oscillations in Dr. Boogie...

Started by Connoisseur of Distortion, April 14, 2005, 12:02:32 AM

Previous topic - Next topic

Bucksears

Quote from: Bob NI realize it's not perfect, but it sure is a lot closer than the backline amps. At least being in the ballpark you have some of the characteristics that you're looking for.

My sentiments exactly. The cool thing is that these things sound SO much better than almost everything on the commercial market.

As far as NOT having to have a large rig goes, I LOVE having my JCM800, Dual Recto, Dumble and Mark IIC+ emus and being able to bypass them and have my SRRI for clean, trem and reverb. (although I would love to hear the Dr. Boogey through a closed back 2x or 4x12) Beats the heck out of digital modeling.

Bob N

I know exactly what you're saying here. I'm sure the guitarists would agree that they LOVE their rigs and don't mind carrying them, BUT this setup gives them opportunities to explore different sounds in a tight package where carrying 2 or 3 rigs to a gig isn't practical, both space and money wise, for a single guitarist. This is REALLY important in the case of one of the bands, O.D.M. where they have 3 guitarists... Space is at a premium on stage already with the bodies, let alone the rigs...

I just finished up with their NEW website and you can check 'em out at www.musicodm.com if you feel like listening. I'm just glad that website is FINALLY done! 2 1/2 months of HARD work on that one! Now I can have my nights and weekends back...

michael_ibrahim

a few things that might help with stability,...

1) You should also simulate miller capacitance for each stage (which would be about 1.6pF*Gain). This is particularly important for reducing oscillations, as well as dulling the sound a bit, which if you listen carefully, is what a DR sounds like.

2) Add a unity gain inverting stage at the output. The DR preamp has 4 inverting stages and one non-inverting follower. This means that roughly speaking, the input signal is in phase with the output signal. When you then bring the two signals close to each other (say in the footswitch), you can get coupling between the input and output. Since they're in phase, adding a unity gain inverting stage will help pedal stability.

smccusker

Quote from: Connoisseur of Distortioni boxed it up today, and it sounds spectacular. EXCEPT that it oscillates when i dampen my strings. AND that i pick up 101 KUFO when my guitar is off. also, interestingly enough, i can change the pitch of and eventually stop the oscillations, and also tune the radio, by lowering my tone on my guitar... but eventually i end up with a very flat tone...  :(

i have been getting the impression that long wires might be to blame for this... but i need to know which wires are suspect for this particular circuit! please, if you can point me in the right direction, it would be very much appreciated.

I have this exact same problem with a build of the tychobrahe octavia i just finished.  As suggested, I put my tuner infront of it, and the problem stopped.
I'll try some of the other things people suggested.
Guitar -> Amp