English Channel - Vox Top-Boost In A Box

From the excellent project at Run Off Groove, here's a box of Vox that, erm... rocks!

Based on a '61 Vox AC30 Top Boost, this overdrive gives all the rich, sparkling break-up of that classic amp.

Highly tweakable tone with Volume (Gain), Bass, Treble, Treble Cut and Master Volume controls, and trim pots on all the FETs for perfect biasing. All in a package that'll fit a 1590B.

WARNING: This circuit requires precise biasing of the FETs, so a Digital Multimeter is required. It'll be all-but impossible to do it by ear, hence the difficulty rating.

Pot spacing is 21mm - take that into account when choosing your knobs.

Board-mounted pots for minimal wiring and easy enclosure mounting.

If you want the PCB without parts there's a link for that at the bottom of the page.

Partial kit: PCB, all board-mounted components, pots.

Full kit: As above, plus footswitch and appropriate daughterboard/components for your selected bypass type (see Downloads section for details of those), jack sockets, DC socket, battery snap, hook-up wire, LED.

Enclosure (pre-drilled) is available as an option with full kits, and will not take a battery. Knobs are not included.

Inspired by: English Channel

Difficulty: Hard

PCB size: 100 x 22mm

Knobs required: 5

Enclosure: 1590B

Download INSTRUCTION PDF

Product Code: EngChan

Brand: Pedal Parts

Weight: 130.0g

Product Condition: New

Kit type*

£39.60 inc. tax

£33.00 ex. tax

? Tax based on United Kingdom.

Customer Reviews

3 review(s) posted (write review)

Fun challenge!
"Had fun building this pedal, though not without a few challenges along the way. By user error, I did not read the instructions for the standard true bypass switch, and so needed to run an extra wire for the led resistor. A few niggles in the instructions, the vertical format instructions seems to correct it, but for this one it doesn't explain that trim 3 and 4 are both for transistor 4, with 3 managing the 4.5v drain, and 4 for the 1.6v source. I do wish that the main board and the true bypass board lined up better seems they are the opposite way round and the wiring needs to cross over each other. One hiccup I've got is I can't get trim 5 to bias below 6.3v. Probably something I've done wrong, but it doesn't seem to be negatively effecting the sound. It sounds great so I'm not unhappy about it at all!" Nick - 23 April 2025

Why's this not called vox in a box?
":(" George - 18 June 2017

Vox in a box
"This kit is amazing. It sounds exactly like an early 60'ies Top Boost, incredibly dynamic and sparkly. I have A/B tested the pedal on a EH 22cal power amp against an original 63 Top Boost, and it's very hard to tell the difference on low to medium volume. I built 2 of these for a musician friend and he uses them to make his Vox AC30CC sound like a proper AC30. Easy build, the biasing takes some patience. Very clean pcb layout and minimal offboard wiring." Tjærand - 26 March 2014