[dokebi]

I was wondering if there was an opamp that would work in an amp with only 1.5v such as from an AA battery.

 

[tangent]

You mean 0.9V, since that's where the battery's voltage is when it's essentially used up. And as far as I know, the answer is "no". There are a few that work on 1.8V, for operation on 2xAA or 2xAAA. They probably don't sound wonderful, though.

Unless size is of the utmost importance, you might consider looking into DC-DC converters, since these can boost the voltage enough to allow use of a better op-amp. These have somewhat noisy output voltage, but the improvement you get from using a better chip might be worth it, especially if you use a converter with an ultrasonic switching frequency. I've used a few with frequencies in the 10-30kHz range and they're junk for audio purposes.

 

[AIM9x]

I'm not quite sure how noisy the output voltage from a DC-DC converter is. The Headroom Supreme makes use of a DC-DC converter and I didn't notice it being noisy.

 

[guzzler]

thats got room for a good smoothing circuit though. If your man wants an amp of 1AA battery, he must be looking really small!

g

 

[tangent]

All DC-DC converters are not created equal. There are cheese-ass little DIP-8 package ones with really nasty characteristics, on up to $100 brick units with beautiful output.

 

[Squalish]

I think I heard somewhere that battery powered Headroom amps used a DC-DC converter, do you know if this is true?

 

[tangent]

Yes, it's true. They use Cosel units, IIRC. That's why I brought up the issue of size above -- the good ones are about 4x the size of a DIP-8, or larger.

 

[L Daniel Rosa]

There's 74HC240, but you won't like the sound 'cause it's not really an OPAMP.

 

[AIM9x]

Quote:

Originally posted by Squalish I think I heard somewhere that battery powered Headroom amps used a DC-DC converter, do you know if this is true?

you're a couple days late there squal,

It's true. The supreme and the cosmic make use of DC-DC converters.

 

[Tomo]

Hey,

Only 1.5V not enough headroom. And DC-DC convertor's efficiency will be so low that you one AA battery will be eaten up within few hours. (Of course, the amp will start clipping too.)

I think I can build an amp with 3V using 74HCU04's for 32 ohm cans. Heehee. Mischievous amp.

Tomo

 

[peranders]

Quote:

Originally posted by dokebi I was wondering if there was an opamp that would work in an amp with only 1.5v such as from an AA battery.

I'm a little curious why you ask this. Your application?

 

[dokebi]

I was looking at my MD player and thought, hey this can drive headphones and still have enough juice to spin a little disc. What if?