"New" (to me) Silverface Princeton Reverb

Discussion in 'Glowing Bottle Tube Amp Forum' started by ShawnRocker, Jan 18, 2016.

  1. ShawnRocker

    ShawnRocker TDPRI Member

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    I just picked this amp from a guy who I've interacted with for years on another non-guitar related forum.
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    Evidently he bought it as a teenager around 83 and quit playing after a few years, so it's sat in a closet since. He said it had a noticable hum and was scratchy, so I got it with the understanding it needs work. He told me his research at the time told him it was a 72.

    After a couple months I was finally able to meet him Saturday to complete the transaction. He didn't have a decent cable, so I couldn't tell if was the cable or amp that sounded scratchy, the hum was apparent. Obviously the speaker was replaced with a Muscle Magnet at some point. I did notice the drip edge.

    Sunday I got to my Dad's house (I live in another state), and decided to look into it myself a little before taking it to a tech. 1st thing I notice is the power tubes are mismatched, and it appears to have the wrong tube in the rectifier.
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    The mismatched 6v6's
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    So I pulled the chassis and sprayed some electronics cleaner in the pots, tightened a couple of obviously loose things and put her back together.
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    Plugged it in and it was 90% perfect. Still a slight hum, reverb won't engage, and I have to turn the Intensity knob way up to have it noticable. Otherwise it sounds amazing.

    Here's a couple clips. The 1st is just to show how clean it is, the 2nd is jamming with my Dad. The PR is the louder and soloing amp.

    https://m.soundcloud.com/racer5/audio-recording-2016-01-17-14/s-GRzyf

    https://m.soundcloud.com/racer5/audio-recording-2016-01-17-15/s-ulqag

    I played it a lot yesterday and by last night it developed a slight rattle. I have an old friend who's an amp tech here in town, I'm gonna take it to him to look over today but I think I'm gonna replace all the tubes and see what happens before doing anything else.

    So I emailed the guy and told him it seems to need way less work than anticipated when we agreed to extremely favorable terms and offered him more money. He said he just hopes I enjoy it and he's glad it's getting used.

    I'm thinking this is an extremely early Drip Edge since it has the same tube allotment as the late Blackfaces, but I need to research more. I'm not too versed in all that.

    I appreciate any inside any of you have into either the model, or functionality, of this amp.
     
  2. charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

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    Great amp.
    I gigged mine this past weekend.
    I play in a 5-piece band with a well-behaved drummer and, for me, a PR is loud enough for most gigs.
    I like bigger speakers and bigger boxes, but, on some good advice, I installed an Eminence Ragin' Cajun, and it has a big sound.
     
  3. FenderLover

    FenderLover Friend of Leo's

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    The drip edge is a tell-tale late sixties, like '68. Check the transformer dates.

    Score! You'll enjoy this amp.
     
  4. Mayas caster

    Mayas caster Tele-Holic

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    Yep, Fenderlover is right. Drip edge is 1968. Good news, your amp is just more valuable...
     
  5. Johnny Cache

    Johnny Cache Former Member

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    Nice if it were mine, I'd do a good cleaning of the amp, including sockets and test all the tubes, replace any weak ones, clean the pots and replace the filter cap can. Just for starters. I really like the '81 I picked up last year and did exactly that, plus replaced a bad speaker.
     
  6. Wally

    Wally Telefied Ad Free Member

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    The chassis date stamp indicates that work was done the 3rd week of 1968. The first SF amps were introduced in April, 1967 and had the drip edge. The AA1164 Princeton Reverb schematic calls for a 5U4 rectifier. A check of voltages would be of interest, IMHO.
    FYI, that tube chart is not for a Princeton reverb. Note that there are only 12A-7's on the chart versus 4 noval tubes in this amp. (;^) that is likely a tube chart for the non-reverb BF Princeton, the first of which did call for a GZ34 rectifier. Old story....Fender tube charts are not necessarily reliable sources of information.
    Also, just because power tubes are not the same model or even the same brand doesn't mean that they do not yield similar performance specs. Ime, the amp needs a recap before any tubes are replaced....or at least a tech needs to evaluate things. The preamp tubes and the phase inverter may very well be better than anything you could buy today.
    Nice amp.
     
    Last edited: Jan 18, 2016
  7. Wally

    Wally Telefied Ad Free Member

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    And...the speaker.....the codes there would be of interest. Muscle Magnet imay just be a reseller label...not a manufacturer. Alnico magnet....
     
  8. BobbyZ

    BobbyZ Doctor of Teleocity

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    Make darn sure it has a 1 amp fuse. Look close because the 1 amp fuse looks just like a 3 amp fuse.

    I'd replace all of the electrolytics cap can, bias and bypass. Those are the later 60s bypass caps and they're junk now anyway. (the earlier toliet paper roll ones seem to hold up better but I replace those too)
    Rember the two things that wreck electrolytics are old age and long periods of non use followed by being plugged straight into the wall.

    Grounded cord is just so much nicer. Unless you like getting those "whoops I plug it in wrong again shocks."

    Nice amp ! And it's got the good blue coupling caps keep those. Unless they're bad which is pretty unlikely.

