Series or Parallel 12Volt Power supply - Page 1
Forum section: electronics / beginners

author: kentsangcanada
author_rank: Newbie
timestamp: February 17, 2017, 06:13:18 pm
content: I am looking to power Four audio amplifier (TDA2030A) and Four mic amplifier with one power supplyI have no clue where to start 1) should i wire it in series or parallel? 2) how many amp should the power supply be? 3) should i use one PSU or two PSU? 4) how many amp should the PSU be? 5) if One amplifier circuit Blow up, that would increase the current go to the other amplifier, would it damage the other amplifiers?Audio Amplifier TDA2030A -http://www.ebay.ca/itm/TDA2030A-Mono-15W-Audio-Power-Amplifier-Board-AC-DC-12V-Assembled-/171805068137?hash=item2800614b69:g:nUAAAOSwKrhVZbo1Mic -https://www.aliexpress.com/item/New-CCTV-Mic-Microphone-Sound-Pick-Up-Monitor-Voice-Audio-Security-White-600-ohm-Free-Shipping/32705995331.html

author: Gregg
author_rank: Super Contributor
timestamp: February 17, 2017, 07:30:35 pm
content: Power to the devices you mention should be parallel connected. Similar to the lower half of the drawing that you included, I’m assuming you mean the AMP power supply, all of the + power inputs of each device should be wired to the + output of the power supply. Same for the negative; don’t mix up the polarity or you may release the magic smoke. The devices are probably not protected against polarity reversal.

author: Hideki
author_rank: Frequent Contributor
timestamp: February 17, 2017, 07:32:51 pm
content: Quote from: kentsangcanada on February 17, 2017, 06:13:18 pmNever ever in your wildest fantasies should you ever consider connecting them in series, so parallel it is. Like in the second drawing.QuoteFor the worst case scenario with everthing going full power/volume all the time you simply add up all the current requirements. Since this is unlikely (and also depends on what speakers you are using) you will likely get by with a less capable power supply.QuoteThat is entirely up to you and what supplies you can get hold of. If you can't find one that outputs enough current, you can go for two... or three.. or eight?QuoteThis question looks veeeeery similar to 2)QuoteIt is a common misunderstanding that a power supply (working as a voltage source) will FORCE the amount of current through the circuit that is marked on the power supply. If it says 12V 2A it does NOT mean that it will always output 2A. It will try to output 12V as best as it can, and 2A is simply the maximum it can output, not the current it will always output. Ohm's law still applies. If you connect a 10 ohm resistor, 1.2A will flow. If you want 2A through 10 ohm, you will have to increase the voltage to 20V. Since it's a 12V supply, that simply won't happen.

author: james_s
author_rank: Super Contributor
timestamp: February 17, 2017, 08:20:40 pm
content: There is *some* truth to that concern. With the traditional unregulated iron transformer power supplies, particularly the small wall wart type, the output voltage under no/low load can be significantly higher than at rated load. This can cause a problem if you go too big on the power supply, but not because it will "put out too much current" as some assume, but because the voltage will be too high.

author: kentsangcanada
author_rank: Newbie
timestamp: February 17, 2017, 09:14:18 pm
content: So is my calculation correct? it comes to me needing a 4.04 amp power supply if i wire everything paralleland which type of power supply should i use? (is a LED driver the same thing?)

author: james_s
author_rank: Super Contributor
timestamp: February 17, 2017, 09:39:08 pm
content: No, you don't want an LED driver. I would suggest a 12V regulated power supply capable of at least 5 Amps, it's really not that critical. Likely you can get away with significantly less as the devices are unlikely to all be drawing their full rated current. Since it's audio gear you might want a linear power supply although in practice a decent quality switchmode PSU will probably work ok.

