From: rbanksjr@nyx.cs.du.edu (Richard E. Banks Jr.)
Subject: Re: Fuzz Box From Hell (corrected version)
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Date: Thu, 15 Oct 92 01:24:11 GMT

In article <BvDwt2.16J@dcs.glasgow.ac.uk> dam@dcs.glasgow.ac.uk (David Morning) writes:




Here's the schematic of the circuit so you guys won't be lost while trying
to help me find the problem.  Thanks again.
>
>I knew I shouldn't have posted something which had been collecting dust
>for years in my files. Oh well. My original version used 2 batteries to
>provide a split rail supply. In my rush to post it, I bodged the battery
>supply splitter. I wasn't convinced I'd got it right after I'd posted it
>so a built it from scratch at the week-end. There are 2 connection errors
>in the original, both the input resistor and the 680 ohm feedback resistor
>should go to the V/2 rail and NOT the battery -ve.
>
>Sorry folks. This one does the trick. Oh..and it's a 9 volt battery (small type)
>
>
>
>Battery is 9 volts.
>Op-amp is anything. 741 is noisy, TLO71/72 is less noisy, NE5534 is least
>noisy but drains the battery.
>
>                             
>                       ---  Op-Amp                           
>                      |    \                                          
>                      |     \                                                  
>Inputo----||----------| +    \                                 
>        0.47u |       |       \                 0.47uF        
>              |       |        >-----------------||------     
>              |       |       /       |       |          |    
>              |    ---| -    /        |      ---\        -
>              -   |   |     /         -      / \  ZD1   | |
>             | |  |   |    /         | |      -         | |100k
>        68k  | |  |   |   /      330k| |      |          -
>              -   |    ---            -       -          |-------o Output
>              |   |                   |      \ / ZD2     |
>              |   |                   |      ---/        -
>              |   |                   |       |         | |
>              |    -------------------|-------          | |2k2**
>              |                       |                  -
>              |                       -                  |
>              |                      | |                 |
>              |               680ohm | |                 |
>              |                       -                  |
>              |                       |                  |
>               ------------------------------> V/2*      |
>                                                         |
>Input                                                    |          Output
>Gnd o----------------------------------------------------------------o Gnd
>
>
>Battery rail splitter
>=====================
>
>Batt +ve-----------------------------------------> To Op-Amp +Vs
>                                   |
>                                   |
>                                   - 
>                                  | |220k
>                                  | |
>                                   -
>                                   |
>                            -------|------------> To V/2*
>                           |       |
>                          --- ++   -
>                   100uF  ---     | | 200k
>                           |      | |
>                           |       -
>                           |       |
>                           |       |
>Batt -ve -----o\o-------------------------------> To op-amp -Vs
>             Jack socket switch           |
>                                          |
>                                           ------> To Gnd
>
>
>
>
>
>
>Jack socket switch wiring:-
>=========================
>
>                   -------------------
>                  | Sleeve  Ring  Tip |
>   Jack plug ---> |   -     -     -   |
>   goes in here   |  | |   | |   | |  |
>                  |  | |   | |   | |  |
>                   --| |---| |---| |--
>   From battery -----| |   | |   | |
>   -ve terminal       -     -     -
>                            |
>                             -------------> To battery rail splitter
>
>Inserting mono plug shorts sleeve and ring together and activates the
>battery.
>
>
>-- 


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