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Sorry to say in 3 posts what could have been said in 1, but just a word of advice: don't substitute a TC1044S charge pump for the LT1054 in the schematic.  That's a recipe for clock noise because it happens to heterodyne with the clock frequency driving the delay chip.

Also, thanks to you, I just learned that the centre of a barrel jack is indeed referred to as the "tip".  I've always heard those power supplies referred to by the "centre" polarity, i.e. a centre-negative or centre-positive plug.  So, you know, thanks

I think maybe the problem is that the jack on the schematic resembles a 3.5mm mono jack.  Really they're expecting you to use a 2.1mm barrel jack, where the centre is negative (i.e. like the One Spot or the standard Boss PSA power adaptor).  You are indeed OK using the OneSpot (provided you hook up the wires correctly of course ).

I put in both, actually -- there's a toggle that chooses between feedback to the first stage, feedback to the second stage, or no feedback.  I'm all about overkill!  If you don't care about choosing the stage, you could actually implement using a no-load pot, which is easy enough to make yourself, and which I wish I had thought of at the time.

I put in a mix pot as well, and that's fun too, but yeah, not for everyone.  What may be more useful is a depth control, which is pretty easy to implement -- is it in the GGG documents?

Let me know if you come up with any new mods or tweaks you want to share and I can include them in the docs!

Probably the biggest thing I've found yet is to add some resistance in series before the input of the first NE570 (this is the compressor portion) to lower the gain of the compressor stage -- I used 62k.  This will help with the BBD distortion.  To compensate, change the jumpers connecting pins 6-7 and 10-11 on the second NE570 (the expander stages) to resistors, to increase the gain -- here I used 19.1k.  I might go even higher than these values too, as I'm still getting a tiny bit of distortion when I use a guitar with P90s.  Putting it after a distortion pedal could be ghastly!

For whatever reason, as I mentioned above, my BL3102s really want a small capacitance to ground hanging off their pin 7s, so that might be useful to include.  Not sure if that's just my board or not.

Maybe you've already figured this out, but somewhere I found a mention that pin 9 should not be tied to pins 10 and 11 on the first NE570.  I also got uncontrollable noise until I tied pin 12 to pins 10 and 11 on that NE570.

Lastly, I replaced R39 with a 10k resistor and R38 with a trimpot (which will be the depth knob on the finished product) to get my depth control, and I replaced R37 and R36 with a 10k resistor and a 500k reverse audio taper pot to get a rate knob.  Note, though, that you get lots of unusable settings with these values, so I leave it to someone with better taste than me to suggest better values for those

Wait sorry I used the Nom Nom's (Phase 90's) LFO.

I built something like it with 6 stages, switchable to 4 or 2.  I like the different textures, but I rarely use all 6.  I put in a feedback control, and found that I preferred to use the Smoothie LFO and its method of using the JFETs.  The JFET circuitry feels smoother to me.  I can't remember why I picked the Smoothie's LFO, but I remember using an oscilloscope to see that it had either a larger range of rates or a larger amplitude.

I don't think there should be any power supply issues. 

Still may have been heterodyning, breadboards aren't a quiet place.

Yeah, fair enough.  I'll investigate further, but I still kind of doubt it; if it were heterodyning, I think I'd be noticing more of an oscillating pitch, whereas this is mostly static.

I don't mean to drop in and advertise... just one of those "if it were me I'd wanna know" situations

And I do!  That looks very cool.  I'll pass this time, but thanks for the offer.  Maybe if I want to build another one though!  Looks like you've gone with three mode switches, much like the original; I'm planning to go with depth and rate knobs.  I've also identified a few mods that work better for me, such as decreasing the gain on the compressor and increasing it on the expander to avoid BBD distortion, and I'll include spots for the capacitors that I talked about previously.  I'm also going to put in a CV input, to go with a tap tempo unit I built based around the TAPLFO chip.  Mostly, though, I'm looking forward to making my own layout, because fitting all the components onto the board is like crack for an old Tetris addict like me.

No it was an awful ka-chunk ka-chunk static ka-chunk ka-chunk static noise.

Yeah, okay.  I think I've convinced myself that the path through OX1 and OX3 of the MN3102 does in fact provide the negative feedback.  I was also wondering why the signal doesn't seem to be big enough to actually trigger the MN3102, but I'm realizing that it by definition *has* to be big enough, as the wave wouldn't change directions if it didn't manage to trigger OX1.

Given that, I'm thinking now that the reason the small capacitance I added at pin 7 helped to filter out some high frequency noise that was messing up the BBD.  Does this sound reasonable to anyone out there who understands this stuff better than me?

Do you have a testing rig, even if it's just a breadboard?  A third hand for soldering?

Here are some things I wish I knew when I started:

- when tinning the tips of wires, have them angled downward so the solder flows *down* toward the tip and not back toward the sleeve
- a bit of BluTac or double-sided sticky tape is your friend when soldering pots in place onto the board: put them roughly in place, stick them there with the tape/BluTac, and then solder away
- socket your ICs and maybe even your transistors -- fixing one you put in reversed is a major pain

Happy building!

As far as I can tell, this is the definitive online resource on GFS Gold Foils: http://www.offsetguitars.com/forums/viewtopic.php?f=8&t=85754&start=195

I've never tried the single coils but I have three of the humbucker-sized ferrite single coils in a Franken-Epiphone (Frankenphone?), and I looooooove them.  They differ fundamentally from the Strat-sized ones, though.  As far as I know the Strat ones are basically constructed like regular Strat pickups but voiced differently: more like a mini-humbucker, they say.  The humbucker-sized ones I have are constructed more in the spirit of the originals, with the magnets positioned beside the coil, rather than under, around, or in the middle.

No I mean the pulses that the comparator/astable part is putting out are triangle waves, whose amplitude is modulated by the Schmitt/integrator LFO output.

I don't have time for a thorough reply to your questions but...

LFO is formed by standard intergrator/schmitt at IC7, amplitude is increased via IC5, then inverted/buffered via IC6b (non-inverted version fed to IC5b so that both BBDs are swept opposingly) divided by the resistors at its output and fed in to IC6A/Q8 business which is some kind of comparator/astable thingy i'll have to look at properly later.

Cool, thanks.  Yeah that's what I had figured, which is why I'm surprised that the comparator/astable thingamabob (technical term) is putting out triangle waves.

It's still on breadboard at the moment.  I'll take a picture when I get a chance, but I doubt it will be that useful.  I'm more interested in how the circuit is *supposed* to work in theory.