1968 Fender Princeton Reverb REPAIR & DEMO

[@johnbyers3839]

Love your videos. I've owned a number of old Fender amps over the years and rebuilt several of them. I still have a silverface Princeton Reverb which is almost 100% original - my favorite because it is the smallest of the Fender amps with Reverb and Tremelo. I began working in electronics in 1978 and have worked on everything from single-sided thru-hole boards up to 24-layer surface-mount boards. I used to repair power supplies way back when and learned a lot about soldering. I strongly recommend that you never reflow those ratty solder joints. Get a solder puller and some solder wick and remove every bit of the old solder and clean up the flux residue. Then solder the parts back in. It takes a little longer but is worth the effort. You really should inspect the solder joints from both sides of the circuit board as well. These old amps deserve the best workmanship. Keep up the good work.

[@bullwinklemoose8291]

This video was posted on January 15, 2017 and at the end you thank viewers for passing the 3K subscriber mark. Today is September 8, 2019 and you're over 78K subscribers. That's a nice growth rate! Congratulations on the popularity of your channel. I discovered you a month or so ago....I love your amp repair video's the most. It's interesting to see you work through the diagnositics to discover the issues of each amp.

[@CommonGroundser]

As someone with a cheap soldering iron and a cheap multimeter with aspirations of eventually using them (I barely know how to solder, period) for good and not evil, I appreciate the little scolding you gave The Last Guy to Work on This Wonderful Amp. If I ever do haul out the tools and get to work on an amp, it will be my weird Custom Kraft 500--which you worked on, which brought me here, originally. ...NOT my Fender Champ!

[@stenonemarangers]

It nice to know there are genuine people still out there. I am just a player but I am watching most of you videos.

[@echo8287]

I have a princeton around circa 1973. It is a non reverb. I changed the speaker to a Weber silver bell, it sounds great, looks new. It's time to change the caps in it again. The fellow had a nice strat(for $150) that I went to buy, but he already promised it to someone else. He said I've got this amp for sale and when he said $45 I said sold. He gave me the cover for it too.

[@Louisiana1975]

It's so weird that you posted today on this amp. Just last night, a friend gave me one! CRAZY!

[@johngeddes7894]

This video demonstrates just how good even a blackface Princeton can be, especially when a Telecaster is played through it. Nice.

[@michaelreis8266]

Never apologize for voicing dissatisfaction for sub par work, it's the best advertising aside from your results. I love the work ethic and respect you have for old amps, having said that, I'm sure you wouldn't justify shitty work on a cheap amp either. I've subbed, cheers

[@TheGuitologist]

Thanks for subbing, and thanks for commenting! Look forward to hearing more from you in the future. Enjoy the videos. I have hundreds.

[@cannongavin5194]

I guess Im randomly asking but does anybody know a way to log back into an Instagram account?? I somehow forgot my password. I would appreciate any tips you can give me

[@jamesondillon2445]

@Cannon Gavin instablaster ;)

[@cannongavin5194]

@Jameson Dillon thanks for your reply. I got to the site through google and im trying it out atm. Seems to take quite some time so I will get back to you later when my account password hopefully is recovered.

[@cannongavin5194]

@Jameson Dillon it did the trick and I now got access to my account again. I'm so happy! Thanks so much, you saved my ass !

[@57Banjoman]

Love the sounds of your family-like I'm a guest in your shop-when I was building Heathkits, I was amazed that even though my solder joints looked good, some of them were cold, and prevented the unit from working. Love your videos, Sir!

[@electroKrunch]

Always love watching you work, Brad! Common sense & years of experience in practice!

[@justincodyfox]

Man I really dig your videos. Very informative. Just a small note to the schematic differences. I have an all original 64 Princeton Reverb that has the AA764 circuit. That particular circuit calls for a GZ34 Rectifier tube. I guess they went back and forth! Cheers

[@IbervilleMusic]

I changed my Princeton Reverb 65 RI baffle by a plywood one I had made for dirt cheap by a local wood shop and It totally fixed the rattle problem.

[@michael_caz_nyc]

Greatest Amp ever made. I had an original Silverface. I (currently) have the 65 Blackface. I love those: glassy, chimey pristine Cleans. Gorgeous Reverb and Tremolo. Phenomenal amp. oNe LovE from NYC

[@stevenkimsey7039]

I bought the 68 princeton reverb custom reissue about 4 or 5 years ago. Beautiful sounding amp

[@TheGuitologist]

The reverb tube was weak in this video. I would later replace it and also modify the tremolo circuit to deepen the intensity.

