• International Mail Service Disruptions
    A large number of international shipments have been disrupted by the COVID-19 pandemic. International shipments may experience longer than normal delivery times.
    Read more…

Looking For Digital Octave up

RobertJay

New member
I am looking for an Octave Up PCB to be used in a combo pedal for bass distortion. I am unhappy with Green Ringers and other Octave Fuzz circuits. I want Digital Octave up with blend feature, or at least octave up and dry signal being out out.
What happens when I turn the Dist down on the Parentheses Mini Fuzz? Is it clean octave?
Any Suggestions?
I was referred here to look at the Arachnid V2 with custom EEPROM patch - PIT001, but can't find it...
and another recommended I look into the FV-1 boards to use as a dual pitch shift for octaves, but can't find that specifically either.....
 

RobertJay

New member
The Parentheses isn't what you want... The octave in that is essentially a Green Ringer.

This is the Arachnid project:

And this is where you get the custom EEPROM with the Dual Pitch Shifter algorithm:
Thank you. Such a big help. With that extra chip, I noticed the options to purchase and have installed up to 10 digital effects, yes? And would these different effects all work independently one at a time? Or can I have the pitch shift, with chorus and a digital delay all at the same time off of this? I'm assuming it's a one at a time selector switch type of use.
 

PedalPCB

Administrator
Staff member
You can have up to eight. One at a time, selected by the 8-position rotary switch.

What zgrav is referring to is a fair amount of latency in the pitch shift algorithm. It's not horrible, but it's noticeable.

It won't perform in the same league as a DigiTech Whammy or anything like that, but it's pretty much the only true clean octave you can get as a DIY project.
 

RobertJay

New member
Sorry for not being clear. I should have said latency instead of delay.
I was also just turned on to the Octagon multi fx build. It boasts 8 point rotary switch but doesn't offer one with the 20 dollar chip. Comes with?
And I see more than 1 build can get me there. The Arachnid with the eeprom or the Octagon that comes w the ability built in?
 

zgrav

Well-known member
the arachnid is the PCB that uses the FV-1 chip but it does not include the eeprom chip with the 8 different sound programs. you order one or more of those separately and select the programs from a list that you want to have on the eeproms.

the octagon is the same PCB but it comes with one eeprom chip that has 8 programs already on it. you can also order extra eeproms with custom programs to use with that board by changing the eeprom in the socket on the board.

when you order the PCB for an FV-1 project you can order it with the FV-1 chip already soldered in place by just paying the extra charge for the FV-1 chip.
 

RobertJay

New member
Sorry for the confusion, but do both of these pcb's require the EEPROM IC? I see spots on each board for one, The arachnid has advises that the additional IC must be purchased, the Octagon comes pre loaded, but how? Is an EEPROM included? not needed? please advise.
 

RobertJay

New member
And... Do both pcb's require the purchase of additional 8 point rotary switch? The Arachnid offers the 2 dollar addition at purchase the Octagon does not.
 

phi1

Well-known member
I think zgrav summed it up well, but it is confusing, I had to ask a lot of questions the first go too, So no worries.

both require purchase of the fv-1. Both require the 8way rotary switch. The octagon includes the eeprom as part of the order (Hence the higher cost). For the arachnid, you need to go the the eeprom section and build a custom eeprom (pick out your patches). You can also order more eeprom chips from that page and swap them in and out in your build, just be sure to put a socket where the eeprom chip goes.

the arachnid, octagon, module8, and spatialist reverb are all the EXACT same pcb and are constructed the same way. They all have the same build doc. The only difference is the eeprom chip where the code for the patches is stored.
 

