Disclaimer - (1) I know next to nothing about this. I enjoyed my PRII with the factory speaker in it. Do I really prefer the replacement I fitted, or do feel I ought to simply because of the time and money spent? I think there's a genuine improvement. And others quoted below clearly aren't kidding when they rave about their new speaker. But you choose.
Disclaimer - (2) This is all subjective and none of my contributors is claiming that any brand of speaker is badly made or poor value for money, so please don't sue them or me.
Disclaimer - (3) Because this is so subjective, please do not blame me if you spent as much on some legendary speaker as you did for the whole amp, and then found you liked the original speaker better. However, your opinion might be worth repeating here if you think others may be similarly disillusioned.

Would any speaker supplier like to introduce a try-before-you-buy system? Do you know of one already? How about a dealer offering mp3s of genuine like-for-like A/B comparisons? The Celestion website is better than nothing, but in my opinion they should play the same musical phrase through the same amp settings through each speaker.

I have replaced my original speaker with a Jensen C12N reissue (Sep 04). After a couple of rehearsals with my band, here are my impressions. Compared to the original, it has more sparkly top end, more bass, and little more efficiency. At low volume (say master = 3 ) this speaker is louder than the original. At higher volumes the cone breaks up earlier, providing speaker distortion at lower volume than the original. At the max volume I don't think this speaker is louder than the original, due to cone breakup and (I think) the mild compression effect of the ceramic magnet. In general the sound is a little more detailed and 'organic' or 'natural'. The cheap power valves (which I leave in the amp most of the time) used to sound a little nasty when pushed into distortion, but this speaker somehow makes them sound OK.  It took 2-3 hours of playing at medium volume to 'break in'.

I didn't think the original speaker is the dog which some folks make it out to be. But the Jensen improvement is worth the $45 (£30) I paid South Valley Vintage Amps in Gilroy, California, USA (warmly recommended outfit). Knowing what I know now, I don't think I would have paid $100 for this kind of improvement, but that's just me and my Scottish heritage showing through. Other peoples' experiences at the bottom of this page.

March 05 - With the original speaker I used to get a pretty natural-sounding acoustic sound from my Yamaha acoustic with a Martin piezo pickup. It's not so natural with the Jensen! Can't win them all... maybe this says the original speaker was deliberately chosen for a neutral sound in order to make the amp as versatile as possible. (I don't mean Fender intended the amp it for acoustic amplification but I don't believe they chose the speaker carelessly, as some folks seem to suggest.)

Technical bit
The PRII puts out 22W RMS, expects an 8 ohm speaker, and is built for a 12" speaker. The baffle board (front panel where the speaker goes) is 20mm ply and the speaker hole is 270mm diameter. It's held in place by eight screws with 11/32" nuts. (9mm does ok but it's not quite right). If you fit a speaker of less than 22W power handling you can expect it to blow eventually, with a real chance of taking some part of the amp with it. If you fit one of different impedance (ie not 8 ohms) you may destroy the output transformer (rare and expensive). Higher impedance (usually 16 ohms) will stress the primary winding of the OT, and lower impedance (usually 4 ohms) will stress the secondary. Stick to 8 ohms.  If you get a different diameter speaker... it won't fit in the hole! Duh! ......However this still leaves you with plenty of choice if you want to replace the speaker.

The original speaker (Eminence version) weighs about 3Kg (about 6.6lb). Almost any  replacement speaker will weigh more. 

Different speaker models come with varying numbers of mounting holes. After removing the original speaker you may have to remove some of the original mounting pegs. Don't break them off! They will unscrew - this is done from the FRONT of the speaker baffle - remove the grille (see the dismantling page) to get at the cross-heads, and remember they're reverse thread, so turn them clockwise to get them out. (That's the wood-thread which is reverse thread. The nut-thread is normal.)

