Kitronik Bluetooth Stereo Amplifier Kit

Hello, With the 100mm 8ohm Bluetooth stereo amplifier kit, instead of charging the battery via USB would it be possible to charge it via a solar panel? if it could work, would I need to buy any other parts to connect the solar panel? kind regards Tom

Hello Tom, Although we haven’t tried this ourselves it should in theory be possible. You would need to ensure that you don’t provide any more than 5.5V to the board and you also use a blocking diode to stop current flowing back into the solar cell. A solar cell such as this and a diode such as this should be suitable, 3605-50v-200ma-polycrystalline-solar-cel and 1n4001-diode You could use a micro USB lead to connect this to the micro USB port on the board. The time it would take to charge the battery would vary depending on how much sunlight the circuit gets and a 200mA output from the solar cell is the best case situation.

can I use a 3.7V/100mA LiPo battery even though it only has 100mA

Hi Harvey,

Thank you for your email, you could do but the amplifier will not last very long at all.

Best Regards

Cullen

Is it possible to add on a circuit to allow it to be powered by 9v batteries? I've already bought the lead to plug into the wall but would like to make the speaker portable without the Li battery

Hi Dan,

Thank you for your email, in theory you could if you put a resistor between the 9V battery and the Blue tooth amp to account for the additional voltage. You would also need some sort of converter to plug into the board.

however this is likely to increase the current draw of the kit and most 9V batteries do not hold much charge so would probably be about 20% of the run time as the Lipo.

In addition I would recommend against having the power plug and the battery in at the same time as you could then loop the power into the battery which could over heat the battery.

Finally this may affect the reliability of the blue tooth with the power it needs. So in theory yes, in practicality I would not recommend it.

Roughly speaking, how loud is this kit?

Hi Warren,

It can be pretty loud, its probably similar volume to a radio or music players.

Best Regards

Cullen

Hi,at the moment I'm in the process of building a dolls house with a 12v lighting system, is possible to run the Bluetooth amp off any of this system??

Hi Gary,

Thank you for your question, in theory potentially yes but you would need to have quite a powerful resistors as the kits rated for around 5V not 12V. It would also depend on how much current you are supplying to other parts of the dolls house and how you have set up the circuit to divide current and voltage.

So yes you could in theory but it would depend on the circuit and you adding powerful resistors in before the amplifier.

Best Regards

Cullen Lewis

When or how can I use TF or mini SD card on this directly and if its not possible for now, like when can we have that option on this board from you for purchase?

Hi Tomori,

Thank you for your question, this is not currently a functionality this kit has and we are not currently looking at adding it as functionality.

Best Regards

Cullen

How long does it take to fully charge the 1000mAh LiPo battery when the unit is on?

Hi Robert,

Thank you for your email, assuming you are charging from a 500mA power supply and the kit is drawing it's maximum current of about 120mA then you would be looking at 380mA an hour so about 3 hours all told.

Hi, will the speaker play music whilst it is charging? Is there a possibility of the battery being overcharged causing damage?

Hi Maks,

Thank you for your question, it will play while charging that's not a problem.

The kit contains a charger controller to prevent over charging being an issue.

Best Regards

Cullen

Would it be possible to add a push button to put the device in to pairing mode and clear the last paired device. It might be handy if the last paired device is in range but not the one you want to use. Thanks. Bill

HI Bill,

Thank you for your question, I believe the easiest way of doing this is to power cycle the board (this basically just means switch it off and on again) As this should reset the pairing if the devices it is connected too are not in range or are also switched off. You can either use the provided switch or you could add a push button switch to interrupt the power to achieve the same effect.

Best Regards

Cullen

Is it possible to add a 3.5mm audio output instead of having speakers?

Hi David,

Thank you for your question, I would not recommend it as you would need to SMT mount the wire to some of the pins on the board before the amplifier as a custom job.

Best Regards

Cullen

Hi, when will the bluetooth amplifier kit with 8ohm speakers be back in stock? Many thanks.

Hi Gemma,

Thank you for your question, they are all back in stock this afternoon.

Best Regards

Cullen

Can this kit be used with a solar panel to charge it?

Hi Harry, Do you mean can a solar cell be used to charge a LiPo when connected to the circuit? It is unlikely a solar cell would work for this as the kit can draw up 120mA under normal use and more when the LiPo is being charged.

Is there any way you can damage the board or battery if you use a more powerful charger. i.e. 3A charger

Hi Alan,

Thank you for your question, realistically no. With most products they will draw the amount of current they need from a power supply. So even if you have a 3A power supply the kit will draw less than 1A.

