Fender 65 Princeton Reverb RI rattling sound

[Jared Purdy]

I recently purchased this amp (new), and overall, I am very happy with the sound. However, what I have noticed is that the speaker emits an awful low frequency rattle type sound when the volume is above 4.5. The sound comes almost entirely from the low E and A strings, and gets worse the louder its cranked. There is no rattle from the other strings when they are plucked, just normal overdrive. I have read elsewhere about this issue, and am seeking solutions to te problem. And no, I do not want to get rid of the amp!
I traded a Peavey C30 (and a lump of cash) as I found the C30 to be too much for my house. The PRRI is perfect for my environment, and I really love the sound of it. I read on Harmony Central something about installing a new baffle. I am baffled by this, meaning I'm not sure why that would make a difference. The poster said that the baffle that is in the amp is particle board (or maybe MDF), and while that may not be as preferable to Baltic birch ply, I’m not sure if that would really be the solution. The same poster mentioned lose screws on the speaker and the baffle, which he tightened. Aside from the one explanation, there seems to be some truth to this rattling sound as the issue has taken on a life on its own on the net. I have not contacted fender yet, nor have I contacted the store that I purchased it at - yet.
I have also heard about speaker replacements, which I am not too prone to doing as other than the rattle, I quite like to the sound of the Jensen. Speaker replacement will be a last ditch effort as I really don't want to modify the sound of the amp. Can anybody tell me what is causing the rattle type sound (I have ruled out the cabinet or any other component in the amp), and how to fix it??
Regards, Jared Purdy

[überfuzz]

What kind of pick-ups do you have on your guitar? Not hundred % on the effect your writing about, but... I can get the same effect in most of my amps, specially vintage amps. Try to cut some bass with the ton control. Try different guitars. Does it help?

[martin manning]

Looks like the problem is the baffle, and maybe the back panel too:

Billm Audio » Cabinet buzz fix for Princeton Reverb

Apparently "reissue" didn't include the cabinet.

[Jared Purdy]

I have found what is pretty well the solution(s) to the problems that I was encountering, thanks to some folks on TDPRI. First, no, the baffle is fine, and so are the back panels. There is no vibration coming from them. Bill M Audio and Dave Allen of Allen Amps seemed to have stumbled up the same problem (I don't know how or when) and came up with a a better, more beefier OT that is closer to the original spec of the original OT in the DR. It is called the TO20. By itself, the TO20 does not solve the problem of the flabby/farty bass when the volume goes past 4.5. However, the other trick is to swap the GT 6V6s that come with the PRRI for JJ 6V6s, and swap the 12AX7 in V1 for a 12AY7. Togther, those changes are huge in their effect and almost completely eliminate the problem. Jim Campilongo also mentioned that he has two PRRI, along with a pile of vintage PR, DR, etc., etc. He has changed the speakers in all of them, and has found that makes a huge difference. He didn't say if he changed the OT, though he does change the tubes, and has the amps rebiased to run hot at around 30. He does caution that tube and speaker replacement will be more requent with the rebiasing, but he says with the sound that he gets (he plays the PRRI on 10!), is worth it. His favorite speakers are vinatge C 10N Jensen Gold backs and Celestion G10. At this point I'm going to leave the amps the way it is, though somewhere down the road I might try to get my hands on one of those old Jensens, or possibly a Weber.

[JoeM]

I have an upgraded OT in my Princeton too. (For a DR), but that doesnt have any effect on a low frequency rattle, though it did improve the overall sound of the amp. (It has a 12" speaker) Rattles are not an unusual problem with combo amps. My Princeton would rattle between the rear chassis edge and the cabinet, just a thin piece of tape fixed it.

He does caution that tube and speaker replacement will be more [f]requent with the rebiasing

Tubes sure, but speakers?

[Enzo]

I don't know the individuals giving it, but that advice is pretty suspicious to me. You have a rattle/buzz in the cabinetry. It is something vibrating. That it happens more on certain notes is common in that those notes are closer to resonant frequencies in the cabinet, so the vibration increases. Common causes are loose hardware, speakers not tight, chassis edges buzzing against the wood, etc.

SOmeone may have tonal issues with their amp and like the sound of it better with different tubes in it or a new transformer, but those things shouldn;t impact the mechanical relationship between sound and a tight structure.

