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So, I built a ZVex Fuzz Factory from the layout at tagboard effects (http://tagboardeffects.blogspot.co.uk/2012/10/zvex-fuzz-factory-compact-layout.html) using two AC128s from Fuzzdog and it's a lot of crazy fun. And now I want to build another one, but this time with different PNPs. What have you guys tried? What do you think is interesting or fun?

Thanks for the elucidation! 

A voltage regulator will give you 5 volts weather you power supply is pumping out 9.5 or 8 volts. A voltage divider will fluctuate depending on the supply voltage.

Yep, that makes sense.

But what I don't understand is why a voltage divider is used extensively in circuit design, but the PT2399 seems to want the steady 5v?

I suspect its so the chip can draw the current it wants, rather than relying on Ohm's law to play nicely? Also to get 5v out of 9 you need a .8 ratio of R1 to R2, which would probably require some rather funky values on one side or the other (not to mention resistor tolerances could be a bastard at that point). (Also to get the ~30mA a 2399 likes you'd need pretty small resistor values, and at that scale you'd start tipping close to the quarter watt dissipation we play with. Toasty warm boards smell lovely)

The regulator just gives you a steadier voltage, less board real estate, plenty of current to draw on, and simpler to design around.

Then again these are guesses/assumptions. There could be other, better reasons I'm not thinking of.

That sounds about right, thanks! 

Excuse the real noob question here, but I gotsta know. 

Some circuits use a 78(L)05 voltage regulator to supply +5v to a chip such as the 2399. But why not simply divide the 9v voltage with a couple of resistors and get the 5v that way?

I'd welcome some advice regarding options for good lighting and magnification for soldering.

I wear 2x (non-prescription) reading glasses for normal computer work and reading, but have to wear 3x reading glasses when it comes to closer and smaller work like soldering. The problem with this is switching between the 2x and 3x glasses all the time.

For lighting I'm currently using a small desktop halogen 20w lamp but this casts shadows, which is very annoying.

So I'm looking for a solution that provides a good light that doesn't cast shadows and a magnifying solution. I'm not sure I'd get on with a magnifying lamp as I've tried a round magnifying glass before and for me it looks distorted.

What do you advise?

Its just running the PT2399, the little L05 will work fine.

(for reference the 2399 sucks 15-30mA on average, and has an absolute max rating of 100mA)

Thanks for that. 

Wonder why they specified "7805", maybe a typo. Anyway, I'm glad I don't have to use the big guy.

I'm building the Madbean Gravity Wave from the vero layout here - http://tagboardeffects.blogspot.co.uk/2016/02/madbean-gravity-wave-earthquaker.html. I notice that this layout specifies a 7805 for the voltage regulator. Yet Madbean's schematic has a 78L05. I can't tell whether it actually needs a full 1w 7805 or whether the 100mA 78L05 is sufficient. If a 78L05 is OK, then I'm wondering why they put a 7805 on that vero layout.

In the end I just used a higher value CLR. 

I tried the light and magnifier fixture (years ago) and was pretty disappointed. Like others have already mentioned, i use a flip down visor over my glasses and totally sold. Pop it on your head and it's wherever you are ready for action, not tied down to one spot in the ability to see clearly, never in the way of your hands or taking up bench space. They are great!
dave

Which model do you use?

But I spoke too soon. 

The solution in http://www.diystompboxes.com/smfforum/index.php?topic=24291.0 worked in a small test circuit I breadboarded (https://www.build-electronic-circuits.com/wp-content/uploads/2014/04/Astable-Multivibrator-2LED.png) using a 100uF cap, but applying the same principle to the tremolo circuit didn't work. Values of 100uF and below did nothing and a value of 220uF stopped the flashing altogether. I guess it must be due to where I'm tapping the circuit for an led feed.

I stumbled on this thinking of a solution.
http://www.diystompboxes.com/smfforum/index.php?topic=24291.0

That did it! Many thanks. :-)

OK, any idea what value?

I've built the Heartthrob tremolo pedal (Schaller mod) - http://tagboardeffects.blogspot.co.uk/2012/03/heartthrob-tremolo.html - which is based on this schematic - http://www.mrdwab.com/john/temp/Schaller-Hearthob-conversion.jpg

I've hooked up an LED going from the collector of Q4 to ground so that it flashes in time with the tremolo frequency. But when it flashes it's binary on/off, meaning it's either full on or full off. It would be easier on my eye if instead it flashed full on and half off (or half on). I've seen this on a TC ELectronic Viscous Vibe pedal. Is there something I could add, like a capacitor, to achieve this?

I built the Fuzz Factory and wired it up to my testing harness on a breadboard. I then spent over an hour debugging it trying to figure out why this thing was oscillating and giving out so much spurious noise. Then I watched a YouTube demo of one, and realised that there was nothing wrong with it, that's how it's supposed to be.