Lords of the Ring

[giantkiller]

@acerzw,

Obsessive, Compulsive Creativity (OC2, I am my own chemical compound). LOL. If you get to the web page you see will a Finish line for children's pinewood derby races. This version uses cables. I have the race tracking software done and want to hook the 2 together so that after registration the device runs the pc.
OBTW: I've  built hands too.

--giantkiller. No sleep, no life, no time, only progress.LOL.

[acerzw]

Hey GK,

You know you don't have the monopoly on Obsessive Compulsive Disorder on this forum, I got that too! (really).

Does kinda screw up your sleep/wake cycle something cronic... but hey the brightest lights burn quickest 

Acerzw, will post again in the AM...

[giantkiller]

Go this excerpt from the amp site.

Class A power amplifier designed to drive loudspeakers. Initially I wanted to use separate heavily asymmetrical PSU biasing opamp into full class A for the whole swing of output voltage but not after I have heard it play. The sound is gorgeous! This sound is bright and crisp. Bass is so punchy - I did not think my Tannoys Mercury M2.5 would sound so good. Actually after finishing wiring a prototype I spent two days just sitting a listening to my favorite albums again and again...

This is the best design I have came up so far!
I use two 6x6x4cm heatsinks per channel. Power supply is unregulated (just transformer, diode bridge and capacitors) but I cannot hear anything even when I put my ear within few centimeters of the loudspeaker. Opamp has very good power supply rejection ratio. I've tried to keep everything as simple as possible and basically LM317 would be just one extra opamp... If you are looking for better sound, get separate regulated low power supply just for the U1 opamp, something like +-15V at 100-200 mA.
I have also used one LM7805 to get bias for both channels - you may want to use two separate 7805 in a final amp to get better channel separation. R2 pot is anything from 500 to 50k. I have used 22k.

To convert this to a headphone amp just use lower gain (1..3) and possibly regulated power supply. Of course idle current should be brought down to 50-100mA.


I personally prefer AD826 against OPA2604 but the difference is so small I am not even sure that it exists. The amp has so few components and is so simple that no single component can colour the sound too much. And no single electrolytics beside bypass for opamp (2x100uF), at least not in signal path!

The split rail is not bad. But I have never seen a voltage regulator used like that. A slick trick.

Correction to doco here:
http://www.analog.com/en/prod/0,2877,AD826,00.html

(6) AD826 ordered.

[acerzw]

@all

Since it's early in the AM here, and us night owls are out and about, I think its time for a piece of eye candy. Since I haven't built anything yet here's a little tribute to those who can and do, so if you want to feel part of this good old collaborative open source convoy, just print out this sucker and stick it on your wall, your dog, your car, your fridge or anything else that needs brightening up... and then fasten your seat belts for the rest of this journey... 

Acerzw, here's to you all...

(since it's open source please find the original in a zipped Open Office Draw file.)

[giantkiller]

I think this vid applies: