Fender Twin w/ a 15?!

Jason Weaver · Post by **Jason Weaver** » 29 Mar 2005 8:49 am

I have seen a lot of talk around the forum about Twins with 15" speakers. Are people buying them like that, or changing them over from a 2x12? If they are changing them, is there info on how to do this anywhere? Wouldn't that make it identical to a Vibrolux?

Thank you all in advance for answering my many questions,

Jason

Brad Sarno · Post by **Brad Sarno** » 29 Mar 2005 9:16 am

You'd need to build a new baffle and carefully place the new hole so the speaker doesn't bump into the transformer. That would not make it like a Vibrolux. A Vibrolux is half the power, has 2-10", and also has no midrange control. You may be thinking of a Vibrosonic which is pretty much a Twin with a 15". I'm not sure but I think a Vibrosonic was an 8 ohm amp where the Twin is a 4 ohm amp. Ken Fox??

I've got a '69 Twin all cleaned up inside with a JBL D130. It's probably my favorite steel amp of them all.

Brad Sarno

Bob Metzger · Post by **Bob Metzger** » 29 Mar 2005 9:30 am

Hi Jason,

Many steel players prefer an 15" speaker in their amp for steel guitar use. The Fender Twin Reverb amp has two 12" speakers (hence, the Twin Reverb name). The problem that arises in changing the amp to one 15" speaker, besides the baffleboard and carpentry issues, is the impedance matching of the amp to the speaker(s) for most efficient power transfer.

A stock Twin Reverb uses two 8 ohm 12" speakers wired in parallel to make a 4 ohm output impedance. Most 15" speakers are 8 ohms, or at least the ones steel players traditional like to use. If you find a 4 ohm 15" speaker (like a Peavey Black Widow), you're good to go after making a baffle board for a 15" speaker and installing it into the Twin. However, alot of players like to use a 8 ohm 15" JBL D-130 (or another favorite 8 ohm 15" speaker) and this calls for a different output transformer.

The stock Twin Reverb output transformer is Fender part number 022889 (125A29A). The Fender transformer you need for an 8 ohm speaker is Fender part number 022897 (125A30A). Keep in mind that the output transformer is one of the most expensive parts in a tube amp.

Incidentally, this is the output transformer for a Fender Vibrosonic Reverb, essentially a Fender Twin Reverb with a 15" speaker (usually a JBL D 130). If you can find one of these amps, you will save yourself several steps. They are sought after by steel players who want to use a tube amp.

I think what you mean is a Vibrolux Reverb (not a Vibrolux, which is a completely different amp) but the answer is still, unfortunately, 'No'. The Vibrolux Reverb has two 10" speakers but only about half the power of a Twin Reverb (two 6L6 tubes in its power amp as opposed to four 6L6 tubes for the Twin Reverb) and that power difference is really critical for steel guitar applications. A Vibrolux Reverb would really only work for very quiet, low volume gigs and also, I don't think it's possible to fit a 15" speaker in the VR cabinet.

Your best bet is to look for a Vibrosonic Reverb or a Twin Reverb that has been already successfully converted. Otherwise, you might want to delve a bit more deeply into the cult of the Twin Reverb before buying. This amp has evolved quite alot and there are many differences between the various models of Twin Reverb amp.

Bob M.

Jason Weaver · Post by **Jason Weaver** » 29 Mar 2005 9:41 am

I did mean Vibrosonic! I was just talking with a friend a few days ago about his Vibrolux, and I still had it on the brain!

I would think that the Twin would be more readily available than the Vibrosonic, and therefore more affordable. Is that a correct assumption?

Also, my Vibrolux friend has many Fenders and he (as well as his other Fender amp friends) like to "blackface" them. Is that tone as desired amonth the steel community? I think he was tinkering with the idea of selling his Twin. I know he takes incredible care of all his amps, and would buy it in a heartbeat if I could afford it.

If I did end up with a Twin, where could I go online to find info on the baffle switch? Anyone on here have anything?

Thanks again,

Jason

jim milewski · Post by **jim milewski** » 29 Mar 2005 9:55 am

I have a baffle board ready to go, it came out of the reissue twin that I sold, I also have a couple 4 ohm BW 15 speakers, as Brad said you have to be careful on the placement due to the output transformer

Bryan Knox · Post by **Bryan Knox** » 29 Mar 2005 10:01 am

Jason,
As a lover and player of old Fender amps, may I encourage you to please not (for the lack of a better term) "hack" a vintage Fender? Granted, there's been a ton of Twins converted to a single 15" speaker, but it really kills what a Twin was all about.

Now I'm a firm believer in "hey, it's mine and I'll do what I want to with it" but it's just sad to see a classic amp changed from a classic to a mod. (just my opinion)

Now, if you are dead set on it, I would highly recommend the nice guys over at the Amp Workshop forum. http://pub58.ezboard.com/bampworkshop
Our own Andy Zynda is a member over there as I am and you can get a wealth of information about all types of amps. It's been a valuable resource to me over the years.

