Hi there,
I'm thinking about building my own iPod dock - I have a pair of Infinity Kappa 42i 4" two-way speakers (45wrms, 4Ohm, 80Hz-20Khz) that I bought for a car I had for a very short space of time - they're virtually unused but were quite expensive at the time and I remember them having a nice, clean sound.
I plan on powering these with a STA540 stereo amp kit (Audio Amplifier Kit - STA540 - SparkFun Electronics). This should be plenty of volume for my intended application (kitchen-worktop music!)
However, I would also like to run a single larger bass/mid driver, probably around the 6" size, mounted on the underside of the dock (which will be on feet and raised up). So I'm looking for a simple mono amp kit that, like the STA540, will run from 12-18v dc - capable of driving something around 30-50wrms between 4-8Ohms (plus an affordable bass driver to go with it).
One other thing I guess I need to figure out is how to connect the stereo signal into such a mono power amp. Is there a simple IC available that will combine the channels?
Enclosure design is not sorted yet (should each of the speakers by isolated, ported? I'm no audiophile, but suggestions here would be gratefully accepted!) - but I'll probably just go for something along the lines of a simple centre AV speaker look:
... raised slightly, for the downward bass driver. Power supply is likely to be external - (probably a laptop style 18v brick - enought power for the amplifier circuit, but easy to drop down to 12v for other purposes - I don't really like messing with high voltages). With the dock connector on top - fairly plain and boring I guess!
Cheers,
John
I'm thinking about building my own iPod dock - I have a pair of Infinity Kappa 42i 4" two-way speakers (45wrms, 4Ohm, 80Hz-20Khz) that I bought for a car I had for a very short space of time - they're virtually unused but were quite expensive at the time and I remember them having a nice, clean sound.
I plan on powering these with a STA540 stereo amp kit (Audio Amplifier Kit - STA540 - SparkFun Electronics). This should be plenty of volume for my intended application (kitchen-worktop music!)
However, I would also like to run a single larger bass/mid driver, probably around the 6" size, mounted on the underside of the dock (which will be on feet and raised up). So I'm looking for a simple mono amp kit that, like the STA540, will run from 12-18v dc - capable of driving something around 30-50wrms between 4-8Ohms (plus an affordable bass driver to go with it).
One other thing I guess I need to figure out is how to connect the stereo signal into such a mono power amp. Is there a simple IC available that will combine the channels?
Enclosure design is not sorted yet (should each of the speakers by isolated, ported? I'm no audiophile, but suggestions here would be gratefully accepted!) - but I'll probably just go for something along the lines of a simple centre AV speaker look:
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... raised slightly, for the downward bass driver. Power supply is likely to be external - (probably a laptop style 18v brick - enought power for the amplifier circuit, but easy to drop down to 12v for other purposes - I don't really like messing with high voltages). With the dock connector on top - fairly plain and boring I guess!
Cheers,
John
Well, I don't know if I've made any major boo-boos, but I've got the following parts on the way:
(Pico-part) Sparkfun STA540 amp kit (STMicro ST540)
(Farnell) Burr-Brown/TI OPA2227 (replace LM385 in STA540 module)
(Quasar Electronics) 3100KT Stereo Preamplifier with Tone Controls Kit (TDA1524A)
(Quasar Electronics) 3105KT 18W BTL Mono Amplifier Module Kit (HA13118)
The STA540 and TDA1524A are to drive the main Infinity 4" co-axial speakers, while the HA13118 is purely for the single bass driver (likely to go with a Visaton WS17E-4 for that). I know the specs on the HA13118 aren't amazing, but I only plan on using that single speaker to 'round out' the lower frequencies a little.
I've also got two LM3916 controllers on the way to build a pair of simple vu meters for the case.
Finally, I got some nice solid aluminum knobs for the tone controls (balance, bass, treble, preamp level) and the main volume of the two amp outputs.
We'll see how it goes!
(Pico-part) Sparkfun STA540 amp kit (STMicro ST540)
(Farnell) Burr-Brown/TI OPA2227 (replace LM385 in STA540 module)
(Quasar Electronics) 3100KT Stereo Preamplifier with Tone Controls Kit (TDA1524A)
(Quasar Electronics) 3105KT 18W BTL Mono Amplifier Module Kit (HA13118)
The STA540 and TDA1524A are to drive the main Infinity 4" co-axial speakers, while the HA13118 is purely for the single bass driver (likely to go with a Visaton WS17E-4 for that). I know the specs on the HA13118 aren't amazing, but I only plan on using that single speaker to 'round out' the lower frequencies a little.
I've also got two LM3916 controllers on the way to build a pair of simple vu meters for the case.
Finally, I got some nice solid aluminum knobs for the tone controls (balance, bass, treble, preamp level) and the main volume of the two amp outputs.
We'll see how it goes!
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