— Fender^® Guitar Amps —

Output Transformer Numbers & Impedances

Amplifier Model

     FEI #

Early '60s FMI #

    FMI #

Output

  '65 CBS FEI #

    1966 –

Impedance

Bandmaster 6G7A

45217

---

---

4 ohms

Bandmaster

---

125A6A

022848

4 ohms

Bandmaster Reverb

---

125A6A

022848

4 ohms

Bassman 5F6/5F6A

45249

---

---

2 ohms

Bassman 6G6

---

125A5A

---

8 ohms

Bassman, other than above

---

125A13A

022871

4 ohms

Bassman 50

---

125A13A

022871

4 ohms

Bassman 10 (combo)

---

125A13A

021848

8 ohms

Bassman 10 (head)

---

---

013897

8 ohm ctr-tap

Bassman 70

---

---

013897

8 ohm ctr-tap

Bassman 100

---

---

021657

4 ohms

Bassman 135

---

---

013691

8 ohm ctr-tap

Bronco

---

125A35A

022905

3.2 ohms

Champ

---

125A35A

022905

3.2 ohms

Concert 6G12

45249

---

---

2 ohms

Concert AB763

---

125A9A

022855

2 ohms

Deluxe 5E3

?

---

---

8 ohms

Deluxe, Deluxe Reverb

---

125A1A

022640

8 ohms

Harvard

---

125A2A

---

?

Musicmaster Bass

---

---

026839

8 ohms

Princeton 5B2

7765

---

---

8 ohms

Princeton 5F2A

265

---

---

8 ohms

Princeton, other than above

---

125A10B

022913

8 ohms

Princeton Reverb

---

125A10B

022913

8 ohms

Pro Amp 5C5, 5D5, 5E5, 5E5-A

1846

---

---

8 ohms

Pro AB763, 6G5A

---

125A7A

---

8 ohms

Pro Reverb, all

---

125A6A

022848

4 ohms

Quad Reverb

---

125A29A

022889

4 ohms

Quad Reverb (1978)

---

---

013691

8 ohm ctr-tap

Showman 6G14 (2-5881's)

45550

---

---

8 ohms

Showman 6G14-A (4-5881's)

---

125A4A

---

8 ohms

Single Showman (one spkr)

---

125A30A

022897

8 ohms

Dual Showman (two spkrs)

---

125A29A

022889

4 ohms

Super 6G4

45216

---

---

4 ohms

Super 6G4-A

---

125A6A

022848

4 ohms

Super Reverb

---

125A9A

022855

2 ohms

Super Reverb (1978)

013897

---

---

8 ohm ctr-tap

Super Six Reverb (1976)

---

125A29A

022889

4 ohms

Super Six  Reverb (1978)

013691

---

---

8 ohm ctr-tap

Super Twin, Super Twin Reverb

012413

---

---

4 ohms

Tremolux 5E9, 5E9-A, 5G9

108

---

---

8 ohms

Tremolux 6G9, 6G9-A

45217

---

---

8 ohms

Tremolux 6G9-B, AA763, AB763

---

125A6A

022848

4 ohms

Twin 5F8, 5F8-A, 6G8-A (4-5881's)

45268

---

---

4 ohms

Twin 6G8 (4-6L6's)

45548

---

---

4 ohms

Twin Reverb, all

---

125A29A

022889

4 ohms

Vibro-Champ

---

125A35A

022905

3.2 ohms

Vibrolux 6G11

45217

---

---

8 ohms

Vibrolux 6G11-A, AA763

---

125A7A

---

8 ohms

Vibrolux Reverb

---

125A6A

022848

4 ohms

Vibrosonic 6G13-A ("8-ohm")

45548

---

---

4 ohms

Vibrosonic 6G13-A ("16-ohm")

45550

---

---

8 ohms

Vibrosonic Reverb

---

125A30A

022897

8 ohms

Vibroverb 6G16

---

125A6A

---

4 ohms

Vibroverb AA763, AB763

---

125A7A

---

8 ohms

Output impedances are nominal and frequency-dependent.  Many amps work with either 4 or 8 ohm loads to allow for extension speakers.

Some blackface Fender amps use an 8-ohm, center-tapped transformer.  When a second speaker is plugged in, the center-tap of the output coil is selected, halving the output impedance to 4 ohms.

For more on impedance matching and cabinet wiring, check out our speaker wiring iFAQ.

Fender^® is a registered trademark of  Fender^® Musical Instruments Corporation.