Fender Twin Reverb Replacement Speakers and Other Upgrades

Jim Cooley · Post by **Jim Cooley** » 1 Mar 2011 2:37 pm

My early 1972 Silverface Twin Reverb 100 Watt amp is on a tech's bench, ready for some repairs and general maintenance. I recently heard a couple of audio files of a Twin Reverb with 12" JBL's and love the sound, so now I am seriously considering replacing the old speakers. If anyone has one or two 12 "JBL's (D120F?) that you are willing to part with at a reasonable price, let me know. I will also consider alternatives to the JBLs. I wouldn't mind reducing the weight, either, but not at the expense of tone.

While the amp is on the bench, I am having the reverb enabled on both channels. I also need to decide whether to disable the Master Volume, like on the Blackface models, and whether to convert from balance to a bias adjustment for the output tubes. I realize that much of this is subjective, but any input in those areas is welcome.

Thanks,

-Jim-

Ken Metcalf · Post by **Ken Metcalf** » 1 Mar 2011 4:44 pm

I have Celestion Green back 25 watt speakers in my 67 Twin and they add some forgiveness to a twin aka compression.

Upgrading speakers trumps swapping pickups etc.

I have a Weber 50 watt in my Deluxe to clean it up.

Rich Hlaves · Post by **Rich Hlaves** » 1 Mar 2011 4:57 pm

Jim,

First speakers and this is very subjective so hear goes. I just love the Weber Neo 12s (15s too but that would be another thread). I think they sound better than the JBL D120 that they are modeled after. Very smooth and rich in the Twin I put them in with solid bottom end. My second choices would be EV SRO-12L or the EVM-12L, both very heavy speakers adding to the weight of an already heavy amp.

I would leave the master volume in the amp. The SF Twin works just like the BF amp with the mater volume dimed. Unless you are going to have the amp entirely blackfaced I would leave it alone. No gain in tone with that one. You also loose the ability to use the MV if you someday need it.

As far as the change to fixed adjusable bias, I think that is a good mod. You could also have the tech just add a bias pot and then have both balance and bias adjust as long as your balance pot is in good shape. You can't buy that one any longer. A trim pot could be added inside the chassis so no hole would need to be drilled.

Just my $0.02 US,

Rich

Tim Whitlock · Post by **Tim Whitlock** » 1 Mar 2011 5:32 pm

I second the Weber Neomag 12. Wonderful JBL-like sound and I think the mids are a bit sweeter than the D120F. Plus your Twin will lose a few pounds in the bargain.

Dan Beller-McKenna · Post by **Dan Beller-McKenna** » 1 Mar 2011 6:29 pm

Anyone using Jensen neo 12s in their twins?

Dan

Jim Cooley · Post by **Jim Cooley** » 1 Mar 2011 9:17 pm

How about SICAs?

-Jim-

Ken Fox · Post by **Ken Fox** » 2 Mar 2011 6:41 am

We use Jensen Neos in our 212 version of the steel amp, as replacements for Twins and also in N-112 amps. They sound great!

The SICA do not fit American standard bolt hole spacing and would require new speaker studs or the old ones moved out 1/8" each to accomindate a SICA 12". No issue with their 15" speakers.

The Jensen and SICA 12" are both listed on our website, see link below.

Dan Tyack · Post by **Dan Tyack** » 2 Mar 2011 7:17 am

I would try replacing just one of the speakers with a JBL type (D120, K120, Weber Neomag, Black Widow), you might like the sound better than replacing both. I am a big fan of using different sounding speakers in a 2X12" cab or amp. Make sure it's 8 ohms.

Ken Fox · Post by **Ken Fox** » 2 Mar 2011 7:31 am

Be aware the D130F are phased backward to all other speakers, red is negative and black is positive. You mix one with a regular speaker and get it out of phase and the amp will sound like a sick puppy!!''
\Like Dan, I like mixing speakers. Best sounding Super reverbs we ever restored had two alnico magnet and two ceramic magnet speakers.

Marc Jenkins · Post by **Marc Jenkins** » 2 Mar 2011 7:14 pm

Has anyone compared 12" vintage JBL to Weber NEO to SICA in a Twin? I've got one Weber Neo, but I've found that Neo speakers lack a bit of volume compared to the Alnico or Ceramic versions they copy.

