Question about resistor in boost section of LaVache

Stompboxes circuits published in magazines, books or on DIY electronics websites.
Post Reply
User avatar
fishfude
Breadboard Brother
Information
Posts: 65
Joined: 14 Mar 2012, 20:18
Has thanked: 37 times

Post by fishfude »

Hi Folks,

I have a question about the purpose of the 3.3M resistor (R5) in the boost section of the LaVache pedal from Madbeans. Its a variant of the Lovepedal Les Lius Overdrive which I believe is built upon the Electradistortion.

Here is the schematic

When the switch is open its just a huge resistor in parallel with R4 and when the switch is closed its bypassed completely.

What am I missing!?

Thanks!
Attachments
LaVache.pdf
(1.16 MiB) Downloaded 74 times

User avatar
marshmellow
Cap Cooler
Information
Posts: 469
Joined: 16 Aug 2007, 07:31
Location: Germany
Has thanked: 20 times
Been thanked: 127 times

Post by marshmellow »

C2 has very low impedance for audio frequencies, it bypasses R4 for AC signals in order to maximise the gain of the stage. With the switch open, R5 is in series with C2, so C2 is practically out of the circuit. The resistor is there to connect the second leg of the capacitor to ground, otherwise it could plop when the switch is engaged.
Last edited by marshmellow on 08 Apr 2017, 12:21, edited 1 time in total.

User avatar
phatt
Transistor Tuner
Information
Posts: 1224
Joined: 04 Aug 2010, 05:17
Location: Morayfield SE Qld AU
Has thanked: 8 times
Been thanked: 343 times

Post by phatt »

it's just there to discharge the capacitor otherwise you would get a loud pop when you close the switch. :thumbsup
Phil.

User avatar
fishfude
Breadboard Brother
Information
Posts: 65
Joined: 14 Mar 2012, 20:18
Has thanked: 37 times

Post by fishfude »

Thanks for the info folks!!

Post Reply