Tube Head for a 4 ohm Speaker?

David Biagini · Post by **David Biagini** » 29 Jul 2000 9:17 am

I have an early Session 400 w/15" JBL. According to the back of the amp it is a 4 ohm load. I've been looking for a tube head to use with this speaker, giving me the advantage of also having the Session 400 as a backup up in case the head fails.

I've found some very nice Fender Showman's but they take an 8 ohm speaker load. Does anyone know of a tube head that would be good for pedal steel that will take a 4 ohm load?

Bobby Lee · Post by **Bobby Lee** » 29 Jul 2000 1:09 pm

I think that Fender amps usually say that the external speaker jack is takes an 8 ohm load. The jack puts the speaker in parallel with the internal 8 ohm speaker for a total load of 4 ohms.

I personally would not hesitate to run an old Fender tube amp at 4 ohms. The Twin Reverb runs at 4 ohms. I've reconfigured a Pro Reverb to run two 12's at 4 ohms. Both of these sound great for steel, IMHO.

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<img align=right src="http://b0b.com/Averybob.gif" width=64 height=81>Bobby Lee - email: quasar@b0b.com - gigs - CDs
Sierra Session S-12 (E9), Speedy West D-10 (E9, D6),
Sierra 8 Laptop (D13), Fender Stringmaster D-8 (D13, A6)

David Biagini · Post by **David Biagini** » 29 Jul 2000 1:28 pm

You're right, Bobby. I just found an early silverface Dual Showman Reverb head that takes a 4 ohm load. It sounds great with plenty of clean headroom and may soon have a new home!

Hamilton Barnard · Post by **Hamilton Barnard** » 29 Jul 2000 6:51 pm

The Showman Reverbs are fabulous amps. You might check and make sure that the JBL is 4 ohm because most of them were 8.

And only the older blackface single Showmans were 8 ohm.

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Make mine old...and country.

Dave Zirbel · Post by **Dave Zirbel** » 29 Jul 2000 6:57 pm

Last night I did a gig with Buckeye and I powered a 4 ohm JBL E-130 with a 1971 Twin Reverb. It sounded great and had plenty of power and headroom! I think I had the volume on 4 , maybe 5. I think I'm going to stay with tubes. My Sho-Bud with a George'l 10-1 pickup and my Telecaster sounded real nice. I won't need to lug two amps anymore.

Dave

Ron Whitworth · Post by **Ron Whitworth** » 29 Jul 2000 9:32 pm

Hey guys..Are you sure we are moving forward here?? Just kidding of course!Since I own 2 Twin's; a Vibrosonic & I just last week bought a Showman Reverb head I've got a lot of room to talk..Just can't beat the sound of those tubes!!! Transistor's just don't glow in the dark!! Hey Ricky; you need to be in this discussion!!! Later..Ron

Bob Hoffnar · Post by **Bob Hoffnar** » 29 Jul 2000 10:28 pm

I'm lucky that I get to try out lots of amps at rehersal studios. I've been going for the Marshall's lately. If they are not too beat up and you set them right they sound fantastic for the steel. I like those Soldano 100 watt heads also. I just picked up a VHT 100 watt head to try out and I'm having great results recording. Try everything you can out and spend some time with it. Lots of great gear out there.

Some solid state stuff sounds great also. I've been playing with an old Standel that really has the mojo.

Bob

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Franklin D-10
[This message was edited by Bob Hoffnar on 30 July 2000 at 01:18 AM.]

Dan Tyack · Post by **Dan Tyack** » 30 Jul 2000 3:13 am

I don't know, but I been told....

That a Showman (black face) is 8 ohms, but a DUal Showman is 4 ohms (dual = 2X15" speakers). -

Hamilton Barnard · Post by **Hamilton Barnard** » 30 Jul 2000 1:46 pm

Hey Bob, what Marshalls have you been pluggin' into? I own six of those things and have never plugged my Emmons into one!

BTW, I just picked up a '66 JTM-50 plexi.

Bob Hoffnar · Post by **Bob Hoffnar** » 30 Jul 2000 4:07 pm

Hamilton,
I don't know the model numbers. I remember that the ones that sounded the best had 4 EL34 power tubes in them. The speaker cabs have a nice sound also. 4 low power speakers have a sweet sound. I just plug into everything I can get my hands on and then turn knobs until it sounds good. Although some Marshalls sound pretty bad. Real squonky high end.

I'm shooting for a clear,full,clean sound with them and some really work out.

Bob

Hamilton Barnard · Post by **Hamilton Barnard** » 31 Jul 2000 5:30 pm

Real squonky high end.

Yep, they'll do that, especially if plugged into the high gain input (top one). However, that squonky high end turns into that legendary Marshall sound when the volume knob hits at least "8".

