Patrick Posted January 27, 2011 Share Posted January 27, 2011 I picked up a 1970 Fender Princeton Reverb a couple of weeks ago. Near mint, 9.5 out of 10 condition. I wanted it because it's a nice match to my near mint 1970 Fender Pro Reverb. The Princeton Reverb is all original except for a speaker change. The photos showed the speaker as a Multivox 10" aftermarket speaker. (never heard of it) Everything else is all original. From the photos . . the 6V6s, the 12AX7s, the 5AR4, the caps all looked original. Apparently they are. I was pretty sure when I received it, it was going to need a cap job and the speaker would sound like sh**. No so! What a sweet sounding amp!! Reverb is a little shallow, but not terrible. Vibe sounds great. It breaks up earlier than I expected to . . .but that could be a good thing too. If I don't push it, it will give me a real sweet clean sound as well. Now, I'm not sure if I should do any mods to it. I was going to stick a Celestian Vintage in it and maybe go with a Fender Deluxe tranny . . . more iron more balls. Have a B+ Phase inverter mod done as well . . and maybe go with Sprague Orange Drops. But again . . . it really sounds pretty good as is. Any of you amp guys have any suggestions? Link to comment Share on other sites More sharing options...
Hfan Posted January 27, 2011 Share Posted January 27, 2011 Those old Fender amps are great. the 70 is Silverface or Blackface? Many of these smaller Fenders after transitioning to Silverface still retained the Blackface circuitry. Although many of the Silverface circuits sound killer as is. If your reverb is a little weak I believe there is one pre amp tube associated with the Reverb circuit its that way on my 73 twin anyway. Hard to believe that the filter caps are still good, amazing. I've tinkered a lot with mine, know just enough to be dangerous. If you do want to do any cap refurb to it for reliability, common school of thought is to replace the electrolytic caps (polarized with a + and - connection) first. These usually fail first, believe that these are the filter and cathode caps. If at all possible keep the original non electrolytic signal path (bypass I think) caps. You may have the blue Mallorys in a 70 fender these are desired. Lots of guys get a cap job and they wind up pulling perfectly good signal path caps affecting the tone. Enjoy the new toy. Link to comment Share on other sites More sharing options...
kbp810 Posted January 27, 2011 Share Posted January 27, 2011 If ain't broke don't fix it! When it comes to vintage gear, I personally like to try and keep it original as possible... with the exception of perhaps speakers (and of course tubes!). A cap job might be a good idea for the sake of saftey and/or forward thinking (i.e. like changing the brakes on your car before they start grinding the rotors) - as Hfan said, I would stick to just replacing the electrolytics. For the reverb, a good strong 12at7 in the second socket from the right might just bring that reverb back to life All that aside... nice find, and a great amp! Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 Pete: It's a silver face. But, fender didn't change the circuitry away from the original black face circuitry until late 1970s on the smaller amps. The earlier silver faces are defined by having the "tail" under the Fender logo and the "drip edge" around the grill. That's usually indicative of the change in circuitry in the smaller amps like the Princetons and Deluxes. This 1970 is pretty much exactly the same as a 1964 or 65 black face. kbp810 . . . I agree with you on leaving it alone. I guess unless something goes wrong with it, I will probably do just that. But, if I do need to bring it in for a cap job, I'll probably go balls to the wall. I know from your prior posts that you are a pretty serious amp guy. My expertise is somewhat limited to being able to accurately operate the on and off switch. How familiar are you with Princeton Reverbs? If it was your amp, and you were going to mod it . . what would you do to it? I'm not necessarily looking for more power ...just want to capitalize on that vintage black face Fender vibe. Link to comment Share on other sites More sharing options...
