Transformless amplifier

[jack121]

Hi Thanks for reading.
I want to build a simple discrete amp with the absolutly lowest number of components possible, preferably a two stage with driver transistor and output transistor, as cheap as possible, i don't want to spend any serious money, just a few bucks.
As power supplies are expensive, do you know of any design that runs off the mains ac 240volts, just a bridge rectifier and smoothing capacitors, no transformer.
A cheap and cheerful amp for music reproduction that works and is stable, not concerned about hi-fi sound or super low distortion
Thanks

 

[Nigel Goodwin]

No - your requirements are unsafe and unworkable.

You NEED a mains transformer, for safety, and to get the voltage down to a level where it's usable.

You also can't make an amplifier (that's worth having) with only two transistors.

 

[Papabravo]

Hi Thanks for reading.
I want to build a simple discrete amp with the absolutly lowest number of components possible, preferably a two stage with driver transistor and output transistor, as cheap as possible, i don't want to spend any serious money, just a few bucks.
As power supplies are expensive, do you know of any design that runs off the mains ac 240volts, just a bridge rectifier and smoothing capacitors, no transformer.
A cheap and cheerful amp for music reproduction that works and is stable, not concerned about hi-fi sound or super low distortion
Thanks

The definition of insanity is asking the same question on multiple forums expecting more congenial results. Electronics is pretty much the same in all corners of the universe.

 

[For The Popcorn]

But he used many of the KEY words!

>Cheap

>Simple

>Little

>Cheerful (new one on me)

>Quick

>Dirty

So it must be possible

 

[danadak]

You can build a zero component amplifier, and it is pretty safe -

Regards, Dana.

 

[gary350]

1N34 diode radio plays music and very low number of parts. NO power supply. I received 1 of these for my birthday 1958. I built 1 in electronic class 1970. Diode is 1N34. I learned just from experimenting 2 diodes in parallel music is louder. Maybe diode resistance is less with 2 in parallel??? L1 & C1 are the resonance circuit for radio frequency that you want to receive. It will only power 1 ear plug type ear phone. Antenna is a 3 ft long wire with an alligator clip on the end. When I was 8 years old I had good hearing I could hear the music play fairly loud. I'm not sure what requirements are for the ear phone. When I was in high school stores had this same type radio that picked up TV sound no video but 6 months later no more for sale. Circuit drawing shows ground but factory radio had no ground and it works.

Here are a few bucks.

 

[Lightium]

Here are specs for that kind of earphone.

Crystal Earphone - ScienceKitStore Catalog

catalog.sciencekitstore.com

 

[cooperhow]

Hi! Could you explain more on your requirement? It would be helpful if you could let us know the voltage, ohms of the amplifier, power output, DI or AI, and terminal product. Good luck with the project!

 

[Pommie]

1N34 diode radio plays music and very low number of parts. NO power supply. I received 1 of these for my birthday 1958. I built 1 in electronic class 1970. Diode is 1N34. I learned just from experimenting 2 diodes in parallel music is louder. Maybe diode resistance is less with 2 in parallel??? L1 & C1 are the resonance circuit for radio frequency that you want to receive. It will only power 1 ear plug type ear phone. Antenna is a 3 ft long wire with an alligator clip on the end. When I was 8 years old I had good hearing I could hear the music play fairly loud. I'm not sure what requirements are for the ear phone. When I was in high school stores had this same type radio that picked up TV sound no video but 6 months later no more for sale. Circuit drawing shows ground but factory radio had no ground and it works.

View attachment 137851

Here are a few bucks.

View attachment 137852

We called that a crystal set. I built one when I was 10 and listened to the moon landing on it.

Mike.

 

[KellyGreené]

It's pretty unsafe to create an amplifier without a transformer. But, maybe if you could give detailed specs or requirements, someone might be able to help you out.