The amp shouldn;t do this. Fender doesn't send out amps expecting them to have rattles.

You bought the amp NEW, it has a warranty. That is what warranties are for. Take the amp to the nearest authorized Fender repair shop. ASk them to make the amp right. Don't tear up your amp, and don;'t let someone on HArmony Central tell you you need to replace your baffle board. If the baffle board is rattling, it is more likely because it is mounted loose than because it is particle board.

[Gtr_tech]

The output tubes themselves can contribute unwanted artifacts to the audio output too. Small pwr tubes in combos don't tend to like the vibration in that sort of environment and can/will be mechanically rattled to the point of shifting/loosening of teh elements inside the glass. This will often result in rattley noises on freq's that make the tube resonate internally. EL84s are especially prone to this. My advise to customers with tube combos that use El84s or 6V6s is to treat the output tubes like strings.....change them when its time. Especially when the mfgr mounts them an inch away from a spkr cone. And things like the Crate V series with the cabinets made of some mystery wood that resonates like crazy....those will eat output tubes even faster.

The ROHS solder can also cause bizarro problems as well. I see it all the time....

[Jared Purdy]

I don't know the individuals giving it, but that advice is pretty suspicious to me. You have a rattle/buzz in the cabinetry. It is something vibrating. That it happens more on certain notes is common in that those notes are closer to resonant frequencies in the cabinet, so the vibration increases. Common causes are loose hardware, speakers not tight, chassis edges buzzing against the wood, etc.

SOmeone may have tonal issues with their amp and like the sound of it better with different tubes in it or a new transformer, but those things shouldn;t impact the mechanical relationship between sound and a tight structure.

The amp shouldn;t do this. Fender doesn't send out amps expecting them to have rattles.

You bought the amp NEW, it has a warranty. That is what warranties are for. Take the amp to the nearest authorized Fender repair shop. ASk them to make the amp right. Don't tear up your amp, and don;'t let someone on HArmony Central tell you you need to replace your baffle board. If the baffle board is rattling, it is more likely because it is mounted loose than because it is particle board.

Hey Enzo, nice to hear from you!

No rattle or vibration in the cab Enzo. It's definately the speaker, and the number of people that I have communicated with about this share the same experiences. After I did those minor "mods", I took the amp to a local store that had a stock PRRI and we did a comparison. Night and day. You can still hear it (speaker "fart", as it has been colloquially dubbed) in mine when you hit the strings with some force -when the volume is cranked - though it is much less than what it was. I'm thinking of putting in a Jensen P10Q, which has tighter bass., and a smoother breakup. I use to get notices when you guys replied to my posts, but I did not get these, that's why I didn't reply. Thanks for the feed back.
Jared

[davor]

Hi Jared

I have the same problem. Just bought a new Fender 65 Princeton Reverb Reissue and it rattles when hitting the E string. I want to use this amp in the studio. Now I am pretty desperate, don't know what to do. You wrote that it is definately the speaker. Which modes have you done exactly? Have you put a new speaker at the end? Thanks in advance for your respond.

Davor

[Jared Purdy]

There is hope! And, it actually works. Okay, this is what I did. I can attest to a couple of the changes being 100%, the others are dicey in terms of what they did to solve that particular problem. First, you need to change the power and pre amp tubes. I tried JJs and then went to Tung Sols for the 6V6s, and the 12AX7s, which I am happy with. The JJs, help but they are raspy compared to the Tung Sols. The biggest difference you will see is by putting a 12AY7 in V1 (which means you need to take out the 12AX7 that is in there now). It will really increase the head room and tighten up the bass. Before I did that, I had already changed the stock output transformer (an easy task with a soldering gun) for a BillM Audi TO20 OT, which is 2x the size and the weight of the stock OT. It is a drop in replacement, same holes, same screws. Wires are colour coded to match the Fender OT so its easy to install. It also tightens up the bass, broadens the frequency and boosts the volume by at least 10%. I decided to go a little further and put in a Celestion G10 Gold alNico. By God that speaker produces an outstanding sound. It's worth every penny at $200US. Lastly, I decided to remove the PARTICLE BOARD front baffle (why would the y put that in there???), carefully take off the grill cloth, and replace the PB baffle with a 3/4" birch plywood baffle. Between the tubes, the TO20 OT and the speaker, I spent almost $400, but it is worth it (the 3/4 ply was in my garage ). I can crank that amp to 10, and it sings like a thousand angels. I'll never sell it. I have it posted on youtube in 3 seperate videos to demonstrate the problem. If you search under PRRI mods or jj10holeblindlemon, you should find it. Let me know if you can't access it and I'll send the link.

