Quote: Originally Posted by Kippei It is a overkill for a 20000mAh capacity to power a max 30mA cmoy amp? If you connect 8 2500 mAh 1.2v batteries in series you get 9.6v and 2500mAh, NOT 8x2500 (20,000mAh) If you connected them in parallel (which it seems you shouldn't) then...

They'd probably work, but I doubt they'd work much better than a regular resistor... I had a thought about that radioshack metal film resistor "variety pack." It doesn't come with any 47K ohm resistors, but it does come with 5 100k ohm resistors. What you could do is solder 2 100kohm...

The only metal film resistors at radioshack come in a 'variety pack' type thing; 50 resistors of different values. Unfortunately, 47K ohm is not one of the included values, which means you'll have to look elsewhere. I can give you part numbers at digikey if you PM me, but digikey has a minum...

Quote: Originally Posted by Garbz "crowbar" diodes are zener diodes. Just to clarify. My bad; must have misread something. Yes R3 and R4 are both 47 ohm; really. The input caps strip dc offset from your source. If you can be sure all sources the amp may be used with have...

The A47 should drive 64ohm phones fine with no changes. If you felt comfortable with modifiing the layout you could use one opa4134 instead of 2x opa2134 the TLE2426 come in several different packages. From the sound of it you have the three pin LP package. The schematic on that page you...

The idea of a buffer is to seperate the op-amp from the load (your headphones). When the amp is driving headphones, it sees a fairly difficult load (the lower impedance your phones are the tougher it is on the op-amp), if the op-amp is forced to strain too hard to drive the load, distortion and...

I've gotten 200mAh on e-bay, and seen higher. might be worth a look.

Quote: Originally Posted by XxATOLxX Is lead solder better? I'm currently using 96/4 lead free. I was thinking of getting some silver solder for my next project. I use the leaded silver solder from radioshack, sold on a 2 or 2.5 oz. spindle. I'm quite happy with it, especially...

That buffer is supposed to improve the virtual ground by being able to push more current than the TLE by itself. However, if you use large enough power caps (C2+ and C2- in that linked thread) the buffer won't make much of an improvement, IMHO. The current will be drawn from the caps for the...

It's completely do-able; I've done it several times to my first couple of dismal layouts... I did have to solder some some trimmed leads onto the super short ones. Just be careful about getting the components too hot, and you should be fine.

I assume you'll be making your own board w/ surface mount components?

Oops, nevermind. Sorry!

I use 91%; the common stuff is usually 70%, and I'd think even that'd be fine.

I might be wrong here, but I believe that measurement is the output impedance of the battery. Output impedance affects how 'stiff' the battery voltage (or any source of voltage) is in the face of low impedance loads. A battery with an internal impedance of .02 ohms is VERY stiff; you ought...

I didn't use anything special; but it is kind of a PITA. It's very important you find a way to hold the chip down, otherwise you'll just move it all over the place with the iron (as I did for 30-40 mins). The small vise-grips work well, just don't crush the chip!