Super Twin Reverb Speakers

Jerry Malvern · Post by **Jerry Malvern** » 12 Jun 2007 12:44 pm

I did a search and found alot on this amps speakers. Most of it was before Eminence came out with the Commonwealth speakers. Any opinions as to whether these speakers might work?

David Doggett · Post by **David Doggett** » 12 Jun 2007 5:24 pm

Jerry, are you asking about the stock speakers (Jensens?) or the Eminence Commonwealth? Any set of speakers that can handle 100 watts each would work; or any single speaker that could handle 200 watts. Other than power handling capacity, it depends on the kind of sound you want. And are you talking about playing pedal steel through it?

Jerry Malvern · Post by **Jerry Malvern** » 12 Jun 2007 7:43 pm

Thanks Dave, I was hoping you'd reply. I have a Fender/Eminence 15 that came out of a steel king (sk rated at 200 watts), and tried the same speaker out of a Custom 15 Twin and a Black Widow from a Nasville 400 and all of them break up and starts to distort too soon. Sounds like the amp is just too powerful for the speakers. No where near full volume and this is with the boost off. Yes, its for pedal steel. I wrote Eminence earlier today, tech feels that two 12's Commonwealth might work,( over the single 15) but wont guarantee it.

Donny Hinson · Post by **Donny Hinson** » 12 Jun 2007 8:09 pm

Jerry, please tell us more. You said "Super Twin Reverb"? The 180-watt, 25+ year-old Fender tube amp? What's wrong with the stock speakers? How are you testing the various speakers? Are they in a cabinet? I used one of these amps for many years, and they put out a lot of power, but a Black Widow should sound fine. I suspect you have an amp problem if you're getting early breakup, or you're leaving out some pertinent information.

With all the new, light-weight neodymium speakers that are out now, there's no way I'd be looking at old-design speakers that weigh over 20 pounds apeice anymore.

Jerry Malvern · Post by **Jerry Malvern** » 12 Jun 2007 8:59 pm

Yes Donny, the 180 watts, 25 year old, heavy as all get out Fender Super Twin Reverb. Amp just serviced, tubes, caps, filters, solder joints redone, tube sockets tightened. Took it back to the tech and rechecked everything. ( and this tech is one of the few that UNDERSTANDS clean! ) It does not matter, in cabinets, out of cabs, still the same. All of them act like they are overdriven.

Mickey Lawson · Post by **Mickey Lawson** » 12 Jun 2007 9:44 pm

Jerry, web site for original vintage speakers and specs. Always liked the sound of my old Ampeg Gemini I, ordered a Jensen C12Q for my Nashville 112. Got the sound I wanted. Shipping FedEx Saver took 2-days.
http://www.tubedepot.com/jenvin.html

David Doggett · Post by **David Doggett** » 12 Jun 2007 10:10 pm

Jerry, I'm not sure what the problem is. I actually have never heard the stock speakers in the combo. I bought my Super Twin Reverb without speakers and put it in a head cabinet. I have an Eminence 15" that came in a '90s Vibrasonic combo. I took the chassis out and converted the Vibrasonic cabinet into a closed-back reflex, using the chassis slot as a port. With the STR that speaker doesn't break up at any volume I've used; but the closed back may have something to do with that. I've had the amp volume on 10, but I was using a volume pedal that is backed off at least half-way for the attack - I just use all that power for sustain. I wouldn't want to be in the same room with that thing cranked way up with no volume pedal.

I also play the STR through two JBL D130s in closed-back Marrs cabinets. The original backs seemed a little flimsy, so I replaced them with 1/2" plywood. I also added tubes to the ports. All those mods boosted the bass efficiency, and also help protect the speakers.

Both these closed-back cabinets with 15s have such strong bass that I usually use something like: bass 3, mid 8, treble 3. So even with the amp on 10, I am not really pushing those speakers in terms of bass. Possibly in an open back cabinet with the bass cranked up there would be much earlier breakup in both the speaker and the amp. The STR seems a little grittier to me than a silver-face Twin, but I would never describe it as having early breakup.

If you look at what regular guitar players use with high-power amps, it is mostly closed-back stacks. The idea of 180 tube watts through an open-back cabinet just seems a little scary to me; although it worked fine for Ted Nugent on regular guitar - and apparently for one Donny Hinson on pedal steel back when he was young enough to enjoy shaking the dust out of the stage floor.

One way to test whether the early breakup is from the amp or the speaker would be to run the amp into a heavy duty bass cabinet. If that breaks up, it's gotta be the amp. If the bass cab doesn't break up, but your Eminence and Black Widow do, it's possible that you have blown them somehow. I guess it is also possible that they just can't handle the power in an open back cab, but it seems like even in an open-back cab they should only breakup at top volume - not anything I would describe as early.

There are also some oddball possibilities, such as some kind of cabinet vibration. Are you putting a 15 in the original STR combo cabinet? The transformer on that thing is so big, a 15 might not fit without bumping into something and potentially causing vibration.

Rainer Hackstaette · Post by **Rainer Hackstaette** » 13 Jun 2007 3:43 am

Jerry,

I have a Super Twin Reverb in a Dual Showman head cab that I run into an open back cab with a Peavey 1501-4 speaker. I get no breakup at any volume, even with the boost on.

