Akashic Guitar effects PCB lookup
VOL

1590B · 1 knobs

Fuzz Dog· epicmod

EPically Modded Boost

Based on the Briggs' Modded EP Boost

Category
Boost
Controls
Vol
Difficulty
Medium
Price
£36.00
Tags
boost

From the vendor

For many years the EP Boost has been good and what it's meant to do - bring you 20dB of clean boost akin to the EP-3 tape echo pre-amp (apparently - anyone AB'd it?).

..and many years ago the legend that is Fred Briggs decided it could be improved upon. Here's our take on those improvements (detailed here) for your delectation.

An on-board charge pump gets you around 16V from your 9V supply, giving you lots of headroom for more cleans, even at max boost. The output is now pumped through a FET stage rather than the original BJT, again ensuring distortion is less likely. A master volume keeps things in check, and Mark Hammer's SWTC gives you treble bleed to calm your highs if you need to. The latter is very subtle, but it works.

The charge pump is optional - if you have a spare 18V output on your PSU then by all means feed it the pure Vs.

Available with through-hole or SMT FETs, so if you're capable of the fiddly little stuff then save yourself a few £.

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: Briggs' Modded EP Boost

Difficulty: Medium

PCB size: 50 x 33mm

Knobs required: 3

Enclosure: 1590B

Direct-Connect compatible (4-way)

Download the INSTRUCTION PDF

Schematic

The schematic is in the vendor's build document, page 3. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 29 rows

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RefValueNormalizedTypeNotes
Resistors 12
R11M1M
R233K33k
R31M1M
R44K74.7k
R5470R470
R61M1M
R73K33.3k
R81K1k
R9100R100
R1010K10k
R1110K10k
R13100R100
Capacitors 10
C147n47n
C210u10uelec
C310u10uelec
C410u10uelec
C510n10n
C610u10uelec
C15100u100uelec
C1610u10uelec
C1710u10uelec
C18100u100uelec
Diodes 3
D41N41481N4148
D51N41481N4148
D11N58171N5817
Transistors 2
Q12N5457/MMBF54572N5457/MMBF5457
Q22N5457/MMBF54572N5457/MMBF5457
ICs 1
IC2TL7660SEPA*TL7660SEPA
Potentiometers 1
VOL100KBB100kPotentiometer