The Original Speaker
The standard-model factory-fitted speaker was Fender part number 019465. In the early days it was made by Pyle and had a smaller magnet assembly. That part number didn't change when Fender changed to Eminence. I don't think there's much difference in the sound,  and it definitely makes no difference to the value of the amp. The Eminence weighs about 3Kg (6.6lb). There's a range of amp serial numbers running from F309xxx to F312xxx (includes part of 1983 and part of 1984) where it could be a Pyle or an Eminence. Maybe there was a time when they had Ps and Es on the shelf, all mixed up. And I already know the serial numbers weren't issued consecutively. Maybe both kinds of randomness were in operation at the same time.

                      Pyle normal-issue speaker from start of production                                                                                                                                                                        Eminence normal-issue speaker from 1983? 84? onward.
                                photo - Greg G (thanks!)                                                                                                                                                                                                                 photo - me. I've done some dusting since.

The Original Upgrade Speaker
The PRII was offered with an Electro-Voice speaker as a factory-fitted option, called model 12F. I don't know how much more it cost or weighed. I was pleased to hear from Greg in Texas. He bought his PRII, with the EV option, new in 1982. He had the chance temporarily to change his speaker for the Pyle or Eminence, and  reports that the EV is much, much louder. The thought scares me because I think the PRII is plenty loud with the stock speaker. The EV looks like this;

(photo -  thanks to Bob Herrmann)

Big magnet, eh? I wonder what effect that has on the sound. Viewed from the front, this speaker has an aluminium central dome - under normal lighting it's normally visible through the grille cloth - which makes me think it produces piercing highs. One contributor below says it was great for clean work. He replaced his with a Celestion Greenback, which has a more bluesy reputation. But I haven't heard either.

Replacement Options
A different speaker will make your amp sound different. There are trade-offs to capitalise on, or beware of. You could choose another speaker purely on efficiency, and end up with a speaker which is far louder but sounds dreadful. Speakers also introduce their own type of distortion when pushed hard; it's a different kind of distortion to that introduced by the electronics, and has a distinct character of its own which we may or may not like. It's called 'cone break-up'; it's the opposite of the hi-fi ideal of the speaker behaving as a 'perfect piston'. You could fit a speaker which has a far higher power rating; it will last forever and will never add any of its own distortion (which  will be a plus or a minus depending on your taste). Or you could fit a speaker with no spare power handling capacity, so the amp can push it into cone break-up more easily.

Then there's which material the cone's made from, the magnet type (ferro, alnico, ceramic), the magnet size, the material of the centre cap, the presence or absence of varnish on the edge of the cone (doping)... the options just go on and on. Alnico magnets 'compress' the dynamic range - as you turn up the volume, it eventually reaches a point where it doesn't get any louder, just distorts more (but in a nice way). Ferro magnets do this least, with ceramics in between.

(The original speakers, all types, are rear-loaded - see photos above - they're bolted to the back of the baffle-board. Some speaker cabs are front-loaded, ie, you bring the speaker to the cab from the front and it makes contact with the front of the baffle-board. I believe that's preferred if the speaker is very heavy or the baffle-board is weak. Plus it moves the speaker about 25mm forward compared to rear-loading, so if you've got a very deep speaker.... anyway, I can't imagine anyone wanting to do this on a PRII but if you do, then you have to read the new speaker's specification sheet carefully for the required hole-dimension and baffle-board thickness. The existing baffle-board is 270mm diameter, 20mm thick. The rest of this page assumes rear-loading.)

If everything else appears equal, check how many screw holes there are around the rim of the speakers you're considering  buying. The original has eight, evenly spaced around the circle. If your new one has six, you'll have to spend an extra hour removing two screws and precisely re-positioning four others. Celestions need four, I believe, so that would simply mean removing the other four.

With some other amps, you can't fit some speakers (even with the correct cone size) because the magnet is too big and hits some part of the chassis. Considering how big the magnet is on the EV speaker factory option, magnet-size probably isn't an issue on the PRII, but please let me know if you run into such a problem. Also - a tech on the FDP described this - with a non-standard speaker,  it is possible, on some amps, for  the new magnet to be too big / too powerful / too close to one of the valves/tubes; you can fit the speaker in, but the magnet bends the electron beam inside the valve, thus reducing the signal! I mention this for interest; I don't think it's going to happen on a PRII.

