Simple Pre-Amplifier and Treble Booster, in: Practical Electronics, March 1966 🇬🇧

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modman
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Post by modman »

Full PDF:
Practical-Electronics-1966-03- Treble Boost Preamp 01.jpg
Practical-Electronics-1966-03- Treble Boost Preamp 02.jpg
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PaulBass
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Post by PaulBass »

Nice. You can add a rotary switch to selective different boost frequencies. Are there any suitable OC71 replacements that can be used?

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tonyharker
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Post by tonyharker »

Not only have you got a treble booster you have got the MoJo of a Germanium treble booster :)

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Ben N
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Post by Ben N »

:scratch: Now where have I seen that topography before?

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ppluis0
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Post by ppluis0 »

PaulBass wrote: 23 Nov 2021, 03:43 Are there any suitable OC71 replacements that can be used?
Hi Paul,

If we not ask for the same pinout there are 794 germanium PNP transistors that can be replacement of the OC71:

https://alltransistors.com/crsearch.php ... 2=0&r1r2=0

Cheers,
Jose

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Ben N
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Post by Ben N »

It says, "Output 2 will be used in a later article next month." Now the suspense is killing me. Hey, Modman, is the Delorean gassed up?

OK, I couldn't wait. And here it is (the issue--I couldn't isolate the articles):https://worldradiohistory.com/UK/Practi ... -S-OCR.pdf.
Cool stuff! With 2 boards you can combine the preamp/treble booster with a "bistable trigger" for a three-way guitar effects unit that offers "fractured sound"! (It's what all the kids want these days.)

Other cool stuff with the same basic layout: a Wide Range Harmonic Oscillator and Metronome, a "regenerative coincidence detector" and "ultrasonic sawtooth generator" for PCM amplification application to boost the efficiency of a class AB amplifier, and an envelope amplifier & "vocal effects sound unit" for using one signal (say a microphone) to control the envelope of another.

And some cool articles about film sound, radio receivers and analog computing, and an introduction to vacuum tubes, among other things.

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modman
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Post by modman »

Hey Ben,
:thumbsup
So glad to hear somebody is reading them more attentively than me.... and this stuff was more puzzling than anything else.
The trick is: open the pdf (in browser or local software) then print the selected pages to PDF:
Practical-Electronics-1966-04- Bonanaza boards.pdf
(247.04 KiB) Downloaded 50 times
Practical-Electronics-1966-04- Bonanaza boards 04.jpg
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