Speakers for Silverface Twin Rverb

Byron Walcher · Post by **Byron Walcher** » 30 Jan 2007 12:14 pm

I have recently aquired a SFTR, traded my '66 Showman for it which means I've got way too much $ in it but the sound is unreal so what the heck. It has Altec 417b speakers in it . Problem is that they break up way too early-about 3 1/2 on the amp. It is definitely the speakers and not the amp. I hooked the head up to my K130 8 ohm cab and get deafening volume with no beakup. Problem is, I love the sound of these Altecs. Is this early breakup normal for them? The guy I got it from will trade me for some good D or K 120 recones, which I like but I like the sound of the Altecs better. If there is something wrong with them it would be the same $ to recone them as the JBLs. Any advice would be much appreciated, I have no experience with the Altecs at all so don't know what the capabilities are supposed to be.
Byron

Lee Jeffriess · Post by **Lee Jeffriess** » 30 Jan 2007 5:10 pm

Byron, stay with the Altecs, there is a couple of reasons you should like them better.
One there not beamy like the JBLs they are way smoother all the ugly stuff has been moved up to the next order, its there but we dont hear it.
Two the 417C and, its 15 inch counterparts the 418B and the 421A share the same vioce coil and, at 1 watt they are one db more effcient than the JBLs.
The biggest advantage is probably the reconing, modern JBL kits are more heavey duty than there vintage originals and, from what I understand are being phased out by lansing.
The Altec has a couple of quality options for recones, there is a good EV kit with a composit dome, but I realy recomend Great plains audio in Oklahoma city there recones are perfect, they repro all the theater Hi Fi and, MI speakers and, all the work is done by ex Altec techs with remanufactured and, deadstock parts.
I have two 418Bs one with an original cone and one with a great plains kit, theres nothing in it.
Also you may try unhooking one of the 12s you have, it could be just a be a bad coil in one of them, or abad connection some where.
Lee

Byron Walcher · Post by **Byron Walcher** » 30 Jan 2007 5:19 pm

Thanks Lee, do I understand then that in your opinion the early breakup that I'm getting is not typical of this speaker? It's not real intense, at first I thought it was typical tube amp distortion.
Byron

Chip McConnell · Post by **Chip McConnell** » 30 Jan 2007 6:24 pm

Hey Byron- up until recently I had a Silverface Twin Reverb with those same speakers. Breakup like you are describing is not at all typical- something is going on there.

Lee Jeffriess · Post by **Lee Jeffriess** » 30 Jan 2007 11:57 pm

As Chip says, thats not normal, those Altecs with the exception of the Stephens tru sonic are about the most efficient speakers you could have, I would imagine the twin would overdrive before you made them clip.
One of those speakers alone can handle the output of that amp.
The only down side to them is if they fall on there face, the air pressure can mess them up, theres some pretty tight tolarances in there, thats what happend with my 418 and,the same thing your describing, it got distorted at low volume.
BTW, if you go with Great plains Audio, be sure to request dead stock aluminium domes.
As i said see if you can isolate the problem first, it may only be one bad speaker,or maybe your terminals.
It does sound like a fractured voice coil.
They are worth the effort, you couldnt find replacements for the price of reconing and, IMHO you wont get anything on par
All the best
Lee

James Morehead · Post by **James Morehead** » 31 Jan 2007 6:43 am

Byron, I, too, am a huge fan of the altec speakers. I have a pair of Rick Johnson 15" extension cabs loaded with 418B's. I drive them with a '71 TwinReverb in a head cabinet. I like these speakers better than EV's, JBL's, BW's, ect. I have no problem cranking it up. I play a Shobud D10 with original pickups, and a shobud pot pedal with an Allen Bradley 500K pot.
You have a great pair of speakers there. Once you figure out and solve the problem, you will be in tone heaven!

Ken Fox · Post by **Ken Fox** » 31 Jan 2007 7:25 am

I would suspect the speaker are due for a re-cone. The only place to do it right (IMHO) is Great Plains Audio. They are the official Altec folks with the right kits:

http://www.greatplainsaudio.com/service.html

Mark Tomlinson · Post by **Mark Tomlinson** » 31 Jan 2007 8:19 am

Sure, the speakers may be the problem - but you also might have some tube issues there, so be sure to have the power tube and pre-amp sections of the circuit checked. It's not uncommon to find modifications on the Fender Silverface (CBS era) amps, trying to re-fit the circuitry back to the older Fender Blackface specification.

http://www.thetubestore.com/inonfenlatbl.html
http://www.unclespot.com/SF2BF.html
http://www.ampwares.com/ffg/twin_reverb_sf.html
http://www.fender.com/support/dating/amp_dating.php

James Morehead · Post by **James Morehead** » 31 Jan 2007 1:48 pm

If Byron plugged into his other cabinet and the issues went away, the amp is probably ok. One of those altecs is probably suspect. Double check your speaker wiring first before anything else. If that checks out, then unhook one speaker at a time, and you will isolate the culprit pretty quickly.

