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I'm looking for a LM308 in the UK to do this project - http://tagboardeffects.blogspot.co.uk/2015/10/giant-hogweed.html - does anyone know a supplier preferably in the UK?

I think I've probably learnt more about pedal building when something's gone wrong. For example, how to measure voltage readings, why those voltages are what they are, and the importance of really checking your soldering. ;-)

I've chosen to go with 1N5817 in series.

I recently built a Timmy clone and it had one on the vero layout, but my latest build (Lunar Module Deluxe) didn't have one, so I simply soldered one in line with the positive 9v lead.

I've built the Lunar Module Deluxe pedal here - http://tagboardeffects.blogspot.co.uk/2012/02/great-modern-take-on-classic-fuzz.html

Schematic - http://4.bp.blogspot.com/-jtoWoktqNs4/T0AQyiJsOUI/AAAAAAAAA8A/U5vbjO3-zig/s1600/lm_scheme.gif

Here's the thing. If I wind up the Pre-Gain and Fuzz controls and put my finger on the metal body of Q1 (BC109C) there is a loud hum and noise, like that when you touch the end of a guitar jack with your finger. Should a transistor react in this way?

Wondering what the thinking is on this for 9v circuits. Do you strap a diode across the +/- terminals or do you use a (Schottky) diode in series with the positive supply? The pedal I'm building doesn't have one on the board so I'm wondering whether it's best to add a 1N5817 in series. Or maybe nothing at all is OK?

The problem is solved. 

Well, you see it was like this...nah, it was my own dumb fault. You know when I said "I've double and triple checked all solder joints, vero breaks, and jumpers". Wrong. I needed to quadruple check them, because a small smidgeon of solder was shorting out a couple of vero strips. So, it works now. And I shall stand in a corner with a dunce's hat on for the next day. But better than that I shall learn to more closely check my solder work next time.

Thanks to all who tried to help. 

And I really do need to get that audio probe together...

The schematic is here http://the7line.clan.su/_pu/0/92883033.gif

An audio probe sounds like a good idea. What do you recommend?

Picture of the board to follow (better in daylight).

At this stage I suspect a duff PT2399. So I'll try and find a simple test circuit that uses one and breadboard it.

I've just completed a build of the Mad Professor Deep Blue Delay as per this vero layout - http://tagboardeffects.blogspot.co.uk/2012/02/mad-professor-deep-blue-delay.html (the vero layout is the first one there) and the delays don't work.

• I'm getting a clean, dry output. The volume control works, but there are no delays.
• The "Delay", "Mix" and "Repeat" controls do nothing.
• I've double and triple checked all solder joints, vero breaks, and jumpers
• I get the same dry output when I take the PT2399 out of its socket as when it's in its socket

Could it be that I have a dead PT2399? Is there any way to test this chip in isolation?

Voltages are (using a 9v battery which measures 8.8v):

PT2399
1 - 4.97
2 - 2.49
3 - 0.00
4 - 0.00
5 - 3.47
6 - 2.49
7 - 4.46
8 - 4.59
9 - 0.07
10 - 4.45
11 - 4.42
12 - 0.06
13 - 1.66
14 - 4.87
15 - 0.05
16 - 3.58

OP275
1 - 3.51
2 - 3.56
3 - 3.56
4 - 0.00
5 - 3.55
6 - 3.55
7 - 3.56
8 - 7.06

78L05 regulator
I - 7.29
G - 0.00
O - 4.97

I've become a massive fan of the blue monolithic capacitors. Small form factor, non polarised, and at higher values fit far better into cramped vero builds.

As a general rule, I use them for 100nf, and 1uf (simply because I picked up a 100 pack of each!), but the 1uf are a great size.

"blue monolithic capacitors" - Is that a brand type?

Thank-you all for the advice. :-)

As a relative newbie to pedal building, I'm trying to use components that won't degrade the audio signal or be microphonic. I've already de-soldered and removed some cheap ceramic discs and electrolytics that I got off eBay and replaced them with decent NP0/C0G multilayers and Panasonic electrolytics. It's been a challenge finding the right quality caps and small form factor!

I guess my question, now, is, is it OK to use general purpose 100nF multilayer ceramic caps in those two positions?

Specifically, these - https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=65_75_70&products_id=219

Thanks for the info, guys. Much appreciated. 

The schematic is this one - http://the7line.clan.su/_pu/0/92883033.gif

The two 100nF caps are strapped across pins 9/10 (OP1-OUT and OP1-IN) and 11/12 (OP2-IN and OP2-OUT) of the PT2399. So I'm guessing they're quite important?

I'm building the Mad Professor Deep Blue Delay clone from this vero layout - http://tagboardeffects.blogspot.co.uk/2012/02/mad-professor-deep-blue-delay.html (the first vero layout there).

There are two 100nF capacitors at the bottom right of the larger IC, that look like they are ceramic types. Ideally I would like to use good quality polyester film capacitors, or NP0/C0G multilayer ceramics. But I can't find any small enough to fit in that tight space. I've been told that using plain ceramic caps is bad for audio.

So, what are my options?

If you are happy with the coverage and durability of the Rustoleum, you could use the same stuff for your current project, then dull the gloss finish with some #0000 steel wool (or the equivalent synthetic 3M pad). You might want to add a few more coats if you go this route to avoid burning through the clear coat.

Yes, that's a possibility. Thanks. At this stage, I'm not sure about the durability of Rustoleum Crystal Clear, so I'd be interested to hear what other people use for clear coat sprays.

Hi all, I'm new to pedal building and new to this forum. I recently got into this by taking the challenge of building a pedal and learning about electronics. You can read about my efforts over on the Fretboard forum - http://www.thefretboard.co.uk/discussion/121368/c18q1-learn-electronics-and-build-a-pedal/p1

So, here's my question - I'm using Posca pens for my (cheesy) pedal enclosure artwork and for my first pedal I applied a few layers of Rustoleum Crystal Clear Gloss spray (https://www.amazon.co.uk/Rustoleum-AE0040001E8-400ml-Crystal-Clear/dp/B001W03PRM). This is OK, but I'm wondering if folks here have any other recommendations? The pedal I'm currently working on is housed in a Hammond 1590BB Black enclosure which happens to have a nice matte, textured finish. I don't want to clear coat this with a gloss spray, so need to use something matte. Any tips or recommendations?