blocking dist

[anthillrich]

i have been seeing the term blocking distortion, and i dont know what it means exactly. i think it happens when one stage sends to much signal to the next, and some of the wave is chopped off.

is that even close?
could someone point me to a thread that explains it in simple terms( im a simpleton), or a reply with an explanation.
as always, im grateful for the knowledge shared by the members of this forum.
thanx, rich

[tedmich]

what I know is from Aiken Amps:
Blocking Distortion


others will know more!

[Chuck H]

i think it happens when one stage sends to much signal to the next, and some of the wave is chopped off.

is that even close?

Nope

The macro explaination (which is the only one I can convey) is that by driving a tube too hard at it's grid it will try to put out more than it should. A tube by it's nature will try to draw current from it's own grid in this circumstance. Unless the grid circuit is designed to provide enough current the bias conditions will shift and the tube will go into cutoff until current drops and bias is restored. This can effect the whole waveform or or only part of it depending on the nature and severity of the condition. It's usually audible as bad distortion and is easily distinguished from good distortion.

Chuck

[hasserl]

I've had amps with blocking distortion so bad the sound would completely cut out for a split second until it recovered. More common is the unpleasant distortion Chuck mentioned above, also called "farting out" in some circumstances.

[Enzo]

And when some of the wave is chopped off, we refer to that as clipping. WHich is not he same as blocking distortion.

[anthillrich]

thanks for the replies. i read the Aiken article you suggested, its a little over my head, well, alot actually, but it helped.
out of curiousity, would it sound like say, a NEIL YOUNG guitar solo? that extreme break up sound where it sounds like the amp is ready to explode?
anyway, thanx, rich.

[cbarrow7625]

Ha! Pretty close! I never thought of it that way before. Good one.

In some cases, I think his amps are right on the hairy edge of blocking distortion where the pick attack get all flubby sounding but the note still rings out afterward.

[Jag]

That's always what I thought was happening in Cinnamon Girl or Hey Hey My My... (or is it My My Hey Hey...).