Frankenstein SF Princeton Reverb (or is it?)

Rojobou

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I'm hoping someone out there can shed some light on what I really have here. I bought this Princeton Reverb in the early '90s in Cambridge, MA, and have never made any mods to it. It's starting to act up, and after (eventual) success in getting my '74 Twin Reverb re-capped, I figured it was time to open it up. Turns out, it's full of questions, and I haven't been able to find many answers...

I knew there was some trouble before, as the amp is clearly a Silverface, but the cabinet appears to be from a 1965 Princeton (non-reverb), production #2. Upon taking the chassis out, I found the transformers to be dated 1968, and some of the chassis stamps also appear to point to 1968. When I removed the reverb pan, I found an old-fashioned wax seal with the letter "R" on it. On top of all that, the chassis has a label inside that says "Feb 27 1978".

The baffle plate doesn't appear to have any sort of triangular wood piece under the grille cloth for mounting the Fender logo, and the grille cloth does not have holes in it where that Fender logo would typically be. Not sure whether that means anything, and of course it could be a homemade baffle plate

I've posted a bunch of pictures - I'm not sure whether to consider this a wacky "parts-Princeton" that someone put together, or if this is some rare prototype from the early runs of the SF model. Since everything in the chassis is original, I'd hate to start replacing parts then learn this is some piece of history. I'm leaning towards this being a rebuild, where the original SF cabinet was somehow destroyed in 1978, and the chassis was installed into an old non-reverb cabinet. But, that chassis production #2 is so enticing, and that "R" stamp is like some sort of DaVinci Code mystery...
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Any info is better than none - thanks in advance!
 

Phrygian77

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The white Mallory and black yellow/red ended cathode caps are indicative of mid to late 70's. The '68 chassis stamp is odd, but who knows. You're not talking top of the line amp in that era, and Fender was throwing parts together to make whatever.
 

slider313

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It's a '68 chassis in a '65 cabinet and highly unlikely done at Fender. The Feb. 27th, 1978 sticker was probably the date when the amp went in for service. Fender would usually ink stamp a return for service piece but perhaps by 1978 a sticker was used. As for the "R" in the cabinet; I've never seen that before.
 

King Fan

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^^^ this. Agree, you have great '60s-era guts and cab, rehashed together and with a few cap updates at a later date. Most folks would replace all the white Mallories *and* other electrolytics. Most of all it needs a new cap can — not an easy DIY. Most folks would try to keep the original blue molded caps; the brown blobs are usually OK too. The resistors should be checked for excessive drift, especially the ones that get hot — dropping resistors, plates, etc. some folks would put metal oxides for the dropping resistors. Don’t ignore the bias cap and resistor.

Can’t see on this screen. Is that a 2-prong cord? Is there still a death cap?

Is the amp noisy, weak, or otherwise out of sorts?
 

schmee

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"I knew there was some trouble before, as the amp is clearly a Silverface, but the cabinet appears to be from a 1965 Princeton (non-reverb), production #2. Upon taking the chassis out, I found the transformers to be dated 1968, and some of the chassis stamps also appear to point to 1968. When I removed the reverb pan, I found an old-fashioned wax seal with the letter "R" on it. On top of all that, the chassis has a label inside that says "Feb 27 1978".

The baffle plate doesn't appear to have any sort of triangular wood piece under the grille cloth for mounting the Fender logo, and the grille cloth does not have holes in it where that Fender logo would typically be. Not sure whether that means anything, and of course it could be a homemade baffle plate"


#1: A 65 BF non reverb Princeton cab would not fit a Princeton Reverb. A later BF Princeton cab should not fit a SF Princeton Reverb either.... But it's close... 1/4" too narrow. Looks like they put the wrong sticker in, or it's been replaced.
#2: Early Princetons didn't have the Fender logo '64-'65. Neither did some of the Deluxes. But I'm not sure if the wooden triangle was there or not. You may very well have an early BF cab.
#3 You appear to have a genuine '68 amp there! Lucky you. Does the faceplate have two black vertical lines either side of the amp name? They did that only 67-69.
#4 If it has a removeable speaker baffle (?) it's not a later cab and definitely not a '78. It could have come from the factory with a '65 cabinet I suppose. Not sure Fender practiced FIFO back then .
 