[@DavidWatts83]

Setting the bias for power tubes running cooler would deepen the tremolo (bias vary). Nice video by the way. I have a 72 Princeton reverb which i love!

[@SuperHeliboy]

I have no idea what you are doing but I am fascinated. Watched the whole rebuild and loved it.

[@Stasisofseasons]

So got my 68 custom Twin reissue fixed! It had something to do with the tube heating section something about them putting a board that over heats, it was fixed by wiring that to the hardwired tube socket! I'm sure you get what the tech did! LOL I found a guy in detroit and I was able to give him the symptoms because of your channel Brad! Either way! Saw this and thought about it!

[@michaelcross934]

Hey, man - we learn a hell of a lot from you! Thanks for what YOU do and keep on truckin'. Cheers, Mike in Victoria. BC - another guitar addict.... and glad to be one :)

[@TheGuitologist]

Thanks Michael! Rock on, Buddy!

[@guitarmedia9171]

Good way to help people understand how there is some things they can check on, under the hood from time to time.

[@matthewf1979]

Always great work brother! I have a suggestion for just about any vintage Fender amp. The stock amp feet are steel and rattle like crazy on hard floors. A set of rubber feet from Lowes or Home Depot, etc eliminates the problem. Casters on the larger amps do the same thing. If it's a bedroom amp, remove the casters and install rubber feet. The baffle is a mandatory change for me. 3/8" for 10"'s 1/2" for 12"'s and 15"'s. Get the good 5 or 7 ply birch, 100% worth the extra $5! Primer, ultra flat black spray paint, new hardware and the lumber is around $50. Brad's a great guy and he will make your clusterfuck run like a raped ape!

[@noternunstoned]

I have the same early drip edge prince but also had to get the power supply rebuilt/replaced and the same 3 prong added and death cap removed etc. Wonderful amp, full of history and countless top100 recordings. Great vid. I learned a lot and even though I am not the world's neatest solderer, I don't think I ever was as bad as that shoddy, disrespectfu crap you had to clean up.l

[@DeadKoby]

I'm just starting the video, 575 is Heppner speakers. I have these in my Cordovox amp.

[@skycarl]

Very cool Brad,,,, I had a 64 Princeton back in 65 when I was a kid playing my Mustang through it. Geez I wish I had that amp today. Liked the way you showed the comparison between the black face and silver.

[@TheGuitologist]

I bet that was a great amp. Yeah, I know there are already a ton of Fender vids out there, but one more won't hurt. :)

[@matthewf1979]

The blue Sozo and yellow Jupiter caps are really good now production replacements for the Astron and Ajax caps. The cost is worth it with Blackface/Tweed/Drip Edge amps. Great for high end clones/reproductions too. I would use those in later "Blackfaced" too. There's a noticeable difference with those caps compared to cheap poly/orange drop/metalized caps. And they look right, people like that.

[@robertgandy4007]

40:00 For those wondering, the amp here isn't broken. The nasty sound is most likely from recording the amp with the camera's microphone, the preamp of which is hopelessly clipping and begging for life. I'm sure the amp sounds great.

[@Mauitaoist]

I just blew out the 1K resistor on the red lead to the output trans....... Rectifire was very hot too.... I think I will replace the rect tube as well as the 1K resitor, Your video helped me very much, thank you

[@thomastommy1192]

I paid $25.00 for an amp just like this. Back in the mid 70's. I used it for a while. Then I sold it for $35.00. lol. I was maybe 14, lol cool video. Sure brought back memories. Thanks for sharing.

[@TheGuitologist]

You're a born capitalist. :D

[@thomastommy1192]

The Guitologist Thank you. I take that as a compliment, lol

[@joesimon2018]

I have a 79 Princeton that I added a 12 inch Jensen to. I also gave it the Stokes mod. It's more like a single channel Deluxe Reverb now.

[@maxschoenhals2293]

Excellent video on one of the best amps for the money ever built. I bought mine when I started playing in '74 and still own it, and it's still stock. Instead of hacking it up and changing the speaker, just use the speaker output, folks.

