Audio Amplifier without transistors or tubes?

[jacquesl]

Hi,

Is it possible to build a small amp or a big amp without the need of any semiconductors or tubes?
Just plain old coils, caps, Resistors or any homemade switching conductors.

And here I have a mystery question, is it possible to change the impedance of a coil by disturbing it with a other magnetic field or something? Like in a transformer


I think this project will be must easier to build then my “Transmitters without transistors or Tubes”
Transmitters without transistors or Tubes


check out a picture of a MJ2955 Transistor slashed open

[djQUAN]

I have seen from a '60s magazine a schem of a 1kW switching amplifier which uses special switching diodes and trasformers.

it does use semiconductors but no transistors or tubes.

[lumanauw]

Hi, jacquesl

Why do you want to advoid transistor/tubes? I'm not allergic to transistors, but still looking for a more linear transistor (if possible, have linearity like simple plain resistor supplied with current )

I'm not thinking about how to do it, but from the word "Amplifier" it means a device to "amplify".
How do you make an "amplifier" without a device to "amplify" anything?

[heater]

Jacquesl, this time you may be lucky, check out magnetic amplifiers, there is a scan of a book on this here:http://www.pmillett.com/tecnical_books_online.htm

[jacquesl]

Yo, thanks heater, this is some ultra good stuff man.
Do you think magnetic amplifiers can deliver some good quality sound and the other part will it cause some serous magnetic interferences with my other stuff, like to give some free bad sectors to my Hard drives and cause my TV to change the image to weird shapes and colours

[jacquesl]

Is there any way to make a switch with a transformer?

I see this transformer even have a Bias on him

[Christer]

Originally posted by jacquesl
Is there any way to make a switch with a transformer?

I see this transformer even have a Bias on him

Not quite transformers, but there are relays. I suppose one could build a very-low-frequency class D amp using relays instead of transistors.

[jacquesl]

I don’t know if relays will do the job “It probably depends on the load, It will make some serous noise like click click click click and it will cause a interference on the TV and on AM radio it will act like a spark gap transmitter.

[Christer]

Originally posted by jacquesl
I don’t know if relays will do the job “It probably depends on the load, It will make some serous noise like click click click click and it will cause a interference on the TV and on AM radio it will act like a spark gap transmitter.

It would need heavy filtering, and note that I said ver low frequencies. That was mainly because relays are slow, but it will also help to filter out sparks, since they will produce very high frequencies in comparison to the signal. As for the mechanical noise, yes that might be a problem, but I suppose this was rather about what one could possibly do than what might provide a good alternative to standard technology.

[jacquesl]

Yip your 100% correct. Well lets start a project like this and see if we can out perform the transistor and maybe come up with a new technology and maybe we can win a Nobel prize one day