PCB Mania No Noise Gate - Dang Useful Utility Pedal!!!

Readers of this blog should be well aware at this point that I'm a fan of high gain distortion and fuzz pedals. I'm also a fan of vintage transistors actually used in those high gain pedals. While you can get some absolutely amazing tones using high-gain distortion effects, you can also get a lot of tones you don't actually want. The most common is a hiss (high or low pitched) or a hum, though there are other unwanted noises that can detract from your sound. Given the prevalence of the issue, it should be unsurprising that there is a solution out there - Noise Gates. Many companies have produced a variety of pedals that essentially act as a high-pass filter - louder tones, i.e. what you actually want to hear, sail through while the softer hiss tones are filtered out. In this entry, I build PCB Mania's No Noise Gate - which is based on the Electroharmonix Noise Gate. The current EHX Silencer pedal is a bit more capable as it includes an effects loop rather than simply acting as a filter.

The No Noise Gate is a fairly simple PCB and it is a quick build. The documentation calls for an LM4558 IC, but the originals are hard to find. That being said, the JRC4580 is a reasonable replacement (it's probably overkill!), though there are others. There are a lot of good op-amps out there, so finding one that will work if you can't find the 4558 shouldn't be too hard. It is worth experimenting with several - especially since one typically connects them through a DIP-8 socket and changing out the IC can be done easily if one is careful

In terms of the economics associated with this particular build - it falls short of a lot of other builds I've done. The EHX Silencer retails for around $75 new, and it includes an effects loop, so I'd put the value of the version sans loop at, say, $60. While it can be built for less, this is actually the first pedal where I thought it might be worth a comparison to the actual BOM.

• PCB - $9.00 (€7.90)
• Resistors (22 1% metal film @ an average of $0.08 each) - $1.76
• Film Capacitors (6 @ an average of $0.15 each) - $0.90
• Electrolytic Capacitors (6 @ an average of $0.12 each) - $0.72
• Transistors (Two 2N3904, one 2N5485) - $4.95 (most of the cost in the 2N5485)
• JRC4580DD + DIP-8 socket - $2.40
• 3PDT Stomp Switch - $3.69
• In / Out Jacks (Switchcraft 111X) - $4.56
• DC Jack - $1.25
• LED and Bezel - $0.31
• Enclosure (Drilled and UV Printed Tayda 125B) - $14.49
• 500K Log Potentiometer - $0.75
• Knob (I used a nice aluminum one) - $2.20
• Wiring allowance - $0.25
• TOTAL:  $47.23

So, the fully marked up cost is still about 25% off retail. That being said, there are a lot of places where one can save some money. If you drill and paint your own enclosure (or buy drilling and UV printing in bulk), the enclosure cost can drop quite a bit. The enclosure itself, even with a powder coat, is only about $6, and you can get the drilling and UV printing down to $2.00 each if you're in large bulk. You can also save on the transistors and knobs - but most of the rest is pretty bare bones unless you're dealing in thousands of passive components.

Of course, any direct retail cost comparison ignores one very important facet of the "do it yourself" route - the fact that you get to personalize the pedal to your specific taste. I'm a huge fan of Tolkien's The Lord of the Rings, and I decided to do an homage to the scene where Gandalf faces off against the Balrog in Moria. As the purpose of the pedal is to keep all of the "evil noise" from "passing" - well, the quote is fairly obvious. 

Though you can't see it, to get the enclosure to work the way I wanted took a little extra effort. The original set up of the board calls for an A500K potentiometer with the knob squarely in the middle of the enclosure. That would have covered up the lovely Balrog, so I moved the knob to the top. So I could still solder the pot to the PCB - thus providing support for the PCB and meaning I didn't have to set up rails or other standoffs - I substituted the A500K for a C500K (inverse log) so the knob would still function normally and not be reversed.

The pedal itself works amazingly well. I'd tested it outside the enclosure while my main computer was down and I was immediately impressed by how much of the hiss it took away. I'll likely be permanently integrating it into my pedal train for those times when I have the gain turned up really high, which if I'm being honest, is a lot of the time!