125B · 4 knobs
Apollo Mk. IPreamp Drive
Based on the Catalinbread WIIO· 2 other boards clone it
- Category
- Overdrive· Overdrive / Amp Emulation
- Controls
- Gain · Bass · Master · Feedback
- Difficulty
- Intermediate
- Price
- $12.50in stock
From the vendor
An adaptation of the Hiwatt amplifier used by Pete Townshend of The Who during their “Live at Leeds” performance from 1970.
The Apollo Preamp Drive Mk. I is an adaptation of the Catalinbread WIIO, based on the Hiwatt amplifiers used by Pete Townshend of The Who, particularly their Live at Leeds show from February 14, 1970. (The artwork for the original pedal makes it obvious that “WIIO” is intended to resemble “WHO”.)
The WIIO was originally released in 2009 as a limited run of 100. The limited availability caused a huge debacle as people from gear forums bought up all the preorders and flipped them for profit, capitalizing on Catalinbread’s favored status among gear aficionados.
Catalinbread was not happy with the way the circuit turned out, so before releasing the non-limited version, they overhauled the circuit to reduce the gain and tweak the EQ so it was more versatile as an amp platform. Most people agree that the second version is superior, but the hype surrounding the first version has given it a lasting reputation.
The WIIO was succeeded by the RAH, which is largely the same circuit but with a midrange knob added, and the circuit re-voiced for Led Zeppelin’s famous show at the Royal Albert Hall. (They even referred to the RAH as the “Royal Albert Hall Edition of the WIIO” in the manual.) The WIIO was discontinued shortly after the release of the RAH.
The Apollo Mk. I is a direct adaptation of the V2 WIIO (non-limited version). The only modification is the addition of a trimmer that makes a feedback resistor variable, allowing adjustments to the gain, tone and feel of the circuit. The RAH is also available as the Apollo Mk. II.
Important note: According to Catalinbread[1], the WIIO (and thus this pedal) should only be run at 9V. It should not be used with an 18V adapter or with the Aion FX 18V bypass PCB.
Notes & references • See this thread at TGP (erksin was their customer support lead and often responded on forums on behalf of the company) ↩
Schematic
The schematic is in the vendor's build document, page 6. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 58 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 22 | ||||
| R1 | 10M | 10M | Metal film resistor, 1/4W | |
| R2 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R3 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R4 | 1k | 1k | Metal film resistor, 1/4W | |
| R5 | 12k | 12k | Metal film resistor, 1/4W | |
| R6 | 10M | 10M | Metal film resistor, 1/4W | |
| R7 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R8 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R9 | 100k | 100k | Metal film resistor, 1/4W | |
| R10 | 10k | 10k | Metal film resistor, 1/4W | |
| R11 | 10M | 10M | Metal film resistor, 1/4W | |
| R12 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R13 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R14 | 130R | 130 | Metal film resistor, 1/4W | |
| R15 | 47k | 47k | Metal film resistor, 1/4W | |
| R16 | 12k | 12k | Metal film resistor, 1/4W | |
| R17 | 12k | 12k | Metal film resistor, 1/4W | |
| R18 | 62k | 62k | Metal film resistor, 1/4W | |
| R19 | 82k | 82k | Metal film resistor, 1/4W | |
| R20 | 100R | 100 | Metal film resistor, 1/4W | |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| Capacitors 20 | ||||
| C1 | 270pF | 270p | MLCC capacitor, NP0/C0G | |
| C2 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C3 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C4 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C5 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C7 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C8 | 4n7 | 4.7n | Film capacitor, 7.2 x 2.5mm | |
| C9 | 10n | 10n | Film capacitor, 7.2 x 2.5mm | |
| C10 | 10n | 10n | Film capacitor, 7.2 x 2.5mm | |
| C11 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C12 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C13 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C14 | 470n | 470n | Film capacitor, 7.2 x 3mm | |
| C15 | 10uF | 10u | Electrolytic capacitor, 5mm | |
| C16 | 2n2 | 2.2n | Film capacitor, 7.2 x 2.5mm | |
| C17 | 2n2 | 2.2n | Film capacitor, 7.2 x 2.5mm | |
| C18 | 47uF | 47u | Electrolytic capacitor, 5mm | |
| C19 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C20 | 100n | 100n | MLCC capacitor, X7R | |
| Diodes 4 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| Z1 | 1N4739A | 1N4739A | Zener diode, 9V, DO-41 | |
| Z2 | 1N4739A | 1N4739A | Zener diode, 9V, DO-41 | |
| Z3 | 1N4739A | 1N4739A | Zener diode, 9V, DO-41 | |
| Transistors 3 | ||||
| Q1 | BS170 | BS170 | MOSFET, N-channel, TO-92 | |
| Q2 | BS170 | BS170 | MOSFET, N-channel, TO-92 | |
| Q3 | BS170 | BS170 | MOSFET, N-channel, TO-92 | |
| Potentiometers 3 | ||||
| GAIN | 500kA | A500k | 16mm right-angle PCB mount pot | |
| BASS | 500kA | A500k | 16mm right-angle PCB mount pot | |
| MSTR. | 100kA | A100k | 16mm right-angle PCB mount pot | |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | Available from Aion FX. |
| Jacks & sockets 3 | ||||
| IN | 1/4" stereo | 1/4" STEREO | 1/4" phone jack, closed frame | Switchcraft 112BX or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Lumberg NEB/J 21 C or equivalent. |
| Hardware 1 | ||||
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |
| Other 1 | ||||
| FDBK. | 250k trimmer T | 250K TRIMMER T | rimmer, 10%, 1/4" | See build notes. |
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