Also, quite often I run across whats left of "modded" amps in local music stores. You may find a cabinet that already been modified if time is on your side. Just the other day I saw a Super Reverb that had been modded to accept a single 15"

God Bless,
Bryan

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Help prevent juvenile delinquency...teach children to STEEL

[This message was edited by Bryan Knox on 29 March 2005 at 10:14 AM.]

Danny Naccarato · Post by **Danny Naccarato** » 29 Mar 2005 10:07 am

You might also want to consider a Dual Showman Reverb. It is basically a Twin or Vibrosonic head, with Reverb, and the output is 4 ohm. I have one, modded by Ken Fox. The speaker is a 1501-4 BW in a Marrs cabinet. If you can find a Twin or Vibrosonic cabinet, it'll fit, if you want one piece.....

Dave Grafe · Post by **Dave Grafe** » 29 Mar 2005 10:27 am

Just a note for anyone considering changing output transformers in ANY tube amp: The plate voltage (375 to 600 volts) in tube amplifiers remains stored in the filter caps INDEFINITELY (that means it's there for a long, LONG time). Unless you know how to properly drain this charge beforehand (or you are really into high voltage shocks and that funny metallic taste in your mouth that remains afterwards) PLEASE have a qualified tech do this for you.

There's a big kick in that box, trust me.

David Doggett · Post by **David Doggett** » 29 Mar 2005 10:50 am

Brad and Bob are right. The Vibrosonic was a Twin Reverb with an 8 ohm transformer and a single 8 ohm 15" speaker. Converting a Twin from 2x12 to 1x15 requires hacking up the cabinet and using a modern 4 ohm 15" speaker or a vintage 8 ohm that has been reconed for 4 ohms. Another option is to run two 8 ohm 15" speakers in parallel to give a total load of 4 ohm, and this also adds some volume and covers a room better. You can run this parallel load directly into the 4 ohm internal speaker jack with a simple Y connector. The best option of all is to take the Twin chassis out and put it in a Dual Showman head (from Mojotone and other cabinet makers for about $200). You have a smaller lighter package, and can use any speakers with it. Sell the old combo cabinet, or save it for resale.

About the black-face thing - regular guitar players worship black-face for the warmth, crunch and early breakup. The warmth can work well for steel (ask Lloyd Green), but only if you use about half the amp's volume - fine for studio work, but not enough clean head room for most live steel work. The sliver-faces have more clean head room for steel and they cost less. The ones with the most clean headroom for steel are the late '70s 135 watt models with the ultralinear transformer (same advice for Twins, Vibrosonics and Duals).

Finally, if you want the Twin sound, don't overlook a Super Twin. These are the same handwired late '70s silver-face ultralinear type amps (in spite of the black-face cosmetics), but with six 6L6 power tubes and 180 all-tube watts. I play some loud clubs where a Twin or Dual wont keep up, but the Super Twin will hang in there anywhere. They have the same gorgeous clean Fender tube tone, and the added advantage of a 5-band EQ separate from the usual 3-knob EQ, so you can have two different EQ settings that are switchable with a foot switch. These monsters are heavy, so I put mine in a Dual head cabinet. I play it through a single 4 ohm 15" speaker, or two 8 ohm 15" speakders in parallel.

Also, don't forget that some top steelers (Buddy Cage, Dan Tyack, Robert Randolph) prefer 2 or more 12" speakers. They cut through a loud mix better, but I prefer the sweet mid voicing and fuller bass of 15" speakers.

seldomfed · Post by **seldomfed** » 29 Mar 2005 11:19 am

Fender makes the

'65 Twin Custom 15 , 85 watt, ’65 Twin Reverb Reissue chassis, coupled with an enlarged cabinet and single 15” speaker instead of the usual pair of 12’s - they came out with this last year just before the Steel King. I think some of the forumites have these.

chris

------------------
Chris Kennison
Ft. Collins, Colorado
"Listen Sooner"
www.book-em-danno.com
www.seldomfed.com

Jack Stoner · Post by **Jack Stoner** » 29 Mar 2005 3:01 pm

The Twin cabinet does not need to be "hacked up" to convert it to a 15", or at least the models that had the front baffle screwed to the mounting strips. I know some of the later ones were glued in.

I had a Twin (AB768 chassis) that came with two 12" D120-F JBL's. I removed the speakers and Fender baffle. Built a new one for the 15" (it has to be to one side so the power and output transformers do not interfere), installed a 4 ohm K-130 JBL. Worked great. I used Fender grille cloth and reused the Fender nameplate and it looked "stock". I sold it with the 15" to a rock lead guitar player and he liked it. I had kept the original Fender baffle just in case.

That old Fender Twin may still be floating around KC somewhere. It was sold to a guy in South KCMO in 81 after I bought a Peavey Session 500.

(I bought the speaker and the Fender grille cloth from Quigley's Music on Troost). [This message was edited by Jack Stoner on 29 March 2005 at 03:04 PM.]

Jon Light (deceased) · Post by **Jon Light (deceased)** » 29 Mar 2005 3:35 pm

Just to address one statement/question you made, Jason---

I would think that the Twin would be more readily available than the Vibrosonic, and therefore more affordable. Is that a correct assumption?

