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Oh right, I should have mentioned that I omitted all of the FET switching stuff.  What I've got on the breadboard is more or less the same as the schematic on this page: http://topopiccione.atspace.com/PJ18BossDC2.html

I decided that it was finally time to tackle The Big Boy, the chorus pedal I've been curious about since I was 15 years old and reading Guitar Player magazine: the Boss DC-2.  I've got it working on my breadboard, but I hoped someone out there would be kind enough to explain how the clock circuits feeding the BBDs work.

I've been working from the schematic that's floating around out there (http://www.freeinfosociety.com/electronics/schemview.php?id=123), substituting BL3207s and BL3102s for the BBDs and clocks.  I'm using TL072s for all the op amps, and BC327s for the PNP transistors in the clocks.  Once I sorted out some small issues, it made sounds, but those sounds were awful noises.  Poking around with my scope, it appeared that the problem was that the clock wasn't producing a usable pulse to feed the BBD.  By dumb luck, I decided to probe the signal fed to pin 7 of one of the BL3102s while the other one was connected to one of its outputs, and all of a sudden the output pulse was nice and clean.  Figuring it must be the parasitic capacitance of the probe, I added small capacitances to ground from pin 7 of both BL3102s and now it works.

So, my question to you is: why??  What did this do?  How does the clock work at all?  I'll break down some of my questions into point form, referencing parts by their numbering on the above linked schematic, and focusing on a single delay line, IC9.

- I get that op amp 6b feeds an attenuated copy of the LFO signal to the non-inverting input of 6a.  I *think* that Q8 forms a current source, that charges the 100p capacitor I guess?

- Probing the output of 6a, I see that it produces a triangle wave of constant absolute slope (i.e. positive and then negative with the same amplitude) but with wavelength and amplitude changing according to the LFO signal.  I didn't understand why the op amp's output could be anything but square, as it looks like it's wired up to work like a comparator, but am I correct in guessing that, by feeding the output of 6a into the oscillating circuitry of the BL3102 and back out through some other stuff into the inverting input, there is somehow negative feedback occurring here?

- Moreover, the triangle wave coming out of 6a doesn't go very high or low.  The datasheet of the MN3102 (I can't read the full datasheet of the BL3102 as it's in Chinese) says that the input to pin 7 registers high as a signal between Vdd-1 and Vdd, and low as a signal between 0V and 1V.  The triangle wave doesn't span this range, so how is it driving pin 7?

- Lastly, what did adding the small capacitance to ground at pin 7 do?  Why does it magically work now?

Any and all help is welcomed.  I didn't find anyone doing a real circuit explanation/analysis of this in any of my Googling, so whatever you can provide is greatly appreciated.

I'm torn, because that is undeniably sweet, but on the other hand, that is some painful rubato

Cool, glad it worked   I actually thought you'd put the LED and CLR between the collector and +9V, but that's good too.

If you're using a standard NPN bipolar junction transistor, and the emitter is also grounded, I think it should be OK as no current will flow from base to emitter, and so no current will flow from collector to emitter either.  Someone please correct me if I'm wrong though!

But: won't the extra transistor/resistor/routing take up as much space as the extra row of lugs on the 3PDT switch?

Perhaps something based on the Millenium bypass?  You could hook up a transistor with the base connected to the "off" position lug and to a resistor to +9V (or whatever your supply is).  When the boost is off, the base is pulled to ground and shuts off the LED; then, when the boost is on, the base is left at +9V and the transistor turns on.

Very very cool!  How much storage does the code use up on the Arduino?  Like others, I'm wondering about attempting to use an ATtiny chip or a bare uC, but the Arduino Nano looks like it would probably be just as small in the end.

When I wrote that I thought I didn't need it for either, but I double-checked and saw that it's required for the Aquaboy Deluxe.  The Total Recall doesn't use it.

Just checking here, are the MN3101s at smallbear also from Xvive?  If not, I can still use them with an MN3005 right?

I'm mostly looking at building an Aquaboy Deluxe and/or a Total Recall, so it doesn't matter either way, but I thought I'd check.

Whichever way you go, wiring up a blend control somehow (maybe a simple buffer on a little piece of perfboard to go before the circuit and split the signal?) would be a great thing for a bass version of any of those pedals, I think.

Re: 100n cap from pin 1 to ground, I think it's probably to provide extra filtering right next to each chip to keep that digital noise from getting to other parts of the circuit.

