A Shrunk Down Fender Twin Reverb?

**Tom Karol** · 11-11-2009, 01:59 PM

I was just wondering. Just about everyone, including me, holds the Fender Twin Reverb amp in high regard. But everyone also seems to agree that they're just too heavy and too powerful for most situations. So, does anyone make 'half' a Twin Reverb - same circuit topology, but 2-6L6's, 40w or so, 1-12" speaker, and under 50 lbs.? A Deluxe Reverb doesn't fit the bill. Neither does a Hot Rod Deluxe. Hmm, what's the story?

**randyc** · 11-11-2009, 02:05 PM

Originally Posted by Tom Karol

I was just wondering. Just about everyone, including me, holds the Fender Twin Reverb amp in high regard. But everyone also seems to agree that they're just too heavy and too powerful for most situations. So, does anyone make 'half' a Twin Reverb - same circuit topology, but 2-6L6's, 40w or so, and under 50 lbs.? A Deluxe Reverb doesn't fit the bill. Neither does a Hot Rod Deluxe. Hmm, what's the story?

Well, I frequently used a Bassman with a single 4 ohm 12. Sounded great and wasn't very heavy at all. That's pretty close to 1/2 Twin. Oops, I just realized that your question is more to the point of who makes one NOW. Sorry

(But Bassman amps are still very available, I think.)

Oh yeah, the amplifier that I designed and built for my brother (posted here a couple of months back, with photos) was a 45 watt model, considerably smaller and lighter than a Bassman and cost a lot less to build

Take a peek - if interested, I'd be happy to send schematic and parts list by e-mail ...

Randy

**Bill C** · 11-11-2009, 02:27 PM

Originally Posted by Tom Karol

I was just wondering. Just about everyone, including me, holds the Fender Twin Reverb amp in high regard. But everyone also seems to agree that they're just too heavy and too powerful for most situations. So, does anyone make 'half' a Twin Reverb - same circuit topology, but 2-6L6's, 40w or so, 1-12" speaker, and under 50 lbs.? A Deluxe Reverb doesn't fit the bill. Neither does a Hot Rod Deluxe. Hmm, what's the story?

how about this ...

Headstrong King Reverb Amp Replica of the Blackface Super Reverb

... not sure about the circuit, but otherwise it looks close to your spec

**dh82c** · 11-11-2009, 02:30 PM

Originally Posted by randyc

Well, I frequently used a Bassman with a single 4 ohm 12. Sounded great and wasn't very heavy at all. That's pretty close to 1/2 Twin. Oops, I just realized that your question is more to the point of who makes one NOW. Sorry

(But Bassman amps are still very available, I think.)

Oh yeah, the amplifier that I designed and built for my brother (posted here a couple of months back, with photos) was a 45 watt model, considerably smaller and lighter than a Bassman and cost a lot less to build

Take a peek - if interested, I'd be happy to send schematic and parts list by e-mail ...

Randy

Ok.. I am not ENTIRELY joking. Get a twin reverb. Pull the 2 outside power tubes. Unplug one speaker (I would suggest pulling the speaker from the poweramp side so you dont have one end that is too heavy).

Half a twin.

NOTE: If you pull the two outside power tubes you really should unplug one of the speakers. If not you will have an impedance mismatch that a)doesnt sound great b)could harm the output transformer.

Nice thing about that is that you have power to spare if you ever need it. It will be cleaner than a Pro Reverb (beefier output transformer, solidstate rectifier). You can turn it back to a 100W amp any time you want (or have a spare speaker/power tubes). Big amps are hard to get rid of these days. You can get an SF Twin for the same price as a SF Princeton Reverb.

**randyc** · 11-11-2009, 02:35 PM

Yes, that works fine if one speaker is disconnected. It saves nary an ounce of weight, however, and is still a fairly large amplifier.

The advantages (in addition to a more manageable power level) is that the two most expensive parts - power transformer and output transformer - will live forever under the reduced current/power dissipation.

My Twin is currently configured exactly this way except that I took it one step further and used two 4 ohm speakers. It is the loudest 50 watt amplifier around, LOL. (Was never used for guitar, I always used the thing in its original configuration as a keyboard amplifier.)

**Tom Karol** · 11-11-2009, 02:46 PM

Well, I was just curious about why there isn't one - seems like a marketing no-brainer to me. You know, when I had a late 60's Twin with SRO's, it was so heavy that I took the speakers out and put them in a Bandmaster cabinet. Then I cut the original combo cabinet off and made it into a head. Now that I think of it, I could have pulled 2 of the power tubes and mated the head with a 1-12 open-back cabinet. Voila!

**derek** · 11-11-2009, 02:47 PM

I think the Pro Reverb is what you are looking for. It was a 2x12 40 + watts (depending on year) with 2 6L6 tubes. 2 channels, 58lbs. They started as black face and then silver face versions.

**dh82c** · 11-11-2009, 02:49 PM

Well... a 100 watt TR is about 70lbs. One 12in JBL is about 15lbs.
Shaving 20% off the weight cant hurt

**dh82c** · 11-11-2009, 02:56 PM

Originally Posted by Tom Karol

You know, when I had a late 60's Twin with SRO's, it was so heavy that I took the speakers out and put them in a Bandmaster cabinet. Then I cut the original combo cabinet off and made it into a head.

My first fender was one of the 135 Watt twins that had been cut to a head. Even at that it was still weighed a ton and change.

**derek** · 11-11-2009, 04:41 PM

The way I would go (in fact, did go) would be to have a small builder who specializes in Fender circuit clone amps build you one. That way you can get the circuit you want the speaker config, etc.

**kawa** · 11-11-2009, 08:01 PM

2Ch and 2Speaker presence sounds.
10" Spkr makes good range sounds and for safety play.
I'm using now my main gear.

**BigDaddyLoveHandles** · 11-11-2009, 08:31 PM

What about going the head + cabinet route? If you don't mind making two trips you never lug all of it as once. What do you think of the Bandmaster heads? I think the current Bandmaster VM is 40 watts. You have a lot of choice as to cabinets, then.

**nado64** · 11-12-2009, 05:26 AM

The Vibrolux is an half of a fender twin. 2 6L6 and 2 Speakers 10".
The Heritage Kenny Burrell amp is a clone.

**derek** · 11-12-2009, 12:53 PM

The Vibrolux is not the same circuit though. It is a 5E11 , while the twin is a 5E8A. However, at 40 watts, 2 6L6s, 2x10, and 46lbs, it is pretty darned close for a production model. Probably the answer to what the OP is asking, unless he goes for a custom job, whether head or combo.

**dh82c** · 11-12-2009, 05:25 PM

Put 2 6L6s and a weber CopperCap in a Deluxe Reverb.
Deluxes run their plates too hot for 6V6s anyway.
You dont have a mid control but no one uses that anyway

**randyc** · 11-12-2009, 05:37 PM

Originally Posted by dh82c

Put 2 6L6s and a weber CopperCap in a Deluxe Reverb.
Deluxes run their plates too hot for 6V6s anyway.
You dont have a mid control but no one uses that anyway

You're SO right about those overstressed 6V6 tubes in the Deluxe !

But if you were trying to get double the power from a Deluxe (i.e. go from 22 watts to say 45 watts), you'd also have to replace both transformers. Might as well leave the Deluxe alone and buy another amp, IMO.

What's a Weber CopperCap ?

Randy

PS: never mind - just looked it up, the coppercap is just his name for a silicon rectifier

**dh82c** · 11-12-2009, 08:39 PM

remember randy.. double the power.. another 3db.

I think what is more important (and what a twin has is aces) is clean overhead (or not so clean if you like early Jim Hall).

You will get a little less sag when you push the deluxe with a SS rectifier (which is a plus with 6L6s). I say Weber copper caps because they are usually considered the best bang for the buck. If you have a soldering iron there is nothing stopping you from putting a couple of pairs of diodes in there yourself.

The Filament Current draw on the 6L6s is more than 6V6s but still within what fender power transformer can handle. Ditto for the fender OT. The only place I am not sure about is the speaker power handling. Maybe someone can chime in and educate me.

For clean volume my 77 DR smokes my 68 Super Reverb, even with 6V6s.
the SR IS louder but has earlier breakup (and at 86lbs it is a back breaker too).
The deluxe does break up as well.. just not as pretty.
Two completely different beasts. I love them both but for different reasons.

**randyc** · 11-12-2009, 09:14 PM

OK, DH, that all sounds good to me EXCEPT that it's not 1/2 Twin

What you are proposing is a beefier Deluxe.

To obtain 45 watts from the Deluxe you gotta' replace both transformers. The filament drain, which you mentioned is double for a 6L6, but screen current and plate current also have to increase --- can't get something for nothing, right ? If the output power is doubled and the plate voltage remains about constant, the plate CURRENT has to double and the Deluxe transformers won't handle it (well ... maybe for a little while

but not on a long-term basis.

I know, I know, you're suggesting the silicon rectifier as a replacement for the glass one to minimize voltage drop across the rectifier and that does help, but you only gain maybe 15 volts or so ... that's negligible when we're talking a 400 volt power supply, or thereabouts. In fact, you will LOSE that fifteen volts by the additional voltage drop across the secondary of the power transformer (caused by additional plate current consumption). You're trying to win a battle with Mother Nature and she rarely loses !

No offense intended - ALL of your points are valid but I just don't think that you're ending up with 1/2 Twin .... if you could, by simply exchanging tubes and re-adjusting the bias, don't you think people would have been doing this for years ?

Cheers, good stuff, thanks for your comments !
Randy

P.S. Almost forgot ... even if the output transformer in the Deluxe would handle (a) the increased plate current and (b) double the amount of power, it STILL would have to be replaced because the impedance would be incorrect (6V6 and 6L6 don't have very similar output characteristics).

P.P.S. Oh yeah, doubling power consumption also means substantial increase in internal temperatures, there most likely would be internal components needing replacement with beefier ones,

**cosmic gumbo** · 11-12-2009, 09:21 PM

I've played with a guy who swears by his new fender vibrolux 40W 2x10. It sounds real good to me. Nice size.

**N8RD7** · 11-15-2009, 11:43 AM

It's probably too heavy, but a Mesa Mark I is basically a Twin Reverb circuit with a few extras, and you can run one on two tubes, plus you can sub in 6V6 tubes instead of 6L6. So, you could have anywhere from 22, 44, 60 or 100 watts on tap. I've always wanted one, but never pulled the trigger and now they are out of production again.

**gawfshot** · 06-05-2010, 03:33 AM

Originally Posted by dh82c

NOTE: If you pull the two outside power tubes you really should unplug one of the speakers. If not you will have an impedance mismatch that a)doesnt sound great b)could harm the output transformer.

If I have a single 4ohm 15" speaker should I replace it with an 8 ohm?

**SamBooka** · 06-05-2010, 07:43 AM

yep. That is how it works.
Where did you find a 4ohm 15?

**randyc** · 06-05-2010, 01:42 PM

Originally Posted by SamBooka

... Where did you find a 4ohm 15?

During my search for a 4 ohm 15 inch speaker a few months back, I settled on Carvin. Best open-back performance specifications at about 1/2 the price of competitors. Other models required sealed enclosures for flat frequency response and the enclosure dimensions were quite large (which, of course, means heavy).

I found either three or four 4 ohm 15 inch speakers, IIRC ... if it's important, I'll look through my scribbled notes to locate part numbers. An internet search in the usual places would probably be quicker, however.

FWIW, locating the speaker on the Carvin website was sort of an obscure exercise. Can't recall exactly why but it wasn't straightforward (like doing a search for "15 inch 4 ohm loudspeaker").

cheers.
randyc

**djelley** · 10-08-2015, 04:18 PM

I am a HUGE fan of the Fender Supersonic 22.

**wintermoon** · 10-08-2015, 04:27 PM

yes, only a Twin is a Twin.
but if you don't need as much volume a Vibrolux Reverb is a good choice.
2 X 10 instead of 2 X 12, and it will sound different, but I use them for small gigs instead of my usual '67 Twin.