Pro2055 External Speaker Jacks

[Alarms50]

I currently have two external speakers connected to my Pro2055 from the external speaker jack. Would there be a problem if I added a third speaker using the earphone jack on the front panel? I know this jack is at reduced volume, and that is what I am looking for. The question I am looking for an answer to is would I damage the 2055 by using both jacks (headphone & external speaker) at the same time?

 

[n2mdk]

I think if you plug something into the headphone jack it will shut off all the other speakers.

 

[gmclam]

What speakers?

I currently have two external speakers connected to my Pro2055 from the external speaker jack. Would there be a problem if I added a third speaker using the earphone jack on the front panel?

That depends. First are these unamplified speakers or amplified speakers? If amplified speakers, I expect the input impedance to be high (~10K) and you'll have no problem. But if the speakers are amplified, then it depends on their impedance. I'd also need to check and see what the impedance of the headphone jack of the PRO-2055 is; usually 8 ohms. If you're connecting several speakers it could EASILY overload the PRO-2055.

I know this jack is at reduced volume, and that is what I am looking for. The question I am looking for an answer to is would I damage the 2055 by using both jacks (headphone & external speaker) at the same time?

You'll need to provide more specific details (impedance of all device you are connecting) in order for us to give you an accurate answer.

 

[Alarms50]

I have two eight ohm speakers currently connected to the external (rear) speaker jack. I would like to connect another eight ohm speaker to the headphone (front) jack. None of the speakers are amplified.

 

[gmclam]

PRO-2055 speakers

When something is plugged into the rear speaker jack, it disconnects the internal speaker. When something is connected to the front headphone jack, it disconnects all other speakers; including the internal speaker or anything connected to the rear jack.

The specs say 1.5 watts maximum into 8 ohms. If you are running 2 speakers in parallel, that's 4 ohms so you are already pushing it. If you are running two 8 ohm speakers in series, that would be 16 ohms and would be OK. Hooking a 3rd speaker would not work, unless also 16 ohms. If you had 4 speakers, 2 each in series and each set of 2 connected in parallel, that would maintain the 8 ohm load.

Looking at the schematic and owner's manual, they really don't supply any additional information. The earphone jack is limited by internal resistors, but the rear speaker jack is not. So connecting too low of a load to the rear jack could cause damage.

 

[Alarms50]

Thanks. The two I already have are in series. As stated before the third speaker I want to add, I would like at reduced volume. The easiest solution I see is to run the third speaker to the headphone jack (which cuts out the other two) but that is OK. I will just need to remember to unplug the headphone jack to listen to the other two. Again, thanks for the help.

 

[N1BHH]

I find no problems with adding speakers. I have one which is sufficient to my needs connected to my scanner. I connect multiple speakers in parallel when I need to.

gmclam says: If amplified speakers, I expect the input impedance to be high (~10K) and you'll have no problem. But if the speakers are amplified, then it depends on their impedance.

"If amplified speakers" and "if the speakers are amplified" are the same thing, but I think you meant to say something different in that opposition sentence, such as "If the speakers are not amplified, then it depends on their impedance." Actually amplified and non-amplified speakers present almost the same relative impedance, on the order of 4-8 ohms nominally.

The headphone jack is a stereo headphone jack.

 

[gmclam]

Correction...

gmclam says: If amplified speakers, I expect the input impedance to be high (~10K) and you'll have no problem. But if the speakers are amplified, then it depends on their impedance.

"If amplified speakers" and "if the speakers are amplified" are the same thing, but I think you meant to say something different in that opposition sentence, such as "If the speakers are not amplified, then it depends on their impedance."

You are correct!! Thanks for pointing this out!

Actually amplified and non-amplified speakers present almost the same relative impedance, on the order of 4-8 ohms nominally.

Amplified speakers can be virtually any impedance, but I was specifically talking about using amplified speakers with a so-called "high" impedance, of about 10K.