Speaker Ohmage?

  • Thread starter Thread starter ecktronic
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ecktronic

ecktronic

Mixing and Mastering.
Does anyone know what Ohmage I should go for?
Im looking at the Vintage 30s speakers for my JCM2000 DSL50.

I have a choice between 8 and 16 Ohms.

Cheers,
Eck
 
Well, it looks like that headis rated to put out 16 ohms if you are running it into one cab's worth of speakers... soooo...

You could buy 4x 8-ohm speakers, wire two sets in series and combine the two sets in parallel...

Or just buy 16 ohm speakers and wire as many as you'd like in parallel.

That's just my rudimentary knowledge of speaker wiring and what one of the sales sites that carries that amp led me to believe.

Of course, the site also says the head can run 2 cabinets at 8 ohms, so if you were doing two cabs worth and running both, I'd say go for the 8's - that way you could wire them all up as 8 ohms, and if you ever wanted to switch to a single cab, you could rewire the one you were going to use as such - each set of 2 8ohm speakers in series, and then the sets of series-wired speakers in parallel.
 
Now im even more confused. :|

Cheers though,
Eck
 
Depends on several factors
What are you putting them in, 2x12, 4x12?

2 speakers in a 2x12 can be wired for a total load of either half or double their individual ratings. For instance, 2 8 ohm speakers can be wired series for 16 ohms, or parallel for 4 ohms.

With 4 speakers, you can wire 4 speakers to have the same impedance as an individual speaker or 1/4 of that. 4 16 ohm speakers can be wired series / parallel to yield 16 ohms, or parallel / parallel to yield 4 ohms.

Then it's a matter of deciding what impedance you want you amp to see. Are you going to run more than one cab at a time? You should use cabs with the same impedance and make sure they will give the correct load for your amp.

Lots of questions to be answered first.
 
Why don't you see what ohmage the speakers you are replacing are and get that.
 
You have to match ohmage ratings. If your amp is giving you the option of 8 or 16, that just opens you to a wider range of cabinet choices. There is no sound advantage.

If you were to run your head at an 8 ohm rating into a 16 ohm cabinet, you will not damage your speakers, but they won't sound to their full. Vise versa, your speakers would blow.

Some people actually prefer mixing ohmage in that way though. In some instances, it sounds better.
 
Guitarer said:
You have to match ohmage ratings. If your amp is giving you the option of 8 or 16, that just opens you to a wider range of cabinet choices. There is no sound advantage.

If you were to run your head at an 8 ohm rating into a 16 ohm cabinet, you will not damage your speakers, but they won't sound to their full. Vise versa, your speakers would blow.
Click to expand...

Um, no. Whether the speakers would blow or not depends on their current handling ability.
 
ggunn said:
Um, no. Whether the speakers would blow or not depends on their current handling ability.
Click to expand...

Uhh, yeah...And your speakers ohmage is directly related to how much current they get. Setting your ohm rating on your amp to be more than your speakers resistance would be giving them too much current, causing them to blow.
 
Guitarer said:
Uhh, yeah...And your speakers ohmage is directly related to how much current they get. Setting your ohm rating on your amp to be more than your speakers resistance would be giving them too much current, causing them to blow.
Click to expand...

Regardless of speaker impedance or where you set your amp, it's still totally dependant on the speaker's power handling capacity versus what you're feeding it. You're probably more likely to hurt the amp than the speakers - unless they are very low power handling.
 
Guitarer said:
Uhh, yeah...And your speakers ohmage is directly related to how much current they get. Setting your ohm rating on your amp to be more than your speakers resistance would be giving them too much current, causing them to blow.
Click to expand...

Nope. Well, sort of, but......

Sigh.
 
Guitarer said:
Uhh, yeah...And your speakers ohmage is directly related to how much current they get. Setting your ohm rating on your amp to be more than your speakers resistance would be giving them too much current, causing them to blow.
Click to expand...

