Uknown Diagram Component

TylerW

Hi guys,
Today I decided to try and make my own pedal and went for the classic big muff pi.
I'm using a stripboard and I'm following this diagram(http://www.turretboard.org/wp-content/uploads/2011/10/J-Mascis-RedBlack.pdf) the only problem is that I can't identify one of the components.
The one I can't identify is the dark grey circles found at GL,IM,QL and SM.
If anyone could tell me what those are I would greatly appreciate it.

Thanks!

Gearhead

Does turretboard.org not mention 4 diodes that you can choose yourself? At first glance these would be clipping diodes, afaIk you can vary the tone by changing the diodes there. They probably list some commonly used parts...

psyx

I built a BMP variant some time ago... The transistors dont seem to be marked. A good choice of transistor which offers a bit more gain is the 2N5089... And as far as the clipping diodes go, the ones I used were 1N4148B... Which are commonly used for this application

Edit: The 2N5088 is used in the NYC RI BMP AFAIK... It offers slightly less gain.

peterleroux

Those look like the right positions for the four diodes, and I don't see them anywhere else on the board. The rule with a
Big Muff is that there are no rules, over the years EHX has used so many different parts and values, so feel free to substitute until you find a sound you like

Johnny-B

TylerW wrote: Hi guys,
Today I decided to try and make my own pedal and went for the classic big muff pi.
I'm using a stripboard and I'm following this diagram(http://www.turretboard.org/wp-content/uploads/2011/10/J-Mascis-RedBlack.pdf) the only problem is that I can't identify one of the components.
The one I can't identify is the dark grey circles found at GL,IM,QL and SM.
If anyone could tell me what those are I would greatly appreciate it.

Thanks!

These are clipping diodes in the feedback loop. They create the distortion by chopping off the top and bottom of the signal waveform. I suggest you use 1N4148 or similar. If you want I have dozens of vintage 1N4148. If you would like to collect 4, you are welcome.

TylerW

Thanks for all the help guys! Can't wait to get started ?

Nicholas-L

In most cases yes the 1N4148 Diode is what you will use, but you can use whatever diodes you have or what you can find.
If you want to experiment a bit try BAT46 diodes or 1N914/BAV99 diodes.

Or even give them a swap and mix up.

But whatever you do, just enjoy yourself. ?