[@mikec.4909]

Very interesting video! I really admire the quality of your work! The amp sounds great! Dig that Tele, too!

[@GIGMUSIC-o6z]

My favorite guitar amp. Great tone.

[@Ibaneddie76]

Love old Princetons they are so great but why do people mess with them? Good thing people are smart enough to bring them to you, you do great work I wish you were in my area I'de have you do all of my work you are a quality dude all around.

[@philbrown6787]

Recent conversation I had .... Buddy - "I love that little blackline Princeton you sold to me. For $250, too!" Me - "Oh, shut up" (sold him that amp in the 90's.)

[@garyeggleton1142]

Very nice job.....I built a Princeton Reverb last winter with a 12 inch speaker, deluxe reverb OT, and a GZ34 rectifier , and had a friend build me a custom cab made of oak......best amp to practice with up til the volume is on 5, but think it still needs a better speaker to be awesome and im not a fan of this phase inverter when overdriven, at least I believe thats why it dont sound great cranked for that reason. My homemade 5E3 sounds better turned down too, and same PI.

[@megshed]

Never heard a Princeton sound so bad !! It should sound rich and smooth with that great reverb and vib !!

[@TheGuitologist]

I actually agree with you on this one. The camera I was using for this video was my iPhone, and it's been dropped so many times, the mic was screwed up. I've since gotten a new camera because of it. You can hear all the crappy artifacts and overload and buzzing going on. Mic is totally shot. I guarantee you it wasn't the amp. :)

[@jsullivan2112]

Yikes look at all that water damage in the bottom, you can see it in the wood. Definitely why that Tolex separated. Likely sitting in a basement that got flooded. Anyways these videos are super fun, I've been binge watching them all evening!

[@frantisca]

Like your Tele :) Ha: 3.000 subs back in 2017, now you reached beyond the 100K: kudos ! That's well deserved ;-) \m/

[@TimmyP1955]

Looks like the right front PT mounting nut is missing. That baffle has had the speaker hole hogged out - badly ;-( If you move the PI B+ to the next higher node, and change the output coupling caps from .1 to .01, you get more headroom and a much better sounding overdrive.

[@NewHopeAudio]

great work. i love the Princeton Reverb. my favorite amp.

[@joeychamblee6258]

Great video. My old solder iron was a weird little weller from Home Depot. It made very similar joints. It said it was a decent wattage, but it never got even close as hot as the solder station I replaced it with.

[@TheGuitologist]

Decent tools are essential. The iron I'm using the video was an emergency Wal-Mart replacement I got one night when everything else was closed and my Weller died. I lucked out and it actually does a pretty good job so I've kept using it.

[@arose460]

It was my first time and my cat helped me he held a flash light . I didn't have a solder iron, I had to heat a screw driver on my moms cuznz stove top. It worked good and I did the work for a pack of USA menthol 100s. He got tje better end of the deal 4sho. Ps me neice wrote this I cant read or right shes 5 and we love watchong you.

[@kgradio]

Did you replace that cap that was in backwards? I would imagine it was ruined from the reverse polarity but I thought you said you just flipped it around.

[@timothyjay2012]

I've always wondered if you could put a Ppimv in to a Fender Princeton Reverb amp so you could drive it like the old Plexi heads??

[@scottmatheson2390]

The buzzing problem is unfortunate given the work you put into it and the glorious sounds these models are known for producing. I can't imagine what humbuckers would sound like but I suspect they'd threaten to rattle the little amp to pieces.

[@Guitarzan8]

3k subs. Congrats! Yuk yuk. 137k as I type this from the future. Nice job on the vids, nice work on the amps, and for me nice training tips! Don’t let the trolls get you down. I want to see more and more even if it’s repetitive.

[@chrismorse3862]

So did you change your technique to clipping out components and soldering to their remaining leads after this video? Have seen you do it in other videos, is it different when it's a pcb

[@utubehound69]

I had a Twin Reverb with a face plate like that chrome & blue lettering but it didn't have that drip edge never seen that before. I know it was old 1 owner that never used but twice a year at the VFW I don't remember if he told me the year he bought it. What year is those silver faces w/that aqua blue silkscreen lettering? I traded a Crate Bass amp & a Red Flying V no name Gtr for that Twin Reverb. I lost it Pawn for $150 years ago. Man that amp was so clean & loud.

