The only major difference in tone between the two circuits would be attributable to the different tone caps. For some models like the blackface Concert, there was no change in phase-inverter resistor values, and no changes in tone stack cap values fascinating! And for other models, the tone stack did not change from. The "universal" changes do seem to be the oscillator circuit, cathode resistor change from 56K to K, and the addition of the ohm grid stopper resistors. Did you know that early blackface amps do not have white silk screening around the bright switches?
It's not certain when Fender added the white rectangle around the bright switches, but they are there by early Whether this was added before the end of is not known yet. This feature would have been phased-in at slightly different times for the different amps as faceplates were ordered and used in somewhat different amounts and at somewhat different rates for each model. Some general information about cabinet construction: An interesting feature on the tweed-style cabinets is the use of a dowel reinforcement in the top on either side of chassis.
You can't see the dowels unless the tweed covering is removed, but this reinforcement prevented the wood from splitting due to the weight of the chassis. Baffle boards were made of plywood from to Particle board some call it MDF - medium density fiberboard baffles debuted in and were used through the early s. The baffle board was removable on amps made from to about and glued-in thereafter.
From circa to the early s, the cabinets were no longer made from solid pine boards, but cheaper laminated, multi-piece pine boards. Each side of the cabinet was made from several pieces about three or four inches wide, glued side-to-side, to make up a plank the depth of the cabinet.
These laminated cabs were not finger joined, but rabbet joined. The baffle board on these rabbet joined cabinets was mortised into the sides and bottom i. That's why these post cabinets have the grill cloth stretched across a frame that is attached by a velcro-like system to the baffle. CBS almost certainly went to this construction method to save money, though at the expense of overall quality. And with Fender, there are always exceptions to the rule.
I have received reports of some pre-CBS blackface amps with one or more sides made from a multi-piece board. As well, I have received reports of some particle board bottoms used in master volume-era silverface amps. I'm often asked if the marking on the inside of the cabinets are date codes. Sometimes date codes are ink stamped on the inside of the cabinet mainly blackface and silverface amps including the piggyback speaker cabs , but those handwritten numbers you see in wax pencil or lumber crayon are actually matching marks.
As a worker would through a run of cabinets and fit baffles to each one, he would mark the cab and baffle so they could be "married up" again after the baffle was grilled.
The cabs were probably numbered sequentially within the production run. We've received some interesting reports about some oddball amps. The first was a brown Super Amp. The latest date code on it indicated 30th week of and the circuit and layout were neither 6G4 nor 6G4-A. This must have been one of those "Leo messed with it" amps that Forrest White speaks of in his book. This circuit is unique and transitional - part 6G4 in places, part 6G4-A in places, part "unique experimentation" in places.
An October Deluxe Reverb was reported with transformers all Schumacher all dated to mid, except the reverb drive transformer which dated to December 62! The tube chart indicated the AA circuit, but there were some very strange original resistor values inside.
Specifically, the reverb drive tube's cathode bias resistor was a 1K, 1-watt, instead of the normal 2. The tail resistor in the phase inverter was 6. The bias feed resistors were 68K instead of the normal K, and there was a disc ceramic cap on the board connected between the phase inverter plates. The ceramic cap is more commonly found on brown and blonde amps to prevent parasitic oscillation. Some amp techs have observed examples of blonde and blackface amps with power transformers without center-tapped filament windings.
These amps are usually the ones that have "hum" problems if they don't have filament resistors added. Somewhere along the line Fender went to a center-tapped filament winding and no ohm filament resistors.
These amps could be modified simply by lifting the center tap, and installing the ohm resistors in the usual place on the power lamp socket. Sometime in late , the cloth covered wire went away. However, several amps from the late '60s non-reverb Princeton, Vibrolux Reverb, Bandmaster Reverb, and possibly a Deluxe Reverb with oddball wire have been reported. IPVC wiring is usually found in electronics like computers, not lo-fi amps. Keep your eyes peeled for wire with very thin, cream to yellow insulation.
Scanning a few internet discussion pages, I've noticed quite a bit of misinformation going around regarding Fender tube amps mainly from people who haven't studied the available published literature on Fender amps, i. The good thing is that the misinformation is often corrected by someone who is knowledgeable. One of the most common topics that falls into this category is early silverface amps.
