Hi, there!
Signed up just now...
Just picked a Carlsbro Cobra 90 Keyboard out of a dumpster. It is in good working order, with only a little bit of crackling from some of the pots. But since I am who I am, I was wondering if an Lansing Subwoofer Model 515-8G would fit inside. And would it give more omph? Salvaged the Lansing speaker from a wrecked cinemaspeaker years back, and it has been sitting on shelf ever since. It is in very good shape, so it's a shame not to find a use for it.
Signed up just now...
Just picked a Carlsbro Cobra 90 Keyboard out of a dumpster. It is in good working order, with only a little bit of crackling from some of the pots. But since I am who I am, I was wondering if an Lansing Subwoofer Model 515-8G would fit inside. And would it give more omph? Salvaged the Lansing speaker from a wrecked cinemaspeaker years back, and it has been sitting on shelf ever since. It is in very good shape, so it's a shame not to find a use for it.
Not sure it will fit, guess original speaker is 12", but hey, a ruler is your friend.
Thanks God, NOT a "subwoofer" which would be very low efficiency and muddy sound, but an old style PA woofer, high efficiency.
BUT: original speaker is 4 ohm Altec Lansing one is presumably 8 ohm, that would reduce available power to about 50W RMS.
Personally, I would leave original Cobra speaker there, then build a separate powered box with a built-in 100-150W power board, and join both together, Cobra has a Line Out jack, for wall shaking sound.
Thanks God, NOT a "subwoofer" which would be very low efficiency and muddy sound, but an old style PA woofer, high efficiency.
BUT: original speaker is 4 ohm Altec Lansing one is presumably 8 ohm, that would reduce available power to about 50W RMS.
Personally, I would leave original Cobra speaker there, then build a separate powered box with a built-in 100-150W power board, and join both together, Cobra has a Line Out jack, for wall shaking sound.
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...and for the record, I'm not a musician, I'm just passionate about old sound equipment. BTW, the two output jacks on the back... Are those for external, unpowered speakers?
Hello
As shown in the attached diagram, the 2 rear sockets are for external speakers yes! it is an amp that enjoys a good reputation among musicians it would be wise to restore it, and to sell it will make at least one happy, because these amps are rare. Then with 2 x 3055 at the output, you shouldn't expect a surge of watts either, but an acoustic guitar is not made for playing hard rock!!!
As shown in the attached diagram, the 2 rear sockets are for external speakers yes! it is an amp that enjoys a good reputation among musicians it would be wise to restore it, and to sell it will make at least one happy, because these amps are rare. Then with 2 x 3055 at the output, you shouldn't expect a surge of watts either, but an acoustic guitar is not made for playing hard rock!!!
Even more if you build the 100-150W powered woofer using the 15" Lansing 😉
Which then you use or not depending on Party size 🙂
Your Combo in theory does not need those speaker out jacks since it has its own 4 ohm internal speaker which is already the lowest impedance those 2N3055 can drive, BUT I am quite certain they stock a "Cobra90" chassis which is also used in the separate PA head version, so it´s pre-punched at the metallurgical shop.
Small World: at this very moment I am finishing 3 Guitar combos (to be delivered on Saturday) where I am in the same situation, all 3 backpanels have the speaker out holes punched but I am leaving them unused, and will cover them with the warranty label sticker, just to avoid Musicians obsessing about them 😉 but Carlsbro chose to fit the speaker jacks anyway which is also fine.
In fact I make practically the same product, sold thousands, it fills a particular niche very well: a small basic multipurpose 100W PA, catering both to Microphones and Instruments.
A steady seller for over 40 years now, still much in demand by solo performers, small Clubs, Bars, School theaters or Churches.
Since I fully make panels in-house (and PCBs, transformers, cabinets, speakers, etc.) it´seasy to customize, from 6 XLR to 6 "Guitar" jacks to anything in between, as needed, also in combo or head/cabinet versions.
My version:
Eerily similar ... until you remember "form follows function" and the job is the same.
I even used 2N3055 in the 80´s, go figure 😱