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Changing speakers in 67 Twin Reverb

PostPosted: Thu Dec 19, 2013 1:46 pm
by BirdofParadise
I'm considering replacing the 2- 12" Jensen speakers in my 67 Fender Twin with a singe 15" JBL D130F. The amp's output is 4 ohms and the current speakers are 8 ohms wired in parallel for a 4 ohm load. The JBL is 8 ohm. Are there any problems or potential damage to the amp?

Re: Changing speakers in 67 Twin Reverb

PostPosted: Thu Dec 19, 2013 2:01 pm
by smokymtguitar09
It want damage your amp, but there will be a slight loss in volume. However; with the improvement in the low end and perhaps overall performance you may not notice the volume loss. I have recently experimented with various speaker hook-ups with my 1966 Fender Pro Reverb (2 X12" speakers) that has a 4 ohm output. I have a JBL 15 D130F mounted in a separate speaker cabinet that is 8 ohms and it works just great. I tried two JBL K-120 12" speakers in the amp and they really sounded great, but I could hardly lift it to put it in a chair much less carry it, so back to the orignals and using the external speaker. Actually, I have a couple of 25 watt Eminence Alnico speakers mounted that are very light and will carry the 40 watt amp output easily and they sound better than the original Oxford Fender speakers which I've boxed up for re-installation if need be.

If you can contact Ken Fox at Fox Amps he is a storehouse of knowledge on vintage amps and speakers. He is on the internet and used to built exact copies of the 57 Fender Bassman amps.

Hope that helps - Ronnie Evans

Re: Changing speakers in 67 Twin Reverb

PostPosted: Tue Dec 24, 2013 9:24 am
by BirdofParadise
Boy did I get more info than I bargained for in chasing the classic "Chet sound", so here's a bit of what I learned especially from th several steel guitar forums Advice resulted in also considering the Peavey Black Widow 1501-4 and Eminence EPS-15C 4 and Weber California as replacements. If go with the JBL, I can remove the inner most power tubes to get the 4 ohm output but at reduced power. (BTW, did you know that 16 ohm JBL D130s are really 8 ohms? According to the designer and engineer this was a JBL lie!!),

Based of my research, the Weber appears to had been made to be a direct replacement for the JBL; however, the Eminence speaker may have the same sound qualities with a far lighter weight due to a more powerful neodymium magnet. One advantage would be in moving to 4 ohms resistance with the Peavey or Eminence speakers. I have been advised not to significantly alter the Twin - either by building a separate cabinet while removing the internal speakers to reduce weight or removing/storing the original speaker mounting board and building a new one.

But who knows about the tone in my hands!! What to do??!!!

Like guitars, so many choice and so little time.

Anymore I play primarily for my own satisfaction, but would like to get out again. At this point my preferred fingerstyle guitar is a 1989 Gibson CH that I recently found in like new condition. In addition, I own a 1971 L-5 Custom from the NAMM Show purchased new in '71, the Gibson JS-Chet made for Chet (described elsewhere on this board), a 1976 Super Chet, an early '80s Gibson custom shop Chet CE serial # A002. I also own several Taylors played through an AER Compact 60.

Merry Christmas to all!!

Re: Changing speakers in 67 Twin Reverb

PostPosted: Fri May 09, 2014 7:38 am
by BirdofParadise
Well, the deed is done!! I was able to find a JBL D-130F in need of a recone job. Through my local sound tech who has "major" connections in the industry, I was able to score an OEM cone kit (apparently there are still a few available if one know where to look) and have the speaker repaired. I made a new baffle with aged cloth, appropriate badge and installed after removing the existing baffle and speakers.

I'm still learning how to adjust the amp settings but it sounds better that I know how to play. An added bonus is that its a bit lighter than with the twin 12's


Re: Changing speakers in 67 Twin Reverb

PostPosted: Fri May 09, 2014 8:52 am
by Norm
The twin has a lot more output than Chet's Standel I think. In the grand scale of things it probably won't make much difference but there is one thing a lot of folks overlook.

As I understand it, Chet and Paul both tended to run their guitar volume setting full out, maybe with the treble backed off a bit and would control the actual heard volume from the amp itself.

Doing it this way makes the guitar earn its keep and allows the pickups to deliver a better tone.

Re: Changing speakers in 67 Twin Reverb

PostPosted: Fri May 09, 2014 8:59 am
by BirdofParadise
Thanks Norm

Re: Changing speakers in 67 Twin Reverb

PostPosted: Sat May 10, 2014 9:05 am
by Norm
hard to believe but those great recordings of Chet and his D'Angelico were made with a Fender tweed Deluxe amp I think. He came up in radio so a big, powerful amp was not necessary. The Fender Pro amp was a bit bigger. Chet had one of these and used it to swap out for his 25 watt Standel The Twin was originally a 25 watt amp and didn't get beefed up to it's current output until the sixties

Jerry Reed Looooved Twin Reverbs