Thursday, May 17, 2018
Run Off Groove Double D
Still a few Run Off Groove designs I haven't laid out yet, and this is one of them. It's based around the 4049 IC chip and features 2 channels of amp-like distortion. I've laid it out to fit in a 125B with dual footswitches. Bias Q1 to 4.5v and then adjust to taste as usual. More info, schematic and footswitch wiring diagram on the ROG site.
can i make a request, please do a musicman sabre II preamp that i can use like a stomp pedal? pleeeaaasse....
ReplyDeleteSabrotone has stripboard layouts for guitar and bass versions of this on his website.
DeleteI had seen this circuit a while back. It might be something I'm looking for but I would want to add a tone stack to both channels. Where should I add that in?
ReplyDeleteEasiest approach would probably be adding in a couple SWTCs just before the Volume controls.
Deletehttp://www.muzique.com/lab/swtc.htm
You could also tack on a couple of the BMP tone stack boards in the same place. I'd recommend using the one with the gain recovery stage.
great. Thanks.
DeleteI have a couple questions:
ReplyDelete1- there is a 470uF electrolytic that appears in your layout that is not in the original schematic. is this for power filtering? if not, what is its function.
2- there is a 100 OHM resistor in your layout in the power chain prior to everything in the circuit that uses power. this resistor is also not shown in the original schematic.
PLEASE ADVISE.
Thank you as always for this AMAZING resource.
I visit DAILY and this website is a wonderful repository of knowledge.
1 - yes, power filtering. A lot of circuits that use the CD4049UBE chip have large power filtering caps.
Delete2- Also power filtering/smoothing, also present in a lot of 4049 designs.
I assumed as much.
DeleteThanks for the speedy response.
Verified.
ReplyDeleteSounds amp-like as described by ROG.
Compared to the 3 Legged Dog, the bounce channel here sounds fuller, smoother, and more natural. The 3 Legged Dog's treble is harsh enough that most people would want to add a tone control (The SWTC 2 works well). Both channels of the Double D are balanced enough as is. You can dial down the gain on both circuits with your guitar's volume, but of course the Double D already has a lower gain channel. I did get some whine from the bounce channel at max gain, but it disappeared after replacing the trimpot with a fixed resistor. If you had to build just one, the more balanced, refined, and versatile Double D is the way to go. However, the brighter and tighter 3 Legged Dog is an easy build for anyone wanting something a little more aggressive.