# Arachnid v2 PCB



## Joyner (Oct 2, 2019)

Just received the board and clock module. A few comments

For the price of the board (Arachnid) it came taped to order print out. This leaves a residue however slight. PCB's nominally are shipped in a polybag or wrapped and tapped to protect pad openings finish. 

There is no documentation with the clock module, A one-pager would certainly cover it.

The parts list has no part numbers or distributor numbers This does not suffice as a BOM one can order parts from without extra searching.


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## Chuck D. Bones (Oct 2, 2019)

Yeah, I'm not fond of the tape either, but since you should have IPA handy anyway, the adhesive is easily cleaned off.

I agree that the clock module should at least have a hookup diagram and a schematic.

Parts selection is at the builders' discretion.  You are expected to do the legwork.  Some of the harder-to-find parts like the XTAL are available for a nominal price on this site.

This place is very DIY, but if you take the time to read the forums you will find that there is TON of information there and plenty of knowledgeable folks who are happy to help if you ask nicely.

You could have had a private conversation with PedalPCB staff instead of complaining in a public forum.

Here's a little help to get you started on parts:
Resistors - get 1/8W 1% metal film from Tayda, Mouser or DigiKey.  Some 1/4W will fit easily, some won't.  Read the specs before you buy.  Pad spacings are 0.3" (7.5mm), resistors are usually placed on 0.1" centers.
Capacitors - the rectangular ones between 470pF and 1uF are film.  10% tolerance, 50V - 100V rating is good.  Get them from Small Bear, Mammoth, Tayda, DigiKey or Mouser.  The capacitors have generally the same pad spacings as resistors.  Smaller value caps are ceramic or silver mica.  Larger value round caps are electrolytic, aluminum or tantalum.


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## Joyner (Oct 2, 2019)

It is understood that it is DIY, however a parts list should include a basic description, I can figure most parts as I design pcbs for a living. You can spend a lot of time picking the right switch for example or picking the right speed grade ic. When you mark up a pcb 2-3x than it cost to make or more documentation should be more complete.


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## Robert (Oct 2, 2019)

First off, feedback is appreciated, even when it's negative.  (or constructive)

I couldn't agree more about the tape.   It's something that has needed improvement for a while but (aside from a little sticky residue) has caused no real issues so hasn't been an urgent situation.

I'll work up a wiring diagram for the clock module this weekend.    It's fairly simple and has been discussed here on the forum, but there does need to be a link on the product page with some basic usage info.  

As far as listing specific part numbers in the parts list, there isn't a particularly "ideal" solution here with the exception of a few specific parts.    Parts preference (and sourcing) varies from person to person.  Some folks (myself included) love Tayda, some would prefer Mouser / DigiKey, and others order from various eBay dealers.     There's no one-size-fits-all part number that spans across all dealers, especially with passive components (which make up the majority of the components on these boards).

In cases where a _specific_ part is required I do try to list sources, but generally leave sourcing components up to the builder.   

I do have a plan for parts sourcing info for the projects, but at this point it's just a "crazy idea" that hasn't made it much further than the brainstorming phase.


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## Chuck D. Bones (Oct 2, 2019)

I think if you provide the part numbers that you would use to build a pedal, that should suffice.  Anyone who wants to can use those parts numbers and be good to go.  Anyone who wants to sub their favorite parts is free to do so.  We can look up the specs for the part numbers provided in the build docs and know exactly what size will fit.


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## Barry (Oct 2, 2019)

Granted a little more info on builds would be a benefit, but I must say the volume and quality of boards here far surpasses most sites I've shopped


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## Joyner (Oct 2, 2019)

Thank you for the timely response, it is very much appreciated. As it is my mantra that if I can be critical of something I can apply as much energy in praising as well. Ying and Yang.   The ship time was quick and put in the mail very shortly after placing the order. The board is neatly arranged, decent quality and will suit my purpose for modding to a prototype idea. As I am evaluating several mixed signal asics, this is very helpful.







Robert said:


> First off, feedback is appreciated, even when it's negative.  (or constructive)
> 
> I couldn't agree more about the tape.   It's something that has needed improvement for a while but (aside from a little sticky residue) has caused no real issues so hasn't been an urgent situation.
> 
> ...


