Spin Semiconductor

Hey there,

I've had a board built using the following schematic, and everything is working great, CV control, pot controls, 8 step switch, everything sounds good.. EXCEPT the clipping led which seems to come on when it should be off, and off when it should be on.. So I fire it up, and without any inputs or outputs, on any program, the LED is on.. If I feed it a too-hot signal like an 8v AC square wave the led will go out. I'm attaching the schematic, does anyone have any ideas? Appreciate all the help I can get.

This is a eurorack module (+12V/-12V) that backpacks the FV-1 breakout from electrosmith which is basically the "typical application" circuit from the FV-1 datasheet.

Clip LED is backwards and should be connected to +3.3V not ground. See FV-1 datasheet schematic.

Oh wow, of course it is!

Thank you, I don't know why I assumed.. Lesson for today.. Did you check the data sheet?

Thanks again.

frank wrote: ↑Wed Aug 25, 2021 2:13 pm Clip LED is backwards and should be connected to +3.3V not ground. See FV-1 datasheet schematic.

Hi I'm new in FV-1 programming, so the first thing I did/do is to read through the forum (I read some topics I was thinking about too and now I don't have to answer the question a second time The clipping LED topic is interesting. It seems I could assign the clip LED connection to two different colored LED (one connected to plus, one to ground). So I would have a green one for "we're on and working" and one for "we're clipping in this moment ?
Best regards on a hot day in europe

HarryR wrote: ↑Sat Aug 16, 2025 8:35 am The clipping LED topic is interesting. It seems I could assign the clip LED connection to two different colored LED (one connected to plus, one to ground). So I would have a green one for "we're on and working" and one for "we're clipping in this moment ?
Best regards on a hot day in europe

Don't recommend it as the the sink and source transistors are different sizes and it is not designed to work that way. You will damage the chip over time and burn it out. If you want to do this then use an external buffer to drive the LEDs.

frank wrote: ↑Sat Aug 16, 2025 2:21 pm

HarryR wrote: ↑Sat Aug 16, 2025 8:35 am The clipping LED topic is interesting. It seems I could assign the clip LED connection to two different colored LED (one connected to plus, one to ground). So I would have a green one for "we're on and working" and one for "we're clipping in this moment ?
Best regards on a hot day in europe

Don't recommend it as the the sink and source transistors are different sizes and it is not designed to work that way. You will damage the chip over time and burn it out. If you want to do this then use an external buffer to drive the LEDs.

Okay, building an external buffer won't be a problem, better than damaging the not unexpensive FV-1.
Thanks for your comment