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Extension speaker for Eden Nemesis NC212 Combo

jcburn

jcburn

Oct 11, 2003
2,628
1,674
53
Tasmania, Australia.
everburn.com.au
#1
Hi all. I have a question for you amp gurus cause even though I have played for many years I am an absolute novice when it comes to understanding amps/ ohms etc.
I have an Eden Nemesis NC212 combo. 320 watt FET amp with 2 12 inch speakers. It also has on the back a 1/4 inch out for an external speaker. Next to it is written 320 watts at 4 ohms. Does that mean that if I add a 4 ohm rated 4x10 cab it would have the same output. Also can I use any old guitar lead or would I need a specific speaker lead.
Then my last question would be if I added a cabinet with different ohmage could I possibly get higher output or could this damage the combo?
Sorry to all if these are dumb questions but would appreciate any help.
Jake.
 
#3
RickenBoogie said:
It probably means that you need to use an 8 ohm ext cab, paired with the 8 ohm internal speaker, giving you a 4 ohm load, and the 320 watts. You MUST use a speaker cable ONLY. Not an instrument cable.
Click to expand...

I own two Nemesis combos, and I can tell you that these amps are wired for a 4-ohm load - not an 8-ohm load. Furthermore, as it explains on this page of the Eden website...

[Invalid or Expired Link Removed]

...they're wired in series - not parallel. I'm a little fuzzy on the applied implications of series wiring, as I have experience with only parallel wiring - and I'm no engineer. But it does mean it'll behave differently - electrically speaking - than a cab wired in parallel.

Ditto on the cable. It must be a speaker cable - not an instrument cable... :hmm:

MM
 
#6
Cool answers folks thanks. Not to harp on too much but would that mean if I added either a 2x10, 4x10 or a 1x15 it would give me a little more output or even just push a little more air to compete with some loud guitarists?
I really love the sound, I just dont want to push the amp any harder than I am (pre gain at about 6.5, post at about 5 - 6).
I suppose the eden 2x10 would be a good match or the 1x15?
 
#10
myhot4 said:
The ext is designed to work in series. hence you can plug in an extension speaker of any impedance without damaging the amp.
Click to expand...
I believe this is incorrect. Adding a speaker wired in series is going to chance the ohm load your amp is "seeing."

If your combo amp has an 8 ohm speaker and you add an 8 ohm extension, your amp is now driving a 4 ohm load. This is fine, so long as the amplifier in your combo is rated to drive a 4 ohm load.

However, if your internal speaker is 4 ohms and you add another cabinet which is rated 4 ohms, your amp will see it as a 2 ohm load and will be tend to overheat (as 2 ohms draws more current than 4, just as 4 draws more than 8) unless it's rated to drive 2 ohms (and this is fairly uncommon among bass amplifiers in my experience).

The trick is to check your manual (RTFM) and see what your amp is capable of. The Eden manual for the NA320 combo ([Invalid or Expired Link Removed]) tells it this way:

Suggested Speaker Systems – Your speaker system should be chosen to accommodate the characteristics of your amplifier and your predominant application. If you will only be using one cabinet, a 4 Ohm model will draw the most current from your amplifier. If you will generally be using two cabinets, they should both be 8 Ohm models so their combined impedance will be 4 ohms. If you are uncertain about your future needs, always go with the 8 Ohm speaker option so that you can add another speaker later if you need to. In general, adding more speakers will give you a greater volume increase than adding a few more watts.​

Resistance (measured in ohms) is a oft misunderstood concept, but not one to be ignored if you value your amplifier.
 
#11
I checked the manual for the RS 212 combo, which explains it's designed to deliver full power at 4 ohms to the internal speakers. Thus, the external speaker output is wired in series "so the amp can't be forced to operate in an unsafe mode." By wiring in series, the total impedance increases when an extension cab is added, regardless of that cab's impedence. And the power will never increase above the 320 watts at 4 ohms. Thus, Eden explains that "when you connect an additional cabinet to your RS combo, you will not get quite as much power to the speakers. However, because of the added speaker surface area, you will still notice an increase in volume -- just not quite as much as you might expect."

My Roland Cube 100 is exactly the same way. The MOST I can get is the full 100 watts, and I believe wattage inevitably drops with an extension cab. With an 8 ohm extension cab -- even my very efficient G-K Neo112 -- fullness increases slightly, but the volume increase is negligible. With a 4 ohm cab, I suspect I'd get a meaningful volume increase.
 
#12
I have a newer RS115 which I thought and read was wired in series, but after contacting Eden and also buying one of their extension RSP115 ext cabs, I have found that the RS115 combos speaker ext. is wired parallel, and not series like the older combos, which was confirmed by the Eden CS, but they didnt seem quite sure either when I talked to them.
 
#14
jcburn said:
Cool answers folks thanks. Not to harp on too much but would that mean if I added either a 2x10, 4x10 or a 1x15 it would give me a little more output or even just push a little more air to compete with some loud guitarists?
I really love the sound, I just dont want to push the amp any harder than I am (pre gain at about 6.5, post at about 5 - 6).
I suppose the eden 2x10 would be a good match or the 1x15?
Click to expand...
Maybe the ext output has a seperate channel in the amp which will be the same power output which is 320watt max @4ohm or if it is not and you run another 4ohm speaker out it will become 2ohm which i have never seen a 2ohm stable guitar or bass amp in my life but if thatvfella put the 8 ohm speaker on it it would become 6ohm but the amp does say 650 watt somewhere sobibwould say the extention speaker turns it into the 650 watt so the 8ohm speaker would turn it into something like a 480 watt maybe anyway food for thought
 

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