Princeton Reverb restoration

Twist · 9th August 2011

Hi all,

I was recently given a Silverface by a family friend who no longer used it. The amp appears to be all original and likely haven't really been played since when it was bought back in the late 60's/early 70's. (He couldn't quite remember.) It has probably not seen more than 50 hours of playing in its life so far.

It sounds gorgeous, though a little dark. The reverb is so noisy that, even at low volume, I cannot turn it up without being blown out of the room, and all the knobs crack and pop when I turn them.

I am not very experienced with servicing amps, and my question is: will changing tubes be enough to bring this amp up to a less noisy standard, or should I really have it brought in to an amp check-over? And, if so, how much should I expect to pay if there is nothing "wrong" with the amp, save for a little beauty treatment?

Also, it's a US 115 ac amp now being played in Copenhagen, Denmark, through a step-down converter from 220. Will this affect the sound? I notice a great deal of ground noise when I don't touch the strings, and am thinking I should maybe get a better converter.

Many thanks for your time and help.

Christopher

AndyFromDenver · 9th August 2011

It's so much more likely capacitors, resistors, or pots that are the issue rather than tubes. I'd definitely take it to someone. Just think, in about a week you will be playing your guitar through a beautiful vintage amp

lucky!
For starters on the reverb, try a new rca cable cause the og ones with the metal mesh covering are likely super old with a questionable connection, then just spend some time turning all the pots to try and clean out the dirt.

nedorama · 16th August 2011

The biggest thing to change is the Electrolytic capacitor can, which filters out noise from the power. These capacitors go bad over time, and your amp is due to have them replaced. This is considered normal wear and tear and won't negatively affect the sound of your amp. It will remove any problem noise, and prevent those capacitors from blowing and then something downstream may suffer.

Google "Fender Death Cap mod" to ensure that the power cord is effectively wired. With a modern 3 prong cord, the polarity switch is not used.

You may also have a reverb driver or recovery tube (12AX7A) that needs replacing. The preamp tubes can be replaced by you fairly easily. With the amp on, try gently tapping the smaller tubes with a pencil eraser to listen for any noise.

Once you get the amp up and running, there are plenty of options if you want, but they're also great stock. I like both my Princeton and Princeton Reverb; the Princeton is fairly stock while the PR I've tweaked a bit more.

Congrats and enjoy!

drbob1 · 16th August 2011

Good suggestions so far. Are you handy with a soldering iron? If not, take it to a tech and as for the power supply caps to be replaced, general cleaning, pots cleaned, tube sockets cleaned, tubes tested, solder joints checked, reverb tank tested... Then you'll know what needs doing next. With that many hours, the tubes are likely minty fresh (just sitting there doesn't hurt them, it's being used that wears them out). The speaker, however, is likely dried out and tired. It may need a recone, or just to be put in a box and saved for when you sell. Replace it with a Jensen or JBL10" pulled from an old organ (or a Fane alnico since you're in Europe). Those will open up the sound a lot.

The reverb problem could be a driver tube (12AT7) or socket, more likely a bad cable or the reverb tank could have died (they're mechanical and don't last, but they're easily replaced with modern exact alternatives from Hammond). Using the convertor won't be a big problem, the different frequency in Europe (50 cycles vs 60 cycles) shouldn't affect a guitar amp except the speed of the tremelo, maybe.

9th August 2011	#1
Twist Gear interested Joined: Aug 2010 Posts: 3 Thread Starter	Princeton Reverb restoration Hi all, I was recently given a Silverface by a family friend who no longer used it. The amp appears to be all original and likely haven't really been played since when it was bought back in the late 60's/early 70's. (He couldn't quite remember.) It has probably not seen more than 50 hours of playing in its life so far. It sounds gorgeous, though a little dark. The reverb is so noisy that, even at low volume, I cannot turn it up without being blown out of the room, and all the knobs crack and pop when I turn them. I am not very experienced with servicing amps, and my question is: will changing tubes be enough to bring this amp up to a less noisy standard, or should I really have it brought in to an amp check-over? And, if so, how much should I expect to pay if there is nothing "wrong" with the amp, save for a little beauty treatment? Also, it's a US 115 ac amp now being played in Copenhagen, Denmark, through a step-down converter from 220. Will this affect the sound? I notice a great deal of ground noise when I don't touch the strings, and am thinking I should maybe get a better converter. Many thanks for your time and help. Christopher

9th August 2011	#2
AndyFromDenver Lives for gear Joined: May 2010 Location: Athens, GA Posts: 756 1 Review written	It's so much more likely capacitors, resistors, or pots that are the issue rather than tubes. I'd definitely take it to someone. Just think, in about a week you will be playing your guitar through a beautiful vintage amp lucky! For starters on the reverb, try a new rca cable cause the og ones with the metal mesh covering are likely super old with a questionable connection, then just spend some time turning all the pots to try and clean out the dirt. __________________ Good credit, bad credit, no credit, what is credit, can't read or write... www.myspace.com/marshmallowcoast http://en.wikipedia.org/wiki/M_Coast

16th August 2011	#3
nedorama Lives for gear Joined: Jan 2008 Posts: 1,242	The biggest thing to change is the Electrolytic capacitor can, which filters out noise from the power. These capacitors go bad over time, and your amp is due to have them replaced. This is considered normal wear and tear and won't negatively affect the sound of your amp. It will remove any problem noise, and prevent those capacitors from blowing and then something downstream may suffer. Google "Fender Death Cap mod" to ensure that the power cord is effectively wired. With a modern 3 prong cord, the polarity switch is not used. You may also have a reverb driver or recovery tube (12AX7A) that needs replacing. The preamp tubes can be replaced by you fairly easily. With the amp on, try gently tapping the smaller tubes with a pencil eraser to listen for any noise. Once you get the amp up and running, there are plenty of options if you want, but they're also great stock. I like both my Princeton and Princeton Reverb; the Princeton is fairly stock while the PR I've tweaked a bit more. Congrats and enjoy! __________________ nedorama Monkey Boy Studios Summit 2BA-221, TLA-50 mBox Pro 3, Pro Tools 10.1.3 Radial JDI x 2, ProD2, ProRMP '65 Bandmaster 2x12 combo with Dr. Z Brake Lite, '65 Showman, '74 Princeton, '77 Princeton Reverb, Dr. Z. Mini Z Head, Dr. Z 1x12 Cab, pedals, George L's cabling

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

16th August 2011	#4
drbob1 Lives for gear Joined: Nov 2009 Posts: 1,420 3 Reviews written	Good suggestions so far. Are you handy with a soldering iron? If not, take it to a tech and as for the power supply caps to be replaced, general cleaning, pots cleaned, tube sockets cleaned, tubes tested, solder joints checked, reverb tank tested... Then you'll know what needs doing next. With that many hours, the tubes are likely minty fresh (just sitting there doesn't hurt them, it's being used that wears them out). The speaker, however, is likely dried out and tired. It may need a recone, or just to be put in a box and saved for when you sell. Replace it with a Jensen or JBL10" pulled from an old organ (or a Fane alnico since you're in Europe). Those will open up the sound a lot. The reverb problem could be a driver tube (12AT7) or socket, more likely a bad cable or the reverb tank could have died (they're mechanical and don't last, but they're easily replaced with modern exact alternatives from Hammond). Using the convertor won't be a big problem, the different frequency in Europe (50 cycles vs 60 cycles) shouldn't affect a guitar amp except the speed of the tremelo, maybe.