help with bluesbreaker build

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matoni
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Post by matoni »

Hello,
I recently made a board containing a Keeley moded blues driver and a blues breaker. THe blues driver works fine, however, the blues breaker I am having issues with. I get signal up until pin 1 of the op-amp, then I get nothing. I am pretty sure it is not an op-amp problem because I have switched it out for many other TLO72s and I get the same problem every time. I have built two boards and I am getting the same problem on both boards, so I believe it to be a board problem. I got the boards from JLCPCB, so Its probably not a reliability problem. Here is a screenshot of the eagle schematic. Maybe I made the schematic incorrectly? I have also tried jumping the input signal to the test point seen on the schematic, and it works fine for like 5 seconds and then it gets all fuzzy and fizzles out. No clue what could be causing this. Please let me know if my schematic or board looks messed up from the original schematic. Thanks so much in advance for all of your help/
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this is a screenshot of my eagle board
this is a screenshot of my eagle board
this is a screenshot of my eagle schematic
this is a screenshot of my eagle schematic

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mauman
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Post by mauman »

The first cap at the input (10 nf) should not go to ground, it should break the signal path between the pulldown resistor (your R25) and the bias resistor (your R26.)
BB input snip
BB input snip
BB snip.JPG (21 KiB) Viewed 462 times

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matoni
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Post by matoni »

thanks so much. This fixed the problem!!

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wallybob
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Post by wallybob »

Way to go mauman - well done!

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mauman
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Post by mauman »

Thanks wallybob. I've built waaaaaaaay too many BB's...

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