Browse through the discussion pages linked from the  PRII home  page and you'll see folks raving principally over Webers, Jensens, Tone Tubbys and Celestions. Older Jensens seem to be regarded as the classic Fender-tone speaker. Weber are applying modern techniques and huge amount of know-how to offer a wide range of different-sounding speakers. Jensen are no longer made by the original owner of the Jensen name or by 'vintage' methods; they do 3 relevant ranges,  C12K, C12N and a C12P; all made in Italy; all seem to have their fans. Celestion, apparently, sound British (surprised?), which means they're probably useful for playing the bad guys in American films. July 06; see the bottom of this page for a new-ish Eminence speaker. July 08; one guy I'm in touch with has a Scumback speaker. Who thinks up these names? I'd be pleased to hear from you if you've used any of the above, or others I haven't heard of.

Some new speakers need to be 'broken in' - that is, the flexible parts are stiff when new and don't sound very good for the first 2 or 3 hours of use. After that time they become louder with a fuller tone. This was true of my new Jensen. Some people 'break in' the speaker before fitting - they connect it to a radio and leave it playing for a couple of days. Others say that doesn't help, and it only 'breaks in' when used for the purpose you bought it  for, so just play loud and be patient. If you're anything like me, you need the practice anyway.

Changing the Speaker (new May 08; another approach)

I worked all this out for myself, and so could you, but hey, it only took me half an hour to write up.

You need a new speaker, a cross-head screwdriver and a 9mm or 11/32" spanner. (As I said above, 9mm isn't quite right but it does. 11/32" spanner is exactly right.) Maybe a wood drill, maybe some new speaker connecting tags.

Warning; the speaker screws have very sharp pointed ends (why?). They are like 8 spikes waiting to hurt your hands and damage the speaker cone.

Switch off the amp, unplug it from the wall, pull the speaker jack out of the back panel.

Gently pull the speaker lead off the tags.

After removing the chassis, you need  the spanner to loosen the eight nuts HALF WAY ONLY on the eight speaker screws. (Normal thread; loosen anticlockwise). A ring spanner might not fit around the nut (mine did - just) because of the shape of the speaker metalwork (the 'basket'). A socket won't work unless it's a very long socket, because the screws are long and the socket won't sit down far enought to reach the nut. Once the nuts are loose you can use a socket, with no handle, to unscrew them HALF THE LENGTH of the screws.

Now check the speaker pulls away from the baffle-board. It it's sticking, it may need some gentle prising away. Once you're sure it's detached from the baffle-board, you can safely remove all the nuts, hold the speaker really firmly, and lift it clean out of the cabinet. Don't drop it onto the screws (they will damage the cone).

My new Jensen C12N Reissue has eight mounting holes and went into the cabinet with no changes to the screws. Because of this, the whole job took less than an hour. (If you need to remove or re-position screws, this is done from the front of the baffle board with a cross-head screwdriver. You've already removed the speaker grille as part of the dismantling process. The thread which holds the screw in the wood is reverse thread so they come out clockwise. Remove the unneccessary screws and/or drill new holes in the baffle board as necessary.)

Think about which way 'up' the speaker should be - in my case there are eight steps around the circle; eight ways the speaker could go in. The obvious thing is to rotate it so the label reads the 'right way up' but the real question  is, will the speaker lead reach from the tags to the speaker socket? Also it's important that the speaker lead doesn't lie close to any of the parts that will get hot, so it's best to turn the speaker so the tags point to the 'input' side of the amp.

So choose which way 'up' the speaker will go, place it carefully over the screws (again, avoiding cone damage), place and  tighten the nuts, but not as tight as if you were working on a car; you don't want to distort the shape of the speaker metalwork.  (Tightening is normal thread; clockwise. Engineers will want to tighten one screw, then the one opposite, then another, then the one opposite, etc etc. Non-engineers will never understand why that's important to engineers, and shouldn't worry about it). Connect the speaker lead to the speaker (the Jensen uses the same size tags as the original). Put the chassis back. Replace the upper rear panel. Reconnect all leads. Job done! Now play it hard for a couple of hours to 'break it in', and finally email me with what kind of speaker it is and the difference it's made.

