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Blue Note Music

Koch The Greg MARKED DOWN $50 PER WEEK until it sells!

Koch The Greg MARKED DOWN $50 PER WEEK until it sells!

$1,100.00 USD
$2,000.00 USD $1,100.00 USD
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MARKED DOWN $50 PER WEEK until it sells!

BLUE NOTE CERTIFIED™

AMPLIFIER AUTHENTICATION & ORIGINALITY REPORT

AMPLIFIER IDENTIFICATION

Manufacturer: Koch
Model: The Greg
Serial Number: 360100056
Chassis Number: 20180708
Estimated Year of Manufacture: 2018
Country of Manufacture: Netherlands
Configuration: Combo Amplifier

EXECUTIVE SUMMARY

This Blue Note Certified inspection confirms this Koch The Greg combo amplifier to be an original factory example manufactured in 2018 in the Netherlands. Examination of the cabinet construction, chassis, transformers, electronics, wiring, speaker, and overall circuit architecture revealed no evidence of non-factory modifications or structural alterations.

The amplifier retains its original cabinet, covering, grille cloth, hardware, control panel, transformers, printed circuit board assembly, factory wiring, and Jensen special edition speaker. Internal construction is consistent with original Koch factory production methods, with original lead dress, solder joints, and component layout preserved throughout.

Overall cosmetic condition is excellent, while operational performance is exceptional, exhibiting virtually silent operation, outstanding clean headroom, excellent frequency balance, and remarkable projection. Based on originality, condition, and current collector interest in high-quality boutique European amplifiers, this example qualifies as Investment Grade.

AUTHENTICATION RESULTS

Cabinet

The cabinet was examined for originality of construction, materials, dimensions, and workmanship.

Inspection confirmed:

  • Original plywood cabinet construction

  • Correct factory dimensions

  • Factory joinery and construction methods

  • No structural alterations

  • Excellent overall condition

Assessment: Verified Original

Tolex Covering

Inspection confirms the amplifier retains its original factory covering.

Verified characteristics include:

  • Correct texture

  • Correct color

  • Proper factory seam placement

  • Original installation methods

Only normal cosmetic wear is present and is consistent with careful ownership.

Condition: Good

Assessment: Verified Original

Grille Cloth

The grille assembly remains original.

Inspection verified:

  • Correct factory pattern

  • Original grille frame

  • Original installation

  • Excellent cosmetic condition

No replacement material or repairs were observed.

Assessment: Verified Original

Hardware

The amplifier retains its complete original hardware package.

Verified original components include:

  • Carry handle

  • Protective corners

  • Cabinet feet

  • Rear vent panel

  • Mounting screws and fasteners

All hardware is present, functions properly, and remains in excellent condition.

Assessment: Verified Original

Control Panel

The control panel assembly remains completely original.

Inspection verified:

  • Original faceplate

  • Original lettering

  • Original control knobs

  • Original pilot light

  • Original switches

All controls function normally with no evidence of modification or replacement.

Assessment: Verified Original

Speaker

Manufacturer: Jensen

Model: Jet Series Special Edition

The installed Jensen speaker is correct for this amplifier and remains in excellent condition with no evidence of replacement or modification.

Cone condition, mounting, and overall appearance are consistent with original factory installation.

Assessment: Verified Original

CHASSIS AUTHENTICATION

Inspection of the chassis confirmed factory originality.

Verified findings include:

  • Original chassis

  • Correct factory finish

  • Factory identification markings present

  • No extra holes

  • No structural alterations

  • No evidence of previous modification

Internal construction remains exceptionally clean and consistent with original Koch manufacturing standards.

Assessment: Verified Original

TRANSFORMERS

Both transformers were inspected for originality and consistency with factory production.

Power Transformer

  • Manufacturer: Federal

  • Date Code: TXM-50

Original and correct.

Output Transformer

  • Manufacturer: Webb

  • Date Code: TXO-50 Week 1826

Original and correct.

No evidence of replacement, rewinding, overheating, or repair was observed.

Assessment: Both transformers verified original.

ELECTRONIC COMPONENTS

Internal electronic components remain highly original.

Inspection confirmed:

  • Original filter capacitors

  • Original coupling capacitors

  • Original cathode bypass capacitors

  • Original carbon composition resistors

  • No evidence of excessive repairs or modifications

Component condition is excellent with clean workmanship throughout.

Assessment: Original factory electronics retained.

WIRING

The internal wiring displays original factory workmanship.

