The Blackface/Silverface transition

[charlie chitlin]

Are there any hard-and-fast parameters for this?
Did, for instance, the Deluxe retain the blackface circuit for a couple years?
Did others?
I seem to remember some silver amps ('70-'71) having the same circuit as blackface.
I could always be wrong!
When the circuits changed, did the whole line change?

[JDRNoPro]

I believe it's commonly accepted that 1968 SF "blackline" models are usually BF circuits, but not always guaranteed. "Blackline" refers to thin vertical black lines dividing control sections/knobs on the Silver face plates. The degree and timing of changes varied by models, however, with the lower powered models (Champ, Princeton, Deluxe Reverb) being less affected than the larger models.

A few years back I got a book about the history of Fender amps ...... " Fender Amps - the first 50 years" written by Sprung and Teagle IIRC that has lots of good info and lots of great pix. Great reference if you're interested.

[Wally]

Charlie, as JD notes, the small amps...Deluxe and smaller....chagned mush less than did the larger amps. The first SF amps came out in April of '67 and are identical to the BF amps of the same model that came before. The schematic changes started in May of '68....and the date of the changes vary from model to model.

There are changes in the type of wire used and in the lead dress that have nothing to do with schemtaic changes. There are also changes in the cabinet construction that some of us take note of. I prefer SF amps that were built prior to the change to the glued-in baffle board with a separate Velcro-attached grille board. Even with the changes to the circuit, to the wire type and dress, and to the cab; there are some great amps in the SF era. I would take a SF model Fender to the same model of REissue anyday of the week for my purposes.

Here are some articles that line out soem of the changes to FEnder through the years....and give us some great info on what to look for in a vitnage FEnder.

http://www.superchamp.dk/papers/dati..._tube_amps.htm

http://www.superchamp.dk/papers/dati..._tube_amps.htm

[Chris Winsemius]

- cabs do differ (pre/post '71)
- caps do differ (pre/post '68)
- certain resistors do differ (0,5 vs. 1 Watt)
- material of eyeletboards seems to differ
- various circuit-values do differ
- B+ voltage/nodes do differ
- wire does differ
- acthodebypass-caps do differ

etc., etc.

[Custom Deluxe]

A good rule of thumb to help one quickly tell (if you don't have production codes memorized) is to look at the wiring. If cloth, chances are it's still the BF circuit. If it still has a the GZ-34 & cloth wiring, more than likely it is the BF circuit. If the rect. is different, all bets are off and you need someone familuar with this circuit to verify.

Here is mine June of '67 Deluxe Reverb.

[Glen W]

My mid '68 DR came with cloth wiring, brown turd caps, and the 1200 pf tone sucker caps at the power tube grids.

[vanguard]

it's common knowledge that there are early silver examples of all models with blackface innards.

i've always wondered if, during that transition period, any blackface amps came out of the factory with any silver-face changes. . .

[muchxs]

Originally Posted by vanguard

it's common knowledge that there are early silver examples of all models with blackface innards.

i've always wondered if, during that transition period, any blackface amps came out of the factory with any silver-face changes. . .

It's like you put it in your first comment. The amps got cosmetic changes before the circuits changed.

Open it up, if it has blue caps and cloth wiring it's BF.

Dog turds and plastic, it's SF.

I saw a transitional Bandmaster the other day. Mixed cloth and plastic, dog turds. So they ran outta Ajax caps before they ran outta cloth wire...

Some amps got dog turds all the way through. I guess Champs weren't good enough for blue caps. Yup, they got big ugly matte brown caps that look like dog poo.

[Custom Deluxe]

Originally Posted by Glen W

My mid '68 DR came with cloth wiring, brown turd caps, and the 1200 pf tone sucker caps at the power tube grids.

What rectifier does it use? Is it not using a GZ-34 then.

[wallis222]

Originally Posted by muchxs

Open it up, if it has blue caps and cloth wiring it's BF.

Dog turds and plastic, it's SF.

Had a chuckle, but it's true.

[SoK66]

A simple rule of thumb, first glance check, most from that era have a date stamp right by the PT. If the stamp is post May '68 you're virtually assured it the early SF circuit, which is the runt of the SF litter. DR's & PR's never saw much in the way of changes, but the DRs will have the suppression caps, alrered PI resistance values, higher B+ and changes to the dropping resistor values in the doghouse. Most sound great and don't need much "blackfacing".

[Glen W]

Originally Posted by Glen W

My mid '68 DR came with cloth wiring, brown turd caps, and the 1200 pf tone sucker caps at the power tube grids.

Originally Posted by Custom Deluxe

What rectifier does it use? I'm using not a GZ-34 then.

I bought this amp back in the '80s for $225 - it needed a little TLC. It then had a PT from '73, and a SS plug-in rectifier.

It now has a PT that I bought from Michael Clark back around '97, and a GZ34 recto. I don't know what rectifier the amp came with originally, though...

[jkats]

There are exceptions to the BF/SF circuit rule stated above I had a 68 Bandmaster Reverb (which I know never was issued in a BF version -- only SF) which had the BF-era blue molded caps, cloth wiring and a GZ 34 rectifier, but which also had the SF-era supressor caps and the dreaded bias-balance circuit. I understand that in general, the larger amps received the SF changes first and the smaller amps (Champ, Princeton, and Deluxe Reverb) retained their BF circuits into the 1970s (although with tweaks such as plastic wiring and brown or red coupling/tone caps).

[RaistMagus]

I have encountered a 1969 silverface super reverb that had the paper tag saying it's a BF circuit, but when my tech checked it he told me it actually was the SF circuit (can't recall the exact markings eg. AB763 or smtn, if anyone wants I can check). The 69 dating was deduced from the transformer and speaker markings.

[vanguard]

Originally Posted by RaistMagus

I have encountered a 1969 silverface super reverb that had the paper tag saying it's a BF circuit, but when my tech checked it he told me it actually was the SF circuit (can't recall the exact markings eg. AB763 or smtn, if anyone wants I can check). The 69 dating was deduced from the transformer and speaker markings.

yeah, the tube charts aren't much help on early CBS amps. they used up all the old charts even when they were no longer accurate.

[Wally]

Originally Posted by vanguard

yeah, the tube charts aren't much help on early CBS amps. they used up all the old charts even when they were no longer accurate.

ONe must always be skeptical of tube charts in FEnders. I have had an all-original, near mint 1957 5E3 Deluxe that carried a tube chart with the model number of "5F6A"...which is good for a BAssman amp. There are examples fromt eh blonde/brown 6G era where tube charts do not agree with the circuit. Starting with the BF FEnders, things got very iffy. CBS signed the papers on Jan 4, 1965, IIRC. There are discrepancies bewteen AA165 bAssman amps and AB165 BAssman amps.....those are from January 1965. I think this indicates that hte process and the vagaries are not just a CBS thing, though. There were always instances of 'carry over' use of tube charts, ime. And.....this continued long past the 'early days' of CBS.....well into the SF FEnder amps. I have had a SF Dual Showman that had a tube chart designating the amp as an AB165 BAssman.
The only time a tube chart is really of much importance is when it agrees with the soem or all of the particulars of the amp into which it was glued.
Ex: that 1957 5E3 with the 5F6A model designation was correctly date stamped. That is, the date codes in the amp all matched.