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FDP Forum / Fender Amps: Vintage (before 1985) / Jensen C12N in a 75 Twin Reverb

Previous 20 Messages   Next 20 Messages  

usa metro detroit

Mar 21st, 2017 06:51 PM   Edit   Profile  

All I can say...

I've NOT had an amp with Jensens till now. I've always played amps with Celestions, Eminences or Oxfords. Having no preconceived notions, or nostalgia bias... I tried Jensens first time in my Black-faced 74 Pro Reverb. A pair of Alnico P12Qs right out of the box sounded amazing! Perfect fit! When those speakers are broken in, that amp is going to sound even better! (and to me that amp sounds like a 10!) I've never had a pair of speakers sound that good right out of the box (yea the amp probably has something to do with it.. but I think it's "Right speakers for the Right amp!") After trying Celestions, and Emineneces in my 75 Twin Reverb (also black faced) nothing worked. Celstions V-types were the wrong color of tone, and the Emeince Texas Heats had to much bottom end, resulting in the amp being muddy on the lower registers. I had a Jensen 2014 C12N that I pulled form the Pro.. bought another new one and dropped both in the Twin. WALA! What I heard is what I think a Twin should sound like! Again speakers sound really great right out of the box (all be it one speaker was already broken in)
love the vintage sound!

I think the modern P and C type Jensens are a real good fit in vintage Fenders, might not be good for other amps, but man they sound great with my vintage Fenders.

'Jensen® "reissues", after intensive research and analysis, are made to the same specifications as the original Jensen® speakers used by Leo Fender and others"

My exclellent results, my experiences with Jensens. I have no reason to doubht that statment.

(This message was last edited by pcalu at 09:00 PM, Mar 21st, 2017)

Steve Dallman
Contributing Member

Merrill, Wisconsin

Age is just a number...mine is big
Apr 7th, 2017 12:05 PM   Edit   Profile  

I put a new C12N in my 67 blackface DR and although it was glorious clean, with any type of distortion it produced harsh, strident, piezo-like highs that sounded awful and could not be eq'd out.

No amount of break in helped. Even a beam blocker did not help. I even doped the edge...then softened the dope. No change.

Then Joe Naylor of Reverend came to the rescue, and told me to remove the hard paper dustcap and replace it with a felt one. BINGO

That speaker went from sitting on a shelf to my favorite Fender speaker. It's been in my 65 PR (actual not RI) for several years now.

I've modded some other new Jensens with that hard paper dust cap. I use some rather stiff felt from a craft store. In all cases, the speakers still had bright, clear trebles, but lost the beaming, harsh highs when using distortion, be it amp or pedal.

Friends of mine did the same with their Jensens and all were thrilled.

I would prefer a modded new C12N to the originals.

FWIW, the C12K does not have the hard paper dust cap but a mesh fabric so does not suffer from the same strident high end of the C12N. I rather like the C12K.


usa metro detroit

Apr 7th, 2017 04:15 PM   Edit   Profile  

I don't hear that with the C12Ns in my Twin.

Sometimes it's the tone stack in the amp. I.e. not the right speaker for the amp...and the speaker is not a bad speaker. Just no matter what you do that speaker isn't going to work.. but its not the speaker. Case in point I tried some Emeinece Texas Heat (I know they are a good speaker I have them in another amp... wonderful speaker) but they just didn't gell in the Twin

Won't that dust cap soften with use and with age?

when you apply that felt what happens? Does it soften the treble like a Alnico? That would be cool... sort of a Ceramic-Alnico hybred. The million dollar question: "What's the long-term outcome of your modifications... will they hold up after years of playing?"

(This message was last edited by pcalu at 11:47 AM, Apr 8th, 2017)

Steve Dallman
Contributing Member

Merrill, Wisconsin

Age is just a number...mine is big
Apr 11th, 2017 07:36 AM   Edit   Profile  

I have speakers from the early 60's with felt dust caps that are in fine condition. I've never seen a felt cap deteriorate. I use adhesives that last.

