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

Free online ressources on guitars, amps, effects, guitar technique and more. Dedicated to the fond memory of its founder SPeter Davidoff.
Post Reply
User avatar
modman
a d m i n
Information
Posts: 4888
Joined: 19 Jun 2007, 16:57
Has thanked: 4392 times
Been thanked: 2130 times

Post by modman »

Full PDF:
Practical-Electronics-1966-03- Treble Boost Preamp.pdf
(239.79 KiB) Downloaded 144 times

Practical-Electronics-1966-03- Treble Boost Preamp 01.jpg
Practical-Electronics-1966-03- Treble Boost Preamp 02.jpg
[/hr]
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

User avatar
PaulBass
Breadboard Brother
Information
Posts: 120
Joined: 02 Mar 2010, 08:22
Has thanked: 8 times
Been thanked: 17 times

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?

User avatar
tonyharker
Breadboard Brother
Information
Posts: 62
Joined: 23 Jun 2011, 21:50
Location: United Kingdom
Has thanked: 12 times
Been thanked: 14 times

Post by tonyharker »

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

User avatar
Ben N
Cap Cooler
Information
Posts: 505
Joined: 12 Dec 2008, 03:34
my favorite amplifier: Ampeg J12D Jet
Location: Israel
Has thanked: 191 times
Been thanked: 53 times

Post by Ben N »

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

User avatar
ppluis0
Diode Debunker
Information
Posts: 915
Joined: 14 Jul 2010, 18:33
Location: Argentina
Has thanked: 127 times
Been thanked: 299 times

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

User avatar
Ben N
Cap Cooler
Information
Posts: 505
Joined: 12 Dec 2008, 03:34
my favorite amplifier: Ampeg J12D Jet
Location: Israel
Has thanked: 191 times
Been thanked: 53 times

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.

User avatar
modman
a d m i n
Information
Posts: 4888
Joined: 19 Jun 2007, 16:57
Has thanked: 4392 times
Been thanked: 2130 times

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 114 times
Practical-Electronics-1966-04- Bonanaza boards 04.jpg
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

Post Reply