One thing to remember is to set the master volume to 10 and the distortion pot to "off" (i.e. all the way to the left "1" - you can feel a click when it's off). The distortion is unusable IMHO. If the input volume is set higher than the master volume, the amp will break up - it's meant to be, in order to give the guitar tone some crunch. So, for a clean sound, the master has to be higher than the input volume, and I prefer 10, maxed out.

If your amp still breaks up with these setting, there has to be a problem with the amp or the speakers you're using.

IMO the Super Twin Reverb is the best tube amp for steel, bar none.

Rainer

Donny Hinson · Post by **Donny Hinson** » 13 Jun 2007 3:12 pm

That's a good call, Rainer! I'd forgotten about mentioning the master-volume issue. (I always recommend "maxing out" master-volume controls for the cleanest sound.) Also, it would help to know if this particular amp/guitar combination has ever worked without distorting. Some tube amps can be overloaded by high-output pickups, or by a volume pedal that's amplified. Should that be the case, you'll have to not use as much pedal, or to lower the gain in the pedal (if it's amplified).

The stock "heavy-duty" Jensen (or Oxford) speakers Fender used were their top-of-the-line speakers, and they did a very good job...considering their cost and design.

Jerry Malvern · Post by **Jerry Malvern** » 15 Jun 2007 11:15 am

Well thanks for all the replies. Did every combination suggested and still no dice. THEN noticed power tubes, 5881 .......wrong tubes?

Donny Hinson · Post by **Donny Hinson** » 16 Jun 2007 9:54 am

THEN noticed power tubes, 5881 .......wrong tubes?

Boy, that's an understatement!

...this tech is one of the few that UNDERSTANDS clean!

(I guess it goes without saying you should look around for another amp tech!

)

Jerry Malvern · Post by **Jerry Malvern** » 16 Jun 2007 10:39 am

Your right Donny.

Johnny Thomasson · Post by **Johnny Thomasson** » 17 Jun 2007 4:05 am

I thought 5881s were equivalent to 6L6s. I've had them in my '65 Twin for years. They work/sound better than anything I've ever had.

Donny Hinson · Post by **Donny Hinson** » 17 Jun 2007 4:22 am

No, I wouldn't call them an "equivalent", as they have lower output and a lot more distortion. Some players do use them as a substitute, with varying degrees of success. They're great tubes for crunchy straight guitar work, but lousy when you want clean and clear, with lots of headroom and fidelity.

Johnny Thomasson · Post by **Johnny Thomasson** » 17 Jun 2007 5:23 am

Interesting. Lower output makes sense, because the first thing I noticed was they don't get nearly as hot as 6L6s. It's pretty clean, tho. But I never had to crank the volume past 3, and that would be for a room that would seat, say 500 people. 2 - 2.5 would be right for a club. BTW, I played fiddle thru this amp, not steel.

So, with me not being a tube/electronics expert, what tubes are generally recommended for an amp like mine to get "clean and clear, with lots of headroom and fidelity"? I like my NV400 better with my steel, so maybe I'm missing something.

Thanks in advance.

Ken Fox · Post by **Ken Fox** » 17 Jun 2007 6:14 am

From a website I found:

5881/6L6WGB
This tube was first developed by TungSol for the US Military. They are in short stubby glass envelopes. There is no difference between the 6L6WGB or the 5881, they are the same tube. The 5881 has a maximum plate rating of 360 volts at 23 watts and a maximum screen rating of 270 volts at 3 watts. DO NOT USE IN AMPS CALLING FOR 6L6GC's. They will likely melt down and damage your amp.

Here are ratings for a Sovtek 5881 tube (not the max plate voltage is much less than a typical 6L6GC tube at 500 volts):

3.3 Maximum Ratings

Rate Rate
up to up to
Parameters, units 500 hrs 5000 hrs
------------------------------------------------------------------------
Heater voltage, V:
min 5.7 6
max 7 6.6
Plate voltage, V, max 250 250
The second grid voltage, V, max 250 250
Cathode-to-heater voltage:
of positive polarity V, max 90 90
of negative polarity V, max 200 200
Cathode current, mA, max 90 90
Plate dissipated power, W, max 20.5 20.5
The second grid dissapted power, W, max 2.75 2
Resistance in the first grid circuit, Mohms, max 0.5 0.5
Envelope temperature in the most heated
part against the plate, K, max 483 483

Johnny Thomasson · Post by **Johnny Thomasson** » 17 Jun 2007 7:00 am

Mine are Sovtek 5881/6L6WGB. I just noticed that two are cracked, and the bottom part that used to be silver is now white. Surprisingly, the amp still sounds pretty good, tho' there is some hiss even with the volume turned all the way down.

These tubes are about 20 years old. If I wanted to switch to 6L6GCs, would I need to have the amp rebiased? I have an old 15" JBL in this amp. What do you recommend?

Mickey Lawson · Post by **Mickey Lawson** » 17 Jun 2007 7:14 pm

Interesting 6L6 info:
http://www.tubedepot.com/6l6reviews.html

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