NoNameBand Posted January 27, 2011 Share Posted January 27, 2011 If ain't broke don't fix it! When it comes to vintage gear, I personally like to try and keep it original as possible... with the exception of perhaps speakers (and of course tubes!). A cap job might be a good idea for the sake of saftey and/or forward thinking (i.e. like changing the brakes on your car before they start grinding the rotors) - as Hfan said, I would stick to just replacing the electrolytics. For the reverb, a good strong 12at7 in the second socket from the right might just bring that reverb back to life All that aside... nice find, and a great amp! Patrick, kbp810 is your guy. If I liked the way it sounds now ie; I love the way my ''55 Fender Deluxe sounds and it is all original, I wouldn't change anything. However, if the reverb is a little week, the tube may be the solution. No risk to find out. Congratulations on your NAD. That's a great amp for Heritage jazz boxes and 150's. Link to comment Share on other sites More sharing options...
kbp810 Posted January 27, 2011 Share Posted January 27, 2011 Pete: It's a silver face. But, fender didn't change the circuitry away from the original black face circuitry until late 1970s on the smaller amps. The earlier silver faces are defined by having the "tail" under the Fender logo and the "drip edge" around the grill. That's usually indicative of the change in circuitry in the smaller amps like the Princetons and Deluxes. This 1970 is pretty much exactly the same as a 1964 or 65 black face. kbp810 . . . I agree with you on leaving it alone. I guess unless something goes wrong with it, I will probably do just that. But, if I do need to bring it in for a cap job, I'll probably go balls to the wall. I know from your prior posts that you are a pretty serious amp guy. My expertise is somewhat limited to being able to accurately operate the on and off switch. How familiar are you with Princeton Reverbs? If it was your amp, and you were going to mod it . . what would you do to it? I'm not necessarily looking for more power ...just want to capitalize on that vintage black face Fender vibe. I've never owned a PR personally, but I would start with speaker and a good strong set of tubes One small and simple mod that might help with the early breakup while not greatly altering the circuit would be to replace the 2.7k negative feedfack resistor with a higher value - perhaps in the realm of 6.8 k. That's one change I did on my 5F2 Tweed Princeton build that seemed to have a really positive effect. I could only find the schematic and layout for the blackface version - but I'm fairly sure this was in the same spot on the Silverface. Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 If ain't broke don't fix it! When it comes to vintage gear, I personally like to try and keep it original as possible... with the exception of perhaps speakers (and of course tubes!). A cap job might be a good idea for the sake of saftey and/or forward thinking (i.e. like changing the brakes on your car before they start grinding the rotors) - as Hfan said, I would stick to just replacing the electrolytics. For the reverb, a good strong 12at7 in the second socket from the right might just bring that reverb back to life All that aside... nice find, and a great amp! kpb810 . . . what about reducing the value of the existing 12AT7 cathode bias resistor from 2.2k to 1.8k? Would that run the tube at a slightly higher current? A little more drive to liven up the 'verb? I was also advised that moving the B+ feed from the phase inverter up one notch on the power supply voltage divider would drive the 6V6s a little more, providing a bit more dynamic head room. As it is now, it's clipping just before the 6V6s . . there's nothing left to push them any harder. A little more head room might be good for my arch tops where I don't want the early break up. I'm saying just move that one wire and leaving the rest of the B+ feed for the remainder of the pre amp stages alone. Link to comment Share on other sites More sharing options...
yoslate Posted January 27, 2011 Share Posted January 27, 2011 I have the Princeton Reverb reissue, which may render anything I suggest as moot. Tung-Sol 12AX-7's made a big improvement in the punch and clarity of mine. Speaker suggestion would be an Eminence Ragin' Cajun. Great mids; good low end, for a 10"; a bit round at the top end...balanced, but not bright. The Eminence sounds really good when pushed a bit! Link to comment Share on other sites More sharing options...
