smash drive/grace hybrid

[CoolJohnny]

have benn messing around with the LM 386 chip for awhile and just got around to looking at aaron's smash drive (yeah, i know im a little late to that party). has anyone tried putting the buffer on the input like the grace overdrive from runoffgroove? has anyone tried germanium diodes on the output? im gonn start messing on the breadboard with this but would love to hear anyone else's experience...after rehabing an old silvertone amp im ready for something painfully simple, a one afternoon test/build/house project...

[Electron Tornado]

I built a pedal based on the Smash Drive and Grace Overdrive. The tone is good, but I don't like the way the notes die off with a buzz at the very end. I still haven't figured out why that is, though apparrently it's a common problem when using the 386 in a distortion pedal.  Before you do the buffers from Runoff Groove, try the circuit in this thread: 

http://www.diystompboxes.com/smfforum/index.php?topic=86389.0

The guy who came up with that circuit says he's managed to cure the buzziness at the end of notes.


You won't need diodes for clipping as the 386 will do all the clipping you'll need. Download the datasheet for the 386 and read it as well.

[zambo]

i built one in the same box as a valvecaster. Cant remember which was first in the chain but it sounded pretty rude. I actualy like these 386 designs. The buzzy ending i think is why i moved on. Dano uses a different kind that are supposed to be better. Also there are n 1 2 3 and 4 versions. The 4's do the most voltage i think. Dont know if it makes a difference. Beavis audio had a lot of info on them.

[deadastronaut]

yep...i found the main cure for any fizz at the end of notes was to put a 100uf across the +/-..to smooth the power....... also try the n-3....

im messiing around with the 2 fets into the 386 again at the moment.....

[CoolJohnny]

two fets? ill have to try that. thatnks for your input everyone.

[Electron Tornado]

yep...i found the main cure for any fizz at the end of notes was to put a 100uf across the +/-..to smooth the power....... also try the n-3....

im messiing around with the 2 fets into the 386 again at the moment.....

I have a 220uF cap filtering the power and had the buzz. My pedal has the n-1, so I wonder if the key is to use the n-3. My circuit input is a single JFET from the Grace overdrive from Runoff Groove.  http://www.runoffgroove.com/grace.html

[deadastronaut]

yep...i found the main cure for any fizz at the end of notes was to put a 100uf across the +/-..to smooth the power....... also try the n-3....

im messiing around with the 2 fets into the 386 again at the moment.....

I have a 220uF cap filtering the power and had the buzz. My pedal has the n-1, so I wonder if the key is to use the n-3. My circuit input is a single JFET from the Grace overdrive from Runoff Groove.  http://www.runoffgroove.com/grace.html

yeah, maybe the n-3 will be better...i would have gone for the big daddy input setup...with the 2.2k  2.2uf, and a 20-25k trim instead of the 15k...more tweakable...

also i read a 10uf on pin 7 to ground on the 386 for stability...

[Electron Tornado]

yeah, maybe the n-3 will be better...i would have gone for the big daddy input setup...with the 2.2k  2.2uf, and a 20-25k trim instead of the 15k...more tweakable...

also i read a 10uf on pin 7 to ground on the 386 for stability...

I tried both the Grace and Big Daddy, but didn't like the sound of the Big Daddy. Maybe I should have tried tweaking it some. I do have the 10uf cap on pin 7.