I bought two OPA134's for making a Headphone amp. But I have some 4ohm 5W speakers lying around. Is it possible to make a portable speaker system out of it? Does anyone have a circuit?

 

Search the innergoogle for "current boost schematic diagram". There's a ton of 'em out there.

ak

 

You mean a transconductance amplifier? Normally we use a power amp for the output stage right? But I want to keep the good OPA132 sound. Power amps like LM386 can drive a speaker. But OPA is just an opamp

Search the innergoogle for "current boost schematic diagram". There's a ton of 'em out there.

ak

 

You will need some type of power amp, but don't waste your nice op amp on a 386.

 

You mean a transconductance amplifier?

No, I'm talking about hanging a couple of transistors on the output of the 134 to boost the output current. A complimentary pair (1 NPN, 1 PNP) of transistors can be connected as emitter followers or common emitter amps.

For illustrating the concepts *only*, here are a couple of examples.

http://www.seekic.com/circuit_diagram/Basic_Circuit/POWER_BOOSTER_1.html

http://www.electronicsinfoline.com/...mplifier_has_transient_railtorail_swing.shtml

http://www.deeptronic.com/small-audio-power-amplifier-using-op-amp-and-two-transistors/

Note that the very popular Crown DC series of sound reinforcement amplifiers are basically an opamp plus a dozen or more power transistors.

ak

 

Which complementary pair would you use to make a class AB power amplifier for a 5W output?

 

Hello,

Perhaps the following project from ESP might give you an idea:
http://sound.westhost.com/project76.htm

Bertus

 

Excellent! I will study that

Hello,

Perhaps the following project from ESP might give you an idea:
http://sound.westhost.com/project76.htm

Bertus