Blue Note Music
BASIC INFORMATION
Manufacturer: Kustom
Model: K250-4
Serial Number: 85490
Estimated Production Year: 1976. Signed and dated by Kenny Stopps
Country of Manufacture: USA, Chanute, KS
PRIMARY AUTHENTICATION
Serial Number Verification
X Present
X Correct Format
X Consistent with Model
X Consistent with Production Period
Original Chassis
X Original Stamping Present
X No Additional Holes
X No Unauthorized Modifications
Notes: # 47
Circuit Verification
Verified Through:
X Circuit Layout
X Schematic Comparison
Circuit Identified As: #002-5066-00
Date Code Verification
Transformer Codes
Power Transformer: None visable
Speaker Codes: 038 5008 00
CABINET AUTHENTICATION
Cabinet Construction
Construction:
Heavy plywood with hardwood frame
Covering. X Original
Type: Tuck and Roll
Grill Cloth: Original
Hardware
Handle: Original
Corners: Original
Feet: Original
Logo: Original
TRANSFORMERS
Power Transformer
Manufacturer: UNKNOWN
Date Code: No dates or codes
SPEAKER SYSTEM
Speaker Configuration: 4x12
Speaker Manufacturer: Kustom
Speaker Assessment: Original. all 4 working as they should
ELECTRONICS AUTHENTICATION
Capacitors
Filter Capacitors: Original
Coupling Capacitors: Original
Wiring Harness: Original
Solder Joints: Factory Original
MODIFICATIONS
Functional Modifications: None
Safety Updates: None
STRUCTURAL CONDITION
Cabinet: Moderate Wear
Functionality
Major Service Needed: Channel one does not work. Channel two does
FINAL EVALUATION
Condition Grade: D
A+ — Exceptional / Collector Grade
Outstanding originality and condition. Among the finest examples likely to be encountered.
A — Excellent
Highly desirable example with only minor wear and no significant issues.
B — Very Good
Strong vintage example with normal wear and minor repairs or service replacements.
C — Good Player Grade
Functional amplifier with noticeable modifications, repairs, or originality loss.
D — Project Grade
Requires significant repair, restoration, or maintenance.
F — Parts / Salvage Grade
Major damage or missing components make restoration impractical.
Originality Grade: Fully Original
Structural Grad: S2 Minor Concerns
Repair Grade: R3 Moderate Repair
BLUE NOTE AUTHENTICATION SUMMARY
Production Period: 1976
Originality Assessment 100%
FINAL NARRATIVE SUMMARY
The Kustom K250-4 is an outstanding example of a mid-1970s American-made amplifier, manufactured in Chanute, Kansas, in 1976. This amplifier retains an exceptional level of originality, including its original tuck-and-roll covering, grille cloth, hardware, speaker system, factory wiring harness, capacitors, solder joints, and unmodified chassis, with the correct factory circuit verified. The cabinet remains structurally sound with only moderate cosmetic wear consistent with age, and the chassis shows only minor surface corrosion. Functionally, Channel Two operates properly while Channel One requires repair, and the original two-prong power cord should be upgraded to a grounded three-prong cord during servicing for safe operation. Rated O1 (Fully Original), S2 (Minor Structural Concerns), and R3 (Moderate Repair Required), this amplifier is an excellent restoration candidate whose remarkable originality makes it increasingly desirable to collectors and vintage enthusiasts. Once professionally serviced, it has the potential to be both a dependable performer and a highly collectible example of classic American amplifier design.