[@donrutter6765]

Watchman4u This one is the 68' the same circuit as the earlier blackfaces. Anything newer has a different circuit, not as good. The silver drip edge around the speaker baffle board is a 68.

[@davidclink1425]

I'm about to tackle some Solid State Amps that aren't working. Other than the obvious solder joints, visually blown caps, fuses, etc, I need to know how to check the amplifier part (piece with heat sinks on them) Mine are plug ins and not sure how to verify if they are working if no visual effects. Thanks

[@JamesBurkholder]

The schematic calls for a 25/50 bias filter cap. What value cap did you replace it with?

[@Mooncalf2012]

37:08 May be quicker and more secure to use a C-Clamp to press it in flush.

[@knutarnesingstad2102]

Make it easy. Replace the 1k power drop resistor wita deluxe choke, and add 470r resistors to the screens. Also replace the bias resistor with a 10 k pot and a 22k resistor to the ground to set a proper bias.

[@TheGuitologist]

Adjustable bias is one good mod for these, especially if you're taking one on the road to be used night after night and where you might change tubes often.

[@boggy7665]

I was reading somewhere about speaker cabinets. It was said chipboard was better than plywood, because plywood had undesirable resonances and chipboard had less or none of these. Not trying to start an argument, and I don't have an opinion either way. Just curious.

[@jagtone]

That may be true for hifi cabs, and for higher density board. But the issue of those kinds of resonances is just not relevant for an open-back combo. What is relevant for an amp that gets moved around or stored in less than ideal circumstances is durability and weight, and decent quality plywood (i.e. no gaps) has it by leaps and bounds over any kind of pressed composite material there, which tends to crumble around the edges with time, completely goes to hell if it comes in contact with water, and is heavy as heck. Plus, this isn't the cab material we're talking about, where maybe you want material that has as little resonance as possible, but the baffle board, which vibrates with the speaker and maybe contributes to the sound like the top of an acoustic guitar.

[@aerostoon]

Hey Brad, I was holding my breath when you were seating the speaker nut insert. If the screwdriver slipped off the screw I was hoping it wouldn’t go through the grill cloth!

[@johnlattimer350]

I have a 64 Princeton non-verb that's freaking Awesome!!! But I also have the matching reverb unit that has a glitchy mixer. Any tips on cleaning up the tank? Seems like a finger flick on the knob offers a temporary fix, but I know it can be more stable. Thanks ,John Lattimer

[@donrutter6550]

That's the amp Clapton used in the studio to record Layla.

[@shckltnebay]

Just got one 67-68 so lucky to have one, mine has all the original blue molded caps, even the coupling and can cap is original

[@nickburton4673]

hi I just started a bogan challenger exactly like the one you built. is there a way I could get a higher resolution schematic of the one you used in your video. im a beginner in tube electronics and would appreciate your help. also love your videos. your stuff is awesome. a fender like the one is this video is my dream amp... anyway thanks!

[@TheGuitologist]

I have no idea where that schematic would be at this point. Sorry. You might try setting the video settings as high res as possible and getting some screen shots of it.

[@nickburton4673]

The Guitologist thanks anyway man. im on a phone so ill try a computer when I get a chance. I just ordered new tubes for it. I cant wait to get it going. I have an old jensen p12 I've made a box for that ill power with it. id love to have tank reverb on it but from my research it would be a lot more wiring. but anyway thanks again man.

[@electroKrunch]

Hey Brad, do you have a video on the mods you did to your latest variac? I'd like to put one together...

[@stephanematis]

Very educational. For my reference, how many amps is your variac ?

[@TheGuitologist]

5A

[@stephanematis]

@@TheGuitologist Thanks!

[@Stratboy999]

I used to have a more modern Princeton. I liked it but ended up trading it. Wish I'd kept it really. Good little amp.

[@charlesshaw9090]

Cool vid and lovely amp, or was once. Re the poor soldering; The flux in multi core solder, which allows the metals to flow and bind to component legs, only works on first heat up. Any dodgy joints should be solder sucked clean and resoldered. It's bad practice and asking for trouble to reuse solder blobs especially when they are being overheated.

