NAD - 1971 Princeton Reverb (pics pg 3)

Make it loud here.

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby kosmonautmayhem » Thu Sep 29, 2016 5:47 am

The speed mod is super useful, imo. It took a few tries iirc but I love where it ended up.

I've read that about repairing voice coils a few days ago. I like that idea! Definitely going to give that a try. :)

What did you use to re-glue the dustcap with?
User avatar
kosmonautmayhem
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4898
Joined: Sun Mar 14, 2010 8:26 am
Location: Chicago
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby maximee » Thu Sep 29, 2016 6:34 am

I think I used normal all purpose glue. It's paper and you only need the glue to hold the paper to itself, not much structural stress.
Let us know how it goes. Good luck!

Sorry for the slight derail, Kevin.
User avatar
maximee
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 785
Joined: Mon Mar 05, 2012 2:07 pm
Location: Germany
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Mon Oct 03, 2016 11:31 pm

Nice to know about how to sort out coil rubbing ... hopefully it's not something I'll ever have to deal with.

In the meantime I've learned a valuable lesson about trusting sellers (without checking for myself).

When I got this the seller was sure that the death cap had been removed (he said it had been fully gone over by his amp guy when he got it a few years back).

Playing it at the weekend I went to tweak the reverb and my finger touched the face plate/control plate. There was an immediate/loud thump noise through the speaker. Uh oh...

I was in a rush to get away for the weekend so I didn't have time to do anything then - I just powered it off and got on my way to Cork. Am I right in saying that the thump noise means that the death cap is in there, doing it's 'leaking current to the chassis' thing?

The long and short of it is that I'll need to fully go over the amp this weekend - I'd taken it on faith that the three prong plug was properly grounded and the ground switch disconnected, but I'll need to check that too.

Not a problem - it just needs the 'usual' work done I guess. Amp still sounds great - I'd just rather I didn't have to worry about a cap giving out and me getting electrocuted!
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby mijmog » Tue Oct 04, 2016 1:12 am

wproffitt wrote:Mine has the Oxford speaker too. Every now and again, I think about a speaker swap because I can't leave well enough alone. Then I play through it and all of those thoughts go away. Enjoy!


I took the plunge with my '79 SF PR and put a new baffle in and fitted a super efficient 12" Eminence speaker. I'm so glad I did, its transformed it into a very giggable beast. I just need to buy a Night Light or similar to help tame it, it feels louder than my Super Reverb! I find one ten a little bit "narrow" sounding and not as "hi fi" or detailed as I'd like.

I appreciate though that fitting a 12" takes it quite a way from the original sound of the 10" Oxford, and its a matter of taste, by doing so I've now made my amp harder to play at home, its way too loud for late night sessions.

Currently, I'm considering fitting a Celestion Greenback for the best of both worlds. I had one in my Deluxe Reverb and it was perfect, the right balance between low efficiency so it could be driven hard, and the bigger sound of a 12".
User avatar
mijmog
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 809
Joined: Tue Sep 09, 2008 7:03 am
Location: Lancashire
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby kosmonautmayhem » Tue Oct 04, 2016 6:32 am

I think I may have cut too deep trying to sort of the voice coil.
:fp: Looks like I'll be getting a recone on that one if I can't repair. I've put it away for a bit since I have too many project at them moment. Back to the Weber for now and sounding great!

Kev, I would get that checked out immediately. If you're feeling voltage on the chassis that's nothing to mess around with !!!
User avatar
kosmonautmayhem
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4898
Joined: Sun Mar 14, 2010 8:26 am
Location: Chicago
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Sat Oct 08, 2016 5:06 am

So yep - death cap was in there, as I suspected. That's the last time I take something on trust without checking it first!

Image

Funny to think that such a small thing stands between you and getting 110v earthing through your guitar strings!

Question - does anyone know if the transformers in these 110v models are the same as those used on the export models? I've seen Champs with the original 110v transformer rewired to work with 220v - and from what I saw when I took this apart today the transformer looks similar to those champ transformers. I wouldn't put it past CBS Fender to just use the same transformer for both models if it could be done that way (the only difference being how it's wired up).

