BOSS BF-2 Flanger (Serial 054900) – Japan Vintage

Estimated April 1981 production lot
Very early Made in Japan black label period
ACA specification
Cleaned, inspected, and fully tested

Overview

This listing is for a BOSS BF-2 Flanger from the Japanese vintage era.

The BF-2 was released in June 1980, and this particular unit, with serial number 054900, is estimated to be from April 1981. This makes it a very early example from the Made in Japan black label period.

Carefully cleaned, inspected, and fully tested, this BF-2 retains the classic analog flanger sound that made the model one of BOSS’s most iconic compact modulation pedals.

Based on the serial number, internal PCB markings, IC configuration, potentiometer codes, and component markings, this pedal is estimated to be from the April 1981 production lot. Since BOSS serial numbers from this era function more like lot numbers than strict individual date codes, the safest production estimate is around spring 1981.

All electronic components appear to remain original.
No visible signs of electronic component replacement were found.

Key Features & Condition

Model: BF-2 Flanger
Serial number: 054900
Made in Japan
Black label
Black screw
ACA specification
Estimated April 1981 production lot
Very early BF-2 unit
All electronic components appear original
Fully cleaned and carefully inspected
Tested and confirmed working properly with both ACA adapter and 9V battery
Operation is very good
No noticeable scratchiness in the pots
No accessories included
Pedal only

The unit shows scratches, marks, dirt, and some rust consistent with vintage gear.

Overall cleaning has been performed, and while there are cosmetic signs of age and use, the pedal is in clean condition for its age.

Please refer to the photos for exact cosmetic condition details.

Maintenance / Cleaning Details

The jack contacts were removed and polished with compound to remove oxidation.

No scratchiness or noise was found in the potentiometers during inspection. After cleaning, the pots were checked again and no issues were found, so no contact conditioner was applied.

The rubber bushing appears to have been replaced by a previous owner. It has no noticeable hardening or deterioration, and it is currently in good condition, so it was not replaced during this servicing.

The pedal has been tested with both an ACA adapter and a 9V battery, and operation is good.

Early Enclosure / Transitional Detail

Although this unit has black screws, the enclosure appears to have construction details close to earlier silver-screw BF-2 examples.

On later-style units, the battery snap wiring typically exits through the same area as the switch wiring. However, this unit has a separate wiring hole similar to early examples.

The black screws themselves appear likely to be period-correct based on the aging and rust on the screw threads. For this reason, this unit may represent a transitional-period example from around the changeover from silver-screw to black-screw specifications.

This is not presented as a definitive factory specification claim, but it is a notable early construction detail documented for transparency.

Serial Number / Estimated Production Period

Serial number: 054900

Estimated production lot: April 1981
Estimated range: around March to May 1981

The BF-2 was released in June 1980.

Because this unit is estimated to be from April 1981, it can be considered a very early example from the Made in Japan black label period.

The dating estimate is primarily based on the BOSS 6-digit serial format from this era. When the first two digits “05” are interpreted as the production month code, the result points to April 1981.

Because BOSS serial numbers from this period are generally understood as lot-based numbers, this date should be considered an estimated production lot rather than an exact individual build date.

Production Dating Evidence

Primary evidence:

Serial number: 054900

The first two digits “05” correspond to an estimated April 1981 production lot when interpreted using the common BOSS 6-digit serial dating method for this period.

PCB markings:

PCB reverse marking: BF-2 2291033200
PCB front marking: BF-2 / ET-54A / ET5211-510A

These board markings are consistent with an early to earlier-period BF-2 circuit layout.

Major IC configuration:

NEC C4558C ×2
MN3207 BBD
MN3102 clock driver
TL022CP
78L05AV voltage regulator

This IC configuration is consistent with the early Japanese BF-2 analog BBD circuit design.

Component Date Code Support

Several internal components show markings that are consistent with parts manufactured around early 1981, which supports the estimated April 1981 assembly period.

