Amplifier with a sound. How to build for second harmonic.

[lineup]

What can I technically do when designing an amplifier to make it add plenty of second harmonic?

Create distortion is not too difficult.
But to generate mostly 'earfriendly' second harmonic - how do we do this?

I have one suggestion.
It is wellknown that big MOSFETs generate some 2nd.
But more specifically how do we add them?
How do we build?

Give from your experience and tell me.
Thank you.

[jcx]

Class C?

[freax]

Build a tube amp/use a 2n3055.

[DF96]

Single-ended Class B will give you lots of 2nd.

For a controllable amount, combine a 'clean' channel with a precision full-wave rectifier channel (standard op-amp plus diodes circuit). Use a pot to mix in as little or as much distortion as you like.

[lineup]

Here is something what mean.

It is a small headphone amplifier
with IRF610 diff pair input
and a single end IRFP240 output fed from current source.
There are no bipolar doing any gain.

This harmonics spectra speak for itself.
You get the third harmonic along with the second.

[DF96]

Precision rectifier will give you even-order distortion only, dominated by 2nd.

[jerluwoo]

Perhaps just a poorly designed jfet buffer will do.

[wahab]

Use an input differential with a poor current source , typicaly a resistor
connected to a zener voltage reference.

[triplej]

Originally Posted by wahab

Use an input differential with a poor current source , typicaly a resistor
connected to a zener voltage reference.

Very interesting. Will give that a go!

[nigelwright7557]

Originally Posted by lineup

What can I technically do when designing an amplifier to make it add plenty of second harmonic?
Give from your experience and tell me.
Thank you.

Forget altering the amplifier and get hold of a soft limiter which will give a more rounded wave with plenty of even harmonics.