Rojobou

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The white Mallory and black yellow/red ended cathode caps are indicative of mid to late 70's. The '68 chassis stamp is odd, but who knows. You're not talking top of the line amp in that era, and Fender was throwing parts together to make whatever.
That's great info - maybe the 1978 sticker indicates a partial re-cap with the non-blue-molded caps...
 

Rojobou

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^^^ this. Agree, you have great '60s-era guts and cab, rehashed together and with a few cap updates at a later date. Most folks would replace all the white Mallories *and* other electrolytics. Most of all it needs a new cap can — not an easy DIY. Most folks would try to keep the original blue molded caps; the brown blobs are usually OK too. The resistors should be checked for excessive drift, especially the ones that get hot — dropping resistors, plates, etc. some folks would put metal oxides for the dropping resistors. Don’t ignore the bias cap and resistor.

Can’t see on this screen. Is that a 2-prong cord? Is there still a death cap?

Is the amp noisy, weak, or otherwise out of sorts?
Thanks for that advice - at the very least, I need to replace the 2-prong plug with a modern one. There is indeed still a death cap. When I worked on my '74 Twin Reverb, I had the help of an Electrical Engineer friend of mine, and he was able to check the components in depth (more than I could do with my basic multimeter).

The problem I'm having is a fairly loud (compared to a typical 60-cycle hum) static sound that stays at the same volume, regardless of the volume level (even with volume at zero, the static is there). The amp controls all still work, and sound is coming through, just with that omnipresent static. The static sound does not change with any dial positions of any controls EXCEPT the vibrato speed, where the static oscillates somewhat with the speed setting.
 

Rojobou

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"I knew there was some trouble before, as the amp is clearly a Silverface, but the cabinet appears to be from a 1965 Princeton (non-reverb), production #2. Upon taking the chassis out, I found the transformers to be dated 1968, and some of the chassis stamps also appear to point to 1968. When I removed the reverb pan, I found an old-fashioned wax seal with the letter "R" on it. On top of all that, the chassis has a label inside that says "Feb 27 1978".

The baffle plate doesn't appear to have any sort of triangular wood piece under the grille cloth for mounting the Fender logo, and the grille cloth does not have holes in it where that Fender logo would typically be. Not sure whether that means anything, and of course it could be a homemade baffle plate"


#1: A 65 BF non reverb Princeton cab would not fit a Princeton Reverb. A later BF Princeton cab should not fit a SF Princeton Reverb either.... But it's close... 1/4" too narrow. Looks like they put the wrong sticker in, or it's been replaced.
#2: Early Princetons didn't have the Fender logo '64-'65. Neither did some of the Deluxes. But I'm not sure if the wooden triangle was there or not. You may very well have an early BF cab.
#3 You appear to have a genuine '68 amp there! Lucky you. Does the faceplate have two black vertical lines either side of the amp name? They did that only 67-69.
#4 If it has a removeable speaker baffle (?) it's not a later cab and definitely not a '78. It could have come from the factory with a '65 cabinet I suppose. Not sure Fender practiced FIFO back then .
That's great info - and something I never thought of. So, do you mean the cabinet is about 1/4" too narrow for a SF chassis? I'll take a closer look to see whether anything was modified to create a better fit. It DOES indeed have those two black vertical lines on either side of the "Princeton Reverb-Amp" printed name on the faceplate.

The baffle is removable - it is screwed in with 4 wood screws to a pair of vertical rails glued to the insides of the cab. The baffle also has 8 speaker attachment holes, but only 4 are occupied with screw posts (the speaker only has holes for 4 mounting screws). I've posted a picture of the speaker below - no idea what it is, as whatever labeling it has is long since removed, but it does have some stamped info that may indicate a maker and/or date of manufacture?
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schmee

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That's great info - and something I never thought of. So, do you mean the cabinet is about 1/4" too narrow for a SF chassis? I'll take a closer look to see whether anything was modified to create a better fit. It DOES indeed have those two black vertical lines on either side of the "Princeton Reverb-Amp" printed name on the faceplate.