[@TheGuitologist]

I disagree. You can look at the resulting joint and see the solder joints I reflowed with new solder came out nicely. You can even see the rosin core flowing to the surface during heating. If you wanted to make the process idiot proof where you didn't have to explain too much to someone who was new at soldering, yes, you might as well tell them to suck out old solder and start again, but once you know what a secure joint looks like, that's not always necessary. Thanks for the comment, though! :)

[@andrewmai1541]

I see at 39:02 that the speaker has been changed as the owner wanted. What is this speaker? Is this the speaker used in the demo? Sounds great!

[@TheGuitologist]

Andrew Mai yes, sorry. The speaker is a Celestion Blue.

[@TheGuitologist]

Andrew Mai ...and it was used in the demo with 5U4.

[@andrewmai1541]

Good info. Thanks.

[@Earl00001]

good demo.. wish the mic could have taken it better

[@TheGuitologist]

Agreed. I have a much better camera now with a better audio, so vids will be better quality going forward.

[@briansilcox5720]

Thanks for this one Brad, really enjoy your take on keeping these going strong. I have a nearly identical '69 Princeton Reverb with a 10" JBL... do you know if Fender delivered any this way? The clean tones really suit my preference. Had it since '75.

[@TnTravelers33]

Had this same issue on my 68 fender bandmaster the vibrato channel volume one day just randomly started acting like a backwards volume but the normal channel works with no issues

[@edwhite7475]

That baffle looks like a BEAVER chewed it out...geez.... and all the griping and muttering about the previous "techs" work? THAT is what we call a "Tinkers Damn"...my DAD taught me that working on cars- nice info and trouble shooting tips....pointing out the difference between rectifier tubes performance was GOLD!!!

[@philipdonovan6510]

I'm looking to build a Princeton and while this could have been a great video, the final capture destroys what the whole significance of all this work was ultimately for. a very common occurence on KZbin. Listening through the haze of buzz and frizzle it probably sounds great.

[@RobertLandrum13]

Do you recommend replacing an original cap can with individual filter caps?

[@TheGuitologist]

If economy is a concern and there's plenty of room, yes. But if it's a collectible amp, no.

[@RobertLandrum13]

@@TheGuitologist Well it's a 69 that's all original, 2 prong cord and all. I replaced the 2 prong cord last night with help from your video. I've seen where people have fitted them into the old can and retained the stock look. So I'm not sure what the "right" thing to do with an original 69 is. What electrolytic caps would you recommend? I've also seen where some sites will offer a 25/50 or 50/100 for the bias cap. Which is the right one? It came with a RCA 5u4 rectifier tube. Not sure if that's the right one or if the gz34 is supposed to be in there. Thanks for answering my questions. Love your videos.

[@Wildman9]

Hi Brad,the speaker is a Heppner ,never heard of them.Have you ?👍🎸

[@mavericknonconformist69721]

My dad had a Harvard amp along with a 61 ES 335, Nice rig.

[@wwallusa123]

Did the reverb work? I couldn't tell. You had it cranked at one point but I couldn't hear it due to the overdriven preamp.

[@iantomsic4686]

i like to set a candle that's burned all the down to the bottom directly above the 7025 on my '67princeton. the notes sustain smoothly into feedback. it sounds amazing, but i actually am crazy. is this a thing?

[@leonelrosano2596]

Great video, I have a princeton reverb the same as yours that when I turn it on, after 1 minute it starts making a rain noise that stays for 8 minutes while it heats up. After heating it is perfect. Do you have any idea what could be happening?

[@themrtomward]

Use the standby switch first and wait one minute then hie the on switch let us know if that helps

[@contrabandjoe7974]

Nice work Brad. Question about tone. Does that amp have any clean head room? The entire demo tone was breaking up. Maybe Princeton's are engineered that way. No experience with them

[@TheGuitologist]

The Princeton is probably the most "tweedy" post Blackface era amp. They usually begin to breakup around 5 or 6 on the volume dial depending where you set the tone controls. You can clean it up with your pick attack too. I just didn't show that off much here. Sorry for that.

[@hubbsllc]

I have a 1978 PR head conversion with a Hammond output transformer meant for a Deluxe Reverb and featuring multiple output taps of which the 4- and 8- ohm are available at the rear panel. Simply put, the amp does not do "clean" and "loud" at the same time. if you turn it up past 7, your single notes are warm and sustainy and your chords are crunchy. In that regime it feels like you're playing guitar for the Who. Incidentally, I have also used it as a bass head into a 4x10 sealed cab. You can't get a lot of volume that way, but if you don't need that it's got a great sound with bass.

