God Help Me-BF/SF Help Pleeze!!!!

[chabby]

I just found an early vintage Silver face Vibrolux with it's tube chart inside the cab reading "GZ34" for it's rectifier versus the normal 5U4 that SF's went to.

The amp sounded amazing - to make along story short, I bought it.
Just great condition, great reverb and tremolo or vibrato as it sez on the footswitch. Better cab material in this vintage than what I bought, I just had to have it. Either I got a very early SF amp to blackface specs, or this amp was blackfaced. Because I thought Fender changed to 5U4 in the SF years - no? Regardless, I now own 2 great amps.

[chabby]

I just figured it all out.....you guys won't believe this and I don't know yet if it's a good or bad thing but what I just bought is a Vibrolux Reverb "for Export Only" Amp which is actually an AA864 circuit that is wired for both European at 220 and American 120. That explain why it's got an extra powercord tucked away that I found underneath the reverb tank.

In America this is blackface amp. But this amp is clearly an AA864 Vibrolux Reverb "For Export Only" and has been retrofitted with a 120V cord, while still maintaining it's 220 cord (2 prong). WOW - I don't really care what it is it sounds so friggin awesome I can't wait to get some sample for you all.

This amp is an oddity and very cool. Now I just have to date it. I should have that done in about 1/2 an hour I hope. Just found the date code it was made in 1969 SCORE!!!!!!!!!!!!!!!! This is a blackface circuit in a SF amp and very rare all serial numbers match etc.

[ThermionicScott]

Weird, but cool! I'd keep using the GZ34 unless the plate voltages are unreasonable.

- Scott

[chabby]

Scott - they aren't because I have a blackface amp. Wow

[chabby]

Here's the Pix:

[chabby]

I should say - I have a SF amp for export only that is charted as AA864 with a GZ34 Rect tube and an AB763 blackface circuit. I'm almost having a heart attack.

The black mark line is where someone took a magic marker and blacked out "for Export Only" but you can read it right through the magic marker ink.

Here's the best I can do for now to show chart:

[Dacious]

Chabby, not trying to piss on your BBQ here, but just because it says 'AB763' or has a GZ34, doesn't mean it is a BF circuit. CBS continued Leo's pennypinching ways, and a great many amps kept getting that label weren't the prized circuit.

You have to get the circuit checked to see if it has the varied components. I had a 70 watt Pro Reverb that had a 100 watt Twin Reverb tube chart. The few SF that were AB763, were probably drip-edge grille '68s - which yours isn't. If you have any plastic wiring in the chassis it almost certainly isn't.

Like their guitars, the only consistent thing about FEI/FMI prior to FMIC in 1982 is their inconsistency.

You need to date the amp by EIA codes on the chassis and transformers, and speakers if original. The latest date is around when it can be considered to have been made. I'd be surprised if it comes in at ealier than around '72-73.

I doubt yours was made before 1970 because Export transformers with multivolt selectors for most models only arrived after teh BF era - some may have been earlier. We got them here in Oz (240 volt mains), and the earliest I have ever seen is a '72 Twin. Prior to that Fender Australia bolted a stepdown transformer in the base like the late 60's Concert I saw.

As we noted, not having the BF circuit might be a slight lefdown, but big deal. The amp is still solid, and if it's a pine cab more desirable than the later MDF units, lighter and probably tougher. That amp looks cherry, and the practical difference in value or souond of an early Silverface VR with AB763 and without is 4/5ths of F-all.

[getbent]

I dig those vibroluxes.

[Dacious]

Just thought of another check of how early it is: Silverfaces before 1970 got 4 black line bars painted between the two sets of channel controls, overprinting the blue surround around the normal channel and the rev/vib channel. Yours doesn't look to have that. Pretty sure that means 1970's.

[chabby]

This amp so far falls outside some of the generalities of dating but I have dated the amp by it's serial number and am checking Transformers and chassis next. Used this to date by serial number:Which verified the very earli 69 date. I will get back with the rest of the story as it unfolds. Note that the black vertical lines were gone by 1968, this is a 69. Then they throw this at me - sheesh!:"Some, but not all, export models don't fit exactly into the sequence given and are usually from a year or two later than the serial number would otherwise indicate".
http://www.superchamp.dk/papers/dati..._tube_amps.htm

[chabby]

Well - I've been up all night researching this amp and it's definitley an odd duck. I filled out the survey with serial numbers transformer numbers, speaker numbers cosmetics and the works. It's a missing link of somekind.

Can't wait to lift the tranny and clean it up. Yes, I will bleed off the caps and take pictures. I will be keeping this jewel for number uno. Guess I have a 1979 VR thats going to be for sale soon that hasn't even been delivered to me yet - oh well. Can't afford to right now or it would be the start of a cool collection. Too bad, because I have a feeling the 79 even though its MDF will be cleaner cosmetically since it's 7-10 years newer. Can't wait to get clips of this thing on here for you all to hear. Punchy and clean and what a reverb and trem!