I haven't priced them in a while but---TR's more readily available? Yes. More affordable? Not necessarily. The steeler market being a whole lot smaller than the guitarist market, and the Vibrosonic Reverb being essentially a steel amp (although I believe it has been 'discovered' by guitarists who have changed the market dynamics) VR's could be had for very reasonable prices up to a few years ago. This may no longer hold true.

David Doggett · Post by **David Doggett** » 29 Mar 2005 8:37 pm

Jack's right. Black-face Twins have removable baffles. Sometime in the transition to silver-faces they began glueing the baffles in. It is very difficult to saw the baffle out without messing up the tolex. Better to buy a head cabinet and a separate speaker cabinet. Or if you really want a combo, Mojotone or another cabinet maker can make a new cabinet to Vibrosonic specifications for a 15" speaker.

Danny Naccarato · Post by **Danny Naccarato** » 30 Mar 2005 6:30 am

Here's another thing to think about. My memory is real rusty on this, but I also had a Silverface Vibrosonic with the Ultralinear xformer. It was an 8ohm model. BUT, if I remember right, you can put a "dead" plug into the external speaker jack, which will make the main speaker jack 4 ohms. I'm certain there are some posts about this as it was discussed a few years ago.

Danny

Brad Sarno · Post by **Brad Sarno** » 30 Mar 2005 8:33 am

Some Twins have a removable baffle. My '69 did so there was no hacking of the original, just removal of the old baffle and creating a new one. I had a '70 Pro-Reverb that had the fixed baffle all glued into the cabinet. I decided not to mess with that one. Does anyone know what years had the fixed baffles in Fenders?

Brad

Donny Hinson · Post by **Donny Hinson** » 30 Mar 2005 2:55 pm

Sorry...double post![This message was edited by Donny Hinson on 30 March 2005 at 03:17 PM.]

Donny Hinson · Post by **Donny Hinson** » 30 Mar 2005 3:16 pm

I think everything '72 or later had the glued-in baffles. Earlier examples, like the '70 model Brad mentioned, might have had a cabinet-swap at some time, many have. It's really hard to tell with Fenders, since there are many out there (mostly, the ones in real good cosmetic shape) that aren't what they claim to be.

Kevin Mincke · Post by **Kevin Mincke** » 30 Mar 2005 4:44 pm

I have a 70 or 71? (master volume Twin) that I put a D130-F in the late 70's. The baffle was not glued, but rather than get a new piece of plywood (like I should have)I just off-set the 15" using part of the 12" hole and ended up with a 1/2 moon and filled it with the same piece taken out from the cut. Tight as can be.......

Jason Weaver · Post by **Jason Weaver** » 30 Mar 2005 6:22 pm

Thank you all so much for your wealth of knowledge. I was looking at the moko site that someone mentioned earlier. They sell complete amp kits, and they will be doing a silverface twin with optional 15" speaker in about a year. All of these are Grade A kits with the best of the best components, but they sell them for around $1000!

Also, someone brought it to my attention that Fender's Reissue '65 Twin is now available in a 15" custom. Anyone have any experience with these?

Thanks,

Jason

Dave Van Allen · Post by **Dave Van Allen** » 30 Mar 2005 7:28 pm

Jason,

at the top of the electronics section click on the "search" link (upper right of the page under the "post new topic" button)- search in this section of the forum, on the key words "custom 15" and limit the scope to a year - you will find several threads about the Fender 65 reissue with a 15.

BTW I love my '68 Twin with a 15" (Currently a Weber California but when I got it a JBL D130)

Donny Hinson · Post by **Donny Hinson** » 30 Mar 2005 8:29 pm

Jason, the re-issue version has little to recommend it. I'd suggest getting an old 135-watt ultralinear silverface model, and trying it for a year or so (with the two twelves). Then, if you're still not satisfied, sound-wise, you can change the speaker. For today's sounds, though, I think the two twelves will work just fine.

Al Carmichael · Post by **Al Carmichael** » 30 Mar 2005 9:56 pm

Don't forget to check out the Dual Showman Reverb. If you can find a head, its basically a Twin reverb--I am not sure if the speaker load is four or eight ohms, but other than that its like a Twin Reverb. You could build a separate speaker cab and divide the weight up. Last Twin I had wrenched the muscles in my arm and shoulder, so I sold it!

Bill Yoder · Post by **Bill Yoder** » 31 Mar 2005 8:05 am

I put a 15"JBL in my old twin,it is an 8 ohm speaker,so i put an 8 ohm resistor inparallel.it works just great.

Jason Weaver · Post by **Jason Weaver** » 31 Mar 2005 8:34 am

Al,

I did look into the Dual Showman heads, but the prices I saw were rediculous. They are going for between $700 and $1500!

I would be better off buying the Alembic version of the pre and a power amp, so I could use it for bass and steel.

This is probably what I will do someday when I can afford it. It would be a lot lighter than these Fender combos.

Thank you all for your input,

Jason

Danny Naccarato · Post by **Danny Naccarato** » 31 Mar 2005 1:25 pm

Even if you find a banged up, trashed DSF, send it to Ken and have him go thru the whole thing. He's real reasonable, and does a helluva job.....