Building The Appendage. Share your Experiences

Scott Stites · Posted: Tue Dec 07, 2010 8:50 am Post subject:

Cool! That is an awesome build, too. I've got mine in a rack mount, but I'd like to put it into a portable case.

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

OK, calibration time has come, and it appears I will have some questions.

Firstly, I am using the first version of the build documentation, is there an updated version?

Step 1. Easy, no sweat.
Step 2. I might not be understanding here. Beginning with a .008v reading and no gate LED lit, I cannot seem to get the LED to light nor the jump towards rail voltage IF I am pressing the ribbon. No amount of adjusting seems to get there while pressing down. However when I release, the voltage rises and the LED lights and stays that way. Without pressure I can find the trip point easily. Checking the upper part of the ribbon seems moot as the lowest part is not behaving properly.

If I am to understand correctly, the gate LED should light only while pressure is applied and NOT stay lit after(this would make sense but ...)

Step 3. I skipped to 3 just to see what its all about... VR2 adjustment to -4.75v no problem. Now the adjustment of VR3 will not go into positive voltage, it winds down to 0.00v but no positive gain no matter how many turns. I know VR2/3 are to have some interaction, I can fond no way to get a positive voltage from VR3.

I will leave it there for now. hopefully someone can sort me out.

thanks.

Scott Stites · Posted: Tue Dec 07, 2010 3:43 pm Post subject:

We should probably check to see why problem 1 exists first.

The LED and gate signals are ultimately derived from a comparator determining if voltage is present on the ribbon input.

1. First of all, let's see if the ribbon voltage is correct. If there is no pressure on the ribbon, pin 10 of U13 should be 0V or so. Once you press on the ribbon, that voltage will jump up. The lower you are on the ribbon, the lower that voltage will be.

2. If you get the correct voltage response at pin 10 of U13, make sure that pin 8 of U13 follows that voltage faithfully.

3. If step 2 is OK, make sure the voltage is making it to R47, which connects to pin 2 of the comparator U12 (this would be the end of R47 facing the edge of the board - sorry, didn't mark that).

4. If the voltage is making it to R47, then Pin 1 of U12 should go low when the voltage on R47 exceeds the voltage as set by VR1. When you adjust VR1, you are setting the trip point for the lowest voltage produced by the ribbon.

5. If that is happening, check TP7 to ensure that it is actually tripping high when Pin 1 of U12 trips low. If it is not, check the comparator reference voltage (produced by R54 and R22) on pin 5 of U12. This should be around 1.4 or slightly less (assuming a 15V supply is being used).

Appendage_Comparator.pdf

Description:

Download

Filename:

Appendage_Comparator.pdf

Filesize:

36.8 KB

Downloaded:

1290 Time(s)

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

Hmmm... Pin 10 is 7.97 v+ with no pressure. Dips to 4.5v+ with pressure at low point, back to 7.97 highest point. Pin 8 is following right along.

ADDENDUM:
Tiny tiny teensy short on 2 of the last 3 wires I soldered for the softpot...DUH

getting better now I hope. Be back for more later I am sure.

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

90% there now. TFS is adjusting funny but getting useful results nonetheless. Will deal with them later.

Can already tell this will be amazing.

Scott Stites · Posted: Tue Dec 07, 2010 8:01 pm Post subject:

Wow, cool. I saw the voltage readings on the ribbon, but I couldn't reply because I had to go to my son's Christmas concert. What did you figure out was the deal?

I can dig the cal being a drag - it can be a pain in the ass. I helped Scot Solida with his, and, after over a year since I calibrated mine, it kicked my ass, and I was following my own directions.... Laughing

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

Shorted pads on the board for the ribbon.

EVerything is pretty much sorted, except for the TFS, both modes. Unable to trim the double pressure part. Giving me 13.86v for the widest spread. Trimmer doesnt move it either direction.

Got it closed back up for the night, too much fun to fiddle with anymore without making space sounds.

You have made a wonderful thing Scott.

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas

Scott Stites · Posted: Wed Dec 08, 2010 5:45 pm Post subject:

Well, thanks guys. I suppose it would be a toss-up between tar-and-feathers or sainthood, depending on which side of the cal you're on. Laughing

Seriously, though, the same offer as I've made on the Klee stands to any builder who hits a point that seems insurmountable - send it to my place and I'll get it working one way or the other. For wife-related reasons, the only thing I require would be return postage.

I hope you all enjoy your Appendages as much as I enjoy mine.

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas

Scott Stites · Posted: Fri Dec 10, 2010 8:42 pm Post subject:

Nothing I've done kicks it out like that last link you sent, me, Scot!

As for my offer to help out on any Appendage probs, one should reach me at scott(dot)stites at birthofasynth dot com.

You can see my email less cryptically spelled out at the bottom of my home page here:

www.birthofasynth.com

I'll get the message.

Photon · Posted: Thu Feb 24, 2011 1:39 pm Post subject:

I found a possible error in the build manual. Figure 7-6.
The illustration contradicts the text.

fig.7-6.jpg

Description:

Filesize:

128.25 KB

Viewed:

2350 Time(s)

This image has been reduced to fit the page. Click on it to enlarge.

Scott Stites · Posted: Thu Feb 24, 2011 5:33 pm Post subject:

Yipes!

I believe the illustration is correct. The text is not....

Thanks, Photon!

philpeery · Joined: Nov 08, 2006 Posts: 137 Location: new jersey, usa

Hey Everyone!

I am getting ready (finally) to build my appendage (hmmmm...)! I have the 500mm spoftpot that I bought originally when I got the PCB, but my buddy just GAVE me a 1000mm softpot that they got when cleaning out an electronics lab that was shutdown where he works. Are there any issues or mods that need to be made to use the 1000mm? It would be WAY cool to be able to use it!

Best Regards,
Phil

State Machine · Posted: Sun Jul 10, 2011 8:03 am Post subject:

Hi Phil

philpeery · Joined: Nov 08, 2006 Posts: 137 Location: new jersey, usa

Hey Bill!

Thanks for the info on the softpot! I have started loading resistors on my boards (figured I'd do both at the same time), let the fun begin!

I will post pics of my finsihed appedages (careful, now!) when they are done!

Regards,
Phil

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas

I'll be bringing and playing the Appendage to the E-M festival in Kansas City in two weeks. The Appendage is awesome.

marvkaye · Joined: Mar 14, 2011 Posts: 225 Location: Fla

marvkaye · Joined: Mar 14, 2011 Posts: 225 Location: Fla

While I'm here asking questions, here are a couple for you, Bill.... is there a thread around where you describe your build a bit? I'm curious about how you implemented the CV/Trigger-to-MIDI section of your panel. It's very impressive and I'd really like to learn more about it. I'm also curious about the panel itself... did you have it done by FPE, do it yourself, or what? It's really nicely done. I've been saving up to add a CNC router to my small machine shop so I can start doing my own engraving (and drilling without having to fiddle the dials on my milling machine) and am anxious to learn about tooling, in-filling, etc (among other things). Thanks again for making this new run of Appendage PCBs happen, it's really appreciated.

____________
<Marv>

State Machine · Posted: Thu Jul 14, 2011 9:18 am Post subject:

Hi Marv

State Machine · Posted: Thu Jul 14, 2011 9:26 am Post subject:

marvkaye · Joined: Mar 14, 2011 Posts: 225 Location: Fla

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas

Scot Solida · Joined: Oct 24, 2009 Posts: 100 Location: Hutchinson Kansas