Quick question on Roland Cube 100

[allexcosta]

Trying to help a friend...

Manual doesn't help a lot.
So, he wants to add an external speaker to his combo. What's the wattage without an external cab and with it?

Here's the data:

[Invalid or Expired Link Removed]

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From the manual:

External Speaker Recorder
* Less than 8 ohms, more than 100 W

EXT SPEAKER (External Speaker) Jack
You can connect external speaker here.
When connected, sounds are played from both the CUBE and
the external speakers.
* When connecting to an external speaker, make sure the speaker
conforms to the following specifications.
Impedance: 8 ohms maximum
Allowable power input: 100 watts minimum

Thanks in advance.

 

[LuvMusic]

Went and pulled the PDF version of the owners manual. Here is what it said about the power rating and ext. speaker connection:

Rated Power Output
100w

2. EXT SPEAKER (External Speaker) Jack​

You can connect external speaker here.​

When connected, sounds are played from both the CUBE and​

the external speakers.​

* When connecting to an external speaker, make sure the speaker conforms to the following specifications.​

Impedance: 8 ohm maximum.​

Allowable power input: 100 watts minimum​

* Only use speaker cable to connect the speaker. Do not use any shielded cable designed for use with basses.​

* No sound is output from the CUBE’s speaker or any external speaker when the RECORDING OUT/PHONES jack is in use.

So, looks like 100w output, which makes sense......Cube 100.​

If you attach an external speaker cab, it should not exceed 8 ohms. Will be easy to find a cab that meets this requirement, most cabs are 4 or 8 ohm.​

What the manual doesn't seem to mention is what the combo without the extension is running at....I would guess 8 ohm.​

The allowable minimum input for the cab of 100w refers to how much power the extension cab is rated to handle, it looks like the recommendation is at least 100w, which makes sense.​

See...if the combo is 100w @ 8 ohms and you add an 8 ohm extension cab the resistence drops to 4 ohms which means the amp section will be putting out more than 100W. So you would want an extension that is capable of handling at least 100w.​

So, if your friend is looking for an extension cab, I'd suggest an 8 ohm cab with a rating of at least 100w. I'd guess, with an ext like this, the cube would probably be putting out about 150w (maybe a little more).​

I'll stop rambling here and I hope this helps!​

 

[BillyB_from_LZ]

I think that the external speaker jack is connected in series with the internal speaker, not in parallel with it.

I first saw the photo of the rear panel and when it indicated that the extension cabinet should be 8 ohms "max" I suspected that the extension jack is in series...otherwise the rating would give a minimum extension cabinet impedance.

Looking at the block diagram, it shows the external speaker jack in series, confirming my suspicion. One way to confirm this is to insert a speaker cable into the extension jack but leave the other end open. If you get no sound, the jacks are in series.

Assuming that's the case, in order to get the maximum power out of that amp, you don't connect an extension cabinet at all. Beyond that, the lower the better!

Other than Crate, I don't know of another bass amplifier manufacturer that connects the speaker jacks in series.

Edit: As for the dual power amp thing in the block diagram, its possible that they're using two 50 watt power amp chips and bridging them internally so that we only see a single channel output.