A Few Links

http://www.webervst.com/bt9908.htm is a Guitar Player magazine excerpt, put on the web by US speaker maker Weber. I think some of the prices listed can be improved on...

There's an interesting thread running on the Fender Discussion page; knowledgable-sounding people were comparing notes on the best speaker for the Deluxe Reverb, which is another 22W valve (tube) amp with one 12" speaker.

Watford Valves sell speakers - see their speaker page.. Can you recommend any particular suppliers?
  

Users' Experiences

http://www.youtube.com/watch?v=xWydDp25KmE

http://www.youtube.com/watch?v=vT_7SHLKW3I

"Just wanted to let you know that the Jensen Neo 12-100 speaker for the Princeton Reverb II is working out excellent.
It sure gave it a boost compared to the Eminence speaker which was in the amp.  All in all I am happy with the decision.

Speakers tested

Marshall Wolverine G12 H80, this speaker is quite balanced but a bit harder sounding than the lower wattage models (needs more power put through it I think) the treble seemed to me to be a bit on the harsh side but lowering the treble a little seemed to solve this, the bass and mids were there in abundance but not overpowering and this speaker did not seem to compress or go spongy at all. This speaker is now in the Sessionette 75 and has made it a very loud and punchy amp.

Bob

Derek Rocco of Watford Valves has a PRII and swears by the Celestion Blue speaker, which he uses himself. Apparently it makes the amp significantly louder without changing the tone much. However, when he's at work, checking valves for microphonics and tone, he says a Jensen speaker helps him hear more detail in the valves' sound.

Larry O, writing on the Harmony Central page says....
I replaced the stock speaker  just recently with a Celestion Blue Alnico - 12" 15W 8ohm. Apprehensive at first  because of the cost of the speaker (list $395.00 US, got it for $200.00), and wattage rating. This speaker is said to be designed for low power class - A amps, but.... popped  it in, used at a gig right off the bat. Fantastic. Never took master/channel volume over 5/5.  (okay, I pushed it up to 7 or 8 during one solo). The tone was fabulous at all volumes. I  found it amazing how different the tone controls respond to this speaker. Almost make it a different beast. One note of caution to those pondering the same swap - I could not  remove any of the original speaker mounting screws. (yes, you can - see above) The original speaker is mounted  with eight screws, the Celestion Blue has 4 screw holes. I broke off 4 - yikes...but it did  the trick. (don't do that..... see above; Larry - thanks for sharing so others can be helped!) This set up made my Strat with Lindy Fralin pickups sound just like I dream about. I intend to use this rig for recording and low volume gigs.

(note the 2 guys above have used a speaker with a lower rating than 22W; I assume they know the risks, OR maybe the risks are small because their playing style doesn't involve full-volume power chords for extended periods, and Celestion probably rate their speakers conservatively.)
 

Greg,  writing on the Harmony Central page says....
Prior to a speaker change out, I was a little disappointed. The amp sounded flabby,  lacking definition of colored jazz chords on clean settings. I slapped in my spare, recent  Jensen C12K and everything changed. (He means for the better.)

Bad Bob, writing on the Harmony Central page says....
(I fitted a) Celestion Vintage 30 on advice from a Harmony Central Member and "Holy (expletive deleted)", Was that Dude ever right! "Mesa Boogie Move over".

Raymond DiG, writing on the Harmony Central page says....
Before we go any further, expect to change the stock speaker....... I  had great success with a Jensen C12N. It's reasonably priced and perfect for preserving  that Fender clean and on the brink tone.

