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Doh. It's in the august issue, like the OP said. Must.read.before.posting...

After mounting pots on the enclosure and adding a knob I find the knob stands proud of the enclosure - I'd prefer the base of the knob to be flush with the enclosure if possible, and some options I've been musing are to either use a hacksaw to remove the top part of the pot shaft (which would probably lead to unevenness between different pots on the same pedal) or to pad out the underside with 1 or more washers (which will lose internal enclosure space).

How do others get the base of the knob close to the top of the enclosure, or is a gap considered inevitable? I've not seen any from my usual supplier, but is it perhaps possible to buy pots with shorter shafts ?

You can browse the September issue at http://www.premierguitar.com (upper right of the page).

I briefly browsed but couldn't see the article, I guess the one on the news stands is the October issue? Publishers seem to have a flexible approach to what the current month is.

Last night I learned that if you make enough trace cuts with a drill bit, you not only get a piece of vero that's ready to solder, but also a giant blood blister on your thumb. Yeesh.

For track cutting, ages ago I bought a stripboard cutter and I since forgot where I got it from. It's like a drill bit with a handle, like:

http://www.amazon.co.uk/dp/B0071KZVV0

OTOH you could also make a handle for your drill bit.

I know how you feel, I built my first projects last week, and I got into a real mess with one of them.

But I ordered simple project boards - only taking on the ones marked 'noob' in the projects page in the hope that I wasn't jumping into deep water. If these are your first projects I'd say definitely take it slowly. And read loads about it beforehand. And then read some more. Make it easier for yourself.

I found the Rangemaster with the Road Rage to be a good basic build pair, where I didn't feel excessively out of my depth, but I still learnt quite a bit. But YMMV, the voltage inversion baked my noodle somewhat.

And yes, failure is definitely part of the process. A really important part - failure, and then failing more. Fail FTW. Because that's a great way to learn.

Verify that your trimpot is actually working ... measure the ohms across the two lugs that aren't connected. This would be a weird case, but hey, weird things happen. Use the continuity setting on your multimeter (beep) and follow the circuit for the power and ground connections. Make sure everything's actually connected -- and also make sure nothing's connected that shouldn't be. Your eyes can lie to you.

Thanks Jon, I checked the trimpot, and it checked out ok-ish, it's measuring below the advertised 20k (circa 16.8k) when at its max resistance, but with its 10% tolerance and my general mistrust of my DMM's accuracy it probably scrapes a pass. I rechecked continuity and that seems fine.

Following up on the power/ground suggestion I took another look at my (battery only) test 'rig':



Having read the very helpful 'basic testing rig' post pinned at the top of this Tech Help section I put the makeshift one aside, and made a wallwart-driven test rig with an enclosure I hadn't drilled right and a Road Rage board that I had ordered at the same time as the Mangler, to see what improvement a proper +ve ground with -9v supply would make:



Using that I found I got much better results with the Mangler (I could hear some low signal and some fuzz, but still had the biasing problems. I wasn't sure about the transistors I had swapped in as an earlier test (and forgotten to swap out afterwards) so I put back the transistors that I had originally intended to use, that were within the right hfe ranges, retested, and woohoo! it sounded right! I could then bias the voltage to 4.5v - it's sounding great now, like a fuzz should   

I'm still not sure why the rangemaster board tested and worked fine with my original makeshift battery-driven test rig, and the mangler wouldn't, but it could be that there were multiple issues at play with the mangler. In any case, really pleased now that it's working, very many thanks for your helpful suggestions!

Now to figure out how to properly finish an enclosure...

Try flipping your transistors and report back.

Thanks for your reply, I tried flipping them and I get pretty much the same readings from Q1 and Q2. I'm not sure what to make of that though, as I thought a transistor had only one proper orientation.

This isn't my first build, but while the previous one went swimmingly (rangemaster) the mangler is causing more issues, meaning I'm having to seek the collected wisdom here... thanks for reading...

Project Name: Mangler

General Description of the problem:

No signal being passed through the circuit apparently, and odd biasing readings

Steps I've already taken:

The first thing I tried was to bias the board - my multimeter on the test point shows about 9v which isn't right...
Checked wiring, part values, and orientation (although the positive ground is a tad confusing I think orientation is ok)
Checked my soldering (no bridges or problem joints s far as I can tell)
Tried putting several different pairs of transistors in the sockets, same results
Tested continuity with a multimeter as far as possible using the schematic, no problems there
Done as much testing of on-board components as possible considering they're soldered in place (though my crappy DMM doesn't stretch to capacitor testing)
Replaced all caps and the diode
Tested the test rig, in case that's a problem, using another positive ground effect (rangemaster), and that's working ok.
Tried playing the guitar with everything connected - direct from guitar to amp works fine but no signal with the effect in-between.
Tested Battery (which is fine)

Any substitutions:

None, all component values are as listed in the Mangler PDF

Voltage readings:

    Q1    Q2
E   0     0.01 
B   0.16  0.01
C   0.01  8.98

The 20k trimpot doesn't reduce the voltage much to Q2, I think I'd need a higher value pot for that if there's not some other problem. But I'm guessing the real problem is elsewhere, and with luck not between the keyboard and the chair.

Does anything leap out as being an obvious problem to anyone? I keep coming back to it and drawing a blank - I just can't see what the problem is. Any pointers from you more experienced folks would be much appreciated. I've included some links to pics of the board.