The hard paper dust cap beamed a harsh treble (with distortion.) Replacement with felt smoothed that high end out. I've done this to many Jensens for myself and customers (I'm a retired amp tech) as well as friends.

There has been no downside. You are right. Some speakers just don't sound right in some amps. I dislike Celestions in Fenders. But a Jensen C12N SHOULD be a perfect speaker. In a Fender, and in my DR, it sounded great clean, but not with distortion. After the mod, it sounds great, clean or with distortion. I just replaced the old Jensen in our guitar player's 65 Ampeg Reverb Rocket. I can't remember if we used a Jensen P or Q, but it had the same hard paper dust cap. I did the mod to it, and our guitar player loves it. He isn't even interested in gettting the original Jensen reconed. (I may do it anyway.)



Apr 14th, 2017 08:21 AM   Edit   Profile  

The Jensen C12N is one of my favorite speakers.
I especially like the older American made ones...and in my experience a recone usually IMPROVES the sound of an old one.

It's a brighter sounding speaker and the cleans really sparkle. The overdrive is nice but a bit more buzzy than a P12N. If I had a particularly bright amp like a blackface Fender that I wanted to overdrive a lot I might go with a P12N.


usa metro detroit

Apr 14th, 2017 06:27 PM   Edit   Profile  

This is my opinion with lot of gear on the internet.

Guy X talkes crap about a product that he doesn't have a clue about... guy Y reads it and believes it and then repeats it to guy Z who then does the same.. Guys X is a hack doesn't know what he's talking about & guys Y & Z are too lazy to go check out the gear themselves. Fast forward on the internet a year and the what Guys XYZ have stated is now the TRUTH!

Case in point with Jensens.. SICA Altoparlanti the Italian company who owns Jensen, has maintained all along they have faithfully reproduced the vintage speakers.. To my ears thay have. Here is a link to a video that makes as good as a case that the SICA wasn't just using marketing hype.

External link



Apr 15th, 2017 09:03 AM   Edit   Profile  

Italian Jensen repros aren't the same as their American counterparts.

For example and American C12N Jensen recone kit will not work at all on an Italian Jensen because the coil is a different size.

Some sort of problem with Metric vs. English standard tooling.

There's also the fact that an older speaker magnet will change it's strength a bit as it ages.

I do think Italian Jensens come close and are a great improvement for a lot of amps using a cheaper speaker, but I still prefer a nice vintage one that's been reconed.

A touch less biting on the high end.


usa metro detroit

Apr 15th, 2017 12:50 PM   Edit   Profile  

Agreed guitarcapo... Agreed. But your talking about a 50yr old magnet and cone (in some cases) that's hard to replicate without paying huge big bucks as in Tone Tubbies etc (who make a Alnico that sounds like its 50yrs old right out of the box. For only $299.00 speaker lol...

For the record I'm not saying Jensen RI's are better than other speakers, I'm giving my opinion that Jensens are a good speaker and well worth using/trying.

I think these RI will soften up with age (why wouldn't they?) mine sounded darn good right out of the box and already have gotten warmer with the high-end getting soft

Makes sense they going to be in metric, they are made in Italy. Probably very little of the original materials are used in the RI. I can see them getting the design correct though, to where the speaker replicates the signature sound waves of the vintage speaker.

I've been using Jensens for a bit now and really enjoy them. IMO they give a real nice "Vintage" tone, i.e the Vintage Alnicos and the Vintage Ceramics.

Not new guitar playing, gear or speakers, been playing and gigging since 18 (I'm 50) What I am new to is Jensen.. being primarily a Celestion and Eminence guy.

I don't normally read internet opinions (with the Jensens RI's I just tried them.. found them quite decent. ) After reading some non-professional opinions on gear site like this... they have one thinking Jensens are real junk. Had me going huh? I also have seen people write RI's don't sound like the originals. The Video kinda debunks that notion that the reissues don't sound like the originals.

