ways to improve cleanup on OD Pedals

[hennesboe]

subject says it all.

are there general possibilities to improve the behaviour like increasing the input resistor? 

[Vivek]

Idea 1 : Reduce gain

Idea 2 : add/increase a compliance resistor in series with the diodes

Idea 3: Add different diodes so that they start clipping at higher input signal voltages (in conjunction with idea 1)

[hennesboe]

i actually meant the clean up by reducing the volume on the guitar :-)

[Vivek]

Yes, those steps will help an OD to clean up better while reducing volume of guitar

Or playing softly.

[Vivek]

Do you wish to post a schematic of a particular OD of interest ?

[11-90-an]

welcome to the forum...

we can't help you with your question if you don't give us any information on your OD pedal/s well, yes, lowering the volume control will help, also what Vivek said is excellent. What do you want? Another pedal? or are you looking to mod an existing pedal?

Sorry if this sounds harsh, but if you can't tell us details and such, we can't help you get what you want.

[duck_arse]

[whooska! also, welcome to the forum.]

[hennesboe]

sorry mates - i am new to the party :-)

i only have the vero layout at hand


it does sound pretty good but if I turn the volume knob a bit down, the sound gets muddy and cleanish. there is no inbetween, even if i only slightly turn it down.

long story short: it goes from full blast to kinda meh

i allready experimented with different input resistors - sadly without any success

the guitar i used to test with is a Fender Strat with SC

[amptramp]

The original schematic is here:

https://fuzzcentral.ssguitar.com/mkII.php

but it has been modified to run silicon NPN transistors and to add a 2.2 megohm resistor to ground at the input to minimize switch pop if you have true bypass switching.  The input stage has an emitter resistor to ground which would linearize it if the base was pulled up.

The design is a Fuzz Face with an additional input amplifier stage that has a 100K bias resistor going to ground but nothing pulling it up.  The input signal has to exceed the Vbe of silicon or about 0.65 volts before it sees any signal.  Very low signals will be gated off so low-level cleanup is not possible without adding a resistor from the input base to +9 VDC.  If you retain the 100K to ground, the pullup would have to be under 1.2 megohms but the input impedance is already low, so don't go below a megohm.

The nice thing about a Fuzz Face (the last two stages) is that it has a gradual slide into non-linearity as signal increases but the lower signal level is cut off by the lack of bias on the first transistor.

[iainpunk]

that's a silicon tone bender, not an overdrive!
its a fuzz, and this MK2 isn't one to clean up nicely, especially with Si trannies.

maybe just leave out the first gain stage, leaving you with a fuzz face or a TB MK1.5


cheers, Iain

[iainpunk]

The original schematic is here:

https://fuzzcentral.ssguitar.com/mkII.php

no its modded and the schematic is not in the link

but it has been modified to run silicon NPN transistors and to add a 2.2 megohm resistor to ground at the input to minimize switch pop if you have true bypass switching.  The input stage has an emitter resistor to ground which would linearize it if the base was pulled up.

The design is a Fuzz Face with an additional input amplifier stage that has a 100K bias resistor going to ground but nothing pulling it up.  The input signal has to exceed the Vbe of silicon or about 0.65 volts before it sees any signal.  Very low signals will be gated off so low-level cleanup is not possible without adding a resistor from the input base to +9 VDC.  If you retain the 100K to ground, the pullup would have to be under 1.2 megohms but the input impedance is already low, so don't go below a megohm.

it already has a 470k NFB/miller bias resistor

cheers, Iain

[nooneknows]

maybe just leave out the first gain stage, leaving you with a fuzz face or a TB MK1.5

that's my opinion too, add a wire from one end of the cap between first and second stage:



replace that 0.1uF with a 0.47uF or 1uF (film) to increase bass , that would be enough

[antonis]

it already has a 470k NFB/miller bias resistor

Which resistor is seen by signal as 100k apparent value..
( 470k / [stage gain + 1] )

So, input impedance is the parallel combination of pull-down resistor, 100k, 100k and 2k7 times h_FE