# Sound amplifier and step-up voltage without a transformer

#### Larry_Walker

Joined Apr 14, 2021
6
Hi all,

I am looking for a module or an IC with the following characteristics :
- it amplifies a (more or less) sinusoidal signal between 0V and 1V, having a frequency from 1Hz to 20000Hz.
- the maximum input current is 1A.
- the maximum output voltage is from (more or less) 30V to (more or less) 400V, adjustable.
- the output current is not important (between 0.01 A to 10A ... anything is acceptable).
- the IC (or module) VCC should be 5V (preferably) or 12V, or 15V, or 30V, or +/- 15V.

I know that I can do that easily with a step-up transformer, but I would like to find a miniaturized module or an IC able to doing that.

Could someone point me in the right direction ?
Have someone heard of a "transformer replacement" ?

Thank hou in advance - any help is appreciated.

#### Papabravo

Joined Feb 24, 2006
20,600
First things first. Your input power is 0.707 VAC(rms) * 1 Amp = 0.707 watts
Your output power is several orders of magnitude higher than that. Those power levels are just not available in a miniaturized module or an IC.
The power has to come from somewhere. What somewhere did you have in mind?
The immutable law of power conversion is that the output power will always be less than the input power, and sometimes it will be much less.

#### crutschow

Joined Mar 14, 2008
33,345
Your requirements are (more or less) odd.
It's difficult to avoid a transformer if you want an output of up to 400V from a maximum supply voltage of 30V.
Can you explain exactly what this signal translation is for?

#### schmitt trigger

Joined Jul 12, 2010
771
We all know that transformers are heavy and bulky, but is there another reason for you to don’t want them.
A vacuum tube amplifier’s output transformer, its output winding fed from an audio module, and its plate winding being used now as your signal output, would accomplish exactly what you require.

#### Larry_Walker

Joined Apr 14, 2021
6
The power has to come from somewhere. What somewhere did you have in mind?
... The power comes from the last line of my requirements " - the IC (or module) VCC should be 5V (preferably) or 12V, or 15V, or 30V, or +/- 15V."

It is NOT a trensformer, so the PowerIN=PowerOUT does not apply.

#### Larry_Walker

Joined Apr 14, 2021
6
A vacuum tube amplifier’s output transformer
Do you mean something like this (see image)?

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#### schmitt trigger

Joined Jul 12, 2010
771
No that is an input transformer feeding a cascaded voltage multiplier.
To obtain a few kilovolts of DC voltage.
What I meant is something like this one:
http://www.hammondmfg.com/clsover.htm
Doesn’t have to be “audiophile grade”. You might find something cheaper on Ebay.

#### Audioguru again

Joined Oct 21, 2019
6,437
Your thread title mentions a "sound amplifier". But frequencies below 20Hz are not sounds, they are vibrations that cannot be produced by amplifiers or speakers.

You say the maximum input current is 1A. Is that the signal input current (which is usually a very low current) or is it the power supply input current?

#### Papabravo

Joined Feb 24, 2006
20,600
... The power comes from the last line of my requirements " - the IC (or module) VCC should be 5V (preferably) or 12V, or 15V, or 30V, or +/- 15V."

It is NOT a trensformer, so the PowerIN=PowerOUT does not apply.
It does if you want 4 kilowatts of output power

#### Larry_Walker

Joined Apr 14, 2021
6
I've nailed it !!!
The solution I was looking for is a "Cockcroft-Walton" circuit.
Thank you all - I wouldn't have find it without your stimulating comments.

#### Papabravo

Joined Feb 24, 2006
20,600
I've nailed it !!!
The solution I was looking for is a "Cockcroft-Walton" circuit.
Thank you all - I wouldn't have find it without your stimulating comments.
That's great, but you realize that the wages you must pay for the increase in voltage will be at the expense of the current. A CW voltage multiplier is ONLY for low current applications.

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#### MrChips

Joined Oct 2, 2009
29,827
What you need is a power op-amp.

#### Papabravo

Joined Feb 24, 2006
20,600
"That's not a knife. This here's a KNIFE!