For that matter, I would even consider mixing one SICA and one Weber Neo; they are rated radically different, wattage-wise (SICA 250, Weber 75); anyone foresee any problems?

I'm building a BF Twin clone soon, and would certainly would like to keep the weight down. I play in a couple bands that are quite loud!

Kevin Hatton · Post by **Kevin Hatton** » 2 Mar 2011 8:19 pm

If you like the JBL sound you need to check out the Eminence Deltalite II series. If you get a chance to see Randy Beavers with Leeanne Womack that's what you will be hearing. Bell like sound. It's a relatively new series issue.

Rich Hlaves · Post by **Rich Hlaves** » 3 Mar 2011 9:15 am

Marc Jenkins wrote:Has anyone compared 12" vintage JBL to Weber NEO to SICA in a Twin? I've got one Weber Neo, but I've found that Neo speakers lack a bit of volume compared to the Alnico or Ceramic versions they copy.

I did some looking online and found a few specs. Sensitivity would be a measure of a speakers volume at a given frequency, distance and power level. Once you hit the high 90s you have pretty efficent speakers IMO.

Sica 12 250W - 97.1db
Jensen C12N - 98.4
Eminence Deltalite 12 - 99.9 db

I could not find sensitivity specs on the Weber or vintage JBL D120 of D120F.

Unless you where to A/B these directly with the same amp driving them, it would be hard for even a very perceptive human to hear much difference in volume......but the frequency responce varies greatly in these speakers so the perceived differences in volume may be great while measured volume may be very similar.

My opinion is that it is all about the "T" word, tone. If you get the tone you are looking for from a certain speaker in an amp you have found what you are looking for. Brand, magnet type, weight be damned. It's a trial and error journey and tone quest that all of us hear differently.

I don't own a pair of D120s presently but do own D130s. I really could tell no difference in the volume with either pair in my 2-15 Showman cab. I do think the Weber Neo speaker are smoother with tighter bottom than the D130s. Cranked they are both very loud. I do think I have more clean headroom with the Webers.

From what I remember of the D120s in a Twin of the past. I prefer the tone of the Weber Neo 12 as I said above.

Marc Jenkins · Post by **Marc Jenkins** » 3 Mar 2011 9:56 am

Thanks Rich, that's some great info! I know someone who read a guitar mag shootout, and the Weber Neo was claimed to be over 100 db for sensitivity. Might try the SICA and Weber.

Rich Hlaves · Post by **Rich Hlaves** » 3 Mar 2011 10:26 am

Well, on paper anyway, that would move the Weber to the top of the list. Good to know. There is some very interesting writing by the late Ted Weber on the Weber website descibing early non-Weber Neo designs and the differences in magnetic energy beween the different magnet types. Good reading if you haven't read it yet. He really explains why the early Neo designs sounded so tight and lifeless.

It is posted in the description of each Neo speaker on the website.

Marc Jenkins · Post by **Marc Jenkins** » 3 Mar 2011 10:45 am

Rich, I have read Ted's NEO rant, yup. What's a bit confusing to me is that I have ordered some Weber NEO prototypes, and foudn them to be significantly quieter than their Alnico counterparts. I have a 12A150 in my high-powered Princeton build, and I tried the Neo version, and it was noticeably quieter. Same with the Neo Bluedog I bought. Tone: identical. Huh.

Ken Fox · Post by **Ken Fox** » 3 Mar 2011 11:00 am

If you compare the grequency charts of the SICA and the Delta Lite you will find the Dleta rolls off very fast on the low end. The SICA has a lot more even low end response, meaning less power needed to produce the lwo end. Just a thought. Both are nice speakers. I have some Delta Lites in my PA monitors and they sound nice for sure@

Rich Hlaves · Post by **Rich Hlaves** » 3 Mar 2011 2:00 pm

Ken,
Being a bass speaker by design I would expect that from the Sica. I haven't owned one (yet)so I can't comment but everything you say about them and the fact you use them in your amps says alot in my book. I have never heard a bad word about the brand. I remember discussing them with you prior to the HP Steel amp being released when you where looking for a speaker that would handle the power.