Another example of ya can't always believe what you see on the internet

Contributing Member


Jul 15th, 2018 10:53 AM   Edit   Profile  

I just like having a Blackface Fender how Fullerton put them together. Funny that way.


usa Thumb area Mi

Aug 5th, 2018 07:48 AM   Edit   Profile  

Update on SICA Jensen RI's Kinda a "Special Myth Buster's post"

After reading: "In the late 1990s, under a licensing agreement, SICA Altoparlanti, an Italian speaker manufacturer, commenced production of the legendary Jensen® speakers. These Jensen® "reissues", after intensive research and analysis, are made to the same specifications as the original Jensen® speakers used by Leo Fender and others."

Reading much on the internet about how these are not like the originals, I decided to do two things.

A) Delve into the world of speaker science to understand how a speaker works and...
B) Find out if SICA was being truthful in their claims.

After doing my homework on frequency graphs and Thiele-Small Parameter, I decided to look at the C12N as my base study.

Myth #1 SICA (Italian) Jensen RI can NOT be re-coned.


I was able after a simple search to order the re-cone kit for the Jensen RI C12N, along with the two re-cone kits for vintage Chicago Jensen C12N.

Jensen (Chicago) produced two C12Ns

C6969 (a seamed cone) & C8220 (a solid cone)

Examining the re-cone kits and external data i.e. Frequency graphs & TSPs and any "legit" sources on Chicago Jensens I could find. (few exist)

The Jensen Ris C12N have the same nominal diameter and the same voice coil opening of 1.5 as both the vintage C6969 & C8220.

The Jensen Ris C12N has the same seamed cone as the C6969.

The Vintage C6969: Voice Coil: 1.522″ inside diameter, 1.0″ form length, .375″ windings width, 8 ohms. Cup Spider: 4.0265″ outside diameter, 1.5″ VC opening, .275″ cup height

SICA/Jensen RIs: Voice Coil: 1.472″ inside diameter, 1.125″ form length, .375″ windings width, 8 ohms. Cup spider is 4.095″ outside diameter, 1.0″ VC opening, .225″ cup height

The there is a difference of .025 & .125 of an inch between the SICA/Jensen RI and the original C6969 and the cup spider. Same windings on the voice coils. & Both the Vintage Jensens C12Ns and the SICA/Jensen RI have is same magnet weight of 30oz.


Other than the Cup Spider.... the SICA/Jensen RI C12N is indeed a modern copy of a vintage C6969 seamed cone Chicago C12N. And as far as I know the closest in representation in production.

Now it Makes sense why Fender uses SICA/Jensen RIs in their top-shelf HW reproductions.

IMO.. (and this is me) After years of using RI C12Ns, I believe people who say they don't sound authentic, either have C8220s (& maybe some of these sound different than the C6969 seamed cone? IDK...) Or are forgetting they are comparing 50+yr old speakers to new one ???. Or are being topical to be trendy on internet forums like this...

There are Two negative critiques Jensen Ris C12Ns on the internet that I have read and both IMO are valid.

RI C12Ns don't do average to heavy overdrive. (I should point out neither do the original Jensen C12Ns) Pushing the speaker with average OD accentuates the classic American aggressive mids and high end of the speaker too much. This speaker is best suited for clean to light/moderate overdrive.

The long break in time. Sica also replicated the low efficiency of the vintage Chicago Jensen C12N. The speaker has a heavy doping this makes for a very long break in time. (upside.. cuts down on cone cry and ghost notes)

Fenderguru.com recommends speakers that are low in efficiency. They allow the amp to reach it's sweet spot at a lower volume, thus making it easier to play/work with. Huge plus! I use RI C12Ns in a Twin Reverb, makes managing the volume an easy task.

So there you go a detailed look at the SICA Jensen RI C12N.

love'em or hate'em... they are what they are

Contributing Member


Aug 6th, 2018 11:12 AM   Edit   Profile  

Thx for the intensive research, pcalu. Lived in Ann Arbor 10 yrs.