[@garyeggleton1142]

Original PR has way undersized transformers so yes, they are practice amps and studio recording amps

[@kiaora12]

The Guitologist I'd say the Champ, then Princeton Reverb for breakup. The Non-reverb Princeton stays fairly clean but gets nice saturated tones above 5.

[@johnpick8336]

Hello Brad, Rivera Amps has a KZbin Channel where he discusses his time at Fender and his later Mods to this amp and the Deluxe if you are interested ?

[@artavenue4286]

Thanks for great videos ! If I was to use amp like this in 220 Volt area/ Europe, what would I need to do and to still preserve same sound like in 110 Volt (US) ? Thanks

[@TheGuitologist]

You need a step up transformer for your region.

[@lorenzoparedes2306]

I believe that if the local voltage is 220 and the amp works at 110, a step down transformer is needed, not the other way around.

[@GtrMan863]

will changing my power tubes increase gain or change tone even though I believe the old ones are still good? it's a Blackstar HT60 2014

[@JamesOrcutt]

Cant say enough good things about Fender PR I have a blackFace reissue LOve it

[@FiddlerSteve]

Yes, I have a '78 that's great little amp! Really versatile, sweet sound.

[@donrutter6765]

James Orcutt Clapton used princetons a lot in the studio recordings.

[@jojobar5877]

I like to check pots with an old Simpson 260 and watch the needle. A dead spot will jump right out at ya. What you're doing is fine though. Same result.

[@jackallen6261]

In regards to the loose tolex on the bottom. This is one of those times when hot and wet is bad!!!

[@anonymusum]

And you mean amps - right?

[@jackallen6261]

Yep!

[@frankardos4211]

Hey partner!!! I have in my possession the exact same amp but its the aa764 circuit with the original gz34 rectifier tube. Is that anything unique or just how they came then? Thanks for your vids pal.

[@Ibaneddie76]

I don't see you as being negative, quite the opposite I see you as wanting to do the job the correct way witch is what we should all strive for, specially when it comes to vintage gear like this. It's not like you can just run to Guitar Center and pick one of these up any time.

[@Tonetubbyspeakers]

Excellent work! I wonder how a cap got installed out of phase. Seems like tech-school day one kinda stuff.

[@TheGuitologist]

I won't talk too much about that, I've done it before too. Anyone who does this and says they haven't are lying. :)

[@Tonetubbyspeakers]

I'll grant you that, but it should have been fairly obvious upon final inspection!

[@schizoidmen]

can you tell me what speaker you used to replace the old one with?

[@TheGuitologist]

Celestion Blue AlNiCo

[@banacek60chord43]

Very informative and interesting video; thanks. Just a point and I don't expect you to change your culture but does anyone know why Americans have been taught to say 'sodder' and not solder [soul-der] . Did the manual get wet on the Atlantic crossing, I wonder, or is it like 'nuculer' [sic]: the first guy to say it wrong was powerful and nobody dared to put him right?

[@TheGuitologist]

One of those things, man. We're entitled to drop a letter now and then. I notice the Brits have a hard time with the letter"R", particularly at the end of words, and also the letters "th" often become "ff", as in "I ain't doing nuffin', bruv."

[@banacek60chord43]

That's mainly a southern [savern] affectation, that doesn't seem so prevalent now. A lot of it is put about by actors trying to be what they're not and failing. One of the classics being "Fir'y farzind feavers on a frush's froat."

[@TheGuitologist]

Well, being married to a Brit, I take the piss out of her lack of Rs on a semi-regular basis.

[@banacek60chord43]

'R's or arse?

[@somefuckingname]

And while we are at it, I say TREmolo, not treMOLO like you do. But I'm swedish so what do I know, XD. Thanks for all your videos man, they are great!

[@bluegreenface1193]

That thing roars! Sounds like its gonna blow the speakers, in a good way! Too bad you didnt have the pedal to demo the reverb. I'm gonna build one of my own soon.

[@Nickpaflas]

Where can I get a set of those cool multimeter clips? What brand are they?

[@TheGuitologist]

Not sure on the brand, but these are they: amzn.to/2pfW0gX

[@Nickpaflas]

Excellent. Thanks.

