Can I to add a "ext speaker out" to a combo that has none?

[Edword]

My Ampeg Portabass 228 doesn't have an external speaker jack. I'd like to add one so that I could run the amp through a speaker cab instead of the combo's internal speakers. I use the amp at rehearsal, and need a little bit more volume out of it. There's already a cab available at the practice space that I could use.

Would this be harder than it seems? I'm thinking that I could just measure the impedance, unsolder the wires from the speakers, solder them to a jack, and plug into a cab of the correct impedance. Is that unrealistic?

TIA

[BassmanPaul]

As a general rule of thumb, if a combo does not have an external speaker jack then the combo is giving it's maximum into it's internal speakers. Adding something that shouldn't be there will lead to the demise of the amp section. Sorry.

[edbass]

Originally Posted by Edword

My Ampeg Portabass 228 doesn't have an external speaker jack. I'd like to add one so that I could run the amp through a speaker cab instead of the combo's internal speakers. I use the amp at rehearsal, and need a little bit more volume out of it. There's already a cab available at the practice space that I could use.

Would this be harder than it seems? I'm thinking that I could just measure the impedance, unsolder the wires from the speakers, solder them to a jack, and plug into a cab of the correct impedance. Is that unrealistic?

TIA

As long as the amp sees a load it's designed for, which is probably same load as the internal speaker(s), it shouldn't hurt anything.
Whether or no you accomplish your original goal of increasing your SPL is debatable though, and largely dependant on what cab you plug it into.

Your amp is what it is; it will never be a powerhouse and obviously Ampeg didn't intend for it to drive an external cabinet.
If I were you I'd leave it alone and just send the line out to a bigger amp if you need more juice.

[kb9wyz]

Originally Posted by edbass

Your amp is what it is; it will never be a powerhouse and obviously Ampeg didn't intend for it to drive an external cabinet.
If I were you I'd leave it alone and just send the line out to a bigger amp if you need more juice.

+1

While plugging into a different cab might help a little tiny bit, it won't solve the problem. Get a new amp.

[charlie monroe]

The power section of this amp puts out 200w @ 4 ohms into 2X8" 150w speakers.

I see no reason why, as the OP suggested, he cannot disconnect the speaker cable, verify impedance load and solder up a jack. Edword is aware that he needs to provide an appropriate impedance load. As the amp can handle 4 ohms, there should be plenty of cabs that will work.

Admittedly, it may not yield results that are found to be an improvement, however, if the external cab has more cone area, it will push more air. Perhaps not better, but louder.

edit: Edword, it may be worthwhile to solder up the jack to the speaker side, and add a few feet of cable with a 1/4' male on the output side. This will make it super easy to reconnect if a) you don't like the results, or b) you still have situations where the combo only would prove useful.

[will33]

Originally Posted by charlie monroe

The power section of this amp puts out 200w @ 4 ohms into 2X8" 150w speakers.

I see no reason why, as the OP suggested, he cannot disconnect the speaker cable, verify impedance load and solder up a jack. Edword is aware that he needs to provide an appropriate impedance load. As the amp can handle 4 ohms, there should be plenty of cabs that will work.

Admittedly, it may not yield results that are found to be an improvement, however, if the external cab has more cone area, it will push more air. Perhaps not better, but louder.

edit: Edword, it may be worthwhile to solder up the jack to the speaker side, and add a few feet of cable with a 1/4' male on the output side. This will make it super easy to reconnect if a) you don't like the results, or b) you still have situations where the combo only would prove useful.

This.^^

You can hook it up to whatever you want as long as it doesn't go below 4ohms. Yes, there are a lot of variables but generally, running it out to a 215 or 410 or somethjng should give you noticably more presence than the combo's little 8's. You could even remove the amp portion and build it into a little headcase and use it on any stack of cabs of appropriate impedance. The combo would then turn into a little 4ohm 2x8 cab you could still run it with for quieter practice.

[bobcruz]

Adding a switched jack for the external speaker would be an elegant solution--leaving the combo's internal speakers connected until a speaker cable is inserted into the jack, which would shut off the internal speakers and route power to the external cabinet. Just be sure to get a switched jack that is rated to carry 200+ watts, not a headphone jack.

[Edword]

Thanks to all for your opinions, I will consider each of them closely.