Cardinal tremolo - distortion

[Tommygun011198]

Hi all,
I recently drew up and built a circuit for the cardinal tremolo by 1776 effects but I’m having some issues. The sound produced sounds extremely distorted and there is no modulation in the sound. I followed the bias tutorial on YouTube before testing and I’m fairly confident my soldering is good enough to at least work. I also checked my diptrace file and it seems to be correct to the attached schematic. The two wired LEDs both pulse like they are supposed to, and one of the vactrols has a small hole in it and I can see that the LED there is also pulsing correctly. Ive tried changing the quad opamp as well as the jfets and I seem to get the same issue. Does anyone have any suggestions?
Thank you!
Tom

 

[chordball]

Soldering looks good to me.

Which vactrols are you using? Is this based on V2 of the Cardinal? Just saw a note in the build doc about low headroom in V1.

Once verified, if you have extra pcb's, I'd be interested in one.

 

[Tommygun011198]

These are VTL5C1s, I built it according to this doc

https://cdn.shopify.com/s/files/1/0022/3952/9069/files/Cardinal-Trem-V2.pdf?16138734983046189115

 

[chordball]

OK, that's V2 so you're good there.

Are your VTL5C1's Excelitas or prior, or Xvive? If not, that could be part of, if not the entire problem. It's stressed in the documentation that VTL5C1's must be used, which means no generics or knock-offs as well.

Past that, I'll have to read up some more before I can be of more help.

 

[BrainDrain]

Hi all,
I recently drew up and built a circuit for the cardinal tremolo by 1776 effects but I’m having some issues. The sound produced sounds extremely distorted and there is no modulation in the sound. I followed the bias tutorial on YouTube before testing and I’m fairly confident my soldering is good enough to at least work. I also checked my diptrace file and it seems to be correct to the attached schematic. The two wired LEDs both pulse like they are supposed to, and one of the vactrols has a small hole in it and I can see that the LED there is also pulsing correctly. Ive tried changing the quad opamp as well as the jfets and I seem to get the same issue. Does anyone have any suggestions?
Thank you!
Tom

I’ve been wanting to build this one. I just emailed the 1776 guy the other day asking if his store would reopen but he said no plans to at the moment.

I don’t see anything standing out. Your soldering looks good. My first guess would be the vactrols. They don’t look like xvive or excilitas and I’ve heard of others have problems with the knockoff versions. Not in this specific circuit though. I can’t remember exactly which one it was but I remember reading about someone having a similar issue and the xvive vactrols fixed it. I’d poke around a bit more before swapping them out though. Maybe a resistor value? If all the components are ok it might be helpful to post a picture of a blank pcb to verify against the schematic if you haven’t done it already. Also, Where did you buy the vactrols from?



After it’s verified If you have an extra pcb you’d want to sell or trade for something I’m also interested. I built the Cherry Pie last year and that one sounds amazing, but I’m a trem addict so I can never have enough.