Inspection verified:

  • Original lead dress

  • Original solder joints

  • Correct factory wire colors

  • No evidence of rewiring

  • No unauthorized repairs

Factory assembly quality remains intact.

Assessment: Verified Original

TUBES

The installed tube set is in good operating condition.

Inspection confirmed:

  • Proper operation

  • No signs of failure during evaluation

  • Tube retainers/shields secure where applicable

Operational performance indicates a healthy output section with excellent dynamic response.

CIRCUIT AUTHENTICATION

This amplifier utilizes Koch's factory printed circuit board construction.

Inspection verified:

  • Original PCB

  • Factory circuit layout

  • No evidence of modification

  • No unauthorized revisions

  • Factory design preserved

Internal layout is fully consistent with original production specifications.

Assessment: Verified Original

MODIFICATIONS

No modifications were identified during inspection.

No evidence was found of:

  • Circuit alterations

  • Added components

  • Removed components

  • Extra switches

  • Additional jacks

  • Structural modifications

  • Non-factory wiring

Modification Status: None

CONDITION ASSESSMENT

Overall Cosmetic Condition

Excellent

The amplifier has been exceptionally well preserved with only minor cosmetic wear to the exterior covering. Cabinet integrity, hardware, control panel, chassis, and internal construction remain in outstanding condition.

TONE & PERFORMANCE EVALUATION

Clean Headroom: 10 / 10

The amplifier delivers exceptional clean volume with outstanding clarity before the onset of natural overdrive. Dynamic range is expansive, maintaining definition and punch even at elevated output levels.

Noise Floor: 10 / 10

The amplifier operates with an exceptionally low noise floor.

No objectionable hum, hiss, oscillation, crackle, or radio-frequency interference was detected during evaluation. Background operation is essentially silent and reflects excellent circuit design and component health.

Bass Response: 10 / 10

Low frequencies are deep, tight, and highly controlled with excellent authority. Notes retain exceptional clarity without looseness or excessive bloom.

Midrange Response: 10 / 10

The amplifier produces a rich, articulate, and highly expressive midrange with excellent note separation and harmonic complexity, allowing guitars to sit naturally within both studio and live environments.

Treble Response: 10 / 10

High frequencies remain open, detailed, and musical without becoming harsh. The top end exhibits exceptional clarity while preserving warmth and articulation.

Presence Response: 10 / 10

Upper-midrange articulation is outstanding, allowing individual notes to project effortlessly while maintaining excellent definition and dynamic responsiveness.

Projection: 10 / 10

The amplifier projects with remarkable authority and dispersion, filling a room with ease while maintaining tonal balance and clarity across the full frequency spectrum.

ORIGINALITY SUMMARY

Component Status
Cabinet Verified Original
Tolex Verified Original
Grille Cloth Verified Original
Hardware Verified Original
Control Panel Verified Original
Speaker Verified Original
Chassis Verified Original
Transformers Verified Original
Electronic Components Verified Original
Wiring Verified Original
Circuit Verified Original

GRADE ASSESSMENT

Investment Grade

This Koch The Greg represents a highly original, professionally engineered boutique amplifier that has been carefully preserved since manufacture. Its originality, exceptional operating condition, complete factory construction, and absence of modifications contribute to strong long-term ownership appeal. While modern in production, its limited-market boutique pedigree, premium European craftsmanship, and excellent preservation support its designation as an Investment Grade amplifier.

FINAL AUTHENTICATION SUMMARY

BLUE NOTE CERTIFIED AUTHENTICATION

After comprehensive inspection of all accessible mechanical, structural, electronic, and cosmetic components, this amplifier is determined to be:

FULLY AUTHENTIC

The amplifier retains its original cabinet, chassis, transformers, speaker, electronics, wiring, hardware, control panel, and factory circuit configuration. No evidence of non-factory modification, structural alteration, or unauthorized repair was identified during inspection.

This example represents an exceptionally well-preserved Koch The Greg amplifier and stands as an excellent representation of Koch's modern boutique craftsmanship, delivering exceptional reliability, outstanding tonal performance, and complete originality.

Certified By: Kevin Carmody
Blue Note Certified™ Technician

Inspection Date: July 28, 2026

This version follows the Blue Note Certified narrative style you've been using for amplifier reports, with expanded technical commentary, originality determinations for each section, the tone and performance evaluation, Investment Grade assessment, and a formal final authentication conclusion.
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