The baffle is removable - it is screwed in with 4 wood screws to a pair of vertical rails glued to the insides of the cab. The baffle also has 8 speaker attachment holes, but only 4 are occupied with screw posts (the speaker only has holes for 4 mounting screws). I've posted a picture of the speaker below - no idea what it is, as whatever labeling it has is long since removed, but it does have some stamped info that may indicate a maker and/or date of manufacture? View attachment 1053817 View attachment 1053818
I meant mainly a non reverb wont fit. I'm not 100% about that 1/4" cab width difference though, maybe someone else can confirm. (ie: the BF later non Rev Princeton is supposedly 1/4" narrower than the SF Princeton Reverb) Yours does seem to be an early Princeton Reverb cab. (no logo, date code) Another cool thing!

Not a stock speaker. I think 575 code is a Heppner speaker, probably 1962 on that one. They are good quality speakers but all I have had are pretty warm sounding.
 

slider313

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That's great info - and something I never thought of. So, do you mean the cabinet is about 1/4" too narrow for a SF chassis? I'll take a closer look to see whether anything was modified to create a better fit.
Another thought: the cabinet is from a 1965 Princeton Reverb but Fender used the wrong tube chart. This happened more often than one would expect. ;-)
 

Lowerleftcoast

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Synopsis:

Feb 1978, amp tech has this 1968 silver face in for service. Tech also has a 1965 blackface in the shop. Tech inadvertently swaps cabinets when putting the chassis back in the cabinet.

Hey... it could happen...
 

ETMusic777

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The white Mallory and black yellow/red ended cathode caps are indicative of mid to late 70's. The '68 chassis stamp is odd, but who knows. You're not talking top of the line amp in that era, and Fender was throwing parts together to make whatever.

I disagree on this, respectfully. The white Mallory and black yellow/red ended cathode caps (sometimes marked as "Nashville Electronics" were used from mid 1966, through all of 1967 in to 1968 when they were discontinued. I have them in my blackface 67 Super Reverb, Pro Reverb and Bassman, all which were produced between March 1967 and August 1967. I also have the white Mallory caps in those as well. Other users have reported seeing them in 1966 Deluxe Reverbs. Below is a photo of the internal chassis of my 67 Super and my 67 Pro Reverb which has those caps, you can even see the date 6720 or "1967, 20th week" on one of them.

The #2 Production does not mean that it was the 2nd unit ever produced. #2 is the production line that it came out of.

I think you have a 68 Princeton in a 65 cabinet, and the sticker is a service sticker from 1978.
 

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Phrygian77

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I disagree on this, respectfully. The white Mallory and black yellow/red ended cathode caps (sometimes marked as "Nashville Electronics" were used from mid 1966, through all of 1967 in to 1968 when they were discontinued. I have them in my blackface 67 Super Reverb, Pro Reverb and Bassman, all which were produced between March 1967 and August 1967. I also have the white Mallory caps in those as well. Other users have reported seeing them in 1966 Deluxe Reverbs. Below is a photo of the internal chassis of my 67 Super and my 67 Pro Reverb which has those caps, you can even see the date 6720 or "1967, 20th week" on one of them.

The #2 Production does not mean that it was the 2nd unit ever produced. #2 is the production line that it came out of.

I think you have a 68 Princeton in a 65 cabinet, and the sticker is a service sticker from 1978.


You could be right, my 67' SR had some of those, but they were tack soldered in, like a quick cheap repair. It had a Red Rhodes, Hollywood, CA sticker on the chassis too.

Edit: The white Mallorys that is. I've seen them in many '70s amps, later they switched to using Spraque 30D caps, so sometimes a mix of the silvery 30Ds and Mallorys.
 
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ETMusic777

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You could be right, my 67' SR had some of those, but they were tack soldered in, like a quick cheap repair. It had a Red Rhodes, Hollywood, CA sticker on the chassis too.

Edit: The white Mallorys that is. I've seen them in many '70s amps, later they switched to using Spraque 30D caps, so sometimes a mix of the silvery 30Ds and Mallorys.
Yeah you are right....they used those white Mallorys in the 70s too. I have them in my 73 Bassman Ten. The black and red "Nashville" caps were long gone after 68 though. I had one of those fail in my 67 Pro Reverb, negative bias cap recently and replaced it. I have to put in an order to replace all of those on all of my amps soon.
 

hepular

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probably unpopular counter to @kingfan & a host of common-sense:

replacing the cap-can is mostly difficult if one thinks it necessary to re-ground the cap-can tabs to the chassis with a ginormous soldering iron. Aren't there other, possibly even better ways, to ground those caps?
 




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