[trag-o-caster]

Chabby - congratulations on the new sweetheart my friend!!!

I have a DR from the same year, and it also notes the GZ34 recto tube on the chart. Yes, Fender would continue to use it's older tube charts on amps, even though some of them had switched to the 5U4 recto! INSANE! My DR has the GZ34, but certainly do NOT overlook the special tone qualities that a 5U4 has to offer. It's all a matter of personal tastes, but I think that we arrived at the conclusion that the 5U4 has a little extra compression (squishy), which is something you may, or may not like. I sure do like it in my 73 Pro Reverb.

Have 'er re-capped, and never let 'er go!

P.S. my DR is also missing the black lines on the control plate. It was sold to me as a 68, and Tim Swartz seems quite certain that it's a 69. In the end, it doesn't matter. The only thing that does matter is IT'S MINE!

[milocj]

That amp still has the removable baffle on the cabinet which I think puts it at no later than right around 1970, but that may vary a bit depending on the model of amp.

Ditto on Fender re-using the tube charts. Actually, I don't think there ever was an AA864 circuit. I think that maybe Fender was rushing to get the tube charts out for this amp and jumped the gun a bit. The only printed version of a schematic I have ever found is the AA964. I have an October 1964 VR and it has the AA864 tube chart but from what I remember it matches the AA964 schematic.

You'll have to look at the bias circuit on your amp...it's probably the AB568 version. Also, see if it has the blue tubular caps or the blob type. Either way, congrats on the amp. FWIW, I have Reverend speakers in mine and most new ceramics have sounded better to me than the original Oxfords once the amp gets past 3 or so.

[chet]

I played a VR at a Guitar Center and it had a nice tremelo sound. Cost about $1500.00 tho' so it was outta my range.

If I found one cheap then I'd get one but it's really too big for my needs anyway.

[JohnnyCrash]

Dacious is right. You can NEVER date an old Fender by it's tube charts. If Leo was a penny pincher, CBS was much worse.

Serial number searches are not helping, perhaps due to the export PT...

Have you cracked the chassis and looked inside? Sometimes a builder's name is written inside an SF chassis, sometimes a date too (though my memory on if dates are is fuzzy).

I think you've got most of it down - it's a '69 at earliest, since it's export it may be a year or two later ('70 or '71).

It is very cool to have a strange amp - even better that is sounds good! Congrats on the cool amp!!!

[meyekel]

Yep, Dacious in on the ball. I have a '77 SFDR using a 5AR4/GZ34 rectifier tube but has a wood cabinet not MDF. Definitely not stock, maybe a new cab, a mutt for sure but it sounds great and that's what matters most.

[chabby]

No doubt that is what matters most. And these VR's, I'm just discovering are every bit (and more IMO) as great as DR's. What really grabbed me with them is the punchyness of the 2x10s and the quality of the reverb. This thing could surf for days. But so sensitive to pick attack and pluck it makes you want to chickin pick just to hear that compressed, punchy tone with or wothout the reverb. Personally I like just a touch of reverb if it's quality I have found 3 on the dial to be about the most I'd usually need. The trem is just plain killer and fun to play with. It's an inspiring amp to say the least and dang if I won't have another in a week or two.

This one ain't goin nowhere though - ever. Well, I shouldnt say "ever" life can have it's ups and downs I'm finding out with the double whammy of a divorce last fall and unemployment last april. Thank God I had some savings and lot's of music equipment to sell or I'd be screwed. Any of you that don't have 6 months of salary saved up, get on it fast. Also, if it wasn't for my guitar, amps and music I'd be toast.

[nonvintage]

My SFVR is a 69 also, it has the blacked out for export tube chart and uses a GZ34 rectifier. It was internally not a BF. I had it blackfaced. And I agree with you that I prefer it's sound to DR's. My serial # is A1329X which maybe around September 1969. It had a lot of the so called brown turd caps.

[Dacious]

Chabby, quick way to check if it's BF or SF schemo (or if someone converted it) if you have the chassis out: On the back of the power tube sockets should be 1500ohm resistors running across from pin 1-5 straight across the middle (pin 5 is oriented to the front of the chassis) - don't confuse these with the larger 470ohm resistors from pin 4-6. Running from pin 5-ground on the SF are the grid snubbers, small value ceramic disc cap. They are soldered to pin 5 at one end and to the chassis pointing towards the board on the other end.

If you have these, it's the later schematic.

[chabby]

Thanks Dacious I will and let you know. Non Vintage: Sounds like we may have similar beasts. My serial number is even earlier though at A1292X.
This amp was advertised as 70's amp. But the newest transformer on it is 236968 which is the output transformer which was made on the 68th week of 1969.