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9/29/2000 8:58 AM
Yesterday evening,I finished my DR QUACK version with electronic switch (4053)to bypass it .Whow!! that's funky sound !! it works very good. I put my home made superfuzz behind it, that sound also very good.
10/3/2000 8:57 AM
Paul D.

Which PCB layout did you use? I've used R.G.'s (at GEO) and I can't get it to work. Probably my own fault - R.G.'s work is usually impeccable whereas my own is often very peccable!  
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10/3/2000 11:05 AM

I made the DR QUACK on Veroboard.  
Did you red the recommandations from Mark Hammer about the DR QUACK?  
What's the value of the feedback resistor on the enveloppe detector? It should be minimum 2M2.  
I used a NE5532, and for the transistor a BC557B.  
Don't forget that the incoming signal must be strong enough to be detect by the enveloppe detector.  
Good luck
10/3/2000 11:13 AM

Sorry, the transistor is a BC547B(NPN device) and not BC557B(PNP device)
10/3/2000 2:54 PM
Mark Hammer

Almost ANY npn transistor can be used; 2N3904, 2N5088, etc.  
Not sure how you made yours, but I failed to recognize until late in the game that RG's PC-layout was for press-and-peel transfers. Because of how these are used, the layout is the OPPOSITE of what you would normally see in a hobby magazine (which would assume either photo-sensitive board or hand-drawn resist patterns). It ended up being possible to reverse the relevent components (including turning the dual op-amp upside down and bending all the pins the other way), at which point it worked just fine. Given how easy the board is to make, it may just be easier to make another one properly....assuming that you were as stupid as I was. Bear in mind that the reversed PC-mask problem may lead to transistors being oriented the wrong way. This will surely impair function of the device.  
The recommendation about the feedback resistor value is to be taken seriously; 470k will likely not provide enough gain unless you are feeding the DQ with a line level signal.
10/4/2000 11:09 AM
Paul D.

I did use Mark's advice - 2.7 Meg feedback resistor, etc., & I think I got the PCB orientation right - I'll double check that tomorrow. I've made a mess of the board resoldering - maybe I'll start again from scratch. Thanks for your input.  
10/5/2000 9:34 AM

Please excuse my ignorance but what exactly does the DR Quack do?  
Cheers Ken.
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