The other thing I noticed while checking this out earlier was that it is spanking clean/original - everything is original/unchanged from what I can tell.
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Mon Oct 10, 2016 3:34 am

Things get ... interesting...

So the amp was working fine (albeit with the possibility of death by electric shock somewhere down the line) before the death cap was removed.

I tested it after the cap was removed and it was working (it was a 2 second test before I had to pack up and go).

Yesterday I fire it up hoping to have a good long session with it at home. Immediately the amp was very loud at low volume settings ... breaking up. Playing it with my LP the amp would go from normal to very loud/distorted.

I swapped out power tubes to see whether maybe a tube was acting up - putting in the RCA 6V6s actually made it worse .. the amp was humming loudly without a guitar plugged in.

Right - so in removing the death cap I shouldn't have done anything that would lead to this. The cap was purely leaking a small amount of AC to the chassis - removing it stops the AC leaking to the chassis. Power plug was grounded properly (to the chassis). Nothing else has changed.

I'm pretty sure I have the reverb plugs back the right way in - this would hardly cause the issue if they were the wrong way round, would it?

I think this could just be an unfortunately coincidence - something else goes just as i resolve the death cap issue. Is there anything obvious I'm missing here? I should point out that I didn't check the pre-amp tubes ... I guess one of those could be the culprit as well. Thankfully I've an entire Princeton NR worth of 12AX7s to mess with. Might try that tonight.
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby sookwinder » Fri Oct 14, 2016 4:00 am

Kevin..
- do you have access to a half decent digital multimeter?
- are you confident enough to measure some voltages while the chassis is outside of the cab , but plugged in and turned on?
relaxing alternative to doing actual work ...
User avatar
sookwinder
Mods
Mods
 
Posts: 9589
Joined: Mon Sep 11, 2006 6:47 pm
Location: Melbourne Australia
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Sun Oct 16, 2016 5:01 am

sookwinder wrote:Kevin..
- do you have access to a half decent digital multimeter?
- are you confident enough to measure some voltages while the chassis is outside of the cab , but plugged in and turned on?


- nope, but I've one on the way
- Yes - I'm probably overly cautious, but I don't think that's a bad thing with anything live!
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Sat Nov 19, 2016 6:01 am

Update...

So I sent the amp to a tech rather than messing with it myself.

Turns out that the issue was with one of the tone pots, which was arcing. Issue has been resolved - and in addition the tech quickly spotted that the transformer was one that was used for export models - i.e. it could be wired for 220v. So now the amp is running perfectly, quiet and no more need for a step down transformer!
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby kosmonautmayhem » Sat Nov 19, 2016 12:14 pm

Thats great!

glad it in tip top shape AND you got it wired for your local voltage!

I believe mine has the multiple taps required for higher mains voltage. I think they must've manufactured them like that for a few years.
I also had issues with a tone pot (bass) and ended up replacing it.
User avatar
kosmonautmayhem
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4898
Joined: Sun Mar 14, 2010 8:26 am
Location: Chicago
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Sat Nov 19, 2016 3:41 pm

It makes sense Nick. I mean ... if you have to make amps for different voltages, why have multiple different transformers if you can simply use one part in different ways for either the 110v or Export version.

I knew this could be done with Champs, but I wasn't sure it was common with PRs.

Man ... it sounds glorious though. It's been a while since this was working properly and now that it is I spent all of today playing the ES330 through it (which, by the way, is a glorious noise indeed!). The reverb is just so damn nice...
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby kosmonautmayhem » Sat Nov 19, 2016 6:32 pm

It makes total sense. But I've read about some PRs and think I've even seen schematics that show different transformers.

