Simple, low distortion 1kHz oscillator

[jackinnj]

For anyone in search of a low distortion oscillator, this is the section from the Krohn-Hite 6900B Distortion Analyzer. THD measures 0.002% on both the KH and my HP339b Disto Analyzers.

For a nice simple circuit it compares favorably with the analyzer in the HP339b which is 0.0018% (although the latter is adjustable).

 

[tschrama]

Hi,

Thanx for that circuit! I'm actually busy designing something very similar after a JLH (p. 193 (?) of his book 'audio elec.') circuit which also uses a doubleT-notch filter but a BJT for the feedback signal.

I'm going to try to use a light-bulb for the amplitude stabilisation.

Any suggestions how to do that?

Thanks and greetz,
Thijs

 

[kilowattski]

I'm going to try to use a light-bulb for the amplitude stabilisation.

Ala the old HP 200CD audio oscillator. HP's first product ever, the HP200CD Audio Oscillator, back in 1939 used an incandecent lamp for amplitude stabilisation. Disney was their first big customer. The rest is history.

 

[JOE DIRT®]

#327 bulb by chance?

 

[tschrama]

I use a 3Watt/220Volt types lamp... they work wonderfully in my simple wienbridge oscilator.. giving a reliable 0.005% at 2Vpp.

I was planning this kind of lamp also in a parrallel-T oscilator.. still gotta figure how I will do that....

G,
Thijs