[Steve Conner]

Great news... But is there any of the original amp left? There must be cheaper ways of curing a rattle than that :O

Disclaimer: I couldn't quibble with any of the mods, and I once did cure a rattle by buying a Celestion Gold. The voice coil on the original speaker was rubbing, and I'd always wanted one anyway.

Things to think about: Is it really a rattle, or just nasty-sounding distortion? What does it sound like? Microphonic tubes have a kind of zingy, metallic sound. It's like what you hear if you put the offending tube up to your ear and tap it, only it comes amplified through the speaker.

Speakers and cabinets that are rattling sound somewhat different, and heavy distortion in the electronics sounds different again.

Does the amp still make the sound when it's driving another speaker cabinet?

Does turning down the bass cure it?

Can you hear any plinks or boings if you tap the tubes with the power turned on? (careful, hot!)

Tracking down rattles in amps is a good way to damage your hearing, because it involves sticking your head in the back with it cranked up full. Hearing protection may be advisable.

[davor]

Hi Jared, thanks for your respond! Unfortunately I can not find your videos. Please send me the link. I am very interssting in how you did it.

Which mod have had the bigest impact in term of solving the rattle problem? Sorry, now I see again, you wrote it is the speaker. I assume, the other mods like changing tubes you did just improved the sound quality, didnt they?

Couple of days ago I brought the PRRI back to the store here in zurich, where I had bought it a month ago.

Now I noticed that I even didn't take out the foot switch out of the back. So, maybe this was causing the rattle a bit as well... Today I'll go there and test another PRRI, just to find out, if this problem occurs with every PRRI, or is it just mine...

Where can I buy these things like tubes, transformer etc. you suggest, online?

@Steve: Thanks for your advice. Probably the first thing is gonna be the change of the tubes, as Jared suggests. Although; I have never done this before... If this doesn't help a lot, gonna buy a celestion gold as well. But maybe i won't put it directly into the PRRI but simply buy it within an iso cab:
Sounds - Grossmann-Audio

this thing should help me to record silently also in my flat (I hope at least)... And so i don't have to change the existing speaker in the amp, which seems to be a bit tricky for me, because I think I am not talented for such a mechanical work... :-)

I really love the sound Jim Campilongo has on his video: http://www.youtube.com/watch?v=gHVG4kDurtY
...an hope, somehow the rattle can be solved.

Thanks guys for the cool ideas!
Davor

[MWJB]

Changing tubes (preamp or power) only works temporarily...after a while the rattle returns.

Putting a 12AY7 in V1 does not tighten the bass, it just massively cuts gain & changes the tone, your amp won't sound like a 65 Princeton with a 12AY7 in V1.

I very much doubt that an after market OT, or a new speaker is going to cure the rattle...though you may prefer the sound of them.

Changing the baffle board is probably the best solution...perhaps even a new cab (cheaper than $400).

Fender UK's advice is to fill any voids between cab & baffle board with mastic...I don't recommend this, it doesn't cure the problem, just masks it for a while. I'd start by removing the baffle board & countersinking the mounting holes on the rear to ensure that the baffle sits perfectly flush with the cab (you'll need to remove & refit the grill cloth, you might decide a new baffle is less hassle), if the mounting screws pull the back of the baffle proud around the screws, so the board does not sit flat, you will get vibration...it's not a new phenomenon, it affected some SF Fenders too.

This problem is so widespread I'd consider it a warranty issue & expect Fender to deal with it...not that I have much faith that they will.

[Steve Conner]

Ah, so they're known to have a rattly baffle board? Would some self-adhesive foam weatherstripping maybe help to shut it up?

[MWJB]

I think that's the same logic behind the mastic trick, I guess it's worth a try in the first instance....some spring cradle type tube retainers might help too, short term? 6V6 retainers aren't common but if you use JJ6V6 with the longer bottle you might find a GZ34/5881 retainer that works, may need some rubber spacers?