ROG Brittania

[freshmex18]

So I've built this pedal

http://www.runoffgroove.com/britannia.html

using this layout

http://tagboardeffects.blogspot.com/2014/09/rog-britannia.html

and got it working.  It sounds great (if maybe just a little bit too gainy).

The ROG website has the clipping diodes just before Q2 as 4148s but tagboard has them as red LEDs (D3 and D4 on the tagboard layout).  I put the 4148s and the Red LEDs on a switch and I've been going back and forth and I am just not hearing a difference.  What exactly am I supposed to be listening for?  Or is it such a subtle difference that I am not going to hear at bedroom levels it anyway?

[radio]

As  it  is written in the description of the ROG Britannia , they are limiting the voltage at the gate(s) of the fet stages

[freshmex18]

Ah, I misread the text about the red LEDs limiting the other gain stages from clipping too hard but not at Q2.

So then, what is the advantage for choosing the red LEDs before Q2 vs. the 4148s?  I don't notice a gain drop when switching between the two

[radio]

With the silicon diodes you limit the signal at the gate at about 0.6V versus 1.2V with red leds

Instinctively I would have done the opposite so I can only assume they got a better result

simulating the 2nd triode stage!?