The time you are more likely to damage something is when you do not have enough current as the kit trying to draw more current than is possible can cause damage.

Best Regards

Cullen

Can the circuit board and the speakers for this kit be in very close range when assembled (within 1cm) without damage?

Hi,
They can be in close range without damage however, there is every chance that you may experience some interference.
Many thanks

is it possible to connect a 3.7V 3000 mAh Li-polymer battery with this instead of the 1000 mAh?

Hi Kristof,

Thank you for your question, provided the JST plug on the battery is identical to the one on the 1000mAh battery we supply this should be fine. It would just have more current available and the kit would draw the current as required.

Best Regards

Cullen

Hi, would you recommend the 4 ohm speakers or the 8 ohm speakers for better audio quality? I've heard somewhere that the 4 ohm speakers would have a higher impedance making the electricity flow through them more easily.

Hi Maks,

Thank you for your question, so the short answer is it is complicated.

The longer answer is that the Ohms of the Speaker is basically their resistance. 4 Ohm speakers draw more current than 8 ohm speakers if they were electronically the same otherwise. This means you can run an 8 ohm speaker well from a lower wattage amplifier.

Watts of the Speaker and amplifier also play into audio quality a bit but are more relevant for the top end volume and power consumption.

What is most relevant is the Sensitivity / Mean Sound Pressure Level / SPL / Volume Response ( It gets called a lot of things). This will basically be a value that will look something like 1W/1m 94 dB. The bigger the number in front of the dB the better as the speaker is more sensitive.

Hope that helps!

Hi there, bought this kit. All worked fine until soldering the speaker cables. Now we can't get any sound. Led flashes to say music playing. Any ideas? Could we have damaged board soldering cables on to it? Anyway to test and failing that can I order a replacement board only? Thanks
Stephen

Hi Stephen, Sorry to hear this isn't working as expected. The best option is to drop us an email to support@kitronik.co.uk with some further details, such as how often is the LED flashing, if you can find the amp kit on your phone or similar device, and also a photo of the top and bottom of the circuit board. We should then be able to help further on this.

Do you sell a USB to micro USB cable for this kit? We would like to charge the battery via a lap top or phone charger.

Hi David,

Thank you for your question, we do sell them on the link below, our product code 4154.

https://www.kitronik.co.uk/4154-1m-usb-type-a-to-micro-b-usb-noodle-cable.html

Hello, I just noticed that this product is out of stock. I was hoping to be the 3160-B option as am wondering when I can expect this product to be available for purchase again?

Hi there,

Thank you for your email, we have finished our latest batch today so should be available to buy tomorrow.

Best regards

Cullen

The kit just arrived, nicely packaged, thank you!

I was hoping to receive also some insight into the speaker box volume or dimensions but there was nothing. Is there some recommendation for a sealed enclosure for the 100mm 20W 8ohm speakers? I plan to build these speakers into 1960s vintage Bang Olufsen speaker boxes.

Hi Harri, There are no recommendations that we have been given by the supplier. However you would want to make sure the enclosures is a little bigger than the speaker as a minimum. Also if both are being housed in one enclosure that there is sufficient space between them to ensure you don't get any feedback from one speaker into the other. Other than that the enclosure should be a case of making it how you want.

What is the sound quality like if I connect only one speaker? Is there a difference if it's the left or right one?

Hi Harri,

Thank you for your question. So I would strongly recommend using both speakers. Because of how stereo amplifiers work they divide up the sound file and send it through separate speakers. If you only had one speaker you would lose a portion of the sound file. How much this would be would depend on how the sound file is mixed but you are best off using both speakers or if you only want one speaker buying a mono amplifier.

Hello, sorry if I missed this in the description but would I have to buy the lipo battery and a charger for it separately in order to make the kit rechargeable? Would this then sum up to about 60 pounds? thanks

Hi Peter,

Thank you for your question, you would need to purchase the power supply separately to this kit. If you wanted it to be powered by a rechargeable battery I would get the 4652 polymer lithium battery for £4.25 ex VAT. This would plug into the JST connector on the board. You could either charge this separately if you already own a lithium charger or you can connect a micro USB such as is commonly found in phone chargers to the micro USB port and this will charge the Lipo battery while it is plugged in.

If you bought the most expensive variant of the kit 2160-B along with the lipo battery this would be 34.25 ex VAT or £41.10 inc VAT.

