Hi everyone and sorry for the intrusion, but i really need your help.
I'm building a sort of preamp/di for an acoustic guitar based on the DOD 410 (for the preamp part), plus a 5 band eq and a balanced line-driver (courtesy of Th-custom).
Now, i have two main issues:
1 - the guy who asked me to build this pre, asked also to put an hi-pass filter at the beginning of the signal chain; i'm relatively a newbie at building pedals and above all at electronics. I've searched online but i didn't found something really relevant to guitar pedals, and the little information i reached are way too complicated for me.
Can you, if it's possible, explain me some way to implement such filter, from the simplest (on-off with fixed cut value) to the most complicated?
2 - i'm building the pre itself (DOD 401) using the veroboard layout from GuitarFXLayout (http://tagboardeffects.blogspot.it/2013/10/dod-studio-bifet-preamp-410.html) and, as i'm using a 5 band eq after it, i just want to bypass the circuit tone control. How can i obtain this result?
Thank you in advance for the answer, i'm sorry for my incompetence throwing shadows on the whole diy community (no ok, now i'm exagerating ;D )
I'm not super familiar with the circuits you're building (maybe post a schematic if you get a chance), but you can often tailor the bass response of a circuit by changing the value of the input capacitor (almost always the first cap in the circuit). I lower value will result in less bass. You could put two or three caps on a switch and use that to change the value of the input capacitor, which will in turn effect the amount of bass passed to the circuit. 0.1uF is usually "full frequency". 0.068uF or 0.033uF are common in circuit intended for guitar. Halving the value will increase the cut off frequency by an octave. It might take some experimentation to find values that you like.
Quote from: Aleph Null on June 17, 2016, 05:44:05 PM
I'm not super familiar with the circuits you're building (maybe post a schematic if you get a chance), but you can often tailor the bass response of a circuit by changing the value of the input capacitor (almost always the first cap in the circuit). I lower value will result in less bass. You could put two or three caps on a switch and use that to change the value of the input capacitor, which will in turn effect the amount of bass passed to the circuit. 0.1uF is usually "full frequency". 0.068uF or 0.033uF are common in circuit intended for guitar. Halving the value will increase the cut off frequency by an octave. It might take some experimentation to find values that you like.
Thank you so much pal :D !
I've never considered to modify the input cap, i'll try something like this, but i've noticed the input cap it's 0.01uF, so i don't know if i have some space of manouver here.
Anyway, here's the schematic, if it helps:
(https://ironman28.files.wordpress.com/2014/11/dod410.jpg)
Credits to IronMan Elec
The actual capacitor values and cut-off frequencies will depend on other particulars of the circuit. The values I gave were just common examples. Halving the value should still raise the cut-off frequency one octave. So maybe try 5000pF (0.005uF) and 2500pF (0.0025uF), or something in that neighborhood. You might need to go higher or lower depending on what you are using the preamp for. A HPF can be useful for bass, guitar, or even mandolin, but the ideal cut-off frequency will be different for each instrument.