Contributing Member


Aug 6th, 2018 12:46 PM   Edit   Profile  

Nice deep dive!


usa Thumb area Mi

Aug 6th, 2018 06:29 PM   Edit   Profile  

Thanks. As one can tell the difference between the vintage C6969 and the RI are pretty marginal. Close enough where I think someone is really splitting hairs to say there is a difference mechanically

I'll add for the casual reader

Overdrive & the Jensen RI C12N.

What I found what works best is the tried and true Ibanez Tube Screamers. (or the Boss Blues Driver/ i.e. pedals of that nature) These dirt boxes shunt a lot of high frequencies and push a lot of mids.

I experimented with a lot of dirt pedals to see what the RI C12Ns responded best with.

I found transparent pedals like my Archer & by Blue Note (by J Rocket) let too many high frequencies through and was causing that high-end bite that so many complain about with the RIs. In fact, they just sound god awful through an RI C12N, same goes for heavy distortion boxes..

To my amazement... I found the more you dial up the mids on your amp, the more these speakers get sweeter.

My TR's EQ settings Treb 3, Mids 6 & Base 3.

Focus on the mids and these speakers bloom, get a dirt box like a TB.. No high treble bite, only cream and sugar..

Contributing Member


Aug 8th, 2018 08:42 AM   Edit   Profile  

Thx again, pcalu.



Bobby Roadrunner
Oct 21st, 2018 09:51 PM   Edit   Profile  

I have a 1974 Twin reverb, I rebuilt to ab763 specs in the Vibrato channel using Mojotone Oil in paper caps. I redid the normal channel with Mojotone Dijon caps .02 caps and changed the slope resistor to 56K and then changed the plate resistors to 220K. makes both channels totally different. Also, I put in a 22K resistor instead of the 820 ohm resistor for the negative feedback. Mostly based on the knowledge of Steve Dahlman, I took a shot and put in new Jensen C12N speakers. I really expected them to be harsh and thin. To my surprise, I think they sound awesome in this amp, even right out of the box. In the same amp, I tried Weber California’s, Weber Chicago’s, some alnico green print eminence from the early 70’s, a few different Emenince, like the Red White and Blue, as well as a Tonker. Even JBL K120’s. To my ear, the Jensen’s sound fits the twin perfectly. Also, the 3db lower efficiency really tames the twins high power.


usa Thumb area Mi

Oct 27th, 2018 02:22 PM   Edit   Profile  

Same here Avspecialist

With my 1975 Twin (its Black-faced) I push the mids up around 8+ & dial the treb and base in around 4..I crank up the reg volume to 8+: and employ the master volume to control it all.

I get a nice Tweed Twin Overdrive at a low/gig volume to boot!!!)

IMO that's the trick with American voiced speakers: i.e To keep them from sounding harsh when using overdrive (one pushes the mids till the top end treble bite "if any" disappears.

I like a lot of speakers but the two companies I use the most are Sica/Jensen and Eminence.

(This message was last edited by pcalu at 10:36 PM, Oct 27th, 2018)


usa Thumb area Mi

Dec 16th, 2018 06:28 AM   Edit   Profile  

Little Update:

Earlier this week, on the internet, I talked to an actual Sica Jensen sales rep ( I believe in Ripa Italy for it was 4 am my time.. yes I like to burn the midnight oil, lol) He gave me some excellent insight of the development on the Reissues. We mostly talk about the Ri C12N. He explained in the mid-1990s when they took up the challenge there was no prints to go on, no BOM (bill of materials) nothing! They had to reverse engineer everything. Destroyed a few vintage C12Ns in the process. According to the Rep, they got lucking and found two NOS C12Ns in perfect condition that they used for the TSPs. In their R&D they looked to make the Reissue’s power handling better than the originals. That goes with my findings (cited earlier) of the thicker walled Voice coil, and the shorter former (underhung design) to improve heat transference i.e the Bain of all voice coils. In their research, they also found vintage Chicago Jensen were all over the map when it came to their resonant frequencies (which they expected) all due to 50+ years of abuse on the surround, the decay of the paper fibers etc.. as much at 40 hz! So when some claim… Ris don’t sound anything like the vintage Jensen that’s because that vintage speaker he/she is referring too the resonant frequency has drifted considerably!

