class A amplifier on 12V car rails

[muddasirwaheedmalik]

hi , is there any simple class A low wattage amp design using single car 12v rail, no DC/DC switching no EMF shielding etc, i assume with 12V one can get 12x12/4=36W maximum disspation though which i can get 18W , classA into 4Ohm and may be 36W into bridged ??? any idea ???

 

[Tekko]

5 watts per channel in 4 ohms and 20 watts absolute max bridged in 4 ohms.

 

[Loudthud]

With a 12V rail you can create an AC waveform of 12V peak to peak. That's about 4.2V RMS or just over 4 Watts into 4 ohms. Look for the "Amp Camp Amp" in the Pass forum. It will run on 12V but for 4 ohms you will have to increase the idle current.

 

[CBS240]

I had a car amp once, Forum or something like that, had two fairly large EI transformers in it. Curiosity got me to investigate the circuit, it used the 12V B+ from the car and drove a step up output transformer in push-pull class AB. 50W per ch. There was no SMPS.

 

[Bone]

Use the JLH design as original. Works fine on 12v. use resistor values for 17v. Been there done it. Sounds great. Kit here on ebay 2pcs JLH 1969 A CLASS A amplifier kit sc | eBay . Note this is for 24 v.

See original article here The Class-A Amplifier Site . I used transistors 2N3906, BD139 and 2 x 2n3055s. Gives about 3.5 watts

 

[davidsrsb]

Car "12V" is actually 13.5~13.8V when the engine is on and car amps are specified at this higher voltage.