Man, I bet that 330 sounds otherworldly I your newly serviced PR! 8)
User avatar
kosmonautmayhem
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4898
Joined: Sun Mar 14, 2010 8:26 am
Location: Chicago
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Mon Nov 21, 2016 1:00 am

The funny thing is that whatever was going wrong with this amp (with the arcing of the tone pot etc) wasn't immediately a 'show stopper' in terms of the amp functioning. My initial impressions of the Princeton were based on an amp that was already malfunctioning, but had yet to fully break down.

How do I know this? Well ... my first impression of the PR was that it was a lot louder and broke up a hell of a lot more than the non-reverb Princeton ... I was getting break up at around 3 on the dial that actually sounded pretty good when I bought the amp!

Now that it's returned to how it should be the differences between the Prinecton and Princeton Reverb are more subtle at lower volumes and only really become clear when you push the PR a bit (when it does it's beautiful break up thing, while the Princeton NR just gets a bit louder).

If anyone is looking for an ideal bedroom/home use amp, I think the non-reverb Princeton is the way to go over the PR. The overall volume pushed out is lower and while it doesn't break up the way the PR does, it can be easily coaxed into break up using a boost pedal ... and will do so at lower volume compared to how the PR breaks up naturally. I find that the Princeton NR is still civilised in terms of volume at around 4 on the dial - whereas the PR sounds a lot louder from 3.5 onwards.

Obviously it's relative - what I'm describing as loud here is still manageable in most scenarios. The loudest sounding combo amp I ever owned/played was the original Bluesbreaker reissue - that thing just didn't do low volume at all. I live in an apartment - I'm conscious at all times of my neighbour downstairs, and while she's never once complained about noise (I've checked with her multiple times to be sure), I don't like to put other people through what I had in my last place (where I'd a loud and inconsiderate neighbour upstairs).

Anyway - all above for what it's worth...
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

Re: NAD - 1971 Princeton Reverb (pics pg 3)

Postby Despot » Wed Jan 11, 2017 2:14 am

Bit of an update here...

So before Christmas I took the Princeton Reverb down to Cork to play some music with old friends from university. We do this a few times a year and it's a good excuse for us to play and drink beer.

For most of the day I was forced to play the Princeton at lower volume than I would have liked, as one of the guys was using his home amp (a 1 watt Emery Sounds micro baby). This meant that the Princeton was at just under 3/volume. This is a little too low to really get it going.

Towards the end of the day before we were wrapping up to go for drinks I borrowed a friend's '61 RI SG Standard - '57 classic pickups and vibrola. I stuck it through the Klon into the PR and turned it up to about 3.5/4, which is where I usually like to have it for playing at home. And man ... what a sound! I hit a chord on it and realised that it had that biting SG tone from a lot of the Ryan Adams and the Cardinals stuff (think Cold Roses in particular). I'd never really been super taken with that SG before, but suddenly that magic combination of SG - Klon - Princeton Reverb just worked. The Klon bumped the mids in just the right way, but the SG/Princeton combo gave the bite. It was one of those occasions where you think "man, that sounds way better than how I normally sound" - there's an embarrassing video of me that one of the guys has (showed me later over beers) where I'm enjoying it so much I lose the ability to talk and just start making sort of owwwwweeeewoowwwwee sounds, grinning like an idiot!

If you've seen my recent NGD post about the ES355, one of the things I love about that guitar is how close it sounds to that SG - through the Princeton it gets to the same sound very easily. The ES355 sounds like a decent guitar through the Swart (which, by the way, makes the ES330 and Jazzmaster sound amazing), but through the Princeton it's tremendous. I've never been a fan of those '57 classic pickups (I had a reissue ES345 with them a few years back and I found it to be a bit dark sounding, but overall just lacking in character), but it could be that the Swart just isn't the best amp for them. Or perhaps I just have never set the pickup height properly to brighten them up...
User avatar
Despot
PAT. # 2.972.923
PAT. # 2.972.923
 
Posts: 4302
Joined: Fri Jul 20, 2012 9:11 am
Location: Dublin, Ireland
Top

PreviousNext

Return to Amps

Who is online

Users browsing this forum: No registered users and 12 guests