Electro-Harmonix BLACK FINGER User manual

- 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.
Note: This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates,
uses and can radiate radio frequency energy and, if not installed and used in accordance with
the instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
Modifications not expressly approved by the manufacturer could void the user's authority to
operate the equipment under FCC rules.
BLACK FINGER
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. 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.
- THEORY OF OPERATION -
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.
- CONTROLS -
COMPRESS Knob—Varies the amount of compression from minimum (counter-
clockwise) to maximum (clockwise).
WARNING: There are extremely high voltages in the Black Finger even when
it is unplugged –DO NOT OPEN THE BLACK FINGER.

LAMP/LED Switch—Selects the light source to drive the optical attenuator. The
LED is very fast and flat in frequency content. Choose this setting for straight-ahead
compression effects and sustain. Choose LAMP for a slow attack and a reduced
compression on the treble content. This is great for funk chord playing, voice and
keyboards.
SQSH/NORM Switch—Selects between normal attack and a “squashed” long
attack time for the attenuator. This directly affects only the LAMP setting but you will
see a reduction in compression if you leave SQSH on while in LED mode.
PRE-GAIN Knob—Adjusts the amount of signal fed to the attenuator. With this
knob turned toward the minimum (counter-clockwise) position, less of the signal will
pass the compression threshold. This is one way to dial in less effect. More signal in
will mean that more of the signal will pass the compression threshold. This will
maximize the effect when the COMPRESS Knob is turned up, or clip/overdrive the
circuit if the COMPRESS Knob is turned down.
POST-GAIN Knob—Adjusts the level of the OUTPUT signal.
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.
- 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. This
applies only to original purchasers who have bought their product from an authorized
Electro-Harmonix retailer. Repaired or replaced units will then be warranted for the
unexpired portion of the original warranty term.
If you should need to return your unit for service within the warranty period, please
contact the appropriate office listed below. Customers outside the regions listed
below, please contact EHX Customer Service for information on warranty repairs at
[e-mail] or [phone]. USA and Canadian customers: please obtain a
Return Authorization Number (RA#) from EHX Customer Service before returning
your product. Include with your returned unit: a written description of the problem
as well as your name, address, telephone number, e-mail address, and RA#; and a
copy of your receipt clearly showing the purchase date.
United States & Canada
EHX CUSTOMER SERVICE
ELECTRO-HARMONIX
c/o NEW SENSOR CORP.
47-50 33RD STREET
LONG ISLAND CITY, NY 11101
Tel: [phone]
Email: [e-mail]
Europe
JOHN WILLIAMS
ELECTRO-HARMONIX UK
13 CWMDONKIN TERRACE
SWANSEA SA2 0RQ
UNITED KINGDOM
Tel: [phone]
Email: [e-mail]
This warranty gives a purchaser specific legal rights. A purchaser may have even
greater rights depending upon the laws of the jurisdiction within which the product
was purchased.
To hear demos on all EHX pedals visit us on the web at www.ehx.com
Email us at [e-mail]

LAMP/LED Switch—Selects the light source to drive the optical attenuator. The
LED is very fast and flat in frequency content. Choose this setting for straight-ahead
compression effects and sustain. Choose LAMP for a slow attack and a reduced
compression on the treble content. This is great for funk chord playing, voice and
keyboards.
SQSH/NORM Switch—Selects between normal attack and a “squashed” long
attack time for the attenuator. This directly affects only the LAMP setting but you will
see a reduction in compression if you leave SQSH on while in LED mode.
PRE-GAIN Knob—Adjusts the amount of signal fed to the attenuator. With this
knob turned toward the minimum (counter-clockwise) position, less of the signal will
pass the compression threshold. This is one way to dial in less effect. More signal in
will mean that more of the signal will pass the compression threshold. This will
maximize the effect when the COMPRESS Knob is turned up, or clip/overdrive the
circuit if the COMPRESS Knob is turned down.
POST-GAIN Knob—Adjusts the level of the OUTPUT signal.
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.
- 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. This
applies only to original purchasers who have bought their product from an authorized
Electro-Harmonix retailer. Repaired or replaced units will then be warranted for the
unexpired portion of the original warranty term.
If you should need to return your unit for service within the warranty period, please
contact the appropriate office listed below. Customers outside the regions listed
below, please contact EHX Customer Service for information on warranty repairs at
[email protected] or [phone]. USA and Canadian customers: please obtain a
Return Authorization Number (RA#) from EHX Customer Service before returning
your product. Include with your returned unit: a written description of the problem
as well as your name, address, telephone number, e-mail address, and RA#; and a
copy of your receipt clearly showing the purchase date.
United States & Canada
EHX CUSTOMER SERVICE
ELECTRO-HARMONIX
c/o NEW SENSOR CORP.
47-50 33RD STREET
LONG ISLAND CITY, NY 11101
Tel: [phone]
Email: [email protected]
Europe
JOHN WILLIAMS
ELECTRO-HARMONIX UK
13 CWMDONKIN TERRACE
SWANSEA SA2 0RQ
UNITED KINGDOM
Tel: [phone]
Email: [email protected]
This warranty gives a purchaser specific legal rights. A purchaser may have even
greater rights depending upon the laws of the jurisdiction within which the product
was purchased.
To hear demos on all EHX pedals visit us on the web at www.ehx.com
Email us at inf[email protected]

- 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.
Note: This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates,
uses and can radiate radio frequency energy and, if not installed and used in accordance with
the instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
Modifications not expressly approved by the manufacturer could void the user's authority to
operate the equipment under FCC rules.
BLACK FINGER
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. 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.
- THEORY OF OPERATION -
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.
- CONTROLS -
COMPRESS Knob—Varies the amount of compression from minimum (counter-
clockwise) to maximum (clockwise).
WARNING: There are extremely high voltages in the Black Finger even when
it is unplugged –DO NOT OPEN THE BLACK FINGER.