Wednesday, March 19, 2014

x0xi0 #330-133.5 : Full Build. Next Steps

The x0xi0 mid-build in 2011.
As you can see, this x0x build hit a wall. I followed through the original documentation and built the whole kit in place of doing it in parts. I then had to shelve this project since there were some gaps and errors in those PDFs. I've done numerous other projects since.

A recent x0x repair for someone else inspired me to finally put this project to rest. This has turned out to be advantageous since Brian's documentation is now into its fourth revision and appears to be quite complete. I've been able to do a sweep of updates with little risk and the results have paid off.

2014. It looks sad now but all will be well soon.
So, now that I've reviewed where I left off, here's where it stands. In the interest of extreme experimentation I've socketed most of the transistors and a few key components:

  • R47: This extends the low range on the x0xi0
  • R61: this controls the ENV MOD setting when Brian's pot is set to 0. 10K is the default in the document.
  • R97: as per my original build, this adds a 'natural' boost to the resonance. Some people add a pot for this. I don't see the point. 10K is what's in the document. My last build provided boost at 9.2K. My final decision for this build is pending. What I want is the same behaviour as the the last build. 90% turn in the pot gives my a proper 303 calibration. The extra 10% is the boost and nearly reaches self-oscillation. More than enough for me!
  • C21: This add more bass boost and in this case has an effect on VCF Out as well.
The LEDs were also never placed so this task is under way now. here's a dorky photoshop file I've kept on hand to experiment with color combinations:

I'm using the same set of LEDs as the last build but different values appear to be useful here. These will be more intense than the first build but I have time to try out a few combinations.

Blue: 5.6K Ohm
Purple: 100 Ohm
White: 2.2K Ohm

3mm - pending delivery of custom LEDs:
Blue: ?
Purple: ?

There's also loads of wiring to finish up. My pre-assembly calibration succeeded though. VCO, VCF, and ENV all check out.

It's getting there. I want this finished so I can finally have some fun with it.

Friday, February 4, 2011

x0xi0 #330-133.5 : Custom Board VCO

I took a shot at just populating the VCO. This is how the Adafruit documentation suggests one goes about it. As you can see though, this is quite different! The VCO is no longer in a cluster like the original.

So yes - it may make sense to build the x0x outright, then calibrate later (and hopefully not have to troubleshoot). The multiple x0xio headers do allow one to calibrate this though. There are so many jumpers that it must allow access to it. I just need to check.

Thursday, February 3, 2011

x0xi0 #330-133.5 : Custom I/O Full

Finally back in the game. A solid draft of the documentation finally made its way to the ten of us using these PCBs so some of us are getting a head start while the manual is being finalized.

This build approach is different since one drops each component in by type first. I'll need to do testing later because the boards are really only populated fully in the in the end rather than being able to test sections incrementally. This concerns me a little bit because it may complicate troubleshooting. The documentation may eventually include test procedures in phases but we'll see.

Note that my own sourced parts, namely the resistors, are also 1/4W instead of 1/8W. I purchased all my parts before getting the mod kit. I hope I don't kick myself later for replacing them with the smaller ones. It appears I have clearance in the I/O but it's also quite obvious that the through holes and spacing on the PCB were design for 1/8W.

Thursday, August 5, 2010

x0xi0 #330-133.5 : Custom I/O Power Supply

Despite the documentation being in development I went ahead and started building the PSU of the custom PCB. The key step in even this first task was preparation time. Reading through the forum threads, some of Brian's emails and notes, and cross checking the original parts list with the x0xio parts list were all part of the lead up to just get this in place. I also created a separate version of the original parts list that flags all the omitted and replacement components. When these come up I'll then know to reference to the x0xio list for further instructions. I've posted it to download here as a temporary measure.

All in all the actual build steps were quite similar to the original x0xb0x but as you can see from the photo there are some changes that need to be made. For one, there is the additional 12V supply in place that handles the mods' requirements. Secondly there's the need to keep this I/O low profile since the mod board will be stacked above it. Third, as far as I can tell there needs to be some space under the voltage regulators to slide in the heat sinks. You can see how there's just enough space there for between the regulators and the PCB. Fourth, like the mod boards, some spots are tight. You can see how my two capacitors, C7 & C8, are slightly angled. They're just a little wide for one another there. I had to set them properly ahead of time so they don't land into place with extreme angles.