Marc, I belive you. No argument from me. Was that a 12" Neo in the HP Princeton build? I've heard that when you use a 12" speaker in a PR sized cab you get mixed results with certain speakers. Cab and baffle size has been mentioned as the cause.

Marc Jenkins · Post by **Marc Jenkins** » 3 Mar 2011 3:07 pm

Rich, yes, 12" in a HP PR. It is a Weber cab designed for said application, and sounds great with pretty much whatever I throw in there.

Rich Hlaves · Post by **Rich Hlaves** » 3 Mar 2011 4:14 pm

Marc Jenkins wrote:Rich, yes, 12" in a HP PR. It is a Weber cab designed for said application, and sounds great with pretty much whatever I throw in there.

Is that cab deeper/taller than a stock PR? Ted was a crafty guy. I'd like to know what he did to make it work. Pics?

Marc Jenkins · Post by **Marc Jenkins** » 4 Mar 2011 12:18 pm

Rich Hlaves wrote:
Marc Jenkins wrote:Rich, yes, 12" in a HP PR. It is a Weber cab designed for said application, and sounds great with pretty much whatever I throw in there.
Is that cab deeper/taller than a stock PR? Ted was a crafty guy. I'd like to know what he did to make it work. Pics?

I think it's a little deeper. Anyway, here's a couple pics, and the dimensions:

20" wide, 17" tall, 9.5" deep.

Rich Hlaves · Post by **Rich Hlaves** » 4 Mar 2011 1:55 pm

Sweet looking amp. Nice job. really nice job on the logo! Those are stock sizes. I glad it worked out for you.

Michael Brebes · Post by **Michael Brebes** » 4 Mar 2011 2:41 pm

If it's one of the Silverface Twins with the capacitor across two leads of the Master Volume, cutting off the capacitors removes the bright circuit operation and makes it more of a real master volume.

Marc Jenkins · Post by **Marc Jenkins** » 4 Mar 2011 2:53 pm

Rich Hlaves wrote:Sweet looking amp. Nice job. really nice job on the logo! Those are stock sizes. I glad it worked out for you.

Thanks! I know some builders out there buy larger cabs from Weber; one guy uses the 1x15" cab, but loaded with a 12".

Dave Grafe · Post by **Dave Grafe** » 4 Mar 2011 7:15 pm

FYI: My ancient literature lists the sensitivity (1 watt @ 1 meter) for the JBL D120F as 103dB, nearly 6dB better than the SICA and nearly 10dB louder than the "Special Design" Eminence 12", and this with much higher fidelity thrown into the bargain. Not everyone's cup of tea, this high fidelity, but I like my steel to sing clean and pure all the way so the JBL's have been a no-brainer for me for over thirty years now, got 'em in every amp I own and couldn't be happier...

Jim Cooley · Post by **Jim Cooley** » 6 Mar 2011 8:02 pm

I sincerely appreciate everyone's input - lots of valuable information. I got my Twin back from the tech yesterday. FWIW it has some 1972 components but the chassis is stamped Jan 16, 1973. I left the Master Volume alone. I'll just keep it dimed like I always have. I did have the reverb connected to both channels and a bias pot installed in place if the factory balance adjustment.

The factory blue label Fenders sound better than I expected after the tune-up. I A/Bd the Twin against my NV1000 and if I could only keep one of them, it would be the Twin. I dropped off a Session 400 with original 15" Peavey JBL when I picked up the Twin, so haven't been able to compare those two amps, but that will be another story.

After reading everyone's responses and no small amount of online research, I have compiled what appears to be general opinion about the speakers mentioned above. As stated in my original post, tone is the primary consideration. After hearing the Twin/JBL sound files, and researching the topic, I have to try at least one JBL or JBL type speaker in my Twin. It might be interesting to try a JBL/Jensen Neo combo, or something like a Eminence DeltaLite or Weber/Jensen Neo combo. In the meantime, I'm keeping my eyes open for a JBL D120F or K120, maybe two. K120s don't seem to be nearly as expensive.

Nobody mentioned Black Widows. Are they not a good option in a Twin Reverb?