    Weak power transformer in there so you definitely want it in tip top shape. Honestly if I had it I'd be ordering the parts now and not playing it at all.
     
  9. muchxs

    muchxs Doctor of Teleocity

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    It's absolutely mandatory to check the PT. If it's a 022772 and many of them were through 1970... Do not use a 5U4G with it!

    Doesn't matter what the schematic says. Fender schematics often contain errors. This is a big one.

    if I had my druthers I'd skip the whole 5U4G / 5AR4 discussion and just use a 5V4.

    If there's a 5AR4 / GS34 in there... leave it.


    BTW... nice Princeton Reverb! That thing is has all '67 black panel features except it has a silver panel. :cool:
     
  10. ShawnRocker

    ShawnRocker TDPRI Member

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    It has a 5Y3.

    I'm at the tech now. Here's a couple other pictures of some of the stamps I see if it helps date this thing.

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  11. Wally

    Wally Telefied Ad Free Member

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    Muchxs, I'll defer to your experience on this. +1 on the 5V4 being a safer current draw and lower voltage.
    I suppose my statement about tube charts' questionability extends to schematics. Who ya gonna trust, eh? I need to keep this Prin Rev/5U4 thing in mind even though I personally have never had a Prin Rev with a 5U4 come around with a dead PT. As you note, though, the PT is a bit overwhelmed by the Prin Reverb in more than one way, iirc. It is a wonder any of them have the original PT, maybe?
     
  12. Wally

    Wally Telefied Ad Free Member

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    That is a nice Eminence Alnico speaker form 1976 there, ShawnRocker.
     
  13. jondanger

    jondanger Poster Extraordinaire

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    Sure does look like the 10" Emi alnicos that Leo (And Tom Walker) was putting in the Musicman amps of the late '70s - which are high quality. I'd take care of any other issues before I thought about replacing that speaker.

    Great amp - a Princeton would round my stable out nicely, and I'm on the hunt.
     
  14. Wally

    Wally Telefied Ad Free Member

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    +1 on that, Jon....great speakers, ime.
     
  15. bluesfordan

    bluesfordan Friend of Leo's

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    awesome, if you think it sounds good now, wait until you get it fixed up. I had a '74 that I kept for 32 years and stupidly sold in 2006. I have a '69 non-reverb model now and it is an incredible amp now that it has been gone through (thanks Muchxs)
     
  16. muchxs

    muchxs Doctor of Teleocity

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    For all practical purposes that Princeton Reverb is a '67.

    While that Eminence alnico speaker is a good speaker it wouldn't be on my short list for that amp.

    DO NOT use a 5U4G rectifier with your 022772 power transformer. Your transformer is one of the fortunate few that hasn't had its guts boiled out by the wrong rectifier.

    It has a 2 amp rectifier filament winding while the 5U4G rectifier requires 3 amps, a full amp more than is available.
     
  17. 4telecaster4

    4telecaster4 Tele-Meister

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    So if a 5u4 requires 3 amps....if you have a 5u4 amp...sf....can you use the gz34 in it with no problems since it draws 2 amps instead of 3 amps
     
  18. JazzboxBlues

    JazzboxBlues Tele-Afflicted

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    Nice score. I'm sure once you have it all ironed out it will serve you well. I'm increasingly becoming convinced these are truly great at home amps.

    I love all the tech that come with these threads!
     
  19. ShawnRocker

    ShawnRocker TDPRI Member

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    Thank you all for the feedback here, it's been invaluable.

    I was at the techs, here in a small town away from home, for an evaluation meanwhile checking in here. He pulls a "Princeton Reverb" schematic of who knows from what year and is going through all the tubes. He replaces the 5y3 rectifier with something, fires it up, the hum is louder and it, thank god, blows the fuse. He pulls the chassis and starts measuring values. Meanwhile I'm reading these comments, specifically the ones about these transformer being blown because of 5u4g tubes. I finally make an excuse that I gotsta go and he puts it back together and cautions me over and over not to put the 5y3 back in, it's the wrong tube. He says I need a 5u4g, gz34, or 5ar4. I'm thinking this amp has lived the last 30 years with that 5y3 and it promptly blew a fuse with whatever you stuck in it.

    Honestly the hum is not that loud. I have some electronics training and decent soldering skill. I'm gonna try to find a tech back home in San Francisco who specializes in amps of this era. Otherwise I'll dig in here and do it myself. If today and you all have taught me anything, it's to not trust this amp to just anybody.

    I am happy to say I stopped at Radio Shack and picked up a 1a slow burn (thanks to whoever pointed that out, there was indeed a 3a in there) on the way back to Dads. The amp sounded the same as the night before once installed, so at least no damage done.

    I'm going back home tomorrow night on a big ol' jet airliner. Do I pack it up and check it, pack it and send it home FedEx, or try to carry it on ( it's small enough for the overhead)?
     
  20. jondanger

    jondanger Poster Extraordinaire

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    The way I've seen the baggage handlers, uh . . . handle the baggage, I'd feel more comfortable either carry it on, or head to a UPS or Fed Ex and ship it home. I trust the kind of padding that you can achieve with double boxing and packing peanuts more than trying to cram it in a suitcase and checking it. If you do decide to ship it, pull the tubes and pack them separate - you may know this already.
     
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