Electro-Harmonix BLACK FINGER Operating Instructions

All-tube optical compressor

Congratulations on your purchase of the Black Finger! The Black Finger is a warm

sounding compressor pedal useful for both guitar and bass, as well as for home

recording. This pedal features an all-tube signal path using two premium 12AX7EH

vacuum tubes. Carefully reading these instructions will ensure that you will get the

most out of your Black Finger.

Included with the Black Finger is a unique 12VAC/1000mA adapter. Use only the

adapter supplied. Using any other adapter can cause harm to you, the Black Finger

and the adapter.

WARNING: There are extremely high voltages in the Black Finger even when

it is unplugged – DO NOT OPEN THE BLACK FINGER.

Optical compressors work by treating an incoming signal with an optically controlled

attenuator (a type of volume control) comprised of a fixed resistor and a shunt opto-

coupled photocell. Because this attenuator is "passive"—as opposed to the more

common "active" AGC (Automatic Gain Control) compressor circuits—it doesn't add

an electronic signature to the signal, thus preserving the tone and character of the

original sound. Some gain is needed to adjust the output level so that it matches the

original level, and this is accomplished with an all-tube fixed gain pre-amp circuit. In

general, compressors are used to sustain melody lines, minimize changes in signal

level, or add a "forward" percussive effect to instruments or drums.

COMPRESS Knob— Varies the amount of compression from minimum (counter-

clockwise) to maximum (clockwise).

BLACK FINGER

All-tube Optical Compressor

- OPERATING INSTUCTIONS -

- THEORY OF OPERATION -

Table of Contents

Do you have a question about the BLACK FINGER and is the answer not in the manual?

Page 1 All-tube Optical Compressor - OPERATING INSTUCTIONS - Congratulations on your purchase of the Black Finger! The Black Finger is a warm sounding compressor pedal useful for both guitar and bass, as well as for home recording. This pedal features an all-tube signal path using two premium 12AX7EH vacuum tubes.
Page 2 LEVEL LED— Gives a visual indication of the gain reduction caused by the compressor. The brighter the LED is, the greater the compression. STATUS LED— Lights up when the Black Finger effect is engaged. If the STATUS led is off, the unit is in true bypass mode. The footswitch engages/disengages the effect.
Page 3 - WARRANTY INFORMATION - Please register online at http://www.ehx.com/product-registration or complete and return the enclosed warranty card within 10 days of purchase. Electro-Harmonix will repair or replace, at its discretion, a product that fails to operate due to defects in materials or workmanship for a period of one year from date of purchase.
Page 4 - FCC COMPLIANCE - This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. If the device is not installed and used in accordance with the instructions, it may cause harmful interference to radio communications and void the user's authority to guarantee the equipment.