Hi, is the unit capable of supporting a 1000mah battery with a 25c rating? Thanks

Hi Edison, That shouldn't be a problem, the LiPo we recommend is a 1000mAh battery that can has a 0.2C rating. So the battery you are looking at using can handle a large current discharge rate, but as the Bluetooth amp won't get close to this it shouldn't be a problem.

Is a mounting board available to allow me to fix professionally inside a box.

Hi Neil, Unfortunately we don't have anything that would allow you to just fix the board inside of the enclosure. However the board is designed with 3 fixing holes pre-drilled which typically would be used with M3 screws and spacers to attach the board to the enclosure.

Hello,
Can a larger capacity than 1000mAh Li-Po battery be used with this kit? And can it then be charged via the micro usb port? In my country (Estonia) I have only seen 3.7V Li-Po batteries that are only 400mAh or 1200+mAh. I'm worried the capacity of the 400mAh isn't enough

Thank you for your question, you would be absolutely fine to a higher cpacity battery with this kit provided it was still 3.7V. The mAh is how much power is available for the kit to draw on and when taking that power the kit will only draw as much as is required.

The only issue you might encounter is you need to make sure the JST for your battery is also a 2mm JST as otherwise it will not fit the socket on the board.

Is the lipo connecter a micro JST or full size?

Hi Edison, The JST that is used on this kit is from the PH series.

When using this with the 1000mAh lithium battery and 4ohm, 65mm speakers, what is the battery life?

Hi Robbie, Regardless of what speakers are used the kit will run for around 28 hours continuously when operated off a 1000mAh battery at 'normal' volume.

Hi can the Bluetooth amp be wired up to 4 speakers Rather than just the 2?

Hi Fraser, Yes it would be possible to add another 2 speakers. If you put the second speaker in series with the first then you would need to make sure both speakers are either 2 or 4 Ohms, this would give a total impedance of 4 or 8 Ohm. If you put the second speaker in parallel with the first you would need to use 8 or 16 Ohm speakers, as this would give a 4 or 8 Ohm impedance as a total.

How to change name of Bluetooth on it and can I put password , so another people can't connect to it?

Hello, Unfortunately it isn't possible to alter the name of the amplifier and this is set when the unit is built. I do not believe it is possible to add a password either, as the device doesn't hold any sensitive or personal information it wouldn't require a password.

Please can you confirm that I can connect to VBus (usb +5v) on the switch (pad nearest 'on' legend) and to OV on the common sides of C12 & C14. We just need to add some LEDs to a project (built using the board) that don't emulate the on board LED but light constantly while the unit is connected to the USB charger. Soldering to pins 1 & 5 on the micro USB will be tricky. Thanks.

Hi Ian, Yes that would work, however it is worth noting that the Bluetooth amp switches the 0 volts, so the common side of C12/C14 is +5V from the USB, and the switch pad is 0V.

Is it possible to convert this into a mono amp kit?

Hi Niyusha, You could just connect one speaker to the kit, however this would mean you would lose the audio from the other channel. As such it is possible but without a lot of modification it wouldn't be a simple change to ensure all the audio was played. As something this isn't something we would recommend.

Is it possible to bridge the outputs of this amp together in order to use just one mono speaker?

Hi Karl, You could just connect one speaker to the kit, however this would mean you would lose the audio from the other channel. Unfortunately it isn't possible just to bridge the connection to have one output, the board would require a lot of modification to make this work and it wouldn't be a simple change to ensure all the audio was played.

what are the measurements of the on/off switch ? kind regards dave :)

Hi Nathan, The switch used on the amp kit is part 3415, and has the following dimensions L 14, W 13.2, H 9.4mm

Hey would it be possible to use 200mm 8 ohm speakers with this instead of the 100mm?

Hi Fraser, That wouldn't be a problem at all to increase the size of the speakers.

Hi, is it possible to run just 1 speaker with this kit (mono), or would this require modifying the board?

Hi Jeff, You could just connect one speaker to the kit, however this would mean you would lose the audio from the other channel. As such it is possible but without a lot of modification it wouldn't be a simple change to ensure all the audio was played.

Hello what do I do if the motherboard chip for my 100mm 8ohm speakers keeps overheating?

Hello Ringisai, It could be there is a short on the circuit across the IC which is causing this to overheat. The best option is to drop us a photo of the circuit board top and bottom to support@kitronik.co.uk along with details of what is being used to power the speaker kit, if you can include your order number that would also help us. We will then take a look and advise further.