Your bridge problems are a standard rite of passage for Jazzmaster/Jaguar players   The posts are indeed meant to float in the holes.  This is the main "feature" of that vibrato system; relative tuning is supposed to be preserved across strings, unlike with other whammy bars.  Something like the Mastery bridge does away with this, and people love that, but honestly I've found the stock bridge to be more robust than I expected (once I got it set up), and I never have problems with it (anymore).  Part of the characteristic tone of these ridiculous beasts is that hollow plonk that comes from the (lack of) coupling of the bridge and the body, I think.

As for the rattles and what not, it's pretty standard to have to shim the neck so that you can raise the bridge more.  (This is why Fender has several JM/Jags in production that have an angled neck pocket.)  This gets you more down-pressure on the bridge, which keeps things a little more solid, and also helps keep the strings from jumping out of their slots.  You'll have to find a balance between raising the bridge itself and raising the saddles.  I tried raising the saddles a lot initially, and found that the intonation adjustment screws themselves were now at a steep enough angle that they were touching the resonating strings!

Now: even after having done this, you might still get some rattles in the bridge.  Typically this is because manufacturing tolerances are working against you and the grub screws don't fit very precisely in the saddles -- this can also be a problem with the screws that adjust the height at the bridge posts.  When this happens, the screws can rattle so much that they start to turn, and the saddles (and the bridge) will lower themselves while you play!  No matter; a little teflon tape and perhaps a dab of vaseline will put the kibosh on that.  I think some Loctite Blue will also do the trick.

Yep just replied.  Let me know if you didn't get the message!

Also I should mention that though I wrote the code in Arduino, I was really only using the Arduino platform itself to program the ATtiny chip, following these instructions: http://highlowtech.org/?p=1695

Another thing I forgot to mention above is that there's another annoying bug on the board: the diode footprints all came out in the opposite orientation to how they're supposed to be.  I think I must have designed the board right after upgrading KiCad, and a bunch of footprints got garbled -- only noticed after I put the thing together 

My original introduction thread got wiped in the server crash.  I'm Richard and I'm from Vancouver, BC.  I got started building pedals about a year and a half ago, after I ran out of guitars to rewire, and I haven't looked back.  This forum has been a huge help to me and I've really enjoyed using the project documents.  I like to start from scratch and create my own layouts, but I usually start from a Madbean schematic.  I've built a Kingslayer, a Sunking, a NomNom, a Current Lover, a Collosalus, an Afterlife, a Cupcake, a couple of Mudbunnies (Mudbunnys?), and a Retrograde.

My original introduction got some replies from other Vancouver/Canada/nearby people.  Hoping to get some replies from them again!  Maybe we should get a Vancouver meetup going sometime.

Thanks everyone for your kind words

Very nice! Its nice to see some uC implementations on pedals. I've been tinkering with Arduino and tap tempo for some time now. Basic idea that I have is to have a LCD-display that shows tempo and maybe some additional information and rotary encoder so you can adjust the tap tempo on the fly.

Yeah that would be awesome.  I didn't have enough IO pins on the ATtiny to try anything like that, and I was concerned about the amount of time it would take to perform the analogue read on a delay pot, but I'm quite sure if you went with a more powerful uC that would be no sweat

Also, can we talk about how your Flickr username is Dickolas Wang for a minute. Do you have a secret career in film you'd like to tell us about? 

Haha, I haven't really gone by that in a few years now (you know, since I joined the workforce), but that's when I signed up for the Yahoo/Flickr account.  No film career, just a slightly unfortunate first name and some university buddies who, in retrospect, were mildly racist.  Eventually I decided to get out in front of the message.  Until Google Photos makes it easier to embed pictures, I guess D to the W rides again.

So the Arduino sketch and schematic will be posted soon? 
Would really like to use my Arduino to do more then flash LEDs!

Here you go:

https://drive.google.com/folderview?id=0B8Qn1G0R3IKVNWZwVkFOUFhReHc&usp=sharing

I also have four more boards that I'm probably not gonna use... hint hint

We want clips!

I don't really know the first thing about video editing, but if I remember I'll ask my friend to help me throw something together.  Overall though it basically sounds like a Hamlet Delay, so check out Jon's demo videos.  There is a bit more cold digital noise when the tap-tempo is engaged, but nothing serious, and it sounds a little noisier/distorted when both PT2399s are engaged.