[@darrelbigdaddywhite]

Great informative video. I need my Princeton serviced. What's your email if you don't mind? They unplugged my amp speaker at church to use in ear monitors. They failed to put a load box on the amp. The amp plays but my tremolo and reverb do not work anymore and I hear like a 60 second hum when attemting to turn on tremolo. My amp will not be taken back without a load box. I'm right about the load box correct?

[@TheGuitologist]

Yes. Do NOT run a tube amp without some kind of speaker load or dummy load attached to the output transformer secondary leads. I would be willing to take a look at your amp. I am taking a hiatus for the summer though. No outside work for a little while so I can catch up on my own porjects which have piled up. After that, in maybe a couple months or so, hit me back up and we'll talk about sending me the chassis to work on.

[@JettyDeke]

Did this have a 12 inch Celestion alnico blue speaker

[@ajpuckett5888]

I have this exact amp, and it does not have celestions in it.

[@outsider6475]

Great sound! Do you remember which seymour duncan and tv jones type pickups those are?

[@TheGuitologist]

No, sorry.

[@oceanstarlake]

Hi, I have a '79/'80 fender princeton reverb amp that developed a fairly loud and very annoying hum when turned on. Some bozo had put the wrong tubes in it, ( 6L6 5888) instead of the right tubes 6v6's as indicated on the TUBE map..DUH. and me being an idiot never knew that's what happend.Now it has all the right tubes some clean up but it cost a lot of money and the tech still could not get rid of the hum. I'd be grateful if anyone knows what is causing it? is it something repairable? If not why? Does it need a new part? The tech I recently took it to said permanent damage may have occurred due to running it with the wrong tubes

[@roscocsa]

Oh man the sound of that amp...

[@RobiSaintAntoineMatterjam]

Lol, after all that work to fix the buzz coming from the amp (which sounds great, btw), the video itself is kinda buzzing like a mofo when you start playing the amp. Might be video compression artifacting, or clipping somewhere in your recording/editing chain. Buzzers gonna buzz, I guess, lol.

[@JohnLee-mq4hk]

what is a 1/2 12AX7A designation?

[@markbrooks7257]

12ax7’s are duo-triodes. Meaning they are actually two small tubes in a single unit. So, when you’re looking at a schematic, they will look like two sides of a half moon.

[@Ninjametal]

Can I safely swap in a GZ34 rectifier in my 68 champ?

[@mikewhelan9561]

I've had a 78 [id'ed by push pull boost] for 30 years and the vibrato never worked ? Any idea

[@corkyaffolter109]

sometimes they have to have the foot switch plugged in to work the vibrato or just short the plug to ground with a dummy jack

[@TheRycooder]

love your sessions!!!!

[@WorldsOkayestGuitarDemos]

I have a black line Bassman.. it’s awesome.

[@michaelogden5958]

Man, I'd have to get out my solder sucker and completely re-do that stuff! But then, I don't do amp work for profit.

[@davebolden4355]

why not change that main power filter thats 50 years old?

[@TheGuitologist]

Reason #1 - it still works perfectly Reason #2 - when I asked the customer and informed him of the additional expense and wait time, he said 'leave it in' He isn't taking it on tour. Lives here in town. I told him if a power cap craps out, he can always bring it back by.

[@davebolden4355]

like you, I dont want to critique other techs, they are a ticking timebomb waiting to take out other components though. when/if you do change it however i have found that weber makes very nice drop in replacements. they also fit in the ao35 chassis which i have seen you have worked on. keep up the cool vids and great playing.

[@TheGuitologist]

Thanks for the comment. My thoughts on filter caps are thus: Multi-section cans hold up better than the standalone type used in other Fender models. Filter caps almost never explode or dead short under normal operation. Brand new ones can also do that, truth be told. When filter caps go, the amp no longer filters ripple and it'll hum like crazy. Rarely does it mean other components go along with them. If he was relying on it in a gig situation and it had to work reliably every night, I might advise him to change the can now, but it's a couch/studio amp. These might have 15 more years of life in them.

[@davebolden4355]

fascinating, i always thought a sudden failure could destroy a power transformer if it doesnt take out the fuse first which can also destroy tubes.that thinking has me to always err on the side of caution. i just always assume that the dielectric compound would be dry by now. i am no expert though, you tend to find varying opinions on the internet. i respect your logic and it certainly sounds robust like new caps sound.