Author Topic: Another dumb amp question (Read 133 times)

crobbins · « **on:** June 08, 2009, 06:32:41 PM »

What will happen if I plug a 16 ohm speaker into the ext speaker jack on my Fender Twin Reverb?
It says on the back of the amp. Total load 4 ohms, 100 watts rms. Will I damage the speaker, or the amp, or both?

sonicus · « **Reply #1 on:** June 08, 2009, 07:04:26 PM »

A correct answer requires that you know if the two internal speakers are 16 ohms in parallel or 8 ohms in parallel. If you already have 2 8-ohm speakers in parallel then you already have a 4 ohm load.

crobbins · « **Reply #2 on:** June 08, 2009, 07:40:44 PM »

The two speakers are 8 ohm in parallel. I want to add a 3rd speaker...

elwoodblue · « **Reply #3 on:** June 08, 2009, 08:08:49 PM »

Three 8 ohm speakers in parallel would be 2.67 ohms...so you will have to think about other options to get it above 4 ohms.
Two speakers in series plus an extension speaker in parallel will be 5.33 ohms.

Here is a good little ohm calculator.

sonicus · « **Reply #4 on:** June 08, 2009, 09:36:11 PM »

I have a good friend that is in my estimation the best TUBE AMP tech! go to http://unclespot.com for tube amp issues. He can build you a custom hand made amp or work on your fender . He is very knowledgeable about fender circuits. You have to make certain that your output transformer can do what you are asking for .I do remember that there have been variations and modifications there of. Having a pre-amp out jack installed will give you infinite possibilities for more volume and speakers with additional power amps. Perhaps an Alembic F2B pre-amp and Uncle Spot reverb unit and a separate power amp and speakers ? Please excuse me for digressing !

(Message edited by sonicus on June 08, 2009)

crobbins · « **Reply #5 on:** June 09, 2009, 06:36:03 AM »

Thanks. I have a brand new 12 16 ohm Tone Tubby speaker sitting around here collecting dust. I was thinking about building a cabinet for it and plugging it into the ext speaker jack on the twin. Just wondering how it will effect the amp, or speaker. I use to do the same thing with a 15 JBL, but it was 8 ohm...

crobbins · « **Reply #6 on:** June 13, 2009, 08:04:14 AM »

I put the speaker in a vintage Altec-Lansing cabinet from the 60s. It's made of 1 plywood and originaly had a 15 JBL in it. I still have the JBL but it needs reconing. I easly modified the cabinet for the 12 tone-tubby. The Fender Twin has it's 2 original 12 JBLs, plus the tone-tubby. Sounds great.....

lbpesq · « **Reply #7 on:** June 13, 2009, 08:38:05 AM »

Craig:

The Tone Tubby people can recone that JBL with hemp. I had an old JBL K120 that needed reconing. Had them do it, sounds great.

Bill, tgo

crobbins · « **Reply #8 on:** June 13, 2009, 10:12:01 AM »

Cool, I should call them when I have the money. I think I have 2 or 3 of those old 15 JBLs laying around here..

sonicus · « **Reply #9 on:** June 13, 2009, 10:24:17 AM »

I have all my recone jobs done by my good friend Ron @

http://www.unclespot.com I can say that he does high quality work as far as recone and tubeamps go!!!!!! Check out his website!!!

crobbins · « **Reply #10 on:** June 13, 2009, 10:33:11 AM »

I checked out the site earlier, very cool. My tubeamp tech is Robert Dixon in Burbank.

sonicus · « **Reply #11 on:** June 13, 2009, 12:54:03 PM »

Cool , I will pass that info on to all the Cats in Southern California that I know . Thanks___