kbp810 Posted January 27, 2011 Share Posted January 27, 2011 kpb810 . . . what about reducing the value of the existing 12AT7 cathode bias resistor from 2.2k to 1.8k? Would that run the tube at a slightly higher current? A little more drive to liven up the 'verb? I was also advised that moving the B+ feed from the phase inverter up one notch on the power supply voltage divider would drive the 6V6s a little more, providing a bit more dynamic head room. As it is now, it's clipping just before the 6V6s . . there's nothing left to push them any harder. A little more head room might be good for my arch tops where I don't want the early break up. I'm saying just move that one wire and leaving the rest of the B+ feed for the remainder of the pre amp stages alone. Well... my initial guess is still that a fresh 12at7 might do the trick; raising the bias swing is generally a tactic to decrease gain, and a 12at7 already fits the bill of low distortion. The B+ tap move might be worth a try, fairly simple move that can be moved right back just as easily... the voltage at the plates would increase by about 20 volts or so by bypassing that first drop which should only change the bias point by about 1ma. Link to comment Share on other sites More sharing options...
koula901 Posted January 27, 2011 Share Posted January 27, 2011 Patrick, Amp-speak is gobbledygook to me, can't help ya there, but congratulations and I hope you get it to where you'd like it! : ) Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 I have the Princeton Reverb reissue, which may render anything I suggest as moot. Tung-Sol 12AX-7's made a big improvement in the punch and clarity of mine. Speaker suggestion would be an Eminence Ragin' Cajun. Great mids; good low end, for a 10"; a bit round at the top end...balanced, but not bright. The Eminence sounds really good when pushed a bit! Thanks Rob. I'm probably gonna take kbp's advice on the 12AT7 tube change for a start. Yours is the second recommendation I've had on that speaker. Also heard that the Weber C10 and Celestian Vintage were pretty good. Too many choices. Link to comment Share on other sites More sharing options...
NoNameBand Posted January 27, 2011 Share Posted January 27, 2011 Thanks Rob. I'm probably gonna take kbp's advice on the 12AT7 tube change for a start. Yours is the second recommendation I've had on that speaker. Also heard that the Weber C10 and Celestian Vintage were pretty good. Too many choices. Have Kbp810 build you a 3 way cabinet with all 3 speakers in it with switches for each speaker. Like at Circuit City in the speaker room. That way you can have all of it, no choice any more and you can use which ever one speaker you want at a time. There, problem solved. Glad to help. Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 Have Kbp810 build you a 3 way cabinet with all 3 speakers in it with switches for each speaker. Like at Circuit City in the speaker room. That way you can have all of it, no choice any more and you can use which ever one speaker you want at a time. There, problem solved. Glad to help. Even better, kpb810 could put all 3 speakers on a spinning board . . . then it will sound like a Leslie Link to comment Share on other sites More sharing options...
kbp810 Posted January 27, 2011 Share Posted January 27, 2011 Have Kbp810 build you a 3 way cabinet with all 3 speakers in it with switches for each speaker. Like at Circuit City in the speaker room. That way you can have all of it, no choice any more and you can use which ever one speaker you want at a time. There, problem solved. Glad to help. Why stop at just three??? Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 Why stop at just three??? Now, that set up is probably what motivated Phil Spector to incorporate the "wall of sound" into his producing. Link to comment Share on other sites More sharing options...
Patrick Posted January 27, 2011 Author Share Posted January 27, 2011 Patrick, Amp-speak is gobbledygook to me, can't help ya there, but congratulations and I hope you get it to where you'd like it! : ) Thanks Katy; it sounds good as is. Before I do anything to it (except the speaker change, I'll probably do that immediately) I'll play it for a while. I mainly want to run my Strats through it. I've got the larger Pro Reverb for the jazz boxes, semi-hollows and LP style gits. But, tonight I'm going to run my 2 P90 guitars through the Princeton just for shits and giggles. I'll just roll all of the knobs, dime it out and see if it holds together. Link to comment Share on other sites More sharing options...
602a Posted January 27, 2011 Share Posted January 27, 2011 That bad body should sound great with a strat going thru it. Congrats. Link to comment Share on other sites More sharing options...
Gitfiddler Posted January 27, 2011 Share Posted January 27, 2011 Patrick~ Congrats on acquiring one the all time great small amps. Your R6 should sound killer through it. I know a bunch of Bay Area blues players that swear by Princetons for small clubs. They crank em up and roll back the volume on their guitars and wail away. Too much fun! Link to comment Share on other sites More sharing options...
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