Author Topic: Runoffgroove Big Daddy probs.  (Read 2406 times)


Runoffgroove Big Daddy probs.
« on: April 04, 2006, 12:33:17 AM »
Hello all.
     I first built the Big Daddy about a year ago, and really dig the distortion it makes.  However, that build was plagued with a problem, so I recently breadboarded another one, but the problem is still there, in the new one.  Heres the deal:
     The distortion works and sounds great.  However, when I let the notes ring for a while (like at the end of a song), the distortion cuts in and out.  The clean signal remains when the distortion cuts out.
     When I first built this project a year ago, I originally thought there might be a bias issue with the JFET.  But when I bypass the JFET and use just the 386 chip (a la the Smash Drive), I notice the same thing happening.  Its much harder to hear without the JFET driving the chip, but definately there.
     I wonder if this is a common problem or if my chips are just crappy.  I bought mine at Radio Shack some time last year.  All of the chips I bought, 3 in total, exhibit this problem.  One of them is especially noticable.
     So, Big Daddy builders, do you have this problem?  And if not, where did you get your chips from?
Life is like a box of chocolates.  You give it to your girlfriend and she eats up the best pieces and throws the rest away.


Re: Runoffgroove Big Daddy probs.
« Reply #1 on: November 22, 2008, 03:31:31 AM »

Electron Tornado

Re: Runoffgroove Big Daddy probs.
« Reply #2 on: November 22, 2008, 12:41:46 PM »
I just built an overdrive based on the Smash Drive and added the JFET buffer from the Grace Overdrive. I tried the Big Daddy circuit, but didn't care for the sound. You might try the Grace circuit instead. It sounds great and I've had none of the issues you describe. I am used a JRC 386D. Does the 386 data sheet show any versions of the chip with different specs? (I don't have the data sheet handy.)
Thank you, Joe Anthony. (The godfather of rock and roll.)

Anyone can drill a hole. But, if you want it off center or misaligned I'm your man!


Re: Runoffgroove Big Daddy probs.
« Reply #3 on: November 22, 2008, 01:48:02 PM »
386 chips come in various versions..try different versions (1,2,3,4)
Tubes are overrated!!


Re: Runoffgroove Big Daddy probs.
« Reply #4 on: November 23, 2008, 09:54:11 AM »
bought your parts at radio shack? Most likely then that your 386 chip is an LM386-1 or LM386-4 (the only two 386's I can find at radio shack). Maybe you need a JRC386, the LM is prone to some oscillation problems I think. Maybe try a 10 ohm resistor in series with a .047uf cap to ground from the positive side of your output capacitor (from 386 pin 5). Might help it a little bit though I am not entirely sure. best of luck!
Ruby Amp, Noisy Cricket, NPN Boost, modded Mockman 1.0, Bazz Fuss, J201 Fetzer Valve, Valvecaster, modded Valvecaster

Resistance is futile!