The Steel Guitar Forum

Any input on prefered speaker cabinets for '69 silver face dual shoman amps? I'm looking for something with a 15", or is there a better speaker set up for steel? Can you run only one 15 with a dual showman? I understand that the ds is made to play with a 2-15" cabinet. Also what should i look for as far as the speaker goes? watts? ohms? I'm venturing outside the combo world for the first time so any advive is appreciated

The Dual Showman is a 4 ohm amp. That means you can use it with a single 4 ohm speaker, or two 8 ohm speakers in parallel, which gives a 4 ohm load. It will also work fine with an 8 ohm load, but you will loose a little volume and the amp will have to work a little harder.

I like 15" speakers for pedal steel, so with my Dual Showman Reverb I run either a single 4 ohm 200 watt Eminence 15" speaker, or two 8 ohm JBL D130 15" speakers parallel in separate cabs. You could just as well use a 2x12 cabinet. A single 12" would be a little skimpy for a Dual Showman, but if it was a heavy duty one that could handle 100 watts, it would work.

Consider yourself lucky. You have one of the best pedal steel amps ever made - my favorite. In addition to having something easier to carry than a combo, you have the flexibility of using different speakers and cabs.

Funny, I was just about to post about fixing up my '68 Dual Showman.

The Dual Showman was designed for a 4 ohm load. An 8 ohm load should be fine, though... it's going too low that's bad impedance-wise, more than too high (too low overworks the amp). The original cabs of the era were BIG 2x15" cabs, and you might be able to chase one down. But I'd think a single 15" would be MUCH more practical. If you're going anywhere that you need the volume a Showman with 2x15 could produce, you're MUCH better off miking the cab and using something lightweight! It ain't 1968 anymore, and PAs work pretty well now.

I just got my own Dual Showman up and running again tonight, although it still needs a cap job and substantial other work. I was inspired after going amp-hunting the other day and trying a Showman head in a 1x12" combo cab. It quite simply STOMPED every other amp I tried. My Showman is in an ill-fitting 2x12 combo cab with a single worn-out Utah speaker. A new speaker (Jensen Neo, probably) comes first, then I'll probably put the amp in a Deluxe cab... I think 85 watts of tube into a single 12" Neo ought to be quite sufficient for MY needs! And in the small combo cab, it'll be almost portable...

I also prefer the 15 inch speakers. G Walker has some great light weight cabs that can be loaded with JBL D130's or Black Widows.
I think these are great because two cabinets are easy to deal with. They are very light. I think they are the perfect bandstand cabs.

it's going too low that's bad impedance-wise, more than too high

Actually that's completely wrong. 100% mismatch in most Fenders on the low side is safe, although you lose some volume and power. 100% high is also safe - but not quite as much - higher impedances cause a phenomenon known as "flyback" that is far more harmful to the output section than the slight "overworking" of lower impedance. It's been a popular misconception for decades that lower impedance=bad, higher= good, but go over that 100% mismatch either way and the higher impedance will cause far more destruction - with a lower impedance you can "cheat" things a bit by biasing cold, but there's no way to cheat an excessive load.

Regardless, with a Dual Showman you can get away with a 2, 4 or 8 ohm load; the 4 ohm being the optimum as far as power and frequency response.

Since a Twin Reverb is for all purposes, the same amp, then the ohm equation will work for them also?

Jim Sliff wrote:

it's going too low that's bad impedance-wise, more than too high

Actually that's completely wrong. 100% mismatch in most Fenders on the low side is safe, although you lose some volume and power. 100% high is also safe - but not quite as much - higher impedances cause a phenomenon known as "flyback" that is far more harmful to the output section than the slight "overworking" of lower impedance. It's been a popular misconception for decades that lower impedance=bad, higher= good, but go over that 100% mismatch either way and the higher impedance will cause far more destruction - with a lower impedance you can "cheat" things a bit by biasing cold, but there's no way to cheat an excessive load.

Regardless, with a Dual Showman you can get away with a 2, 4 or 8 ohm load; the 4 ohm being the optimum as far as power and frequency response.

