The Apocalypse Audio Dirty Boots Version 5 is a germanium overdrive, the fifth version of the Dirty Boots circuit. It is not a pedal most players will find on a shop wall: it is known today mainly through the vero (stripboard) layout published on the DIY effects blog Guitar FX Layouts in February 2016, which lets builders make their own version of the circuit. The layout adds an extra pre-gain pot that controls how much signal is entering the effect, on top of what earlier versions offered1.
As an overdrive, it sits in the same family as the circuits covered on the site's Overdrive Pedals page, though its germanium-based design sets it apart from the silicon-clipping designs most players know2.
Transistors and building the layout
The transistor choice is the practical question for anyone building this circuit. Builders posting on the Guitar FX Layouts page for the Version 5 layout reported success with a few different 2n586 transistors with Hfe values around 60. Silicon parts also worked: 2n3904 and 2n5087 transistors were reported to work well as substitutions for Q1, which matters for builders who do not have germanium transistors on hand1.
One builder, JDT, built the layout but used 22nF caps instead of the 2nF caps called for. He reported that the layout works, but found that the 22nF coupling caps made it sound more like a distortion than an overdrive, and that a 2.2nF input cap gave a tighter, cleaner overdrive sound. He also noted finding a V5.1 schematic with 20nF caps in front of each transistor1.
"The layout works, in any case."
That cap-value sensitivity is worth knowing before soldering: the coupling caps shape whether the build leans toward overdrive or distortion, so following the layout's stated values is the surer path to the intended sound. For a comparison of how overdrive and distortion circuits differ in character, see Distortion Pedals.
Version 5 compared with Version 6
Guitar FX Layouts also published a layout for the Dirty Boots Version 6, which the blog described as a germanium overdrive based on the first version with a couple of extra controls. The two versions differ in a few concrete ways2:
| Version 5 | Version 6 | |
|---|---|---|
| Gain pot | 25kB2 | 10kB2 |
| Tone controls | Pre-gain pot added1 | Pre-bass and post-treble tone control combo2 |
| Transistors | 2n586 with Hfe around 60 reported working; silicon 2n3904 and 2n5087 substitutions for Q11 | Germanium GT313A specified2 |
The blog author, Zach, noted that the only thing he could see happening with a 25kB gain pot versus a 10kB gain pot is that a builder will get more gain out of it2. On Version 6, he also flagged a pinout caution: the only GT313A datasheet he found was in Russian, which he could not read, so instead of assuming the pinout he went with an alternate germanium pinout in the layout. His advice to builders was to mind the pinout if using the specified GT313A transistors2.
A commenter, Mark, built the Version 6 from his own layout a few months before the post and reported liking it quite a lot2. The Version 6 layout was drawn by the blog author from information posted by RnFR2. Apocalypse Audio's circuits also appeared on the blog in the form of the Apocalypse Audio 4 Horsemen, another overdrive with a published stripboard layout.
Questions
What is the difference between Dirty Boots Version 5 and Version 6?
Version 6 is a germanium overdrive based on the first version of the Dirty Boots with a couple of extra controls, including a pre-bass and post-treble tone control combo, and its schematic uses a 10kB gain pot. Version 5 uses a 25kB gain pot, and a commenter on Guitar FX Layouts noted that a 25kB gain pot instead of a 10kB one gives more gain. Version 6 specifies germanium GT313A transistors.
What transistors work in the Dirty Boots Version 5?
Builders on Guitar FX Layouts reported using several different 2n586 transistors with Hfe values around 60 successfully. Silicon 2n3904 and 2n5087 transistors also worked well as substitutions for Q1, which is useful for builders who do not have germanium parts on hand.
What gain pot value does the Dirty Boots Version 5 use?
Version 5 uses a 25kB gain pot, according to the Guitar FX Layouts write-up. By comparison, the Version 6 schematic uses a 10kB gain pot, and the blog's author noted that using a 25kB pot in place of a 10kB one gives more gain.
Does the Dirty Boots Version 6 use germanium transistors?
Yes. Version 6 is described as a germanium overdrive, and the layout specifies GT313A germanium transistors. The blog author noted that the only datasheet he could find for the GT313A was in Russian, so the layout uses an alternate germanium pinout rather than assuming the pinout from that datasheet.
Is there a stripboard layout for the Dirty Boots?
Yes. Guitar FX Layouts published vero (stripboard) layouts for both Version 5 and Version 6 of the Dirty Boots. The Version 6 layout was drawn by the blog author from information posted by RnFR, and builders have reported successful builds from the Version 5 layout with substituted parts.
Sources (2)
- Guitar FX Layouts: Apocalypse Audio Dirty Boots Version 5, Guitar FX Layouts (tagboardeffects.blogspot.com), 2022-12-22
- Guitar FX Layouts: Apocalypse Audio Dirty Boots Version 6, Guitar FX Layouts (tagboardeffects.blogspot.com), 2016-05-07
