Single Mosfet clipping muting the signal

[Fabeii]

Hi guys!

I was experimenting with some different clipping methods and I came up with something like this:


What is the problem? When the switch selects the single Mosfet clipping the signal from the circuit is completely muted, while the other methods, with both mosfet, works good.

Is there something wrong in my arrangement? I used the AMZ mosfet page as a guide.

Thanks a lot!

edit: just occurred to me that the first mosfet could be shorted as soon as I posted this. Is it something that may happen?

[Kipper4]

I've no idea. It's a bit tough without some circuitry context anyways.

If it was me I'd stick a fancy si fi sticker on the aluminium, use a momentary switch and call it a Metal Train with KILL switch.

If you can't fix it call it a feature.

Carry on

[Fabeii]

I've no idea. It's a bit tough without some circuitry context anyways.

If it was me I'd stick a fancy si fi sticker on the aluminium, use a momentary switch and call it a Metal Train with KILL switch.

If you can't fix it call it a feature.

Carry on

Before that snippet a simple IC gain stage, after that a 100k volume pot.

I like this way of thinking tho! My super secret mute switch feature!

[Rob Strand]

My guess is you don't have a cap between the opamp and the clipper.  The DC is causing the MOSFET to conduct permanently.

[Fabeii]

My guess is you don't have a cap between the opamp and the clipper.  The DC is causing the MOSFET to conduct permanently.

This is nice to know but I've a cap between op-amp and the clipper.
I didn't have much time but the DMM showed continuity between the Source and the Drain pin. So it's a shorted mosfet or a problem with the protoboard's trace.
I'll desolder the mosfet and check it again, maybe this evening.

[Rob Strand]

This is nice to know but I've a cap between op-amp and the clipper.
I didn't have much time but the DMM showed continuity between the Source and the Drain pin. So it's a shorted mosfet or a problem with the protoboard's trace.
I'll desolder the mosfet and check it again, maybe this evening.

Yep, if it's not DC a short would explain it.

[Fabeii]

I can confirm the shorted Mosfet now!

I know it's impossible to tell, but could have been some static shock to fry it?

Thanks all!

[bluebunny]

I know it's impossible to tell, but could have been some static shock to fry it?

You can indeed zorch a MOSFET with static (although, surprisingly, I've never managed it).  To quote R.G., "the (glass) gate on a MOSFET is ~20V wide".  So skating across linoleum in nylon socks will generate plenty more than 20V.  There are doubtless other ways too...

[DaveLT]

I've no idea. It's a bit tough without some circuitry context anyways.

If it was me I'd stick a fancy si fi sticker on the aluminium, use a momentary switch and call it a Metal Train with KILL switch.

If you can't fix it call it a feature.

Carry on

It's not a bug, it's a feature 

[Fabeii]

I know it's impossible to tell, but could have been some static shock to fry it?

You can indeed zorch a MOSFET with static (although, surprisingly, I've never managed it).  To quote R.G., "the (glass) gate on a MOSFET is ~20V wide".  So skating across linoleum in nylon socks will generate plenty more than 20V.  There are doubtless other ways too...

Great! Now thanks to my ODC I've to check on every mosfet, after checking on every resistor even if I pick them from the labeled drawer 

[Kipper4]

I've fried a couple of mosfet mainly through static.
As an old man now I've earned the right to wear the sketchers shoes with the memory foam soles and slipper too. I stopped short of the pipe though.
I also have a cheap nylon rug under my work bench.
Hence the static.
Take your sneakers off and get cotton sock.
Save a mosfets life..........
Or keep the slippers on and spend 20 pence more.