Reagun - Overdrive

Manfred · Post by **Manfred** » 23 Feb 2020, 00:19

It is a good sounding mild overdrive to push a tube amp.

there are unknown small red diodes in the opamp negative feedback.

Here the PN-junktion curve trace of these diodes:

Here the PN-junktion curve trace of the 1S1588 diodes:

PCB-Layout Ready to print PDF-files:

ReagunOverdriveLayoutComponentSide.pdf: (25 KiB) Downloaded 206 times

ReagunOverdriveLayoutSolderSide.pdf: (16.2 KiB) Downloaded 184 times

SprintLayout-6.0 file:

Reagun Overdrive.zip: (41.78 KiB) Downloaded 192 times

Dirk_Hendrik · Post by **Dirk_Hendrik** » 23 Feb 2020, 08:31

Thanks Manfred.
No smoothing cap between th3 1Meg resistor and the diode going to the switching FET's?

peterc · Post by **peterc** » 23 Feb 2020, 12:08

Thanks Manfred

Manfred · Post by **Manfred** » 24 Feb 2020, 00:54

Dirk_Hendrik wrote:Thanks Manfred.
No smoothing cap between th3 1Meg resistor and the diode going to the switching FET's?

Thanks Dirk for the closer look at the schematic, you are right there is a 47n smoothing cap, it appears in the layout but not in the schematic.
Here the corrected schematic:

Manfred · Post by **Manfred** » 29 Aug 2020, 03:48

George Giblet found a bug in the Reagun Distortion schematic that has the same switching circuit as the Overdrive.
It is also the same error in the schematic.
Thanks again George.
Here is the corrected circuit:

mirosol · Post by **mirosol** » 20 Dec 2022, 15:33

...aaand a stripboard layout.
+m

Bulldozerrr · Post by **Bulldozerrr** » 21 Dec 2022, 13:50

The magic diodes, it's probably stabistors?

george giblet · Post by **george giblet** » 10 Sep 2023, 04:00

Something caught my eye when I was looking at the schematic: there is a HPF before the clipper stage. However, the schematic shows the clean signal is post the HPF. I checked the PCB and Manfred's overlay and I'm certain the clean path should connect to the emitter of buffer transistor, before the HPF. The clean path cap should be a 470nF electro.

No impact on any true-bypass layouts since the clean path cap and JFET switching won't be present.

art7710 · Post by **art7710** » 10 Sep 2023, 05:23

There is no magic in the diodes. These are Russian KD102 (КД102) diodes. Very good diodes for screamer-style overdrives
https://ya.ru/images/search?lr=20250&so ... 4102%D0%B0

Manfred · Post by **Manfred** » 10 Sep 2023, 09:28

george giblet wrote: ↑10 Sep 2023, 04:00 Something caught my eye when I was looking at the schematic: there is a HPF before the clipper stage. However, the schematic shows the clean signal is post the HPF. I checked the PCB and Manfred's overlay and I'm certain the clean path should connect to the emitter of buffer transistor, before the HPF. The clean path cap should be a 470nF electro.

No impact on any true-bypass layouts since the clean path cap and JFET switching won't be present.

ReagunOverdriveSchematicCorrected (corrections GG 20 Sept 2023).png

Thanks George for taking another close look, you are right. I have traced the component connection in the layout again.
Not only was the connection wrong but also the value and type of the capacitor, as well as the position of the 47pF capacitor. 47n film -> 0.47uF electrolytic.
I am sorry if this has caused confusion.
Corrected schematic:

george giblet · Post by **george giblet** » 11 Sep 2023, 22:29

Good stuff Manfred, thanks.

I suspect the diode+150 ohm resistor connects in series with the -ve lead of the DC in (but not the battery -ve lead). Similar to the Boss ACA power inlet,
https://www.hobby-hour.com/electronics/ ... ematic.php

FYI, I came across this version.
https://reverb.com/au/item/59422580-nad ... t-shipping

It has a different enclosure and PCB to the common Reagun/Nadine's/Vesta Fire Over Drive. I don't recall seeing Reagun or Vesta File versions with this enclosure. I haven't had a chance to compare the circuits.

Reagun - Overdrive [schematic]