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FDP Forum / Fender Amps: 1985 - Current / Princeton Chorus amps


united states

thats right..
May 1st, 2007 03:31 PM   Edit   Profile  

all the princeton chorus amps. the 2x10's

i get some people saying that they have 2x25 stereo watts, some people saying 65W, and some saying they have 125W

which one is true, or which are they? or did fender make different wattages for them

also, what does it mean on the back of amps when it says "maximum output 38W or whatever. because my 15W fender frontman says that on the back.


Rochester, MN

the quest for tone is never-ending
May 1st, 2007 04:48 PM   Edit   Profile  

hey aurian4parker -

I have a Princeton Chorus amp, actually was my first amp and have always loved the clean sounds from it. Here's some info for you on the amp and other answers for you (anyone, please correct me if I am wrong, but this is how I understand it)

a) The PRINCETON CHORUS amp is 50 watts RMS (2x25 in stereo)...the Fender PRINCETON 65 is a 1x12 solid state amp that is 65 watts RMS
b) the 125 watts they are getting is the PEAK output (a max. output level that can potentially be attained for a split second or less) for the amp...this means very little, as you want to look at the watts RMS which tell you the output the amp is able to continuously produce for you.
c) as far as I know Fender only made 2 versions, the Red Knob version in the 80's and then to the Black Knob version, both 50 watt amps; both 2x10's. They moved production to Mexico in the late 90's I believe and added a DSP model soon after that.

hope this helps a little...


Rick Plays The Blues


ooops I changed that tube again ...
May 1st, 2007 11:00 PM   Edit   Profile  

AMS88: I have to correct you at point b) The 125 watts written on the back of the amp has nothing to do with output. Neither is it RMS nor is it peak output - it is power consumption - it is, what the amp's power tranny input is getting. As simple as that.
Regarding c), I am sure, the red knobs where offered as well in the beginning of the 90ies, until they changed over to the black knobs - but that really was just cosmetics - the amp was not changed. Only change ever was the introduction of the DSP effects instead of reverb and chorus.

I also have a PC. A new red knob was my first amp ever. I sold that, to get a real tube amp, but years later, I bought a used black knob as a home/spare/backup/effects channel amp. Love the cleans. Hate the od.


united states

thats right..
May 2nd, 2007 05:49 AM   Edit   Profile  

so any princeton chorus solid state 2x10 that i find is a 50W?

meaning 2x25?

so if i only had one guitar plugged in, i could only get 25W out of it? or 50?


Rochester, MN

the quest for tone is never-ending
May 2nd, 2007 10:33 AM   Edit   Profile  

thanks for the correction RPTB, that clears things up for me too.

aurian4parker - no, it doesn't have anything to do with 1 or 2 guitars plugged in. I believe there are 2 separate 25 watt power amps in the circuitry, each driving one of the speakers (that's how you get the nice stereo chorus effect between the speakers) so it is still 50 watts total with one guitar plugged in.



Maybe next year!
May 2nd, 2007 01:29 PM   Edit   Profile  

Rick plays the Blues wrote:
"...I bought a used black knob as a home/spare/backup/effects channel amp. Love the cleans. Hate the od."

A good pedal will fix this. I use a Seymour Duncan SFX-03 Twin Tube Classic with the clean channel of my Princeton Chorus - and it sounds terrific. The Twin Tube has two channels I set the pedal's clean channel so that it boosts the amp, sounds even a bit warmer and just on the edge of overdrive. The pedal's gain channel provides a great drive sound. The Twin Tube with my DRRI is also heavenly.


united states

thats right..
May 2nd, 2007 02:37 PM   Edit   Profile  

well the ones im looking into are the solid state ones.

so i believe it is 50W(2x25.)


im pretty excited. either this or ill get one of those stupid complicated line 6 spiderIII's


Rochester, MN

the quest for tone is never-ending
May 2nd, 2007 03:33 PM   Edit   Profile  

sweet! they are very nice sounding SS amps, warm, almost tube sounding clean and great reverb. my only complaints are in line with RPTB's about the drive...never really liked it. I like a BD-2 for blues breakup with it but there are many other pedals out there for OD/Dist. Also, if you are planning on gigging with it, it kinda farts out at louder volumes. Great in the 2-5 range though.

edited to say: I actually used to gig with it in a little rock band when I first started playing, but as my tastes/knowledge evolved I found the need for a tube amp. Now, I wouldn't think of gigging without a tube rig just because they cut through so much better in a live setting. just something to think of if you ARE going to be gigging

(This message was last edited by AMS88 at 03:36 PM, May 2nd, 2007)

Contributing Member

Denver, Colorado

Thread hijacker
May 2nd, 2007 04:19 PM   Edit   Profile  

"I believe there are 2 separate 25 watt power amps in the circuitry, each driving one of the speakers (that's how you get the nice stereo chorus effect between the speakers) so it is still 50 watts total with one guitar plugged in."

