Hi all, i've had a bit of a nightmare with my Parentheses build so I've decided to start again and build it section by section (Octave, boost then rat). I've got to the end of building the octave section and what im hearing into the octave pot is a single oscillator type sound where the pot controls the pitch. This is my first octave build, so I'm a little puzzled as to why this is happening. Is this the sound I should be getting? or is there a problem with the octave section?
SOLVED Parentheses Octave
- Thread starter tmfoh
- Start date
benny_profane
Well-known member
Are the Vf of the diodes matched? Also, the resistors and caps in parallel in that rectification stage should be as close as possible.
Last edited:
Chuck D. Bones
Circuit Wizard
When you get done with your build please be sure to read this post and vote.
benny_profane
Well-known member
I should’ve been more clear there. First, I mistyped and meant Vf for the diodes (but I think you got the meaning). Second, with the other components, you want to try and match the capacitance for capacitors and resistance for resistors. Basically you’re mirroring the circuit path and you want it to be as similar as possible. Do you see the part of the schematic that I’m talking about?
benny_profane
Well-known member
Yeah, those are the values I was referring to. If you're getting a ring mod or purely distorted sound (this type of octave circuit is not clean nor is it precise) rather than an octave fuzz type effect, that's not caused by the resistor/capacitor tolerances. You should evaluate your soldering and the transistors used.
Also, how are you testing each block?
Also, how are you testing each block?
Right, I'm with you. I was thinking that the pot was a control for the octave rather than a blend between a dry signal and the effected signal. With that in mind, i think the octave section is finished. I'm at least happy with what I'm hearing.
So I'm planning on building the boost section (i guess that's next in the order) next and going through it with an audio probe just to make sure there nothing going wrong before that point. It's long but it keeps me in check, also a nice way of learning the circuits in better detail.
benny_profane
Well-known member
The boost Is actually after the distortion. The octave pot controls how much signal comes from the octave circuit and feeds it into the distortion channel (ref the construction around OCT_3 and the OCT_2 input into the distortion circuit). That’s why it cannot be used in isolation (but you can turn it on/off—switching between OCT_3 and OCT_1 connecting to OCT_2). The boost takes either the dry signal or the output of the octave/distortion channel. Since it has a dry input, it can be used in isolation.
