BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[haveyouseenhim]

Awesome. That's exactly the model wanted.

[pakrat]

I'm not sure I can post it here, pm me your email and I'll send it to you. If JOK3RX is doing the RG100 I'd wait for that.... don't wanna step on anyone's toes here.... I do have the real schematic too somewhere, and an actual RG100 amp that I guess I could trace. I would love my Randall in a box!

[J0K3RX]

Awesome. That's exactly the model wanted.

Here's a layout made by Jacob Kokura using mensur's schematic... Probably the closest to the actual Randall. Down side is that it requires 24v but not that big of a deal if it sounds good!

http://dl.dropbox.com/u/8772719/DIY/Randall/MensurRG100schem.jpg

http://dl.dropbox.com/u/8772719/DIY/Randall/JKMensurRandall.pdf


Here's the post about it... I haven't built it, yet... But looks pretty simple and straight forward!
http://www.diystompboxes.com/smfforum/index.php?topic=91777.0

[haveyouseenhim]

Awesome. I'm excited to start this build.

[pakrat]

That's the one I have. The only variable I see is the pot values, but I could always look inside my RG to see what they are.

[haveyouseenhim]

Board is etching as I'm typing

[J0K3RX]

That's the one I have. The only variable I see is the pot values, but I could always look inside my RG to see what they are.

Mensur's values are correct other than the volume knob which I'm sure was tested with B50K instead of the original B10K... The value of pots varies from country to country like in the US a 50k pot will be called 47k in some other country...

The JFETs used on the actual Randall are 2N5484.. Everything on mensur's schematic is for the most part true to the original with the exception of some very minor tweaks and added stuff which actually look like nice improvements!

The pot values from the actual Randall factory schematic are as follows:

Gain - A50K
Vol - B10K
Treb - B50K
Mid - B2K
Bass - A50K
Pres - B2K
Note: The B50K voice pot was added and is not in the original Randall schematic. The voice knob is a sort of "fake variable capacitor" so to speak varying between 47n and 22n which I think is a cool idea!

[pakrat]

Def a cool idea. I've had the parts for this project for months, but projects like the Black Forest keep me from building it 

[J0K3RX]

Might want to check out the x2fet also... supposed to be a Warhead simulator


x2fet:
http://www.techniguitare.com/Fiches/X2FET-V1.pdf

http://pagesperso-orange.fr/sxsyl20/x2fet/X2FET.jpg
http://pagesperso-orange.fr/sxsyl20/x2fet/x2fet.txt
http://pagesperso-orange.fr/sxsyl20/x2fet/x2fet.gif

http://www.diystompboxes.com/smfforum/index.php?topic=70489.0

[haveyouseenhim]

STOP IT    you are loading up my to build list!!!    I just finished drilling the randall pcb

[J0K3RX]

STOP IT    you are loading up my to build list!!!   I just finished drilling the randall pcb

You started it..!  So, you don't want to see the Super Randall designed by Fortin Aplification? The Randall Satan or Natas depending on which way you are looking at it...

[haveyouseenhim]

Keep going... it hurts so good      im etching the x2fet atm    I see more etching going on for me tonight. gotta order more pots though

[pakrat]

The Randall Satan is Ola Englund's signature amp? You can't even get an idea of how good the amp is because that guy can make a gorilla amp sound killer.

[Cap]

Hi guys! I'm back I'm very very busy at the moment but I made a new update: added the gate pot and put a trimpot for presence..so you can decide if leave off it or not.

This is a preview, the complete pdf tomorrow  It's late night here

http://dl.dropbox.com/u/3511352/Black%20Forest%20Gate%2Bpres%20trim.pdf

Ciao!

[haveyouseenhim]

I abso@#$%inlutely love this X2! I just finished biasing and testing and I cant get over how awesome it is. I like meaty obnoxious super high gain distortion. I listen and play a lot of crossover thrash metal/thrash punk, so it's perfect.

[pakrat]

Great looking build Mike. I guess I need to add this one to my list now.... sigh. I have 2 weeks to complete 3 builds for the turkey day shootout and haven't even been able to order parts yet. Looks like it's gonna be a few all-nighters for me.

[pakrat]

@Cap I'm drooling again! Good to have you back in here 

[J0K3RX]

I abso@#$%inlutely love this X2! I just finished biasing and testing and I cant get over how awesome it is. I like meaty obnoxious super high gain distortion. I listen and play a lot of crossover thrash metal/thrash punk, so it's perfect.

Nice job! Any sound samples? All of the sound samples I heard of it sounded like garbage so it would be good to hear a good demo... btw - did you paint the pcb? 

[haveyouseenhim]

I don't have a way of doing quality sound samples here at my house. I'll try to set something up later. One man's garbage is another man's tonal treasure.     And yes, I painted the pcb silver and green to match the actual x2 head.

[J0K3RX]

I don't have a way of doing quality sound samples here at my house. I'll try to set something up later. One man's garbage is another man's tonal treasure.     And yes, I painted the pcb silver and green to match the actual x2 head.

Cool... Reason I asked about the paint is because some paints are conductive...  What jfets did you use on the X2?