The first part is correct, but two 25 watt amps each driving a speaker isn't exactly the same as 50 watts mono.

While I've played alot with a guy who owned one, I don't claim to know any particulars about PC amps (other than I like them and wish used ones were cheaper). But, I gigged for many years as a bass player and used a variety of PA-type power amps driving two cabinets and have dealt with this concept often.

While it 2x25 watts may or may not be louder than an "all other things equal" 50 watt mono amp, there is a difference.

For example, consider the Crate Power Block. Anyone have one? It's 150 watts bridged mono into 8 ohms. But if you run it in stereo, you only get 75 watts per side into two 8 ohm cabinets. Big power amps are even less efficient when you don't bridge them. My current power amp is 750 watts bridged mono into one 4 ohm cabinet but only 275 watts per channel into two 4 ohm cabinets if I remember correctly.

The point? Well, just that if you have the PC and are playing with a guy with a 50 watt mono solid state amp he will be louder with everything else being equal. He won't be twice as loud by a long shot, and two 25 watt amps each driving a speaker will provide a lot more sound than one 25 watt amp driving one speaker, but it's not the same as 50 watts mono.

I still think they're great amps and tried to buy a really nice used one at Guitar Center a few months back but they wouldn't go lower than $225, even when I showed them green cash ready to spend.

Is it worth $225? Probably, but it wasn't to me a the time because I only wanted it; I didn't NEED it.

Sorry for the long post but I just wanted to help you understand what you're looking at.


united states

thats right..
May 2nd, 2007 09:05 PM   Edit   Profile  

well. i found a fender Stage 100 with a footswitch and a separate 2x12 cab all for 300 bucks; so if i play it and like it i may just get it.

what are your opinions on this one? (im sure this one is 100W right? lol)

Rick Plays The Blues


ooops I changed that tube again ...
May 2nd, 2007 10:24 PM   Edit   Profile  

George, sorry to say, you are wrong.

Having 2x25Watts, each side driving one 10" speaker is exactly the same as having a 50W mono power amp driving the same two 10" speakers at once. If you ever experienced any difference, it may have been due to the speakers or due to different impedance. E.g. your example about the Crate Powerblock: 150 Watts bridged at 8 Ohms - so you may drive two 4x12" cabs 16 Ohms each in parallel. Now you connect one cabinet per side, thinking you have 2x75 Watts - but that isn't true. 75 Watts at 8 Ohms, but you connected 16 Ohm - so the power per side is reduced to something around 40 Watts.

But whenever you are sure to have the same power per speaker (checked all influences like impedance and others) and the same speakers and amount of speakers - no difference

Contributing Member

Denver, Colorado

Thread hijacker
May 2nd, 2007 11:20 PM   Edit   Profile  


Okay, I believe you Rick, and if I'm wrong I'll gladly admit it and say thanks for the lesson.

Help me here: since the Princeton Chorus amp doesn't have an option to bridge both channels into one mono signal, how can you get a full 50 watts out of it? Yes, I read the second sentence of your post. I humbly ask "why", or better yet, "how"?

I consider it a 25 watt amp, but a very nice sounding one.

One thing I know I'm wrong about: the Crate Power Block is 150 watts into 8 ohms bridged mono but 75 into FOUR ohms per side. My mistake.

I'm now electrical engineer but I'm one of those guys who obsessively researches everything I buy and I was pretty sure what I thought I knew about power amps for bass was true for all amps.

And I jokingly refer to myself as a thread hijacker but I didn't mean to sidetrack this one so far; I just figured many of us are familiar with the Crate PB to use it as an example.



Does Not Apostrophize Plurals
May 3rd, 2007 01:58 AM   Edit   Profile  

"since the Princeton Chorus amp doesn't have an option to bridge both channels into one mono signal, how can you get a full 50 watts out of it? "

If it helps you to understand, think of it as a stereo amp -- two 25W amps with one speaker each -- because that's exactly what it is.

To clarify this a bit, Fender eventually called the final, pre-DSP version the "Princeton Stereo Chorus." Technically, the total audio output is something like 51.5WRMS according to the schematic. I picked one up on closeout at a big Guitar Center sale for $199.99, brand new, a few years back.

These amps are extremely popular with jazz players who refer to them as "poor-man's Rolands."

They have a very nice reverb and analog chorus and a very strange distortion circuit that few (if any!) owners seem to have figured out. I never did.

They are not very loud amps, but this is probably due to speaker efficiency more than anything else.