Here's a very quick summary that may be helpful: I'll leave you with a bit of juicy info, namely, some preliminary production estimates for several random amp models.
This info will be further refined and presented in a future article and y' all can hardly wait, I know. Bassman blonde 12, units Princeton Reverb blackface 19, units Tremolux blackface 8, units Vibrolux Reverb blackface 10, units Vibroverb reissue 6, units Special thanks to amp tech guru and fellow Jersey Boy, Mark Norwine at Carlson Amplification Inc. Over 6 years in the making! Finally, what everyone has been waiting for!
How to date Fender amps by serial number!! Okay, I know you're all just dying to skip ahead to the serial number tables but try to contain your excitement and read through the article first. I promise the tables will still be there after you finish reading. Besides, no article in the Dating Fender Amps by Serial Number series would be complete without some interesting information, n'est ce pas?
A tweed Vibrolux was reported with a tube chart printed with circuit "5E3" tweed Deluxe instead of the correct 5F11 see photo. Clearly Fender wasn't afraid to use incorrect parts when they were in a bind. We also received a report of a tweed 5G12 Concert. The 5G12 Concert is the earliest version from very late and early so the existence of a tweed example, while extremely rare, is certainly plausible since Fender was making lots of tweed amps during the same time period.
Non-Schumacher transformers - It's been universally accepted that Fender only used Schumacher transformers on amps made in the s and s. These are marked with EIA code "" which is the company number for Schumacher. Well, this universal "truth" was debunked when we found a bunch of amps with transformers made by the Better Coil and Transformers company. These are marked with EIA code "" and are most prevalent during the time period.
These units look, and apparently sound, just like the Schumacher-made units so it's easy to overlook that "" code. Working at FMI - I was able to interview a fellow who wishes to remain anonymous who worked at Fender in in the amp department.
Although his job was somewhat limited, his recollections provided some really fascinating insights to how the amps were built. For instance, he confirmed our assumption that the amp chassis were put into stock after being stamped with serial numbers and that the chassis were pulled from the stock bins randomly just as with Fender guitar neck plates.
He recalled, "We just went to a big bin every morning and loaded our wheeled rack with a batch of whatever chassis we were working on that day. The boss came around and said what we'd be building. The chassis weren't used chronologically. Probably the same as the pots and transformers that we just dug out of the boxes. I think in the corners of the boxes were older pots remaining from earlier dates I think the better, older hands did 35 a day.
Like I said, there were 5 or 6 of us at the benches every day. But it wasn't always 'cool guitar' amps, sometimes I was making Fender Rhodes Satellite amps on bent aluminum, sometimes only Champs. I remember two 'suits' from upstairs standing behind me occasionally doing time studies. They actually held clipboards and stopwatches to measure how long it took for me to attach various parts.
Of course I tended to hurry more when they were there, and I would fumble more, too. Same with the little rectifier boards. When we had filled our cart we'd wheel it over to the Chicano chicks. They were something to behold, all chatting away while soldering so quickly, it didn't hardly seem like they were looking at the amps. After that the foreman would add the tubes, turn 'em on and set the bias.
One has to wonder where all those factory original export back panels are! Maybe they'll show up on eBay. Another interesting tidbit is that a lot of Fenders were imported into Australia in the late s and early s that were stock volt domestic US units.
The Australian Fender Distributor then installed V - V stepdown transformers in the bottom of the cabinets. Note the removal of the voltage selector switch and hard-wiring. Also note the vertical black lines on the control panel found on earliest silverface amps and the large ceramic power resistors coming off the power tube sockets which indicates the AB circuit. I Didn't Know That! Some Fender amp expert I turned out to be. I just discovered that the silverface Bandmaster speaker cabinet the big, tall one without tilt-back legs is ported see photo.
I thought they were completely sealed units. I guess this is what the catalog refers to as "large, individual specially designed baffles. At least that's the reason according to the '69 catalog.
Also, another thing I've never seen before is a what appears to be a shipping tag of some sort see photo.