reflash to the Scandinavian version first.
It's good now, but there goes 3 hours of my day off...

Phoenix 
Scandinavian FW 
 

I've created this blog as a place for me to place information for myself and others to reference to and hopefully find interesting.
Topics may include whatever I need to put down for school work, modding my Nokia N8, technology, and headphone/headphone amplifiers, biking, and maybe some politics.
If you stumble by here, please feel free to ask about anything.