Where is the clipping stage in the BD-2?

[John Lyons]

Oh, I see...yeah, if you have 2 LEDs  in series then it's as uncompressed/clipped at it can get really, pretty much as if no diodes were used.
The signal isn't that big there, not even touching the diodes mush if at all.
More diodes in series = more clean headroom.

Clipping diodes from more to least clipping amount:
Germanium/shotky .3v ish headroom
Silicon diodes .6v ish headroom
LED 1.5 ish volts
Add diodes in series and they double the headroom.

john

[kurtlives]

I am looking for a fat compressed pedal with lots of headroom...

According to what your saying two LEDs in series like I have is my best bet right?

[John Lyons]

Some of your terms are conflicting though.
Fat, ok... Compressed...ok  Lots of headroom...wait a minute.

Compression is the opposite of lots of  headroom for the most part.
"headroom" literally is the space above a "normal" signal where the amplitude
can raise into....room above your head. 
Compression is the result of clipping and a saturated sound (distorted or not)
To have a lot of headroom means not much clipping. Headroom is the ability
to hit the strings harder and you can hear a change in amplitude, or play soft
and have a quieter/less distorted sound.

A compressed/clipped sound wave is taking full advantage of the space to which it has available.
A fat fuzz bar graphically.
A high headroom wave form looks more open, there is space between the peaks depending on the
music.

I think you may be thinking of headroom as level? maybe not...
Not trying to criticize, just trying to clarify the terms.

john

[kurtlives]

Ah I always like learning new terms thanks...

I always thought of headroom as the space I guess before a signal clips.

[John Lyons]

You are right about that.
Headroom is the space before clipping.
You can of course have clipping with some headroom as well.
Clipping has many shades. Some GE devices clip at all levels, some harder than others.

If you look at it in the vertical sense.
The signal gets higher, once you reach the point where the signal hits the
clipping threshold of the diodes and signal clips. If the signal is raised further
whether through dynamics from the player hitting the strings or from raising the gain knob, then the waveform
squashes the sharp peaks at the top flatter, they become wider, which is compression.
This is why distorted/overdriven/fuzzed sounds have a lot of sustain. The signal is always high and the tops are
compressed as opposed to loud clean notes which are long, more vertical yet less jagged spikes with
more open space. The key is to get the signal to clip at the right place. This is where everyone like their
particular diode set up. Since they all have different thresholds they clip at different points.
Lover forward voltage = more clipping or clipping sooner with less gain applied.

john


There are ways to get compression without heavy clipping. This is most likely what you are looking for.
This comes from slightly clipping a few stages. The BD-2 does this. The transistors clip and the diodes clip as well.
It's basically a tube screamer made with discrete transistors. I don't pretend to know the circuit that well, just read about it...
"book smarts"