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Dr Q, Q's????


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9/9/2000 6:29 AM
JMF
 Dr Q, Q's????
First off I must say god bless ampage. I discovered this site a week ago and just finished my 3rd effects pedal. fun, fun, fun......  
 
Anyhow, I just built the Dr Q. I am fairly pleased with it but I have a concern or two. The dynamic range of the envelope is VERY weak. Even with tweaking the trim pot (which I already plan to replace with a surface mount pot), I can't seem to get enough wah out of it. The most I can pull is staccato funk guitar. Is this something I fouled up in the circuit, or is it just a flaw inherent to the Dr Q design. BTW, I am using a fender duo-sonic with 57 reissue strat pickups.  
 
Thanks
  
9/9/2000 6:45 PM
jon
just a guess here, try a guitar with pickups with higher output voltage (humbuckers, active electronix)or use something to get the signal voltage up (LPB-1, etc) sounds like there might not be enough signal voltage to trigger the ECF.  
 
See M. Hammer's excellent article on ECF's ... let me know if you need the link  
cya  
Jon
  
9/9/2000 8:34 PM
JMF
Thanks, yeah if you wouldn't minda link would be tremendous. Also would there by any chance be any micro-synth schems floating around out there
  
9/13/2000 11:08 PM
Tiago
This problem occoured with me too. I build the circuit from the layout in the projects page here in Ampage. Iīm a beginner in DIYing, and they said to me that it was the gain of the envelope detector, that is too low. Replace the 470K resistor on the envelope detector with a 2.2M or 2.7M. This resistor is at the right of the IC, if you made the same layout as me.  
 
I forget to say that the above is for the Jack Ormanīs Dr. Quack, not the Doctor Q. Itīs better make the Dr. Quack, that is a little modified from the Doctor Q. and accept a wider range of dual opamps.  
 
Tiago
  
9/14/2000 6:49 AM
Anders Westerberg
The schems for the microsynth are avaliable on the net but it's a rather complex circuit (3 pages). Let me know if you're still interested and don't find it on the net.
  
9/15/2000 2:39 AM
Mark Hammer
If you're up to it, a single-transistor or single op-amp gain stage at the front end would help a lot. Alternatively, as suggested by others, up the gain of the envelope follower stage by using a feedback resistor in the range of several megohms.
  

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