The JAM Pedals "Blood Spatter" Tubedreamer is a custom artwork version of the Tubedreamer mk.2, an 808-style overdrive pedal. JAM describes the mk.2 as "a warm, rich and articulate 808-style overdrive built to cut through a mix without ever sounding congested or harsh," and at its core is the JRC4558D chip, the op-amp associated with the classic 808 circuit design1. Every custom artwork pedal is a one-of-a-kind hand-painted piece, and JAM notes that the pedal you receive will differ in detail from the pictured example1.
What it does
The Tubedreamer mk.2 is an 808-style overdrive, meaning it follows the circuit approach of the well-known Tube Screamer family: a mid-focused drive stage built around the JRC4558D chip1. The same JRC4558D 808-style overdrive with a high-gain stage also serves as the gain section of JAM's Pink Flow pedal2. For more on the type, see Overdrive Pedals, or compare the classic originals in Boss SD-1 vs Ibanez TS9 Tube Screamer.
Controls and the HIGH GAIN footswitch
The mk.2 carries three knobs and a second footswitch:
| Control | What it does |
|---|---|
| Gain | Sets drive1 |
| Tone | Adjusts tonal balance1 |
| Level | Controls output1 |
| HIGH GAIN footswitch | Activates an additional gain stage1 |
| Clipping toggle | Selects asymmetrical or no-diode operation1 |
The dedicated HIGH GAIN footswitch is the mk.2's headline addition: it brings in an extra gain stage on the fly, alongside the main effect footswitch1. Two internal trimmers set the high gain stage's output independently for the asymmetrical and no-diode modes, so you can match the levels between them or set one up as a deliberate boost1.
JAM also notes a low-gain refinement in the mk.2: "The mk.2 offers finer resolution at lower Gain settings, expanding the range of usable clean push and edge-of-breakup tones"1.
Clipping modes
The Clipping toggle switches between two ways of shaping the drive:
- Asymmetrical mode: three-diode asymmetrical clipping, which JAM describes as giving a natural response to picking and fretting nuances1
- No-diode mode: removes diode clipping for "a more open, dynamic and amp-like response with greater headroom and clarity," in JAM's words1
Programmable startup
The effect and the HIGH GAIN stage can each power up on or off. To set this, disconnect power, hold the relevant footswitch or footswitches while reconnecting power, and the pedal saves the state1. That makes it practical on a board where you want the drive already engaged when you step on stage.
Power and practical notes
The Tubedreamer runs on 9V DC center-negative and draws 60 mA1. That is more than many simple overdrives draw, so it is worth checking your supply's budget per output when adding it to a daisy-chained or isolated setup.
JAM ships to the UK on DDP terms, with 20% UK VAT and all duties included and no extra charges on delivery1. The pedal carries a 30-day money-back guarantee with a refund no questions asked1.
Versions and related pedals
The Blood Spatter is one of several custom artwork Tubedreamers JAM offers, all described as the same sound with different artwork1. Other custom artwork versions include the "Astronaut-y", "Butteskull", "Celestial Window" and "Monterey". The standard TubeDreamer and the Tubedreamer Screamer MK2 cover the same circuit in standard finishes, and JAM's Double Dreamer pairs two drives in one enclosure.
Questions
Does the Blood Spatter Tubedreamer sound different from a standard Tubedreamer?
No. JAM Pedals describes the custom artwork versions, including the Blood Spatter, as the same pedal with different artwork: "Same sound, different artwork." The circuit is the Tubedreamer mk.2, an 808-style overdrive with the JRC4558D chip, a HIGH GAIN footswitch and a Clipping toggle. Each custom artwork pedal is a one-of-a-kind hand-painted piece, so the pedal you receive will differ in detail from the pictured example, but the electronics and controls are the same as the standard mk.2.
What does no-diode mode do on the Tubedreamer?
The Clipping toggle selects asymmetrical or no-diode operation. In no-diode mode the pedal removes diode clipping, which JAM says gives a more open, dynamic and amp-like response with greater headroom and clarity. In asymmetrical mode the pedal uses three-diode asymmetrical clipping, which JAM describes as giving a natural response to picking and fretting nuances. Two internal trimmers let you set the high gain stage's output level independently for each mode.
Is the JAM Tubedreamer true bypass?
Yes. JAM Pedals lists the Tubedreamer's bypass as true bypass, so the signal passes through the pedal's jacks untouched when it is off. The pedal is an overdrive with a 500 kΩ input impedance and an output impedance under 5 kΩ.
What chip is in the JAM Tubedreamer?
The Tubedreamer mk.2 is built around the JRC4558D chip, which JAM calls the legendary core of its 808-style overdrive circuit. The same JRC4558D 808-style overdrive with a high-gain stage is also the gain section of JAM's Pink Flow pedal.
Can the Tubedreamer start up with the effect already on?
Yes. The effect and the HIGH GAIN stage can each power up on or off. To set the startup state, disconnect power, hold the relevant footswitch or footswitches while reconnecting power, and the pedal saves that state. This means you can have the overdrive engaged, the high gain stage engaged, both, or neither when you power up your board.
Sources (2)
- “Blood Spatter” Tubedreamer, JAM Pedals (jampedals.com)
- Pink Flow, JAM Pedals (jampedals.com)
