tone bender mk1 help

Started by dirt_mcgirt, July 26, 2014, 09:30:23 AM

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dirt_mcgirt

I built a tone bender mk1 using the Gary Hurst Tonebender MK1 from the Tagboard FX site.
Everything is working and sounds great except...

2 problems:

Volume is very low. To get unity the volume pot has to be turned all the way, so there's no headroom.

When bypassed there is a very quiet fuzz sound. As if the pedal was effecting maybe 5% of my clean sound.
It will go away if I turn the Attack all the way down.

Any ideas?

JebemMajke

Have you measured your transistors?

Have biased them properly?

dirt_mcgirt

I got a MK1 set of OC75s from smallbear.

dirt_mcgirt

i assumed i could get the set and drop them in and it'd be fine.

....and yes, I'm new to building pedals.

JebemMajke

Change resistors that are biasing q2 ( 21,2 k i guess ) and q3 ( 15k ) with 50k-100k trimpots.

And than max the attack and tune q2 to 8,3v and q3 to your liking ( 3-4 volts for me ).

That's how I did with mine.

Also, if you experience a some kind of high pitched noise just place 1M resistor and 1n cap right after the input to the ground.


dirt_mcgirt

Thanks!
I'll look into this.

I'm still kinda confused with the little bleed through when bypassed.

vigilante397

I've never built a Tonebender, but I have had bleedthrough when bypassed on a build before. My problem every time was that the switch was wired wrong. The best way is to wire it true bypass and ground the effect input when the effect isn't activated.

This is how I wire mine:

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"Some people love music the way other people love chocolate. Some of us love music the way other people love oxygen."

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Electric Warrior

This is how vintage units were wired:


To bring up the volume, remove the 47k in parallel with the level pot.