Pédale de Vibrato et de Super-Aigues  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...

Pédale de Vibrato et de Super-Aigues

Postby Rambozo96 » 17 Nov 2019, 18:42

Hello all I have stumbled upon a schematic with a treble booster and a tremolo effect from a French DIY magazine. What strikes me as very odd is how the aforementioned treble booster uses 2 transistors. They kinda look like 2 identical gain stages running in series. I got the circuit built on PCB and ready for final assembly since curiosity got the better of me. A schematic is provided for those also curious about this or anyone that can shed light on how this circuit works as a treble booster.
You do not have the required permissions to view the files attached to this post.

For this message the author Rambozo96 has received thanks: 3
jrod (18 Nov 2019, 09:00), Manfred (15 Dec 2019, 17:55), modman (18 Nov 2019, 11:09)
Rambozo96
 
Posts: 26
Joined: 08 Oct 2018, 00:01
Has thanked: 9 times
Have thanks: 20 times

Re: Odd 2 transistor treble booster?

Postby idy » 17 Nov 2019, 19:16

The first transistor is a booster. Then there is a "T" filter that cuts bass. The second transistor is a gain recovery stage. So your signal is super hot and super aigue.

For this message the author idy has received thanks:
modman (18 Nov 2019, 11:10)
User avatar
idy
Breadboard Brother
 
Posts: 112
Joined: 14 Dec 2011, 05:41
Location: Idyllwild, CA
Has thanked: 31 times
Have thanks: 28 times

Re: Pédale de Vibrato et de Super-Aigues  [schematic]

Postby modman » 15 Dec 2019, 14:08

Posting this partial page from the French electronics magazine Le Haut-Parleur on Facebook turned up the missing page.
You do not have the required permissions to view the files attached to this post.
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

For this message the author modman has received thanks:
Manfred (15 Dec 2019, 17:55)
User avatar
modman
a d m i n
 
Posts: 4436
Joined: 19 Jun 2007, 17:57
Has thanked: 3449 times
Have thanks: 659 times

Re: Pédale de Vibrato et de Super-Aigues

Postby Rambozo96 » 20 Dec 2019, 02:38

I finally got around to building this, used MP11A NPN Russian germanium so I don’t need a charge pump for the circuit. It’s very thin sounding and almost unusable with how much high end it pumps out. Maybe the T filter can be tweaked to tame the ice pick highs? Probably doesn’t help that I used a Danelectro in the demo.


For this message the author Rambozo96 has received thanks:
modman (20 Dec 2019, 13:07)
Rambozo96
 
Posts: 26
Joined: 08 Oct 2018, 00:01
Has thanked: 9 times
Have thanks: 20 times

Re: Pédale de Vibrato et de Super-Aigues

Postby modman » 20 Dec 2019, 13:25

Thanks for that clip - I don't think anybody has an excuse for demo clips anymore :D
Did you build this part of the circuit or the whole thing?
Screen Shot 2019-12-20 at 13.19.17.png

It may be the transistors, if not start jumpering the filtering between the two transistors. Dropping first 1n5 and the 10k resistor...
You do not have the required permissions to view the files attached to this post.
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal
User avatar
modman
a d m i n
 
Posts: 4436
Joined: 19 Jun 2007, 17:57
Has thanked: 3449 times
Have thanks: 659 times

Re: Pédale de Vibrato et de Super-Aigues

Postby Rambozo96 » 21 Dec 2019, 19:33

Just the treble booster side. I attempted the whole thing last year and couldn’t get either to work BUT my laying out schematics to PCB skilled were fairly weak then. I guess I’ll try different transistors first and see what happens from there.
Rambozo96
 
Posts: 26
Joined: 08 Oct 2018, 00:01
Has thanked: 9 times
Have thanks: 20 times

Re: Pédale de Vibrato et de Super-Aigues

Postby mictester » 26 Dec 2019, 23:22

It's NOT a vibrato - it's a badly designed germanium TREMOLO. It might (sort of) work, but there are LOTS of better circuits around to do this. The treble booster is also poorly designed and will have more hiss than signal!
"Why is it humming?" "Because it doesn't know the words!"
User avatar
mictester
Old Solderhand
 
Posts: 2903
Joined: 11 Sep 2008, 21:29
Location: Somewhat closer to Amsterdam than before!
Has thanked: 33 times
Have thanks: 824 times


Return to Vintage Stompbox Corner ( ... - 1975)

Who is online

Users browsing this forum: No registered users and 6 guests