
Hammond 290AAX Musicmaster Bass Replacement Power Transformer
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Create Free Business AccountKey Features
- Replacement for Fender MUSICMASTER BASE amp (reference only)
- Similar amp P/N 26821 / 026821 (reference only)
- 120V, 60 Hz primary
- Secondary 1: 490Vct @ 90 mA high-voltage winding
- Secondary 3: 6.3V @ 1.25A heater winding
- Bobbin winding; designed for drop in replacement
- RoHS and REACH compliant; 2.95 lbs shipping weight
The 290AAX is a replacement power transformer for a Fender guitar amplifier, listed in the 290 Series of tube guitar amplifier power transformers. The series reference table matches it to the amp model listed as MUSICMASTER BASE, with similar amp part number 26821 (shown as 026821 in the series table). Model and part references are for reference only.
It runs from a 120V, 60 Hz primary. Secondary 1 is the high-voltage winding at 490Vct @ 90 mA (the series table lists it as 490V @ 90 mA), and Secondary 3 supplies 6.3V @ 1.25A for the heaters. The short description summarises it as "490VCT 90mA, 6.3V 1.25A". The winding construction is bobbin.
Like all 290 Series units, the 290AAX is designed for drop in replacement of the original unit. Physically, the series was designed to look similar to original factory units where possible, and materials and design specifications were kept as close as possible to the original part to preserve the stock "tone". That makes it a practical choice for technicians restoring a Musicmaster-era bass amp or replacing a failed transformer.
The part has a shipping weight of 2.95 lbs (1.34 kg), is RoHS and REACH compliant, and carries UPC 623980186214.
Ideal For
- Fender Musicmaster Bass amp transformer replacement
- Vintage tube amp restoration
- Drop in power transformer replacement
- Preserving stock amp tone
Overview
| Series | 290 Series |
| Description | Power transformer, replacement for Fender guitar amp, 290 series |
| Part Number | 290AAX |
| Series Name | Tube Guitar Amplifier - Power Transformers |
| Series Tagline | Replacement & Upgrades |
| Short Description | 490VCT 90mA, 6.3V 1.25A |
Electrical
| Secondary 1 | 490Vct @ 90 mA (series table: 490V @ 90 mA) |
| Secondary 3 | 6.3V @ 1.25A |
| Primary Volts | 120V, 60 Hz |
Identifiers
| UPC | 623980186214 |
| UNSPSC | 39121301 |
Packaging & Shipping
| Shipping Weight | 2.95 lbs (1.34 kg) |
Construction & Finish
| Winding | Bobbin |
Compliance & Certifications
| RoHS Compliant | Yes |
| REACH Compliant | Yes |
Amplifier Reference (Ref. Only)
| Amp Model | MUSICMASTER BASE* |
| Amp Manufacturer | Fender |
| Similar Amp P/N's | 26821 (part page); 026821 (series table) |
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Frequently Asked Questions
Which amp is the 290AAX made to replace?▾
The series table lists the Fender MUSICMASTER BASE, similar amp P/N 026821; these are reference-only matches.
What is the 290AAX primary voltage?▾
120V, 60 Hz.
What are the secondary ratings?▾
Secondary 1 is 490Vct @ 90 mA and Secondary 3 is 6.3V @ 1.25A.
Is the 290AAX bobbin or paper wound?▾
The series table lists the winding as Bobbin.
Will it fit where the original was mounted?▾
The 290 Series is designed for drop in replacement of original units and designed to look similar to factory units where possible.

