Add line-in to Big Muff Pi

[served]

Hi,

Is there a way to add Line-in to big muff Pi?

The signal is too hot for the pedal at the moment.
Maybe I need to add another pot to control the input volume?

Any ideas?

[R.G.]

Maybe I need to add another pot to control the input volume?

[served]

Ok thank you!

I am just struggling with this topic all the time. I think I should start reading something that would explain this

[Mark Hammer]

The first stage of the BMP is a gain stage.  The "Sustain" pot after that adjusts how much of the maximum output level of that gain stage you are going to use to drive the clipping stages.

There are 2 strategies you can adopt, either alone or in combination.

1) Increase the emitter resistor to ground from whatever it presently is (depending on issue, somewhere in the 100R-150R range) to perhaps double that value or nearest common value (e.g., 150R would be transformed into 330R).  This will reduce the gain of the stage.

2) The 100k Sustain pot could be replaced with a 51k fixed resistor and 50k pot, or an 82k fixed resistor and 25k pot, or even a 91k resistor and 10k pot, to mimic a 100k pot that can never be turned up more than 50%/25%/10%.  This will improve the "dialability" of the Sustain pot when signal levels are too high, by taking a portion of the range and distributing it across the full rotation of the pot.

[therecordingart]

Hi,

Is there a way to add Line-in to big muff Pi?

The signal is too hot for the pedal at the moment.
Maybe I need to add another pot to control the input volume?

Any ideas?

A few come to mind. Balanced or unbalanced line level?

[served]

Its unbalanced.

So I will try with Mark Hammer solution.
I would like to adjust the level so I will defenetly use a potentiometer.

As I would not like to mess with sustain control. I will put a potentiometer to emitter-ground.

[served]

I will add Tonepad schematic.
http://tonepad.com/getFileInfo.asp?id=95

I have the second version, The Green Big Muff.

So I added 1k Potentiometer and 220 ohm resistor instead of 390 ohm resistor to Q1.

I tried it with guitar, but I actually don't get the results that I would like to get. But still there might be huge difference with line level signal.
I will try it tomorrow.

[PRR]

> I added 1k Potentiometer.... I tried it with guitar, but I actually don't get the results that I would like

Guitar into 1K really sucks.

1K is kinda too low for Line. 10K or 100K pot is a better bet.

> and 220 ohm resistor instead of 390 ohm resistor to Q1.

That raises gain in Q1, you want less gain.

AFAICT, you don't need Q1 for Line input. It isn't a heavy distorter or tone-bend. Its main point is to boost-up weak guitar to near-Line level so that Q2 will be over-driven.

One switched jack, one 0.1u cap, one 1Meg resisor. The existing Sustain knob can adjust Line level down so that Q2 is distressed less or more to taste, same as it does for guitar from Q1.



You may have other uses for a Line-To-Guitar attenuator; but if you only drive your Muff, this is the simplest way.

[served]

Hi PRR as always good information.

This I didn't think of before. Probably because I remembered this wrong. I thought that Q1 is affecting how this pedal will sound.
I will give this a try in a few hours.

Perviously I added [220ohm and 1K pot series] instead of [390 ohm]. So that I could not turn it to GND and lower than 220 ohm is too low anyway. That way I got more sweep for my pot.