I want to incorporate a headphone jack into the Condor; but it will need a headphone amp circuit of some sort to give it better volume control.
What would be the lowest part count that can get the signal louder with a volume control?
LM386
Is the minimum parts schematic in the datasheet the best one to use for my needs, ya think?
Edit: Since I'm only going to be needing this to power headphones, would a simple boost be sufficient?
I'm not opposed to using the 386, just wondering.
Best for your needs? Can't tell. All you said was headphones and minimum parts count.
The LM386 is specifically designed to drive loads from headphone down to speaker with minimum parts. Headphones are usually in the 30-40 ohm range, a tough load for most opamps and simple transistor circuits. The minimum parts LM386 is one pot, one resistor and two capacitors, plus the LM386. It is quite difficult to get an opamp or transistor circuit under that parts count. And there are a lot of transistor and opamp circuits that can't do a good job of driving a headphone, or will be unreliable at doing it over time.
Does it only have to do this once, or does it need to work semi-forever?
I'll see your LM386 & raise you a TDA7052A...
Quote from: Gurner on June 20, 2011, 11:25:08 AM
I'll see your LM386 & raise you a TDA7052A...
That would work too. Looks like about the same number of parts, though. Could be cheaper because the output doesn't need a big DC blocking cap. Might be harder to find. Still, a very viable alternative.
Quote from: R.G. on June 20, 2011, 11:39:15 AM
Quote from: Gurner on June 20, 2011, 11:25:08 AM
I'll see your LM386 & raise you a TDA7052A...
That would work too. Looks like about the same number of parts, though. Could be cheaper because the output doesn't need a big DC blocking cap. Might be harder to find. Still, a very viable alternative.
The beauty about the TDA7052A is that as you've pointed out, no large blocking cap needed, but also the DC volume is not in the signal path (so no scratchiness at a later date)
(http://img10.imageshack.us/img10/5364/tda7052a.jpg) (http://imageshack.us/photo/my-images/10/tda7052a.jpg/)
I make it just one input cap & one electrolytic cap (as the datasheet says, the 100nf cap can be ommited if the power source is close to pin 1) ....add a 1M pot to control the volume - job done!
You may also look into the TDA2822.
www.electro-dan.co.uk/electronics/TDA2822.html (http://www.electro-dan.co.uk/electronics/TDA2822.html)
design your own volume control and put this inside the pot: http://datasheets.maxim-ic.com/en/ds/MAX97220A-MAX97220D.pdf
Do a Cmoy, it is entry level audiophile quality with the right opamps. (forgot guitar stuff here, you will need 10-50$ BurrBrowns or ADs)
edit: disregard this, i thought you will need a standalone unit, there is no point in putting a headphone amp this good into a guitar amp.
Wow the TDA2822 looks pretty neat. Looks one chip with stereo output. I have wanted to build an iPod amp for the car, this looks like just the device.
There's also a stereo version of the TDA7052A.....after a few months brainstorming they rolled out the name - TDA7053A.
Some other TDA7052A benefits (vs LM386 or TDA2822) ...more ripple rejection, more power, no zobel needed (it's output is *very* clean on a scope)...I'm surprised it hasn't gained more of a fan base amongst the DIY community...that DC vol pin can be brought into play for example as a compressor...it's a cool IC.
What is the typical current consumption of the '7052? Given, it will vary based on load and output level and all that, but so far as quiescent current how does it do? I know from past experiments something like a 386 has fairly low q. consumption (around 6 mA or less), but add that into a circuit using several opamps and such, it all adds up. Overall current usage may be something to consider.
Edit: Looked at the datasheet. Typical q. current about 7 mA, so not too different from 386 in that regard. Also is a zobel really necessary on a 386 if it's only loaded by headphones? I thought it was mainly used to compensate on low-resistance i.e. speaker loads.