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!

I'd prolly just throw a $0.50 diode inline with the thing and call it a day; they usually have voltage drops of between .6 and .8 volts, which should get you close enough.

I wouldn't be surprised to find a TL072, or a couple stacked in parallel in that thing

If you could get one on the cheap (or had an extra) you could always throw a tread in front of it to clean it up. TREAD

I second that; it can be tought to find those buffers anywhere sometimes, and tangent's price has always been the cheapest I've seen. If you want a volume control you could also get the Alps RK97 from tangent; it incorporates an on/off swtich, so it can save you a bit of room and clean up the...

IF you have a paypal balance they can issue you a "virtual debit card" to use at online stores. I've done it a couple of times, rather than wait for paypal to transfer money into my bank account. click the widthdraw link and click on "shop online with a virtual paypal debit card" or something...

Ok- that makes sense. Thanks for clearing that one up, i'm just a bit on the slow side lately...

For the regulator example, if I understand things correctly, to find watts dissipated in the regulator you'd take the drop across the regulator, and multiply by the current consumed by the regultor(Iadj in the feedback loop); not but the total draw of the amp it was powering. At least that's...

That's what the RK097 does

What's the best way to figure out the voltage drop across a component? Using the Voltage divider equation I suppose?

I have a basic electronics question I'd like to put by some of the resident guru's here. Based on my desire to learm more about electronics design and tangent's review I recently purchased "The Art of Electronics" and I'm very impressed so far. I'm about halfway through chapter two, and I've...