SOLVED Hydra Delay - volume and background noise

[Tommygun011198]

Hi all,

I just finished building my 1st FV-1 build - the hydra delay - and I’m struggling with a few issues.

All of the controls and delay heads of the pedal work and I followed the build documents without any modifications (until I switched it on and had some issues) but the problem I have is with the (1) volume control and (2) some background noise or a massively raised noise floor.

1. The volume issue is that the volume knob is extremely sensitive, and I can only turn it clockwise slightly before it exceeds unity volume. I thought this was the fault of the pot so I changed the linear b100k volume pot for a logarithmic a100k pot but the issue was the same. When the pot is fully counterclockwise there is no sound which I would expect from the volume knob, but as soon as it is turned up slightly the volume comes on, there seems to be no gradual ‘ramp’

2. The second issue is with the background noise when the pedal is active which is more than I would normally expect from a pedal.

All the ground pins of the fv1 are grounded as are the tl072 ground pins

I only started building pedals this year so please go easy on a rookie builder.

Any help would be hugely appreciated
Thank you
Tom

 

[Robert]

Verify that your 15K resistors are actually 15K and not 1.5K.

 

[Tommygun011198]

Verify that your 15K resistors are actually 15K and not 1.5K.

they seem to be 1.5k, i dont know how i got that wrong so will change them out tomorrow, how could you tell they were wrong?

 

[Tommygun011198]

Thanks for finding that issue, correcting those resistors has sorted the volume and background noise issues, but now I don’t seem to get any dry signal, I think I’ll reflow the fv1 solder joints but is there anything I should look for?

 

[Robert]

If you have a wet delayed signal there's no need to reflow the FV-1.

The FV-1 isn't in the dry signal path so it wouldn't cause that issue.

 

[Tommygun011198]

i have the wet delayed signal when the mix pot is turned past 9o clock but when it is fully counter clockwise there’s no sound

 

[jwin615]

Per noise if still an issue: Shorten up your ground leads. You're running them near the clock and fv-1. Keep ground as clean as possible.
For dry signal, double check your solders and pad integrity on R4 and R9

Make sure you didn't miss any 15k subs. Should be 5 total. Values are on the product page.

 

[Tommygun011198]

i have the wet delayed signal when the mix pot is turned past 9o clock but when it is fully counter clockwise there’s no sound

Sorry I should clarify, there’s no sound at all

Per noise if still an issue: Shorten up your ground leads. You're running them near the clock and fv-1. Keep ground as clean as possible.
For dry signal, double check your solders and pad integrity on R4 and R9
View attachment 77894
Make sure you didn't miss any 15k subs. Should be 5 total. Values are on the product page.

Thank you for the help, I’m making so many mistakes with this one I completely missed one of the 15k resistors when swapping them out last night. I can’t wait to get this properly working though so will have to correct this when I get home

 

[Tommygun011198]

Thanks everyone for your help, I managed to get it working and it sounds great, cant wait to get the design done!