BAJA JVM overdrive pedal 040218  [documentation]

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

Hi folks
I have not built this one as yet, but see no reason why it will not work :D
This one is based on the Marshall JVM410 OD1 high gain channel (up to just before the passive tone stack as with all my recent high gain preamp models).
Hope some of you enjoy building it :wink: and as usual - vero, perf or pcb layouts are most welcome :thumbsup
cheers
bajaman
Baja JCM overdrive pedal 9v 040218.GIF
be kind to all animals - especially human beings

User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

here is channel OD2 instead - slightly less bass response :wink: only two capacitor values changed around gain control :lol:
Baja JCM overdrive pedal OD2 9v 040218.GIF
be kind to all animals - especially human beings

User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

But wait - there's more :D
Here is the crunch channel for a lighter overdrive and flatter frequency response - again only minor changes around the gain control but only three gain stages (two following the gain control).
All these three JVM410 models are based on the "red" gain structure.
enjoy :thumbsup
bajaman
Baja JCM overdrive pedal Crunch 9v 040218.GIF
be kind to all animals - especially human beings

User avatar
Cub
Cap Cooler
Information
Posts: 458
Joined: 29 Aug 2011, 07:14
Location: The Netherlands
Has thanked: 102 times
Been thanked: 118 times

Post by Cub »

Thank you so much, you're on a roll with the high gain pedals! :applause:
bajaman wrote:here is channel OD2 instead - slightly less bass response :wink: only two capacitor values changed around gain control :lol:
That would make for a very nice switch! Speaking of which, would it also be possible to have a red/orange mode switch? Or are there too many parts involved for that to be practical.
I wish I were a chestnut tree, nourished by the sun.
With twigs and leaves and branches and conkers by the ton.

User avatar
Ice-9
Degoop Doctor
Information
Posts: 1094
Joined: 31 Mar 2009, 15:29
my favorite amplifier: Marshall
Completed builds: Far to many to afford the enclosures for them all. :)
Has thanked: 134 times
Been thanked: 359 times
Contact:

Post by Ice-9 »

Congrats Bajaman on a nice series of amp sim circuits, and you have used my favourite 2SK117 Jfet for the input buffer on most which means I will have to have a few of these put on breadboard as soon as I get a moment.
Cheers for the schematics :applause:
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

would it also be possible to have a red/orange mode switch?
I will take a look - should be possible :wink:
cheers
bajaman
be kind to all animals - especially human beings

User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

:oops: :oops: :oops:
I made a small mistake with the Crunch model
Here are the correct schematics for OD1, OD2 and CRUNCH channels with the red gain mode. By adding a small switch and additional resistor to the third gain stage it is easy to convert all of these to the Orange gain mode :wink: Just switch the 100 ohm resistor off, if you want the Red gain mode :!:
cheers
bajaman
Baja JVM overdrive pedal OD1 9v 040218.GIF
Baja JVM overdrive pedal OD2 9v 040218.GIF
Baja JVM overdrive pedal Crunch 9v 040218.GIF
be kind to all animals - especially human beings

User avatar
Cub
Cap Cooler
Information
Posts: 458
Joined: 29 Aug 2011, 07:14
Location: The Netherlands
Has thanked: 102 times
Been thanked: 118 times

Post by Cub »

bajaman wrote:By adding a small switch and additional resistor to the third gain stage it is easy to convert all of these to the Orange gain mode :wink: Just switch the 100 ohm resistor off, if you want the Red gain mode :!:
This is awesome! OD1 orange is my favourite mode on this amp, very George Lynch! With a OD1/OD2 and an orange/red switch, one pedal will pack four great sounds. :applause:
I wish I were a chestnut tree, nourished by the sun.
With twigs and leaves and branches and conkers by the ton.

User avatar
rcustoms
Resistor Ronker
Information
Posts: 426
Joined: 01 Oct 2009, 14:12
Location: COLOMBIA
Has thanked: 363 times
Been thanked: 520 times
Contact:

Post by rcustoms »

bajaman wrote::oops: :oops: :oops:
I made a small mistake with the Crunch model
Here are the correct schematics for OD1, OD2 and CRUNCH channels with the red gain mode. By adding a small switch and additional resistor to the third gain stage it is easy to convert all of these to the Orange gain mode :wink: Just switch the 100 ohm resistor off, if you want the Red gain mode :!:
cheers
bajaman
Baja JVM overdrive pedal OD1 9v 040218.GIF
Baja JVM overdrive pedal OD2 9v 040218.GIF
Baja JVM overdrive pedal Crunch 9v 040218.GIF
mr steve the images are low definition ,please add more pixels
http://www.rcustomspedals.blogspot.com
guitars,pedals and amps.
@zuleta.rafael(Instagram)

