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Blackface Amps

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After having many lengthy conversations about the "blackface" amps of the mid 1960's, I thought it would be easier to tell the story here. The term describes the cosmetic appearance of Fender amps built from 1963 to 1967. These amps were covered with black Tolex with silver grill cloth and had black control panels. This separates them from the "tweed" amps from the 50's, the early 60's "brown" amps, and the "silverface" amps from 1967 through the 70's. The blackface amps from the Deluxe up to the Twin Reverb and Showman (everything except the Champs and Princetons) were basically the same amp. That is, they were designed using the same circuit with several variations. All were class AB with adjustable fixed bias and used the same two channel preamp, phase inverter, reverb, and vibrato (actually tremolo) circuits. The differences were:

1. Some were combos, some were heads with dedicated cabinets.

2. Most of the combos had reverb, none of the heads did.

3. Output tube sets consisted of 2 6V6's (Deluxe), 4 6L6's (Twin & Showman), or 2 6L6's (everything else).

4. Most had a tube rectifier, the more powerful amps had solid state rectifiers.

5. Power supplies (power transformer & filter capacitors) were designed for the needs of the output tubes. That is, the higher the output power, the more current is needed. It is important to note that in the mid-powered amps (2 6L6) there was a lower current supply (Vibrolux & Tremolux) and a higher current supply (Pro, Super, Vibroverb, etc.) This is why some were rated at 35 watts and some were 40.

6. The output transformers were tailored to the output power and speaker impedances.

7. Many amps had midrange controls. Those that didn't had a fixed resistor that was the equivalent of a midrange pot set approximately at the half-way point.

8. Many had bright switches. This is nothing more than a switched capacitor that allows very high frequencies to bypass the volume pot. As the volume is turned up, the bright switch becomes less effective because all frequencies are bypassing the volume pot.

9. All had tremolo (it was labeled Vibrato) except the Bassman.

10. Probably the biggest difference in sound was a result of the speakers used. Each guitar amp in the line had a unique combination of speakers with the exception of the Super Reverb and the rare Concert, which both had 4x10's and the Twin Reverb and Super Reverb with 2x12's in an open back combo format. 

During the "silverface" years the circuits were gradually changed to give a cleaner sound with greater output power. We now know that none of these alterations were improvements. The early silverface amps can easily be brought back to blackface specs, the later ones can't without making major, expensive changes.

Disclaimer: "Fender, Twin Reverb, Deluxe, Champ, Princeton, Showman, Vibrolux, Tremolux, Pro, Super, Vibroverb, Bassman, Concert, and Super Reverb" are trademarks of Fender Musical Instruments. Gries Amplification is in no way associated with Fender.