Motogee, writing on the Harmony Central page says....
The speaker has been changed to a 1980 Celestion G1265, sounds great 

Skip Bragdon writes from Maine,USA.....
"The PRII was found down in Boston when I first started accummulating all
this gear.  The speaker had a terrible buzzing at low freq. sustained notes, so out it came.  As I stated earlier, the Emin. that replaced it was flat and uninteresting--there started my journey this winter.... if you get a chance to try a WeberVST unit, even for a "test drive", take it.  I installed two new 10" units in my Fender Custom Vib.Rev., and this amp is now a new animal.  Ted Weber is a "hands-on" company owner and is very accommodating and patient.  Answers all email personally with great advice.  My Vib.Rev. had Emin. alnico units which did not have the clarity, loudness, or fidelity as the Webers, and they broke up too soon.  Now I have more headroom but still get plenty of articulate, smooth breakup when pushed--really punchy w/out too much brightness.  I sound like a salesperson--sorry.  Ted has found some great formulas with his speakers and has come up with some original designs too. You probably know his website, but it is www.webervst.com.  I had a Jensen Vibranto unit reconed by his company(I have 3 of those now), but I have not tried it yet.  I think I will have him recone the spkr. from my PRII at some point.

Your speaker code "67(Eminence)-6707" is one I can't figure out. Currently,
the four numbers following the company code are the date of manufacture with four more numbers after that, designating the sequence number, or the number of spkrs. made in that batch.  Wow, hundreds or thousands of units in a batch.  Anyway, I contacted them and was helped by Charlotte Barnett.  If she has your spec numbers and what amp the unit came from, she could help you with an ID.  She gave me more specs than I can understand.  Good luck."

Pat Morford writes...

anyway, you were vascillating about SPEAKER, i havent heard the stock 
speaker, but i tried similar, and the VOX is AMAZING

totthe ABSOLUTE MAGIC speaker is the ALNICO blue or silver vox unit.

i tried all sorts of alnico, and ceramics..i have many types.

i generally like EXCLUSIVELY the round magnet alnico speakers, made by 
many differant manufacturers in many forms.

but trying them all, and regular celestions, the VOX is the ABSOLUTE 
MAGIC UNIT.

there is a new TONE TUBBY with a hemp cone, which is supposed to be an 
upgrade of the vintage vox, i havent heard this.

TOTALLY  worth it. the WEBER version is probably good also. ROUND 
ALNICO RING MAGNET is what you want. i tried several though, and the best bass was by far the VOX, compared to the jensen p that people have been raving about.

i suppose the jensen are more available used ( bell and howell projector 
cabinets, etc) and cheaper..i bet. there are some nice AMPRO cabinets with big alnico ring magnet units as well.

you have twice as many speaker screws as needed for a vox speaker. the hardest part is removing the extras..if you take the velcro cover off the front, and use a phillips in the CLOCKWISE ( tightening, not loostening) direction, they will back out 3/8of an inch. i then wiggled them till they came out, tapping them with a hammer from the back of the enclosure...  leaving just the 4 i needed for the vox speaker.

when i installed the vox, i also put in a speaker wire holder on one of the pins, to route the speaker wire AWAY from the output tubes...where the insulation might have burnt it.  now it runs under the audio transformer. i also wired proprietary cabinet damping material on the SIDE WALLS only of the cabinet..leaving the speaker "sound board"undamped.

(Pat  has some interesting stuff on his website http://nanaimo.ark.com/~pat/index.htm )

-----------------------------

DP2003 on the Fender Discussion Page says his PRII came with the Electro-Voice speaker (an original option from Fender). He replaced it with a Celestion Greenback and says....

" (it was a)  EV 12F.... - technically it is a EVM 12L but Fender branded. It did sound "great" especially for clean work, but not quite what I was looking for with this amp. The Greenback breaks up a little sooner and is a bit rounder sounding to my ears."

 
A different approach altogether - Sudsysul on the Fender Discussion Page says...

My early 70's Marshall JMP 50 head was starting to make some static noises, so I took it to a shop. At Monday's practice, I substituted by plugging my Princeton 2 into my Marshall 1936 2X12 bottom loaded with pre-Rola Celestion Greenbacks, and, WOW!!, was I impressed.

I just bubbled and giggled thru our entire practice, enjoying the chimey tones I was getting, driving the Princeton with a Real Tube pedal, setting the P's volume on 9, pulling the Mid button and setting it low at 3, and letting her rip. We did Beck's "Ended As Lovers," and the big, fat tone was perfect.. so much feel to this wierd combination... strange bedfellows indeed!