Notable examples include:

78L05AV marking: 8108
ALPS potentiometer markings: 134M / 141M
MN3207 marking: 12
MN3102 marking: 13
Multiple electrolytic capacitors with “12” and “13” markings
Transistor markings such as 1C

The 78L05AV “8108” marking is consistent with a 1981 week-code style marking. The ALPS potentiometer markings “134M” and “141M” are also consistent with an early-1981 to spring-1981 component period.

These parts do not provide a single exact build date on their own, but together they strongly support an assembly period around spring 1981.

Other Major Components Documented for Transparency

Operational amplifiers:

NEC C4558C P1240E ×2
TL022CP Malaysia

BBD / clock ICs:

MN3207 12
MN3102 13

Voltage regulator:

F 78L05AV 8108

Potentiometers:

ALPS 214N 141M 50KB
ALPS 214N 134M 250KC
ALPS 214N 50KC N 141M

Transistors:

C732 GR 1C
C1815 GR 1C
K30A Y 18
A733 AP212

All major electronic components appear original, and no electronic component replacement work was observed.

Please note that the rubber bushing appears to have been replaced by a previous owner and was not replaced during this servicing.

About the BOSS BF-2 Flanger

The BOSS BF-2 Flanger is one of the classic analog compact pedals from BOSS’s early Japanese production era.

Released in June 1980, the BF-2 became one of BOSS’s most recognizable and long-running analog modulation pedals.

Using an analog BBD circuit, the BF-2 delivers a wide range of flanging tones, from subtle movement and chorus-like modulation to metallic jet-style sweep sounds.

Controls:

MANUAL
DEPTH
RATE
RES

Power:

9V battery or ACA-type adapter

Note: Battery and ACA adapter are not included.

Included

None. Pedal only.

Battery and ACA adapter are not included.

Shipping / Import Duties / Address Restrictions

Shipping costs and delivery conditions are determined according to the individual listing, destination, package size, declared value, and current customs and shipping requirements.

International orders are shipped from Japan using Japan Post EMS (Express Mail Service).

EMS shipping is available only when the package meets the applicable size, weight, declared value, destination, customs, and service requirements.

If EMS is unavailable for the destination or cannot be used due to the package size, weight, declared value, customs requirements, service limitations, or other shipping conditions, we may contact the buyer for clarification, request an alternative address, or cancel the order.

If free shipping is offered, it normally applies to outbound shipping charges only.

Shipments to the United States are generally sent under DDP conditions in accordance with current U.S. customs and Japan Post requirements.

For qualifying U.S. shipments, the customs duties covered by the DDP declaration are prepaid by the seller before shipment.

However, DDP shipping does not guarantee that the buyer will have no additional charges.

Additional duties, taxes, customs reassessments, customs clearance fees, brokerage fees, carrier handling fees, storage charges, or other expenses not included in the original DDP declaration may still be imposed by U.S. customs authorities or the delivery carrier.

Any such additional charges are the buyer’s responsibility.

Taxes or fees collected separately by Reverb are not included in the Japan Post DDP customs prepayment.

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VAT or taxes collected by Reverb at checkout may not include customs duties, clearance fees, postal handling fees, or carrier charges.

Please Note

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Depending on the destination and local delivery conditions, delivery may be completed without a recipient’s signature or through unattended delivery.

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About RETUNE WORKS

RETUNE WORKS specializes in careful inspection, cleaning, and preservation of musical equipment while respecting original circuits, tone, and historical integrity.

For this BF-2, all electronic components appear to remain original.
No visible signs of electronic component replacement were found.

The rubber bushing appears to have been replaced by a previous owner, and since it has no noticeable hardening or deterioration, it was not replaced during this servicing.

The pedal has been thoroughly cleaned, inspected, and tested to ensure reliable operation while maintaining authenticity.

Our mission is to ensure that quality vintage gear continues to be played, enjoyed, and passed on to the next generation.