Where to establish the correct resonance frequency? They chose to go to the beginning.. the two NOS C12Ns. What they believe the resonance frequency of a brand new vintage C12N

It was explained to me that SICA/Jensen wanted from the start to create a modern functional replica that would perform just like the vintage As if ... someone time traveled to the late 50s/early 60s and brought it back and installed it in an amp. Same period magnet strength, same period efficiency/sensitivity, same period cone design yet with better power handling than the originals. I didn’t ask about the paper cone composition but considering the detail SICA Jensen went through on developing the C12N I’m assuming its close.

Something NOT really understood” to many and was pointed out to me by the REP… SICA Jensen designed these speakers to age like the originals. The Rep highlighted that Fender knows this and wants that in a speaker.

Very interesting stuff. (if you are a vintage speaker geek like me)

Contributing Member


Caught snipping the Bright Cap
Dec 16th, 2018 06:47 AM   Edit   Profile  

That is pretty dang cool!


Lawndale CA

No Chops but Great Tone ©
Jan 18th, 2019 10:11 PM   Edit   Profile  

I've heard the Sica rep marketing "speeches" as well bu tI honestly don't buy it - and I was installing new Jensens when they were made in Chicago and dozens of NIB speakers (New in Bob) through the 70's.

Sica had NOTHING to do with the acquisition of rights to the Jensen speaker name. It was originally purchased by the Recoton company, who then produced "Jensen" speakers using old model numbers with only vaguely related specs. CE took it over around 2000 and Audiovox later - who had Sica manufacture the speakers.

Sica had complete records and specs for the "reissue" speakers. But "reverse engineering" is impossible as specific coil wire and paper used in many originals are no longer made. Which is why the majority do not sound like originals - they are not made to original specs or "aged specs - they're made to what Sica engineers think sounds close. Every once in a while some will sound "in the ballpark" - and so will any other speaker made using similar materials, methods and using the same original "general" specs.

This is all OLD news and has been circulating since 2000. you can simply do a Google search and read the same "but the Sica (or Audiovox, or Recoton) rep said...." on The TDPR, here, the Gear Page and just about every amp-related site.

As fas as CURRENT production speakers go IMO both Warehouse Speakers and Weber make speakers that are much closer to several of the most popular vintage Jensens than Sica does. I stopped installing any new Jensens several years ago after replacing an unusual amount after break in for clients that didn't like the sound.

Last note - as to why Fender used a higher power handling speaker than seemingly necessary is to compensate for player use of mild distortion. The stronger the distortion the higher the power handling needs, regardless of amp power. Clean tones produces smoother waveforms, and the jagged waveforms produced by a distorted signal - if laid out flat - will be FAR longer than the clean-tone waveform.

That "length" is heat,and heat is increased power handling requirements. the more distortion you use, the higher the power handling you need in your speakers. It's possible to blow speakers with an amp at medium volume if a fuzz-like signal is run for an extended period.

This is a VERY simplified description, but is accurate in theory. I refuse to install two 50-watt speakers in a 100 watt amp if the player uses quite a bit of distortion and plays loud because there's a high chance the guy will be back - and not happy - needing one r more reconed.


usa Thumb area Mi

Jan 19th, 2019 10:29 AM   Edit   Profile  

Don't take this the wrong way but there really is a lot of bogus information on the internet.


We can come on a forum and say someone is wrong, but if we don't back it up with cited evidence, then your statements are nothing more than opinions.

That said: "Everyone is entitled to their opinions and their likes and dislikes" & if you like Webers or WGS speakers then rock on! They are great speakers. (no doubt on this... they are great speakers!)

But "Did you read my posts?" if you did, then you know that Chicago Jensen made several C12Ns e.g. C8220 C6969 and another aftermarket C12N for Hammond organs C8774 (I think that's the number)

And as we have seen, the Sica/Jensen C12N Ris is extremely close to the Chicago C12N C6969. Really close! as in .025 and .125 of an inch. (Driver) Even the paper cone fiber is close.

That's not marketing hype!