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## Sasan (Nov 6, 2019)

Could someone please tell me what potis do what?
I couldn't find anything regarding which one on the PCB is ctr1,2,3, mix & vol....thanks


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## Robert (Nov 6, 2019)

Looking at the PCB, the top row is CTRL 3, CTRL 2, CTRL 1.   The bottom row is VOLUME, MIX. 

This would be reversed when looking at the face of the assembled pedal.

The function of each of the three CTRL pots depends on the algorithm.


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## Sasan (Nov 6, 2019)

Robert said:


> Looking at the PCB, the top row is CTRL 3, CTRL 2, CTRL 1.   The bottom row is VOLUME, MIX.
> 
> This would be reversed when looking at the face of the assembled pedal.


Thanks! This was exactly what I was looking for (before creating the decal)


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## Sasan (Nov 7, 2019)

Just wanted to quickly say, I finished building the Arachnid and tried all three EEPROMs that I've bought (Module 8, Octagon & Spacialist).
This thing is KILLER! I'm loving it!!!! 

Is there any way to include more than one EEPROM into the enclosure and make it switchable? Like Drolo's Molecular Disruptor where you have a tiny switch to decide which module you want to activate?


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## phi1 (Nov 7, 2019)

@PedalPCB Shared a trick *here* for selecting between 2 eeproms. I tested it on my previous arachnid build, and will consider modding it permanently. He mentions a rotary sw but a toggle should work fine too. 


I’m currently working on a new arachnid and plan to make a daughter board out of perfboard with two eeproms hooked up to a switch using th method. @PedalPCB teased making a pcb for this, but I’m not sure if there’s been any new development. If he did, it’d need to be carefully planned to fit nicely in the arachnid in a 125B, which would probably be the most common application.


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## Sasan (Nov 8, 2019)

phi1 said:


> @PedalPCB Shared a trick *here* for selecting between 2 eeproms. I tested it on my previous arachnid build, and will consider modding it permanently. He mentions a rotary sw but a toggle should work fine too.


Thanks for that! Unfortunately, neither my English nor my electro-technical skills are sufficient to understand what he wrote


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## phi1 (Nov 8, 2019)

Haha shoot.  Well maybe the pcb for it will come out soon.

Basically:
PCB socket New Eeprom Socket 1 New Eeprom Socket 2
Pin 2          ->       Pin 2                 ->         Pin 2
Pin 3          ->       Pin 3                 ->         Pin 3
Pin 4          ->       Pin 4                 ->         Pin 4
Pin 5          ->       Pin 5                 ->         Pin 5
Pin 6          ->       Pin 6                 ->         Pin 6
Pin 7          ->       Pin 7                 ->         Pin 7
Pin 8          ->       Pin 8                 ->         Pin 8

("->" means they are connected)
(Pins 2, 3, 4 and 7 are all ground, so wiring can be simplified)

Pin 1 from PCB connects to nothing.

New EERPOM Socket 1: Pin 1 -> 47kΩ resistor -> 3.3v (Pin8)
New EEPROM Socket 2: Pin 1 -> 47kΩ resistor -> 3.3v (Pin8)

SPDT Toggle Sw Lugs
*      |             |             |*
     /              \             \
Pin1             GND        Pin1
EEPROM1                     EEPROM2


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## Sasan (Nov 9, 2019)

Awesome. Thanks for the detailed description. Can’t wait to give it a try. Thanks a lot!


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## pgodfrin (Dec 14, 2019)

Greetings (new member, first time Arachnid builder)
Just got a v2 arachnid, I can't seem to id how the on-board eeprom is switched on. Can someone shed some light on that for me please?
phil


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## phi1 (Dec 14, 2019)

Do you mean the patches built into the fv-1 rom? The fv-1 datasheet has all the info you need.

Pin 13 of the fv-1 determines if it uses internal patches (built in to the fv-1) or external patches (on the eeprom chip). Pin13 low (ground) is internal, high is external. 

on the arachnid there’s a resistor that connects to pin 13. You can loop a wire onto that leg of the resistor and connect it to ground with a switch to get the internal rom patches.

if you build the arachnid stock, the eeprom chip will be active. The discussion above in this thread is about how to select between 2 external eeprom chips.


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