(This message was last edited by Golodkin at 01:59 AM, May 3rd, 2007)

Rick Plays The Blues


ooops I changed that tube again ...
May 3rd, 2007 11:14 PM   Edit   Profile  

first about the PC: it is 25W each speaker - in total 50W.
Then: yeah, the Crate PB - I overseen that as well. If you have a stereo amp of whatever rating - the bridged output always has to be for the double impedance.
And then the volume loss in stereo mode gets even bigger. Considering what I explained above. Having the bridged 150W into two 16Ohm cabs in parallel - but then using the same in stereo, having 16Ohm per each side, but each side is rated at 75W into 4Ohm, the power output into the connected 16Ohm is way less than the rated 75W - maybe 25W or 30W (it depends a little on the power amp and power supply design).
Now if you compare: Played in stereo, each cab gets about 30W into its 16Ohm. Played mono bridged, with the cabs in parallel, you get 150W. These 150W are devided into 2x75W per cab. Why, you ask? simply: power is always voltage x current. If you have two cabs in parallel, both get the whole output voltage, but the current is devided into half for each.
Anyway, now each cab gets 75W instead of the approx. 30W in stereo.

It would be different, if in the same situation you had 2 cabs with 4 Ohms each, that you connect in series to meet the 8 Ohms in bridged mode. Now, both cabs get the same current, but the voltage is devided into two halfs. Again, you have 75W per each cab.
But for stereo, now you have 4Ohm cabs and you get the full rated 75W per cab again!

So to come to an conclusion: If you think of Watts per speaker (at least as long as we think of the same speakers or cabs), you may simply add the power per speaker, or if several speakers/cabs are connected to one power amp, the power is devided between the speakers.
The only point is, that you have to be sure to get the rated power out of the power amp, which is not automatically true in every case where you compare bridged mone and stereo. In fact, usually, the cabinets are connected in parallel, and then you are right that you loose some power - but that is due to the power amp not being connected with the rated load but a higher one. Now compare it to the PC: if you bridged the 2x25W power amp (8Ohm each), you would get a 50W into 16Ohm mono amp. Now connect both speakers in series, to match these 16Ohm and again you have (due to the output voltage being devided between the speakers) 25W per speaker / 50W in total.

All of this is especially true for solid state amps, as these are always rated for a minimum impedance. At this impedance, they have the maximum power output. At lower impedances, the are prone to failure. At higher impedances, the work without any problems, but the output power is reduced.

I am not sure, whether or not I could explain everything in a way, that it is understandable, since I am not a native speaker ..... however, I did my best and sure I would try to answer any further questions.

Finally just like to add, that you absolutely also hear the same volume or different volume in the different cases as explained above - not just theory - and even more audible with bass amps

The PC however is not too loud, I agree on that. But it is solid state. Compare it to a Tech21 Trademark60 (just another ss amp of compareable power, that I know) - it isn't too loud either. It is true, that ss amps need higher wattage to be loud ..... and the PC speakers aren't high efficiency speakers either .....



Sep 30th, 2017 12:14 PM   Edit   Profile  

I have a 1988 Princeton Chorus. Does anyone know for a fact OR where I can find the ohm resistance for the Impedance dial?




lets take it apart
Oct 1st, 2017 10:34 AM   Edit   Profile  

here's two cents worth from a old guitar picker and may or may not be correct but the wattage is a add entrancing scam to sell you something it seldom tells output with how much distortion or at what input signal. and the perceived loudness because of speaker efficiency is what you hear if you like it and it will do the job buy it tomorrow you may want something different that's why i have 33 old and newer amps and 40+ guitars
but its really been a fun 60 some years of playing

Contributing Member

Eastun' Carolina

Like Ringo, I'm happy to be here!
Oct 12th, 2017 08:36 PM   Edit   Profile  

I also believe the chorus has to be engaged to get the true stereo effect.

Contributing Member

Too Near Atlanta GA

Amp Tech Emeritus
Oct 13th, 2017 09:23 AM   Edit   Profile  



Contributing Member

St. Louis

"Thumbpicks don't slide into soundholes"
Sep 18th, 2019 02:04 PM   Edit   Profile  

On the red knobbed critters they are true stereo as far as the effects setup is concerned loop included. Great open clean sound and the chorus is rich indeed as is the reverb.
I never could dial in an overdrive sound at any volume that didn't sound fizzy to me. At low volumes you could do it ok but at stage levels it just faded into the sunset when distorted. I have to say it almost rivaled a twin for sounding great at clean tones though.

There are two amps to separate speakers in it but they work simultaneously so you get a pretty decent volume from it.

FDP Forum / Fender Amps: 1985 - Current / Princeton Chorus amps

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