i want to make a small amp that is capable of being run from wither a single or dual 9v supply, one chip i can think of is the OPA549, as it is capable of being run as low as ±3v however i am not sure if it is capable of this, or suited to it - what do you think - i am not aiming for hi quality sound, just sound that can produce a sound that is recognisable as music
The LM386 is designed for low voltage single-supply battery operation. Power output is a mighty 500mW!
I've never heard one so can't comment on the sound.
Datasheet is here:
http://www.national.com/pf/LM/LM386.html
Nice one,
David.
I've never heard one so can't comment on the sound.
Datasheet is here:
http://www.national.com/pf/LM/LM386.html
Nice one,
David.
two 9V's will get you 3.6 watt-hours. How sensitive are the speakers you want to use, and how long do you want to use them?
There already exists a board dedicated to headphone amps, head-fi.org, with extensive diy section for discussion of such designs. Headwize.com is also a good resource, with a library of projects as well as a diy section.
There already exists a board dedicated to headphone amps, head-fi.org, with extensive diy section for discussion of such designs. Headwize.com is also a good resource, with a library of projects as well as a diy section.
The LM386 is definitely class-B (or just barely class AB), so it will not draw much from the battery while it is idling. However, it is definitely not what I would call a hi-fi IC.
In addition to National Semiconductor, SGS Thomson makes really good sounding low powered ICs, take a look at some of their products.
In addition to National Semiconductor, SGS Thomson makes really good sounding low powered ICs, take a look at some of their products.
i've built a couple of LM386 amps and even driving a fairly large speaker (as opposed to headphones) the sound is quite good. I mean of course it's not HiFi quality - it's only .5W for a start! but still, the sound is nice and clear, and still plenty loud
Back when I was at Cary Audio, our SLP-74 tube pre-amp (now discontinued) used a pair of LM386s as the headphone amps. True, it does drive efficient speakers pretty well... actually it has enough power to blow headphones off your head! 😀
Speaking of such things... I think the Crown D75 studio monitor amplifier is the one that has ZERO attenuation on the headphone jack--you could connect an 8 ohm speaker to the headphone jack and get the full 35 watts RMS. Now that's scary
Speaking of such things... I think the Crown D75 studio monitor amplifier is the one that has ZERO attenuation on the headphone jack--you could connect an 8 ohm speaker to the headphone jack and get the full 35 watts RMS. Now that's scary
ok thanks everyone for your help - one last thing
would i be able to use a 'normal' OP amp such as a opa2134 (i thinks thats it anyway) or would it be unable to provide suficant power for amplifying a small speaker?
the reason i ask is because i want to use components i already have, and i know i have some spare dual op amps because i have been upgrading my cd player
would i be able to use a 'normal' OP amp such as a opa2134 (i thinks thats it anyway) or would it be unable to provide suficant power for amplifying a small speaker?
the reason i ask is because i want to use components i already have, and i know i have some spare dual op amps because i have been upgrading my cd player
The limting factor with using a 'normal' op-amp is the device's maximum output current, which is 35mA in the case of the OPA2134.
That'll give you 0.035^2 x 8 = 10mW peak into an 8R load.
Nice one,
David.
That'll give you 0.035^2 x 8 = 10mW peak into an 8R load.
Nice one,
David.
National also has a line of Boomer audio amps. They are "supposed" to have great sound, low power, and low power consumption
Although you said you want to use parts you have, I would really reccomend going with the LM386 or a Boomer from national. You won't be losing any money, they offer free samples.
Oh, and speaking about headphone amps, could I build one with an LM324? Or wouldn't it have enough power?
Thanks, Mike
Although you said you want to use parts you have, I would really reccomend going with the LM386 or a Boomer from national. You won't be losing any money, they offer free samples.
Oh, and speaking about headphone amps, could I build one with an LM324? Or wouldn't it have enough power?
Thanks, Mike
If you look on the websites at TExas Instruments and Linear Tech there are a couple of articles on single-supply headphone amps. Linear actually had an ad in EDN a couple years ago featuring one of their chips for this purpose.soundNERD said:
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