Sometimes a small forgotten treasure comes along! The Voodoo Labs Sparkle Drive is one of these.
Voodoo Lab produces pedals and power supplies since 1986. The company was founded by Josh Fiden in the 80's and started by producing solutions for keyboard players under the brand name DMC. Later they've build MIDI solutions and mixing units but they got their big breakthrough with the GCX Audio Switcher.
Due to the succes of the Voodoo Labs products they ditched the DMC name and Voodoo Labs became a big selling company.
They began producing pedals in the beginning of the 90's and their two knobbed Overdrive pedal was a small succes. This two knobbed pedal would be the basis of a well known Fulltone pedal later on.
In december 2000 they released the Sparkle Drive. The idea for this pedal was brought to Voodoo Labs by James Santiago, at that time a session player that would later be part of Voodoo Labs (also Line 6 and UA). James brought the idea of the clean blend as he was trying to fit this idea into his setup.
James used to use a clean amp and a dirty amp in parallel to produce the sounds he would like. He would leave both amps on at the same time and not switch between amps. Later he would use a single amp and would add a Ibanez TS9 Tubescreamer and some kind of custom made mixer pedal in his rack that would give him the clean blend he needed.
'Big jangly clean highs, tight lows with the overdriven midrange of the TS9; my cleanest dirty leads'
Voodoo Labs designed a pedal that would produce this and gave it a clean blend control that would let the player add clean to the mix. As it is placed before the volume pedal, the added clean could also have some volume to compensate for the volume increase in an overdrive pedal.
A new version, the Sparkle Drive MOD was released in 2011 and features a selector switch to add four different gain sounds from the original design. In this post I'll limit myself to the vintage version.
The circuit
The unit is tightly housed inside an enclosure. Four knobs on the front adds controls to the overdrive section (with controls for gain and tone), the clean blend section and the end volume of the pedal. A single switch on the front lets you decide between effect and bypass.
Voodoo Labs uses a different kind of bypass. It uses a DPDT switch to switch the LED on and off and switch between the clean input and dirty output of the pedal. An optocoupler on the input of the overdrive circuit would mute the audio going through the effect in bypass mode as to make it noise free in bypass mode. This weird bypass works well and doesn't add noticeable coloration of the audio.
There is a good trace of the schematic.You can find the schematic in this Freestompboxes.org thread. You can spot the Tubescreamer circuit in the schematic; the only difference is the input cap and the resistor in the feedback loop of the second opamp. They've added a clean blend by changing the BIAS resistor at the input of the overdrive circuit to a potmeter. This potmeter still works like a BIAS resistor but also works as a volume knob for the clean input signal of the overdrive circuit. By adding a second potmeter at the end of the circuit that acts as a volume control of the overdrive (and by combining both to a dual pot) you get a nice sophisticated clean blend feature.
The sound
This pedal opens up new ways to make your guitar (or bass) sound good. Even amazing! But you need to get to know the way the pedal works to make it really shine!
You can use this pedal as a standard Tubescreamer. Inside the pedal is an almost exact copy of a Tubescreamer. And with the clean control set to fully counterclockwise, this pedal will behave and sound like a standard Tubescreamer. It has the mid emphasis, it has the volume, clipping style and tone of a standard overdrive pedal. And although this sounds good altogether, it can be better!
You can also use this pedal as a standard clean boost pedal. When you set the clean ratio to fully clockwise you'll get a beautiful clean boost pedal with a single volume control to control the amount of volume. The tone is flat / the character of your instrument is clearly apparent and the character of the amp you play shines beautiful through.
But the fun begins when you blend these two ways.
By adding a bit of clean to the sound of the Tubescreamer you'll add clarity, character and transparency to the sound. Suddenly the boxy sounding Tubescreamer will sound big with a lot of new levels of character in specified places.
By adding a bit of Tubescreamer to a clean sound is where, to my ears, the magic happens. You have to rethink the whole overdrive pedal idea on this pedal and accept it more like a transparant clean-ish overdrive pedal that broadens the sound and adds layer upon layer of nice frequencies. In this setting it works wonders with a clean amp. It is pick sensitive, adds depth to the sound and the overdrive aspect is something to love.
A much used setting, and often advertised as the way to make this pedal sound enormous, is:
This setting adds a layer of overdrive to the clean. And by putting the overdrive in such 'ridiculous' setting (I wouldn't use it like this in a standalone Tubescreamer) you can really hear the magic over the transparant, clean sound it brings. This setting really adds the before described:
'Big jangly clean highs, tight lows with the overdriven midrange of the TS9
Mods:
As the circuit is close to a Tubescreamer, the standard modifications for a Tubescreamer can be used in this pedal. A couple of examples:
- Changing out the opamp of the overdrive circuit (U2 in the above named schematic). In the unit there is now a JRC4558 but these circuits change in character by using other IC's. If you add a socket you can experiment with different (dual) opamps.
- Changing out the clipping diodes (D1 / D2 in the above named schematic). A known mod is to change the (Si) diodes to LED's or no clipping diodes. You can add a switch (DPTT) to switch between these settings. Other Si diodes will give a different sound although the effect would be quite little.
- Changing the frequency response of the effect (C4 in the above named schematic). By changing out C4 for a larger value you can lower the frequency response of the pedal. Changing it to 68n, 100n or 220n will give the effect much more low end. Now the pedal becomes perfect for bass! By adding a switch you can choose which version you want to play with.
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