We've got a gig this weekend, and I'll be using this setup for sure. It might look goofy having a little combo stacked on a Marshall cab, but that's what I'm going with. This poor little amp is the Rodney Dangerfield of older Fender stuff.

(he later says the gig went fine, with the  PRII  performing 'miraculously')

Also on the FDP, Coyote-1 says I've run my Princeton Reverb II thru a 4x12 for ages. What you lose in portability, you more than make up for in tone. :)

Back to swopping around 12" speakers in the PRII cabinet, akw from Germany writes on the FDP....
By the way i recommened changing the speaker. I did some experiments with connecting to other combos. A JBL gave me the dream clean sound, a Celestion Vintage 30 made a agressive rock beast. A jensen C12n gave me a good fendry overall sound and even a Fender Gold Label (Eminence) gave me a less boxy and better rock sound.

He recently went into more detail...

I did invest some money in Celestion speakers to get right the one for my PRII.
I purchased a vintage 30, which was harsh and to much of everything (bass, high mids and highs). I would recommend this one only for hard rockers, avantgarde or death metal.
A celestion G12-65 is a fine mid heavy speaker, but lacks of note definition and highs. Its too warm with a amp which tends to be on the fat side (6v6). But maybe great chassis to tame a brittle amp like a DRRI or a twin.
A JBL K120 made the greatest dick dale clean sound I ever had, but sounds awful overdriven. A one trick pony which doesnt fill my bill.
A current Fender gold label was a clear improvement over the stock eminence, but i felt something was lacking - mids and guts!
A bargain on ebay was a new in box Celestion G12H-100 for 40 bucks. A sound with great mids and good bass (Billy Gibbons uses this speaker in his combos!). I doesn't tend to break up but produces the distorted sound very boldly. The philosophy behind is to reproduce the amp sound without adding distortion from the speaker. So far my best choice.
I would like to hear a Greenback and a G12H-30, but the G12H-100 is already a great choice.

-------------------------------------

July 06 - Another e-buddy, Christian Iversen, wrote this on the Fender Discussion page a few months ago and I repeat it here with his permission...

I bought The Tonker on a German instrument store's website, www.thomann.de. They don't carry all of Eminence's Red Coat/Patriot series, but they do have the Red Fang. If I were in Britain I'd check with www.ross-com.co.uk. They have the whole line and even some of their own soundbites of various speakers such as the Red Fang and The Tonker. I don't think you can find a better deal anywhere..."

tusind tak, Christian! a few weeks later he wrote...

Yes I am indeed still using The Tonker and it's all good. :)

It's not broken completely in yet I think, but so far it has gone from 'pretty damn good' to even better...

It's warm, crisp and clean, with just some hair on if you really hit the amp hard - I'm using Texas Specials about even to the guard and I punch my strat every chance I get.

It's loud, but it doesn't fry your brain like an EV 12L would at that. It's loud and still very sweet on your ears

-------------------------------

March 08 - littleuch, on the FDP, says...

I finally got to work my PRII with a Eminence Red, White and Blues this weekend at a jam. I gotta say I feel equally impressed with this speaker as I was with a Celestion Blue Alnico. From clean to natural overdrive to pedal overdrive, I felt magic happening at every turn. The focus seems to be on tighter mids than the blue, but the lows and highs still seemed well defined. This was what I had hoped for with a Weber 12F150, but didn't deliver.

A good match for this amp for anyone looking.

Sep 08 - Mark C writes... "The Celestion Vintage 30 really helped the sound out a great deal.  With the original speaker the sound had too much high end, to the point where it was piercing to my ears.  Now this thing roars like nobodies business. I get a combination of the classic Marshall crunch, and a nice clean sound that fenders are famous for."

May 09 - Mark C  has bought another PRII, this time with a Greenback installed. He says the sound is basically the same as the Vintage 30, only with a little more top end. He can make them sound identical simply by turning up the treble a little on the amp with the Vintage 30.