Bzzzt. Thanks for playing. ;^)

That's not how it works. There's no way that you can hook up an array of speakers such that any one speaker will draw more current than it would if it were connected to the amp all alone. The "ohm rating" setting (assuming yours is adjustable) on your amp is an impedance matching tap on the output transformer to optimize performance, but driving speakers with a combined impedance of a value less than what the amp calls for will not hurt the speakers. The amp, however, may be at risk, depending on how much bigger the load (lower the impedance) you put on it than it was designed (or set) for and how hard you drive it.

The impedance of a speaker and its power handling capacity are two different things and are virtually unrelated.
 
When did I say power handling? Power is wattage. The power your amp puts out is always going to be the same, but the amount of volts that your amp sends out with that wattage is going to change by setting (if your ohms are selectable)

Your amp is going to give the correct amount of volts to get the current through the resistance to power your speakers efficiently. Having your ohm rating on the amp as less than the speaker will give you enough voltage to get that current through the resistance, but by the time it does, too much current will have been dissipated, and it's no longer efficient.

You guys are totally misinterpreting what I'm saying.

(PS, I probably have the terms in the wrong order, because I suck at electronics, but you get what I mean)
 
Guitarer said:
When did I say power handling? Power is wattage. The power your amp puts out is always going to be the same, but the amount of volts that your amp sends out with that wattage is going to change by setting (if your ohms are selectable)

Your amp is going to give the correct amount of volts to get the current through the resistance to power your speakers efficiently. Having your ohm rating on the amp as less than the speaker will give you enough voltage to get that current through the resistance, but by the time it does, too much current will have been dissipated, and it's no longer efficient.

You guys are totally misinterpreting what I'm saying.

(PS, I probably have the terms in the wrong order, because I suck at electronics, but you get what I mean)
Click to expand...

I'm glad you brought this up. It has caused me to question what I know and what I thought I knew about this, so I've been doing some reading. Here's what I've got so far (from http://www.geofex.com/tubeampfaq/tafaqndx.htm):

The impedance of the load (the speakers) is reflected onto the primary of the output transformer, which is the load on the power tubes, and the impedance selector on the output transformer of a tube power amp is for setting the optimum load on the power tubes. If that adjustment is off in either direction, you get less power from the amp.

I have a 50 watt Marshall which has 4, 8, and 16 ohm settings. I have changed this with the same speakers connected, and I heard little difference in the loudness of the amp.
 
ggunn said:
I have a 50 watt Marshall which has 4, 8, and 16 ohm settings. I have changed this with the same speakers connected, and I heard little difference in the loudness of the amp.
Click to expand...
That would make sense, it takes 10 times the power (wattage) to get twice the volume. You really wouldn't hear much of a difference between your head running at 50 watts and your head running at 45 watts. It would just heat up the output transformer. (depending on the settings of the impedance selector)
 
Farview said:
That would make sense, it takes 10 times the power (wattage) to get twice the volume. You really wouldn't hear much of a difference between your head running at 50 watts and your head running at 45 watts. It would just heat up the output transformer. (depending on the settings of the impedance selector)
Click to expand...

And certainly not enough difference to blow the speakers.
 
ggunn said:
I'm glad you brought this up. It has caused me to question what I know and what I thought I knew about this, so I've been doing some reading. Here's what I've got so far (from http://www.geofex.com/tubeampfaq/tafaqndx.htm):

The impedance of the load (the speakers) is reflected onto the primary of the output transformer, which is the load on the power tubes, and the impedance selector on the output transformer of a tube power amp is for setting the optimum load on the power tubes. If that adjustment is off in either direction, you get less power from the amp.

I have a 50 watt Marshall which has 4, 8, and 16 ohm settings. I have changed this with the same speakers connected, and I heard little difference in the loudness of the amp.
Click to expand...

Oh, that's interesting. Yeah, my ohms are selectable like that as well. My cabinet is 8 ohms, but for a while I had it switched to 4 ohms accidentally. When switching it back, I didn't notice a difference in volume, but I did notice the signal cleared up a bit, as the strange fuzziness in my sound is what lead me to discovering I was on the wrong ohm setting.
 
ggunn said:
And certainly not enough difference to blow the speakers.
Click to expand...
I've never heard of speakers blowing, it's normally the output transformer blowing when the impedance is set to 16 oohms and the cabinet is 4 ohms...
 
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