# Unison Double Tracker Noisy



## Tornato (Aug 24, 2019)

Kinda bad noise floor.  Its not a hum but white noise. Ideas?


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## Tornato (Aug 26, 2019)

I'll try replacing the TL072's ? But Does anyone else using the FV-1 have a noisy floor?


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## Tornato (Aug 26, 2019)

Ok So the board doesn't match the instructions. Or the parts list. I used the part values that were printed on the PCB. Was this the problem? I am also using the schematic from the build doc. but it uses the Pythagoras schematic. I assume its the same just using a different programmed Eprom?
Anyway. If I track pin 6 on the TL072 i should find R9 and R10. no such luck???


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## zgrav (Aug 27, 2019)

I have built a few FV-1 effects and the noise floor is good on all of them, but I have not built any of the PCB FV-1 boards that use the toggle to switch between three programs.    There are two TL072 chips on your board, and it looks like R9 and R10 should connect to pin 6 for one of those chips.  Make sure you were not testing the wrong TL072 when you were checking for continuity.  

Try running the board from a 9v battery and see if your noise level improves.  I have had some pedals that were much more sensitive to noise from my power supply and that might be the case here.


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## Tornato (Aug 27, 2019)

Ya I’m having a hard time finding continuity from pin 6 to find R9 on either one of the 72’s ? I will double check and try a battery


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## Tornato (Aug 27, 2019)

Oh and the “mix” control on the schematic says 10k but on the PCB it said 100k. I did what was printed on the board. Could this be the issue?


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## zgrav (Aug 27, 2019)

The  build doc parts lists calls for 10K for the MIX pot, and the schematic also says 10K on the mix pot.  That change may have been part of the reason there was a new revision of the board this past July.   I would go with the build doc and use a 10K pot there.  

Are you checking for continuity on both sides of R9 and R10?   Maybe you were checking the wrong side.


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## Tornato (Aug 27, 2019)

I tried both sides of every resistor on the board ? From both op amps. I’m out of the shop today but I will try again tomorrow


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## zgrav (Aug 27, 2019)

Did you use sockets for your TL072?   Maybe your ICs are not making the right connections through the sockets to your board.  If changing the MIX pot to 10K does not solve  your problem, you should post a picture of each side of your board.


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## Tornato (Aug 27, 2019)

I did socket them. I guess it wouldn’t work if there was no connection. I just assume that the board is different from the schematic.
I’ll try the 10k and see what’s what.
Thanks


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## zgrav (Aug 27, 2019)

You can compare the parts placement and values on your board with the picture in the build docs.  So long as those match, I would assume the schematic and board are in agreement, and use any differences you find to be a part of your troubleshooting.


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## Tornato (Aug 28, 2019)

UGG . I'm having a hard time locating R9 and R10. If you have a similar board, Please locate them for me. I should find continuity from the mix pot to them but no? Also from pin 6 of the TL072, again no? Weird. I did change the mix pot to 10k instead of 100k and it helped a bit. I think im on the right track seeking out the resistors.


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## Sasan (Dec 11, 2019)

Does anyone here have sound samples of the Unison DT?


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## Tornato (Dec 12, 2019)

I would have to get it in a stereo recording to do it justice. In a mono setting this is not ideal


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