Bob Metzger · Post by **Bob Metzger** » 1 Aug 2000 1:29 pm

Fender made Single Showman and Dual Showman amps initially (white tolex) starting around 1960. They came with 12" speaker(s) or 15" speaker(s). The Fender Field Guide doesn't talk about dual Showman 12's but I have seen at least one. Of course, Leo made a number of one-off's for various people. The speaker were always JBL's, D140 F's for bass and D130F's for full range. (I'm sure there were exceptions to that, as well!) Later came amps that said 'Dual Showman' or 'Dual Showman Reverb' on the faceplate. A single Showman had an 8 ohm output, a single speaker (12" or 15") and the output transformer number is 125A30A/022897 (this second number was a later part identifier). A Dual Showman had a 4 ohm output, two 8 ohm speakers wired in parallel and output transformer number is 125A29A/022889. This is the same output tranny found in most Twin Reverbs. Some of the earliest single Showmans (white) had a different output transformer: # 45550/ 8 ohm output. These are the loudest Showmans I've ever heard but they are also the brownest sounding, making it a questionable call for modern steel guitar tone.

Because it is entirely possible for an amp head to be mixed and matched with any cabinet over the 40 year history of these amps, I highly recommend looking at the output transformer number before hooking it up to speakers, in critical applications. This is the definitive step to take if you really want to match the output ohmage of the amp to the speaker properly. Also, double check the speaker ohmage and wiring configuration (series or parallel).

Bob

Hamilton Barnard · Post by **Hamilton Barnard** » 1 Aug 2000 2:13 pm

The Fender Field Guide doesn't talk about dual Showman 12's but I have seen at least one.

I played through one in 1966. Haven't seen or heard of one since. They have to be another one of Fender's rare off-shoots.

I was unaware that D140F's could be factory ordered in a blackface Showman. I had never read that or have I ever seen one.

However, when I saw Jefferson Airplane in 1970, Jack Cassidy was playing bass through two dual Showman Reverbs and his tone was absolutely thunderous and crystal clear. Man, what a concert that was.

Donny Hinson · Post by **Donny Hinson** » 1 Aug 2000 7:43 pm

As a general "rule of thumb", most all 2-speaker Fender tube amps have a 4-ohm transformer, and 1-speaker tube amps have an 8-ohm transformer.

Michael Brebes · Post by **Michael Brebes** » 2 Aug 2000 3:53 am

Besides Fender Twins and Marshalls, another amp or head that outputs 4 ohms and has a very good sound is the Traynor Mark 3, which you can locate used either as a combo w/ 2x12" or an amp head. It's like a Twin but with a Marshall style power amp, using EL34s. I use them for my main rig and I actually like it better than a Twin.

Bob Metzger · Post by **Bob Metzger** » 2 Aug 2000 1:35 pm

Donny,
What if I offered you a Showman head for sale with no cabinet included (and it didn't say "Dual Showman" on the faceplate). How would you know if this amp were originally manufactured to be correctly matched with two speakers or one speaker? Over the years, I've seen so many amp users using stand-alone amp heads with inappropriate speaker arrays (that they were usually unaware of) that we need a definitive test to ascertain the correct output wattage and ohmage of any given amp. When one adds a very critical application such as steel guitar to this equation, you need to get everything right if it's gonna sound any good at all. What you're saying is generally true but not definitive.

For lead or rhythm turntable players (are all you rappers out there listening?), ohmage mismatch is no big deal and might even help you achieve a wild and crazy sound.

Bob[This message was edited by Bob Metzger on 02 August 2000 at 06:39 PM.][This message was edited by Bob Metzger on 02 August 2000 at 06:41 PM.][This message was edited by Bob Metzger on 02 August 2000 at 06:42 PM.]

Bobby Lee · Post by **Bobby Lee** » 2 Aug 2000 9:58 pm

Even though some of them say 8 ohms, I've never run into a Fender amp that had a problem with a 4 ohm load. You guys have more experience than me, though. Have any of you encountered a Fender that blew a fuse because of a 4 ohm load?

My Mesa/Boogie Maverick prototype has separate transformer leads for the 4 and 8 ohm jacks. There are two 4 ohm jacks wired parallel and a single 8 ohm jack. I've plugged three 8 ohm speakers into it without a problem. Actually, it sounded great!

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<img align=right src="http://b0b.com/Averybob.gif" width=64 height=81>Bobby Lee - email: quasar@b0b.com - gigs - CDs
Sierra Session S-12 (E9), Speedy West D-10 (E9, D6),
Sierra 8 Laptop (D13), Fender Stringmaster D-8 (D13, A6)[This message was edited by Bobby Lee on 02 August 2000 at 11:00 PM.]

David Biagini · Post by **David Biagini** » 2 Aug 2000 10:08 pm

Thanks for all the great information. The Dual Showman Reverb I am looking at says 4 ohms under the speaker output jack and at the store we played it through two different 2-12" 4 ohm speaker cabs. With a Telecaster it stayed clean up to painfully loud volume levels.