Re: Jumper points for Rat tone section?
Posted by nocentelli on Aug 29, 2020; 8:54am
URL: http://guitar-fx-layouts.238.s1.nabble.com/Jumper-points-for-Rat-tone-section-tp49113p49124.html
Welcome to the forum!
It would be a lot easier to advise you about modifying a specific layout if you actually linked to the particular layout you are referring to: There are two layouts for the original rat on tagboard fx, and neither have C9 marked. C9 may well be on some schematic for the Rat, but you haven't linked to that either.
If you want to hook up some different tonestacks so you can evaluate how they sound, you need to connect them directly between the 4u7 output cap (this node also has a pair of diodes to ground) and the gate of the JFET.
The 1k5 resistor, 3n3 cap AND the 22n cap of the original circuit will all influence the tone and should therefore not be included if you want to get a true representation of the effect of a new tonestack on the sound, e.g. the 22n limits the bass response, so if you try out a bax active bass+treble stack with the 22n in place, you will not hear the full response of the bass pot.
Using the layout below, you can use the filter1 wire for the "send", but the return needs to go direct to the gate - There is a space on the last/far right-hand column, above the 9v wire, where you could bring this return, but that also leaves a connection to ground through the 22n and 3n3 caps which will reduce the high end slightly, even if the original filter pot is not in circuit. You would need to snip off one or both of the caps (just the 22n would do). You must check that all of the EQ circuits you test have an output cap and omit any ground connections on the output of any EQ circuit that would end up in parallel with the JFET's 1M ground resistor.
I can totally understand the desire to tinker: However, it is MUCH easier and more reliable to experiment on a small breadboard where no soldering is involved. Testing out circuits by modding a working vero always carries the risk that it will become non-working.
URL: http://guitar-fx-layouts.238.s1.nabble.com/Jumper-points-for-Rat-tone-section-tp49113p49124.html
Welcome to the forum!
It would be a lot easier to advise you about modifying a specific layout if you actually linked to the particular layout you are referring to: There are two layouts for the original rat on tagboard fx, and neither have C9 marked. C9 may well be on some schematic for the Rat, but you haven't linked to that either.
If you want to hook up some different tonestacks so you can evaluate how they sound, you need to connect them directly between the 4u7 output cap (this node also has a pair of diodes to ground) and the gate of the JFET.
The 1k5 resistor, 3n3 cap AND the 22n cap of the original circuit will all influence the tone and should therefore not be included if you want to get a true representation of the effect of a new tonestack on the sound, e.g. the 22n limits the bass response, so if you try out a bax active bass+treble stack with the 22n in place, you will not hear the full response of the bass pot.
Using the layout below, you can use the filter1 wire for the "send", but the return needs to go direct to the gate - There is a space on the last/far right-hand column, above the 9v wire, where you could bring this return, but that also leaves a connection to ground through the 22n and 3n3 caps which will reduce the high end slightly, even if the original filter pot is not in circuit. You would need to snip off one or both of the caps (just the 22n would do). You must check that all of the EQ circuits you test have an output cap and omit any ground connections on the output of any EQ circuit that would end up in parallel with the JFET's 1M ground resistor.
I can totally understand the desire to tinker: However, it is MUCH easier and more reliable to experiment on a small breadboard where no soldering is involved. Testing out circuits by modding a working vero always carries the risk that it will become non-working.
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