User avatar
bajaman
Old Solderhand
Information
Posts: 4549
Joined: 26 Jun 2007, 21:18
Location: New Brighton, Christchurch, NZ
Has thanked: 595 times
Been thanked: 2058 times

Post by bajaman »

mr steve the images are low definition ,please add more pixels
Did you try clicking on each image to expand it :?:
Here are some 300dpi images :wink:
Baja JVM overdrive pedal OD1 9v 040218.GIF
Baja JVM overdrive pedal OD2 9v 040218.GIF
Baja JVM overdrive pedal Crunch 9v 040218.GIF
cheers
bajaman
be kind to all animals - especially human beings

User avatar
Willypp
Information
Posts: 28
Joined: 02 Nov 2014, 14:20
Has thanked: 13 times
Been thanked: 17 times

Post by Willypp »

I'm thinking a version that can switch between all three might be a bit of fun...

User avatar
FausterCraster
Information
Posts: 34
Joined: 27 Sep 2016, 05:52
Has thanked: 17 times
Been thanked: 18 times

Post by FausterCraster »

Here all in one, thanks Baja for another great design !
Have fun.
Attachments
Baja JVM overdrive pedal 9v 060218.GIF

User avatar
287m
Breadboard Brother
Information
Posts: 143
Joined: 11 Nov 2014, 22:51
Location: Heaven ~ Hell
Has thanked: 481 times
Been thanked: 74 times

Post by 287m »

FausterCraster, that great!
btw, can you describe with (redrawn) schemo maybe?
noob like me just can't understand at this moment, sorry

User avatar
FausterCraster
Information
Posts: 34
Joined: 27 Sep 2016, 05:52
Has thanked: 17 times
Been thanked: 18 times

Post by FausterCraster »

@287m here you go!
for mechanical switching an option would be a rotary switch 3pole 3 positions.

@Baja, why not to add green channel also, we need your advice here !?
Attachments
Baja JVM overdrive pedal 9v 070218.GIF

User avatar
Willypp
Information
Posts: 28
Joined: 02 Nov 2014, 14:20
Has thanked: 13 times
Been thanked: 17 times

Post by Willypp »

I've had a bit of a go at this, bit I have no idea if it's correct - especially in terms of labeling switches, but I don't see why it shouldn't work. If anyone can bang up a vero layout I'll be your best friend (as we used to say in primary school). The idea is that you can bypass the whole shebang, select crunch or OD, select OD1/2 within OD, and select the orange or red modes, with separate gains for each channel, and a volume each for crunch/OD.

So, 5 knobs, 4 footswitches, 3 channels with 2 modes each... Hopefully in something like a DD. Happy to have opinions and constructive criticism. Done in Photoshop.

Willy.
Attachments
BajaJVM3channel4switches.jpg

User avatar
albru80
Information
Posts: 43
Joined: 10 May 2010, 18:33
Has thanked: 1 time
Been thanked: 51 times

Post by albru80 »

If correct, this could fit in a 1590BB.

User avatar
Willypp
Information
Posts: 28
Joined: 02 Nov 2014, 14:20
Has thanked: 13 times
Been thanked: 17 times

Post by Willypp »

Is that based off my variation?

User avatar
albru80
Information
Posts: 43
Joined: 10 May 2010, 18:33
Has thanked: 1 time
Been thanked: 51 times

Post by albru80 »

Not really but it should give the same results.
It always uses the same JFet buffer at the output (the way FausterCraster drawn it).
Adding an op-amp buffer instead shouldn't make any difference and just make the board larger.
The Crunch/ODs are still selectable.
I think it's correct but...

User avatar
temol
Solder Soldier
Information
Posts: 200
Joined: 25 Feb 2017, 20:58
Has thanked: 23 times
Been thanked: 213 times

Post by temol »

albru80 wrote:If correct, this could fit in a 1590BB.
Are you sure that 2SK117 pinout you have presented is correct?

T.

User avatar
Willypp
Information
Posts: 28
Joined: 02 Nov 2014, 14:20
Has thanked: 13 times
Been thanked: 17 times

Post by Willypp »

Not really but it should give the same results.
It always uses the same JFet buffer at the output (the way FausterCraster drawn it).
Adding an op-amp buffer instead shouldn't make any difference and just make the board larger.
The Crunch/ODs are still selectable.
I think it's correct but...
Awesome. I was just hoping for separate crunch/OD volumes but I reckon I can live without it. Looking at the layout, you'd need to add a pole to each switch for LED indication, yeah?

Post Reply