jbl 130 series

tomsteel · Post by **tomsteel** » 2 Dec 2000 9:45 pm

I was thinking about buying an old 15inch jbl,130 series.The only thing is the speaker is rated at 16 ohms.Would this adversely affect my amplifier?The amp is an old gretsch model that I bought off of ebay.It just says Nashville pro steel model on the front.It is pretty old although I,m not real sure how old.The speaker has been replaced with a newer black widow.I was wanting to put that jbl,130 in there.Can I put a 16 resistor in parallel with the speaker to make it 8 ohms and be ok?

Matt Farrow · Post by **Matt Farrow** » 3 Dec 2000 12:05 pm

If you put a 16 ohm resistor in parallel with the speaker, the resistor will dissipate half (more or less) of the amp's power as heat inside your speaker cabinet. Is your amp solid state or tube? There is no easy answer to this, and opinions differ, but I would wager that your amp would be fine. You may lose a little bottom from your tone, but the D130s have a real good bottom end on them anyway, I doubt you'd notice. With a 16 ohm speaker, your amp will not be able to deliver its full power into the speaker load. BUT---you can have the speaker reconed as an 8 ohm speaker, so keep that in mind if it sells for real cheap.

Matt Farrow

Jon Light (deceased) · Post by **Jon Light (deceased)** » 3 Dec 2000 12:25 pm

Just for clarification (for me)--at 16 ohm the amp won't deliver full wattage but no harm done, right?

Matt Farrow · Post by **Matt Farrow** » 3 Dec 2000 12:40 pm

GENERALLY speaking a 100% impedance mismatch will not do much harm, if any. Depending on the amplifier's design there may be drastic consequences, which is why there's not a real simple answer to that question, and I'd want to look at a schematic or the actual amp before making a decision. For example you wouldn't want to hook up an extra 4x10 cab to a tweed Bassman, as they already run at 2 ohms, that's really hard on output transformers and power tubes. And on lots of old transistor Vox amps, you don't want to hook up extension speakers to those because the output transistors are biased in such a way that they may go into thermal "runaway," and there's no circuit breaker or speaker fuses in there to protect the amp. BUT going UP in impedance means less current will flow (Ohms law I=E/R) so therefore less work will be done by the amp.

Hard to give a decisive answer without all the facts but I'd say that you would be OK.

Farrow

Jon Light (deceased) · Post by **Jon Light (deceased)** » 3 Dec 2000 12:50 pm

Yeah, Matt--the burn-up potential of too-low impedance I'm well aware of. Just rechecking on the higher impedance mismatch.

Lefty · Post by **Lefty** » 3 Dec 2000 3:05 pm

I have (2) of these JBL D-130 16 ohm speakers that came out of some audio speakers my father in law had. They are probably 1965, but look brand new. I have not used them for this reason (16 ohm). I guess I could run them parellel @ 8 ohms, but had wanted to have them in separate enclosures.
Lefty

Ricky Davis · Post by **Ricky Davis** » 3 Dec 2000 11:50 pm

Here is my experience with all different speakers with all different ohms in my twin. I first ask Redd if it was safe and said ok. He said the only difference and affect different ohm loads will have on a "tube" amp; would be a small if any, power change.
I have tried so many different speakers with so many different ohm loads in my twin these last several months and found that there hasn't been any problem what so ever. I can barely notice any volume difference and the only difference I ever heard was the quality of the speaker.
I found the D-130F "not reconed">to be the best.
But then again I now have the two-12 original Blue Backs back in it and it is killer. I put the D-130 in the Christmas Tree amp I'm workin' with right now.
That is my testimony that I've learned and was inlighted by a very very experienced player of "tube" amps.
Redd did not suggest doing different ohm loads in a solid state amp>"you might be lookin' for trouble then".
Ricky

Gene Jones · Post by **Gene Jones** » 4 Dec 2000 6:57 am

TOMSTEELE: I have one of those old JBL's from a Standel amp..after the amp crashed I mounted it in a speaker cabinet like G.D.Walkers..has a nice, soft tone, but I would be afraid to "romp" on it because of it's age. I also have a Gretch, National Pro amp that you wondered about it's age...mine came as a package deal with a Sho~Bud Super-Pro that I bought new in 1982. The amp is still like new..I only used it at home in my music room because of low power. The only other person I know to have one of these amps is Bud Carter who takes it to the steel shows for his demo guitars.

Brad Sarno · Post by **Brad Sarno** » 31 Mar 2005 2:47 pm

Hey Gene, I've got one of those Gretsch Nashville Pro amps too. It's essentially a Sho-Bud single channel. Mine has an Altec speaker in it. The amp is the loudest 60 watts I've heard. Great steel amp.

Brad Sarno

Brad Sarno · Post by **Brad Sarno** » 31 Mar 2005 7:04 pm

Oops, I guess that thread was a little old. I ran across it on a search...

Brad