RobertJay

New member
Man O Man! Thanks. I thought so, but have to ask to clarify. Now that we have that established. If you can believe it, I'm interested in this just for the digital octave capability. It's very hard to find a good octave circuit that isn't fuzz, needs to be played around the 12th fret and the bridge pickup to hear the effect. I'm building a prototype for a bass distortion pedal with octave and chorus, maybe even some delay. Too bad I can only get 1 effect at a time out of this. haha. Now, if I only want to use this circuit for the octave up and dry signal.... Do I even need the rotary switch? I'm sure I can place a jumper between 2 pads and call it a day... thoughts?
also, I would say that there is absolutely NO way to use more effects at one time, but if I could.... How?
Thanks again to all, very helpful.
 

phi1

Well-known member
For sure, you could leave out the rotary switch and diodes. This would default the fv-1 to read patch 0. Just load that the pitch shift patch as patch 0 on your custom eeprom.

there’s a lost the Pythagoras board, which is designed to only have 3 modes instead of 8.

look into the organ donor project, it has octave and kind of a chorusy type thing built in, check out the videos of the eqd organizer.

you can’t use more than one patch at a time. But, you could write a patch that has multiple functions within it. There is some limitation in the amount of code you can jam into one patch, but I think octave up and chorus or delay would be very doable. There is also the limitation of only 3 controls. But there are some ways to work around that.

I’ve gotten pretty handy at writing fv-1 code from scratch, PM me and if that sounds interesting to collaborate on.
 

RobertJay

New member
More answers and another question. Leave the diodes out? Sure, I won't be using them. I was going to ask about these builds and their instructions. Do they come with any? Is there a guide to tell a builder what components are being used for what? Do I need the Crystal if not using the reverb? What about the 78L33. And as with the diodes, if omitting them... a jumper? or simply omit? Suppose the schematic would tell me, but why not ask to confirm?
Yes I am curious about custom eeprom code. Will discuss. Thanks
 

phi1

Well-known member
Study the fv-1 datasheet (just google for it) to understand how each component in the arachnid functions. The Pedalpcb build docs do go into any detail about the “why” because they’re assuming you’re building as designed.

but basically, you need the crystal and 3v3 supply to run the fv-1 regardless of patch. For single patch 0, just omit rotary and those 9 diodes, no need for jumpers.
 

zgrav

Well-known member
If you are not an experienced builder, I would suggest finding the project that best fits your ideas and build it according to spec. the differences in parts cost for what you would change or leave out are very small, and the likelihood of messing something up when you build it is much higher if you are changing things along the way. It is a bit more difficult to get help from others on the forum if you need it if something is not working.

the suggestion to look at the Organ Donor was a good one. take a look at the project, look at the build doc and you will see you basically get a parts list and schematic. you do not get an assembly guide, nor something thatanswers the kinds of questions you are asking and explains how the circuit works. you can find general information like that if you do some searching on the internet. see if you can find some videos of the organ donor being used, or for the EQD Organizer that it is similar to. https://www.google.com/search?client=firefox-b-1-d&q=eqd+organizer

After you successfully build some kind of FV-1 pedal you will be in a much better position to know if the latency in the chip is acceptable for how you want to use it, and you will have an idea of what other kinds of effects, if any, you would like to have in your next version of the pedal.
 

phi1

Well-known member
Good advice from z. If you get a custom eeprom, consider trying out 2 different chorus types to see which you like.

MOD001 is a standard type chorus, where pitch vibrato is mixed which dry signal.

UNI001 is a different type of chorus where a slight detune up and down is constantly applied, but it doesn’t warble back and forth. Comes from the unison Double tracker project, which is not a copy but some similarities with the Keeley 30ms pedal.
 

daeg

Active member
A couple months ago I was playing around with FV-1 code to use an envelope controlled rectifier to hide the latency of the crossfade pitch-shift / digital octave algorithms.

Basically, a (filtered) Green-Ringer esque sound would be over your attack, then fade out as the delay based Pitch-Shift faded in. No perceived latency. Gave the attack a touch of that screaming analog octave punch, but without the nasty intermodulation on sustained notes, double-stops, chords, etc that make analog octaves unusable in most musical contexts.

Got busy with work and never finished it. I'll be moving onto the Daisy soon and probably won't look back.
 
Top