Hi, I was investigating building my own low-budget boombox with prefab FM and class D amp boards (and was worried about poperly combining them in away to avoid RF/EM interference), but I see that these (cheap) prefab integrated multi-function units are available on eBay, partsexpress, etc.
There are many variants built with the same basic LED control panel (actually, there are two out there: one is rectangular, and one is oval). Some have only preamp outputs, while others are advertised with 3 watts amps and others are up to 15-25 watts per channel (hah). I see that those have various sized PC boards attached to the base unit, all pesumably using their own circuitry/amp choices. But none of the pics is clear enoughto see, for example, which amp chipset is used. Some show some possible filter caps onboard.
There are reviews online, including on Youtube, but unfortunately, they mostly don't give enough detail about which "variant" or amp chip/circuit is used. Amazon reviews are all over the map (not suurpisingly). Several are not in English, so I can't understand them. This one shows a few variants:
Does anyone have experience with these and can recommend the betterversion/supplier? I am mostly interested in whether or not they have adequate FM broadcast radio gain/reception with minimal EM/RF Interference.
https://cntronic.com/car-12v-color-...ecoder-board-module-audio-refitting-71409skn1https://www.parts-express.com/Bluetooth-5.0-FM-Media-Player-2-x-25W-Max-Amplifier-Board-320-642https://www.ebay.com/itm/-/175055546593https://www.ebay.com/itm/-/373858239053https://www.amazon.com/dp/B07SN1PFYC/ref=cm_sw_em_r_mt_dp_VWDW1KHT79A7QD8C0JHRttps://www.ebay.com/itm/-/115210604729
Thanks!
Lou
There are many variants built with the same basic LED control panel (actually, there are two out there: one is rectangular, and one is oval). Some have only preamp outputs, while others are advertised with 3 watts amps and others are up to 15-25 watts per channel (hah). I see that those have various sized PC boards attached to the base unit, all pesumably using their own circuitry/amp choices. But none of the pics is clear enoughto see, for example, which amp chipset is used. Some show some possible filter caps onboard.
There are reviews online, including on Youtube, but unfortunately, they mostly don't give enough detail about which "variant" or amp chip/circuit is used. Amazon reviews are all over the map (not suurpisingly). Several are not in English, so I can't understand them. This one shows a few variants:
Does anyone have experience with these and can recommend the betterversion/supplier? I am mostly interested in whether or not they have adequate FM broadcast radio gain/reception with minimal EM/RF Interference.
https://cntronic.com/car-12v-color-...ecoder-board-module-audio-refitting-71409skn1https://www.parts-express.com/Bluetooth-5.0-FM-Media-Player-2-x-25W-Max-Amplifier-Board-320-642https://www.ebay.com/itm/-/175055546593https://www.ebay.com/itm/-/373858239053https://www.amazon.com/dp/B07SN1PFYC/ref=cm_sw_em_r_mt_dp_VWDW1KHT79A7QD8C0JHRttps://www.ebay.com/itm/-/115210604729
Thanks!
Lou
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The FM module is good, for its price. Reception is clear.
It also functions as pre-amp / selector, and price is about $1.5.
They work well enough, 7805 is used to feed them off the amp
supply.
Some have been used to add SD card / USB / Bluetooth / remote operation to older systems which do not have the functions, being from the CD and even cassette era.
The amp is selected from several PCBs, as per supply and output watts.
The cheapest here is $10, it is a complete unit with 4440 iCs, 12V internal transformer and so on, it can be used with a 12V battery also, so used a lot on buses.
Higher outputs are available in 2030 / 1875 variant, 2955/3055 variant, STK 4141 variant, and Mosfet, in increasing order of output.
Even 3116 and 7297 may be available.
Both types are sold, complete amps, and 'kits' (populated PCB, ready to connect).
There are some suppliers in Delhi, you can go through their websites to get some more information.
It also functions as pre-amp / selector, and price is about $1.5.
They work well enough, 7805 is used to feed them off the amp
supply.
Some have been used to add SD card / USB / Bluetooth / remote operation to older systems which do not have the functions, being from the CD and even cassette era.
The amp is selected from several PCBs, as per supply and output watts.
The cheapest here is $10, it is a complete unit with 4440 iCs, 12V internal transformer and so on, it can be used with a 12V battery also, so used a lot on buses.
Higher outputs are available in 2030 / 1875 variant, 2955/3055 variant, STK 4141 variant, and Mosfet, in increasing order of output.
Even 3116 and 7297 may be available.
Both types are sold, complete amps, and 'kits' (populated PCB, ready to connect).
There are some suppliers in Delhi, you can go through their websites to get some more information.
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4440 amp, with bass and treble, 220V AC and option of 12V DC also.
And option to connect 1/4" front mic., to use as PA system, also there is a 1/8" jack on the module.
For $10, quite decent.
Thanks, I haven't seen that one before, but now after googling, I don't see them at that price. Will keep looking.