Author Topic: Input impedance mod for Total Recall?  (Read 158 times)

BramP

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Input impedance mod for Total Recall?
« on: September 03, 2017, 04:38:35 PM »
Hi everyone, newbie from the Netherlands here, just built my first 2 madbean pedals, the Aquaboy and the Total Recall, and I love 'em both. One minor gripe is the lack of headroom/ quickness to clip in my Total Recall. Now I understand that this is quite like the original, but I´ve also read somewhere on this forum that there is an ´impedance mod´ involving an 1M trimpot. Does anybody know where I can find this mod? Or explain it to me?

Thanks in advance and much appreciation for your time.

Bram

madbean

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Re: Input impedance mod for Total Recall?
« Reply #1 on: September 03, 2017, 06:55:43 PM »
You could use a 1M trimmer in place of R2, but it's easier to just raise the value to 220k - 470k.
I own madbeanpedals (duh). I am part owner of Function F(X).

BramP

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Re: Input impedance mod for Total Recall?
« Reply #2 on: September 04, 2017, 05:11:21 AM »
Cool thanks, I will try this! Is there any audible 'downside' to raising the resistance in that place? Maybe a bit of a noob question, but I'm curious what would happen when you put too great a value of resistance there, or put in other words; would there simply be softening of the input volume as you increase resistance or are there certain frequencies that get dampened more than others?





madbean

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Re: Input impedance mod for Total Recall?
« Reply #3 on: September 04, 2017, 06:32:24 AM »
There will be less gain available with the Level control but there should still be a lot on tap. A 220k or 300k should be enough. If you go too high then low Level settings might be a bit less dynamic but this also depends on the guitar pickup output to some degree.
I own madbeanpedals (duh). I am part owner of Function F(X).

BramP

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Re: Input impedance mod for Total Recall?
« Reply #4 on: September 04, 2017, 07:22:35 AM »
Ok thanks, I am using it with fairly high output humbuckers like a Bare Knuckle Ceramic Nailbomb/Juggernaut and a Gibson Burstbucker Lead Pro and I noticed that having the volume on the guitars almost closed gives 'clean' undistorted repeats. I'll swap the resistor tonight and see what happens.

Many thanks for your quick responses and awesome PCBs!

Am kinda curious about that upcoming Reverb thing....

Greetz,

Bram