The Need For Tweed

The Need for Tweed
Fender defined state-of-the-art guitar tone for many years starting in the late 1940s. From sparkly Tele-laden country to roots rock, to humbucker driven blues, Fender amps set the stage.  A comprehensive Fender collection would include “Woodies, Tweeds, Blonde, Brown and Blackface amps. Fender’s dominance started in the late 1940s, but the period from around 1955 through 1968 was golden. Fender hit the sweet spot with Tweed amps and never looked back (note – Early tweeds used octal tubes. While octals do sound good it is generally tough to find metal octals such as 6SC7s which are not microphonic. Glass bottle 6SN7s tend to be fine. Other tubes used in early tweed amps are relatively abundant in today’s market.)
There are ten different tweed models. Each model went through changes during their lifespan. There are as many as eight different schematics for the tweed Super (there may be more!). Starting from the smallest, the four/five watt Champs and Princetons are the only “class A” single ended amps with a single 6V6 for power. The two amps are basically the same with Champs sporting a lone volume control and Princetons having volume and tone controls. Champs started out with 6” speakers and graduated to 8”. Princetons have 8” spkrs. Both are great for recording due to their harmonically rich tone and low volume crunch. They are found on countless records. The Harvard is a great amp with a little more (10 watts) due to the use of two 6V6s in a push-pull configuration and a 10” speaker. Add tremolo and you have the Vibrolux. The Harvard and Vibrolux are two favorites of mine. They are great living room amps and sound warm and satisfying with OD pedals.
The Tremolux is basically a higher powered (15 watts) Vibrolux with a 12” speaker although the phase inverter circuits are different. Leo Fender was doing a lot experimenting with the tweed circuits as you’ll find three different types of phase inverters; Paraphrase, Cathodyne and Long Tail. These circuit differences have an effect on the tone and feel. Cathodyne PI is a little more forgiving and distorts easier. Long tail PI has a little more clean headroom and is used in every Brown/Blonde and Blackface amp. You will also find fixed and cathode biased tweed amps as well as those with and without negative feedback.
The early Deluxes are nice but the later 5E3 narrow panel amps are most desirable, partially because of the switch from octal to 9 pin miniature preamp tubes (12ax7/12ay7) and the Cathodyne phase inverter circuit. The two channels on these amps are interactive and offer quite a variety of tones. They put out around 15 watts and with the relatively low efficiency stock speaker, don’t expect it to cut through a band with a loud drummer.
Tone control circuits used in the above amps are ingenious. The single tone control acts as a treble boost in one direction and a treble cut in the other. For treble boost, a small capacitor is bypassed across the volume control similar to the way a bright switch works on Blackface Fender amps but this time with the tone pot controlling the amount (with the volume on full, this will have no effect). In the other direction there is a larger capacitor that is shunted to ground. That reduces the amount of highs as you turn the control towards “0”. Very clever use of one control to both boost and cut.
The Super, Pro and Bandmaster (all around 30 watts), in their various iterations are basically the same amp circuit with different speaker configurations. The Super has 2×10”. The Pro, with its 15” speaker is a favorite of many, especially the narrow panel ones with the Presence control. The Bandmaster, with its 3×10” speaker configuration is highly collectible because of its rarity and stellar tone.
The 4×10” Bassman is a formidable amp and around 40 watts. Used mostly by guitarists, the 1959 and 1960 5F6-A Bassman amps are tone-full machines. Used for great cleans and a thick overdrive when cranked, you will be hard pressed to find a better sounding amp. One of the many amps in Stevie Ray Vaughn’s arsenal. This circuit was the basis for most Marshall and high gain amps that came after. The low powered Twins are great amps too, and have circuits similar to the Super/Pro/Bandmaster with beefed up power amps and speakers. The high powered Twin is essentially a higher powered Bassman with four 5881 tubes and around 80 watts. The clean tone is glorious. Like a Bassman but larger, warmer and double tone-full. A Keith Richards favorite.