Hmmm. That's a really interesting idea... it's hard to separate conventional wisdom from fact when it comes to tubes.

I think what I'm going to do with mine is put it in a combo with an 8 ohm speaker. I can even pull a pair of output tubes to get a correct impedance match (with less power), if needed. And then I'll get an extension cabinet with another 8 ohm speaker, giving me an ideal 4 ohm load at maximum power - and I can't imagine any situation I'd be in that requires more power than a Showman with two speakers!

Craig A Davidson wrote:Since a Twin Reverb is for all purposes, the same amp, then the ohm equation will work for them also?

Yes. Twins and Showmans used the exact same output transformer and power tube layout.

Yes - the impedance issues for a Twin Reverb are exactly the same as for the Dual Showman Reverb.

I agree with Jim on the flyback issue. For tube amps, it's worse to have a somewhat higher than nominal impedance than a somewhat lower than nominal impedance. The worst thing you can do is to have infinite impedance - i.e., no speaker attached at all. This is the opposite from most solid-state amps, where the worst thing you can do is have a dead short at the output, while an infinite impedance does no harm.

In general, tube amps should be run "at" or "close" to their recommended impedance. With a "typical" solid-state amp, one needs to simply respect whatever low-impedance limit the manufacturer specifies, like "Minimum impedance 4 ohms".

Anybody ever tried something like this?
If you want to use an 8ohm speaker with an amp designed for a 4ohm load, change the impedance of the tubes so they want to see a higher plate to plate impedance. I fooled around with this idea some years ago, by lowering the screen voltages on a pair of 6L6's, 100 volts, using zeners. It requires more drive voltage to get full output power, but it worked. Still sounded good. Don't know all the ramifications of doing this, and have never heard of anybody else doing it, though I did post the idea on Ampage about 10 years ago. Back in the good olde days!..Jerry

Dave S., you're going in the opposite direction from the current trend. Many steelers with Twins are deciding they are just too heavy, so they take the chassis out and put it in a head cab. Dual Showmen are more rare than Twins. If you really want a combo I think it would be easy for you to find a Twin owner happy to make a trade with you; and it will save both of you having to buy another cabinet. With so many people wanting a Dual Showman, I hate to see one taken out of circulation and made into another ordinary combo. In addition to splitting up the weight, a head cab is convenient for setting next to your steel for tweaking, while having maximum flexibility in placing the speakers. I like my speaker(s) in the back line, where I wouldn't be able to reach a combo for tweaking while playing.

The Dual Showman I have is already in a non-stock (and non-Fender, and non-fitting) cabinet... some old ugly 2x12 thing. The faceplate has been treated with a MARKER as well as stickers, and it's been both abused (like tinfoil in the fuse socket!) and modified. It's a road dog... no, it's roadKILL. I can't imagine anyone trading a Twin for it, unless the Twin is in seriously awful shape.

I considered putting it in a head cab, but honestly, I'd rather have a 1x12 combo. A Showman chassis is basically the same size as a Deluxe, and there's only 4 pounds' difference between a Deluxe 1x12 cabinet and a Deluxe head-box. Throw in a light neodymium speaker like the Jensen, and there's probably less than ten pounds between a Showman head and a Showman 1x12. Considering the lighter speaker and no reverb tank, it'll probably weigh almost the same as a Deluxe... a very portable, high-powered tube amp!

And I have some sentimental ties to this amp, too. It fell into my hands (albiet dead) for free, and I would feel guilty about profiting from it, via sale or trade. So if anything, I should be turning it into the best amp it can be, as opposed to "restoring" it to some sort of stock-like condition.

There is something to setting the amp right next to you and the cabinets farther away, but I think I can cope without that. I'll end up with a Matchbox or something to tweak volume/tone at the steel anyway.