Can i connect this to raspberry pi, if i can how can i controls it?

Hi Mistery, We haven't tried this our self, however after a quick bit of searching it does appear that you are able to connect the new raspberry pi 3 to Bluetooth speakers, an example can be seen here https://www.raspberrypi.org/magpi/bluetooth-audio-raspberry-pi-3/. There is no reason why you shouldn't be able to connect to the speaker as it works like any other Bluetooth speaker.

Does this come as a kit that you build? (Like a school kit as I am interested in using it for a product)

Hi Bjorn, The kit is all pre-built except for the power switch and connecting the speakers to the kit, as such there is very little that needs to be soldered on this kit.

Hi, is this compatible with the Polymer Lithium Ion Battery (3.7V, 1Ah) from Kitronik?

Hi Karam, Yes that is fine, we actually link to this battery at the bottom of the page.

How long would the battery life be?

Hi

A 1000mAh LiPo battery can provide up to 28 hours of continuous operation at normal volume. Obviously these are then rechargeable.

Is the micro usb cable shown included?

Hi Ian, The micro USB cable shown in the photo is to give an example of what can be used to power the amp kit. The power supply we used in the example is https://www.kitronik.co.uk/2208-5v-1a-micro-usb-uk-mains-wall-power-supply.html.

Is it possible to mute/lower the status sound level

Hi Jerry, The kit hasn’t been designed to enable a volume/mute control feature to be added as this could all be done from the device that is connected to it. It would be quite difficult and complex to alter the kit to enable you to reduce the overall gain as such we don’t recommend trying to alter the kit to do this.

can i add a third speaker to the circuit

Hi Fergus, You could technically add a third speaker by connecting it in parallel or series with one of the other speakers. However you need to ensure the impedance doesn’t go below 4 ohm’s and is the same as the other output. For instance, if you had an 8 Ohm speaker on output 1, you could connect two 4 Ohm speakers in series to output 2 giving a total impedance on 8 ohm’s on that channel. If you wanted them in parallel you would use two 16 Ohm speakers. If you were wanting to add a third channel to the kit it wouldn’t be possible as it is a two channel amplifier.

Hi, would you be able to add a potentiometer to this? thanks

Hi John, without knowing the reason for wanting to add a potentiometer it is difficult to say. However it is likely that it may not be simple to alter the kit, as such we wouldn’t recommend making changes to the kit.

hi, what is the weight of this product ?

Hi Morgan, The weight of the kit by itself is approximately 25g, if you went with an option with speakers it would weight more depending on the speaker type you picked.

Does this product wome with the speakers aswell?

Hi Shivam, Did you mean does it come with speakers? This product has three possible buying options, without any speakers would be product code 2160, with 65mm speakers would be product code 2160-A, and with 100mm speakers would be 2160-B. If you scroll down on the product page there is a table showing the buying options, it can be found past the photos and product description, just before the dimension information.

Would I be able to add a microphone to the pcb enabling hands free calls? Thanks.

Hi Noah, The board hasn’t been designed to allow you to do this, as such you would have to modify the board to allow a microphone to be added, even then the Bluetooth module hasn’t been programmed to work the same as a hands free device.

Hi, would it be possible modify this kit so that it could be used with your High Power Amp Kit?
Many thanks, Steve

Hi, i would just like to follow up regarding the below. I have now been informed that unfortunately the output can't be fed into anything else even if attenuated. This is because it uses a differential output and not a line out style output. I apologise for any confusion caused.

Hi, What is the range of this device? I want to use it in a RC car and 10 meters would be sufficient.

Hello Jeroen, We have tested the kit here and it can handle 10 meters, with a wall as an obstacles, however certain conditions may reduce this range and 10 meters did appear to be the limit before it started to loss connection.

Hi there,
Is this available yet or just out of stock?

Regards
Dave

Hi Dave, We are currently processing the first build of this kit and are looking at placing a small number into stock in the next day or so. We will then finish the build and add the remaining stock in the near future.

'Some soldering required' - what other than power switch (as stated) and speakers is not already soldered on.

Hi Richard, those are the only two items that would requiring soldering, all the other components are pre mounted onto the board.

When will this product be available to buy as I would like to use it for this years GCSE, is it also possible to connect an Ipod wire to the circuit to create a phone dock?

Hi Chris, as this is a Bluetooth amp kit you wouldn’t connect an iPod lead to the kit, you would connect via Bluetooth. This kit should be available in stock in the next few days as we are just finishing the first batch of manufacturing.