Let's talk Webers and WGS speakers for a second.
NO, they are not Chicago Jensen clones. Not even close.

Both Weber and WGS C12N varients use a much more powerful magnet strength than vintage Chicago Jensens and they use modern voice coils AND...with the WGS G12C, the resonance frequency is much lower (like all modern speakers) to accommodate the modern use of distortion/overdrive.

The Weber/WGS result: a much louder speaker, & much more efficient speaker. With many, a louder speaker equates to a better speaker. For myself and others The tone, the "efficiency rate" and natural break up of the speaker are equally important with the amp in consideration.

A Chicago Jensen that is 60+ yrs old has a lot of abuse on the surround and a lot of fatigue on the cone fiber itself. Resulting in a resonance frequency that will vary from vintage speaker to vintage speaker.

Weber measured the resonance frequencies of one of these and tuned their 12F150 to a 60yr old speaker. Wgs did the same, yet dropped the RF even lower and boosted the power rating even more. (again to accommodate the use of overdrive) The newest addition of the Jensen Ri line "The C12K" was designed in a very similar vein (for the same reasons Weber and WGS did)


That is not what SICA/Jensen did with all their Reissues! (C12K excluded)

From The main Italian Sales REP (from a conversation at 4 am in the morning my time) I'm paraphrasing... "When we developed the C12N and the rest of the Jensen RI line, we wanted to make a true reissue of a Chicago Jensen C12N but with some modern tweaks to help accommodate modern amps. (i.e. a little thicker former and a modern overhung Voice Coil design) We wanted the effect as if someone time-warped back to the 60s and bought one, then time warped back to the here and now. We reversed engineered and destroyed many vintage Chicago C12Ns in the process and got lucky and found two NOS speakers. We went with the resonance frequency that was the closest to the NOS speakers." We froze it in time and proceded from there."

Even the magnet strength of the Sica/Jensen Ri is vintage correct. i.e 30oz that's what a vintage Chicago Jensen C12n has. WGS (at 35oz) and Webers (at 40oz) are not. (That said... that's not a bad thing, just different, and great if you look at a speaker in a modern light)

Another Quote from him. Again I'm paraphrasing "The plan from the get-go by Sica/Jensen was to create a Reissue that would age just like the original. Not sound like a 60ys old speaker out of the box."

Fender knows this and that's one of the many reasons why they go with SICA/Jensen RIs in their amps

I and many others can attest to how a Sica/Jensen Ris sounds after being broken in. All my reissues are aging quite nicely, mellowing with time and there no reason to think that after a decade or two with the amount of playing I do, that these will have a resonance frequency in the ballpark of the vintage originals.

Now all this runs counter to what some read in "a select few" gear forums. IDK for sure why. But I have a good idea why... From my perspective it looks like a certain company's employees still roam the halls of two major gear forums, still spreading their version "of why" their speakers are the best and most authentic. (all under the guise of being a "Joe lunch bucket" with no cited affiliation of the company they always post about.) But... One can't hide who they are: When you look up their posts and find 98% of them are all about a specific brand of speaker, saying how great they are, and the majority of their posts attack the brand that competes for market share with the brand they love to hype) ????

It's a safe bet that they are affiliated with or working for that company and are playing marketing rep undercover. Kinda scandalous if you ask me, but then that's just my opinion.

Kind of gets under the radar of registering as a vendor or paying for advertisement on forums not to mention creates the impression that "in the know people" prefer that brand due to the casual internet chatter. Pretty clever...

But I'm just a user of Sica/ Jensen products and have the same relationship with Eminence. I have had many a conversation with Ems reps too (and use their products too.)

Truth is Webers and WGS are great speakers but.. But totally engineered with a different purpose than Sica Jensen Ris. (the fact is, that's why SICA/Jensen created the MOD and Jet line.. i.e for Modern applications)

(This message was last edited by pcalu at 11:04 PM, Jan 26th, 2019)

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FDP Forum / Fender Amps: Vintage (before 1985) / Jensen C12N in a 75 Twin Reverb

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