I may be wrong, But I don't think you can't fit a Dual Showman chassis in a Deluxe Reverb cab. The Dual Showman is the same chassis dimension as a Twin Reverb, at least the ones I've owned. In fact, They are the same chassis(the twin and the dual s., that is), just a different face plate, the best I know.

think what I'm going to do with mine is put it in a combo with an 8 ohm speaker. I can even pull a pair of output tubes to get a correct impedance match (with less power), if needed.

This works quite well. You have the impedance matching handled, and will lose almost no volume (about 3db, which is almost imperceptible). You'll have a little less headroom, but it warms the amps tone up a bit. I prefer Twins and Showmans (Fender's offcially correct "plural", by the way) in this configuration, although you still have the "big iron" of a Twin...so it won't turn it into something as warm as a Pro Reverb, a far better amp IMO.

FWIW as far as a head/ cab combo, I'd opt for a modded early silverface Bassman or a '64 BF...or later one that's been modded, a Holy Grail if you need reverb, and a 2x12 cabinet loaded with Weber Californias or Chicagos. With the few mods on the Bassman (available all over the net, and totally reversible), good tubes and the right bias setting you can get anything from a warm clean tone to a warm clean tone with a hint...or a lot...of breakup via fingertip control. Use a 5751 preamp tube, some JJ 6L6's and you have a tremendous "medium-power stack" amp for steel that can be tweaked in all sorts of tonal directions.

Dave S. - if you're going for a clean pedal steel kinda sound and you're putting together a single-speaker cab for your Dual Showman Reverb head, you might want to consider a cab with a 4 ohm 15" Peavey Black Widow speaker. I also like the JBL K-130 with that, but it's kinda hard to find a 4 ohm version.

For pedal steel or jazz guitar, I think that combination is very hard to beat. The Black Widow has more pedal steel bite than pretty much anything I can think of. All subject to personal taste, of course, but I really like it.

A great 12" speaker is the EVM-12L. Lots of clarity, and it certainly can put it out. However, I don't think a Dual Showman or Twin Reverb chassis will fit in a Deluxe Reverb box.

I also do the 2-6L6 thing in a Dual-Showman/Twin Reverb sometimes with just one 8 ohm speaker, especially for guitar usage. It's a nice sound for some things, but for pedal steel, I like to have the "full package". Different strokes, I guess.

Well, if it's already in a non-stock cab, might as well do whatever you want with it. I agree with the others that it wont fit in a Deluxe cab - it's too wide. A lightweight speaker sounds like a great idea. A Black Widow or JBL will of course sound great, but you'll be getting into the anvil weight range that at 61 I have sworn off of. Good luck. Let us know how it works out.

It should actually fit in a Deluxe cabinet. I measured it when I started looking at getting a nicer cabinet, and the Dual Showman chassis is actually 1/4" narrower than a Deluxe Reverb chassis... close enough for rock and roll! I don't know why it's so much smaller than a Twin chassis, but it is. Maybe it's the extra tube socket for driving the reverb or something.

Part of my problem is that I often play steel with unamplified acoustic musicians and unamplified singers. I have a more urgent need to get a full tone at low volume than a clean tone at high volume! Of course, I'm hoping to change that... once I get better at pedal steel, I'd like to try to latch on to some of the alt.country bands around here and play loud music.

I'm definitely thinking of having a 1x15" extension cab for it with a Peavey Black Widow (8 ohm). That way, if I need the extra volume and such, it's there. Two 8 ohm speakers in parallel should give me all the volume I need, and hopefully the 12" and 15" will play nicely together... I often like the sound of "mismatched" speakers.

Okay, you can clear the dimension question up over on the Fender Amp Field Guide site (http://www.ampwares.com/ffg/).

Widths in inches are:

BF Deluxe: 22
BF Deluxe Reverb: 24
SF Deluxe Reverb: 24 1/2

BF Showman: 26
SF Showman: 23 3/4
SF Dual Showman Reverb: 26

You apparently have a SF Showman, and it will fit inside a BF or SF Deluxe Reverb, but not a BF Deluxe. A BF Showman, or a SF Dual Showman Reverb will not fit in any Deluxe.