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DIY Stompboxes => Building your own stompbox => Topic started by: therecordingart on May 23, 2011, 03:44:08 PM

Title: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on May 23, 2011, 03:44:08 PM
Hello all...

A few weeks ago I hired Jacob Kokura to construct a PCB layout of a slightly modified version of the distortion channel from the Randall RG100ES. The slight modification is the addition of the "Voicing" section that was available in the Randall Century. (The RG100 and the Century 200 are the sound of Pantera). The schematic used was created by mensur and posted on another forum.

I've assembled one PCB and have signal passing and the unit mostly working. The lows and mids aren't reacting as they should (late night tinkering and my memory is fuzzy), but overall it's working. I could've wired something incorrectly or swapped values somewhere on the board.

Mensur's schematic

http://dl.dropbox.com/u/8772719/DIY/ultimaterandall.jpg

Jacob's layout

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

This is my attempt at giving back to the community that has helped me out quite a bit. If you decide to build one please let me know how it worked out and any changes you've made.
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: Maik on May 23, 2011, 04:18:14 PM
Wow, that´s cool.
Thanks

get yourself 3 beer ;D
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on May 23, 2011, 04:27:26 PM
Quote from: Maik on May 23, 2011, 04:18:14 PM
Wow, that´s cool.
Thanks

get yourself 3 beer ;D

No problem. All I ask is for feedback if you find any issues or any mods that you think bring it to the next level. I'm going to continue my quest to figure out what is going on in the tonestack. I'm guessing it's my fault and not the schematics or layout.
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on May 24, 2011, 09:27:37 AM
Oops....

Mensur's schematic

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

Jacob's layout

http://dl.dropbox.com/u/8772719/DIY/JKMensurRandall.pdf
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: deadastronaut on May 24, 2011, 11:44:10 AM
hmmm nice,but the 24v puts me off!...i'm a 9v kinda guy!.. :)
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on May 24, 2011, 11:45:21 AM
Quote from: deadastronaut on May 24, 2011, 11:44:10 AM
hmmm nice,but the 24v puts me off!...i'm a 9v kinda guy!.. :)

Charge pump.
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: askwho69 on May 31, 2011, 01:29:20 PM
nice layout! what software did you used??ive been waiting for this!!! by the way what errors did you found in your layout? :icon_twisted: :icon_twisted: :icon_twisted:
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: teemuk on May 31, 2011, 04:03:08 PM
Kinda off-topic, but does anyone have the schematics for Century?
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on May 31, 2011, 04:16:46 PM
Quote from: teemuk on May 31, 2011, 04:03:08 PM
Kinda off-topic, but does anyone have the schematics for Century?

http://dl.dropbox.com/u/8772719/DIY/C500%2C%20C1000%2C%20C170%20-%20Schematic.pdf
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: dan5150 on June 01, 2011, 12:02:34 AM
Sweet. I actually just picked up an RG100ES last month. It's great condition, built in 1986 and sounds great.

It also looks like your version has the boost always on (the amp has a volume pull switch that engages the clipping diodes).

Please keep us updated and post sound clips when you are done.
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: teemuk on June 02, 2011, 07:48:55 PM
Thanks. (http://www.dchat.co.uk/ChatRoom/images/smiles/emoticon_thumbsup.gif)
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: tasos on November 26, 2011, 11:38:40 AM
I can't see the files! ;D
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: therecordingart on November 26, 2011, 11:46:56 AM
Quote from: tasos on November 26, 2011, 11:38:40 AM
I can't see the files! ;D

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

http://dl.dropbox.com/u/8772719/DIY/Randall/JKMensurRandall.pdf
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: tasos on November 26, 2011, 12:11:14 PM
Quote from: therecordingart on November 26, 2011, 11:46:56 AM
Quote from: tasos on November 26, 2011, 11:38:40 AM
I can't see the files! ;D

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

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

Realliy nice!
Reccomended power suplly? ;)
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: jcgss77 on November 28, 2011, 06:55:39 PM
If I recall correctly, this is the preamp of the  Randall clone that Mensur built.  If so, this pre is beastly and will net you a lot of heavy-metal distortion.  Very nice sound!
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: deathbr on August 26, 2013, 01:32:52 PM
Someone has this layout, please???
Title: Re: Semi-verified Randall RG100ES schematic and layout
Post by: Hardos174 on November 11, 2015, 07:02:17 AM
Hi everybody!!

There is only deadlinks on this post so if someone of you would be agree to post the layout and pcb files in pdf here it would be really REALLY cool...

Hope somebody will answer to my request?

Thanks to all!