Pull down resistor on BMP

Started by feddozz, March 17, 2016, 04:11:22 AM

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feddozz

Hello,

I searched this but I could not find it specifically for this circuit, and I am not knoledgeable enough to work this out. I am building a BMP ram's head from tag board effects and it has no pull down resistor. I was wondering if a 1M resistor from circuit imput to ground would be beneficial, or at least no detrimental.

In general these circuits do not seem to have it. Is there a reason?

Thanks
V

UPDATE: I searched a bit more. The lack of pull dow resistor is certailnly true for the Kit Rae schematics. I found other schematics with the 1M pull down resistor on. So it should be ok, but a confirmation from the wise would not hurt. Thanks
And "dog balls on your face"...

Elijah-Baley

In the original schematic of the Big Muffs, indeed, there's no included a pulldown resistor. Maybe you don't need it.
Build the pedal, if you get a bump when you engage the pedal you could put a resistor (1M - 2M) under Q1 transistor, from the input strip to the ground strip.
;)
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

antonis

IMHO, there isn't need for (extra)* pull down resistor in this circuit..

You can use a 3PDT switch (if you want an LED indicator) with IN grounded in bypass mode and input resistor(*) in the role of pull-down.. :icon_wink:
(I don't presume that the time between switch throws is enough to cause leakage to the input capacitor..)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

feddozz

#3
Thank you all for the advice.
>3PDT
I was plannign to use a millennium bypass 2. In this circuit, is R1 the limiting resistor for the LED?
And "dog balls on your face"...

GibsonGM

The image didn't come thru, Feddozz.   If you mean the resistor that's in series with the LED, yes that's what it is.
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MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

feddozz

And "dog balls on your face"...

GibsonGM

As I'm reading the actual schematic on Geofex, yes, that's a dropping resistor, and is required...do you want to change the value or something?

http://www.geofex.com/article_folders/millenium/millen.htm
  • SUPPORTER
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...