There is a "cathode interface" mechanism in oxide-coated cathodes that causes some loss of gain at low frequencies. Old Tek scopes sometimes have networks to compensate.
Transistor scopes often had thermal hooks that had to be equalized too.
John
Very low distortion
May 17, 2010
23 Replies
On a sunny day (Thu, 20 May 2010 09:30:47 +1000) it happened David Eather wrote in :
I have seen LDRs used as volume control in the old TV studio audio mixer, no distortion to speak of (tube age). the LDR was driven normal bulb with a DC from the fader. There was some drift IIRC, as bulbs age.. No cracking noises moving the faders! Nice solution.
lume III
Ahh, thanks for the 'hint' I was a bit confused how the gain control was accomplished.
I assume you've seen AN43 by J. Williams, he beats on the Wien bridge oscillator at the end of the app note. The last circuit of which uses an LDR.
George H.
- Hide quoted text -
No, but that won't be true in a minute.
he beats on the Wien bridge
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