Little details like these will be all too easy to miss. On the one hand it's probably smartest to wait for the install manual. Brian's existing manuals are very clear in that respect. On the other hand I couldn't bear having this kit sit in pieces here for any longer. I had to see some action and move forward. The next step is to sort the parts properly for each section and do that dirty work up front. That should make catching unique details a little easier.

Thursday, July 8, 2010

x0xi0 #330-133.5 : Top Panel 'Full Kit' Mod

It took about 3.5 hours to pull the top panel together. Like the I/O mod, the steps were relatively simple. Brian has laid the documentation out in a pretty straightforward way. Three components were missing: one 103k capacitor and two 22K resistors. A quick trip to Supremetronic sorted that out.

There isn't really any testing or calibration one can do until it's wired up to a power supply and x0xb0x so there will certainly be more work to follow once the new x0x is built. I'm hopeful that everything is in order here. It looks absolutely amazing. Dropping the top panel on there gives a quick glimpse of the power of this ├╝ber 303.

Friday, June 11, 2010

x0xi0 #330-133.5 : I/O Mod Board

Now that 99% of my parts were here I couldn't resist and got started on the new build. I spent the first while organizing some of the parts (especially the resistors), reviewing the documentation, and taking notes on some of the support issues a few builders have a come across. At the moment it's a bit of a sea of confusion in some areas but the I/O and Full mod are well documented. The custom PCBs for the main x0x, not so much. Brian suggested I get started on the mod boards first so I took the advice when it was given :)

Generally speaking it was a relatively painless task but a few things cropped up. I've made a habit of socketing ICs and transistors but the layout and spacing for some of these parts doesn't really allow it without making very specific cuts and sizes on the sockets. Working on the I/O was a good introduction for what's to come. In future I'll need to try surrounding parts and see if it even fits. Some of the transistors are also not set up in a linear configuration so a basic socket strip that's been cut won't work. The BC547B has been set up this way. That's a bit disappointing but again, at least now I know that this is the case. Since I'm using the custom PCBs the power supply is being installed there and being left blank and omitted here.

So all in all ~ this build needs one's utmost attention!

Tuesday, June 8, 2010

x0xi0 #330-133.5 : Step Zero

In fall of 2009 I started to get the itch to take another run at a new x0x build. My intent was to build 2 or three of these anyway so Brian Castro's x0xio kit was the right fit: it's more complex, expands the x0x's capabilities, and still retains the original clone's accuracy in the process. He also produced a first run of custom PCBs in April 2010 specifically for his mod so I'm among the first five or so builders putting it together. Needless to say I'm an early adopter on this one! As such the documentation is still incomplete. I'll need to tread carefully so I don't botch up the project. My kit arrived at the beginning of June. It was a patient wait but well worth it.

Goals for this project

Just the x0xio kit. The main board an I/O are equally large as the spread in my self-sourced build.
My goals are somewhat similar to my self-sourced x0xb0x. I still want to maintain some control over the final cost. I managed to avoid several suppliers by using reliable alternatives: James from Willzyx, the new x0x supplier taking over for Adafruit, Brian, the source of the mod itself, and my local electronics supplier. I'm also able to spread some of the costs from my original self-sourced x0x since I purchased parts for multiple units at that time. This project is primarily based on BOM v2.1 and a dizzying list of mod parts from the x0xio site. I'm less concerned about the hours spent this time around, though I may choose to keep tabs on it.

The serial number

Between my self sourced x0x and this modded one, I also came across an incomplete original run x0xb0x, number #330. It needed repairs, testing, and the like. I was able to get it back up and running with a fair bit fussing around. I decided that #330 could be used as the core for this build. The x0xio is dramatically different but I think it'll be worthwhile to have key parts of the original kit be used here. This way its roots are still planted in adafruit territory. So the number represents #330, #133 of the x0xio kit, and number 5 for the custom PCB set.