Byron Walcher · Post by **Byron Walcher** » 31 Jan 2007 2:33 pm

Thanks James and all, I did that and one of the speakers seems to have all of the distortion in it so, off to OK city, the thing is that absent the breakup, this is the best sounding setup I've had, the twin is just unreal. I really appreciate everyone's input,
Byron

James Morehead · Post by **James Morehead** » 31 Jan 2007 5:13 pm

Byron, you can run with just the good speaker in that amp. It will work with just one speaker ok. You just won't have full volume because now it will be 8 ohms instead of 4 ohms. For instance, if you like your volume at 5, now you will need to turn up to 6 to get that same volume---no biggee. You are best off to keep your original cone in your good altec as long as possible. In other words, don't send BOTH speakers to get reconed as a pair, or at least I sure wouldn't. I have had a couple of 418B's that were reconed, and they couldn't come close to the originals I had. I didn't know who reconed them---they were done when I got them. But Great Plains is probably your best bet, since they are ex Altec guys there. Woody Woodel from Nashville can probably do you right, too. But I said all of this, because some folks like to recone their twin speakers in pairs, but I'd just send the bad one.IMO

Jim Sliff · Post by **Jim Sliff** » 1 Feb 2007 6:23 am

If you run one speaker, it's even better is to remove either the two outer or inner pairs of power tubes and have the amp rebiased. Two tubes causes an impedance match at 8 ohms. You will not lose much volume at all, and usually get a slightly warmer sound.

And just to pile on - it's definitely a speaker recone situation.

thurlon hopper · Post by **thurlon hopper** » 3 Feb 2007 2:37 am

Byron, i have an Altec 4178H in a box right now and it is my favorite speaker. In the past i've also used an Altec 4188H in a 65 Twin and that was some of the best sound i ever had. Now i'm using a SF Twin and have the Altec along with a JBL E-130,
EVM 12L that i can easily do comparisons with and the Altec kicks butt big time. Doesn't have the earth jarring lows of the EVM, or the peircing highs of the JBL, but is just buttery smooth all the way across the spectrum. Hope your recone works great for you. TJH

Donny Hinson · Post by **Donny Hinson** » 3 Feb 2007 6:29 am

When you plug their amp into another speaker cabinet, and the "problem" disappears, you might easily figure it's bad speakers...and buy some new ones.

I'd rather suspect your problem is in the amp, and it's probably just loose sockets. The tube sockets must be re-tensioned periodically in all these old amps. The speakers (mounted in the amp) couple a lot of vibration to the chassis, and with loose tube sockets, the result is that the amp sounds like it's distorting. You can get all sorts of nasty noises from this simple problem.

Jim Sliff · Post by **Jim Sliff** » 3 Feb 2007 9:16 am

Donny makes a great point; I assumed that those details would have been checked right away, but many people don't know that those are normal amp-service issues that need to be addressed any time the amp is worked on.

Jerry Meek · Post by **Jerry Meek** » 4 Feb 2007 3:29 pm

Byron
If you don't get your speaker delima taken care of get in touch with me . I have two original and real good Altec 417C-8 speakers I would sell and they sound good with my Dual Showman Reverb or my twin.J.M.

Byron Walcher · Post by **Byron Walcher** » 4 Feb 2007 3:32 pm

Thanks for that insight Donny, the thing is, I know that one of the power tube sockets has an issue, one of the contacts has been bent and my tech was able to get it staightened out enough to work OK but it will make noise if jiggled a bit. It's going back to get that socket replaced. Thing is though, one speaker is way worse than the other.
Thanks again for all the help,
Byron

Byron Walcher · Post by **Byron Walcher** » 4 Feb 2007 9:34 pm

Ok so I plugged the Altecs in the Twin one at a time into my Vibrosonic Reverb, which is an 8 ohm amp, and NO distortion in either speaker. So, it would appear that Mr. Hinson has the correct take on my problem. The Twin Head sounds fine plugged into an ext. cab and the speakers in the Twin sound fine plugged into another amp. As I said, we knew one of the tube sockets was suspect, so this will be a fix that won't cost me anything, my tech guarantees all of his work. I can't thank you all enough, saved me a bunch of time and hassle and saved acouple of nice original Altecs from the knife (ouch).
Byron

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Speakers for Silverface Twin Rverb

Speakers for Silverface Twin Rverb

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