author: Brumby
author_rank: Unknown
timestamp: February 17, 2017, 11:23:53 pm
content: You took the long way round to calculate the current requirement. You could have simply added up the currents that you had noted on each module: 1 + 0.01 + 1 + 0.01 + 1 + 0.01 + 1 + 0.01 = 4.04As for power supplies - please do not go for an LED driver. I would generally steer clear of any supply designed for low voltage lighting for this application, so option B is not on my preferred list.The external plug pack - option A - has appeal for modularity. One capable of the current you require will likely be a switch mode design. A linear supply would be a solid brick (and harder to find). An external switch mode power supply (SMPS) would keep the mains and the switching circuitry away from your amplifiers - which gives you an added safety factor and will help with reducing switching noise. Also, it's easy to replace and by having a socket on the amplifier unit, allows alternate power supply options, such as a 12v battery, to be easily utilised.The internal power unit - option C - is a compact solution, but this is also a switchmode design. You now have mains inside your box, so you have to be careful with that - and you also have the switching circuitry there as well. This might need some attention if the switching noise comes through your audio.I should add - there is also the issue of how well these SMPS units have been designed, particularly with the separation between the mains and low voltage sections. If this is inadequate, there is an increased safety risk. However, the only way to check this is to open them up and look - presuming you know what to look for.Then there is option D. Build your own power supply. The easiest will be to find a suitable transformer, add a bridge rectifier and some capacitors for filtering. This will give you a linear supply, where your only possible issue will be 50/60Hz hum - but that's something that has been dealt with for a very long time.However, there is one thing that I am curious about - and that is: What application are you going to be using this unit for? It seems a bit strange to have four microphones and four power amplifiers running off the one supply. I'm not saying it can't be done - it most certainly can - I'm just wondering why.

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2017, 12:16:13 am
content: Use higher voltage than 12V. It's nowhere near enough for the TDA2030 to work properly!Look at the data sheet for the TDA2030. It isn't specified to work of any voltage lower than 12V total (+/-6V). The ebay seller says their product will work from AC or DC which implies it has a built-in rectifier and smoothing capacitor. A bridge rectifier will typically drop another 1.4V to 2V so there's no guarantee it will work well off 12VDC.http://www.kynix.com/uploadfiles/pdf9675/TDA2030AH.pdfWhat power output are you expecting to get?At only 12V in, the maximum power output, at low distortion, before clipping occurs, will be about 1WRMS into a 4 Ohm load. The TDA2030's output stage drops 6V from the total supply voltage, leaving only 6V peak-to-peak out!Usea minimum voltage of 24VDCto power the TDA2030 in single supply configuration.

author: raspberrypi
author_rank: Frequent Contributor
timestamp: February 18, 2017, 06:43:56 am
content: The description says 12V 15watts 1 amp. 1 amp at 12 volts is 12 watts. It should be 1.25 ampsAlso it mentions distortion of 0.1% (of what?) at 1 watt. Thats going to sound pretty terrible I would imagine, if thats even a real number.

author: james_s
author_rank: Super Contributor
timestamp: February 18, 2017, 07:47:12 am
content: Quote from: raspberrypi on February 18, 2017, 06:43:56 amYes, that's a real number, and no, it doesn't sound terrible. 0.1% THD is actually very good.https://en.wikipedia.org/wiki/Total_harmonic_distortion

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2017, 02:28:01 pm
content: Quote from: raspberrypi on February 18, 2017, 06:43:56 amThe specification is incorrect.It isn't possible to drive put 12W into speaker, with a supply voltage of only 12V, with a single ended class AB topology. Using an amplifier with a rail-to-rail output, the maximum peak output voltage is only 6V, so the maximum RMS power output into a 4 Ohm speaker is only 4.5W. In reality, the TDA2030's output saturates at around 3V of either power rail, so the maximum output power is around a quarter of that.Quote from: kentsangcanada on February 17, 2017, 06:13:18 pmDump the old, obsolete TDA2030. Use the PAM8610, a class D amplifier which will be able to output 15W into a 4 Ohm load. It has two channels so, for a total of four, you only need two amplifier boards.If you've already bought the TDA2030 based boards, then you have a valid reason to return them: the product was mis-sold, as it doesn't meet the advertised specification.https://www.diodes.com/assets/Datasheets/PAM8610.pdfhttp://www.ebay.co.uk/itm/2-10W-Dual-Channel-Hi-Fi-PAM8610-Mini-Amplifier-board-12V-for-Computer-audio-F7/322332393126?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Dbb1655cba11843c4953f1e0a17b713e1%26pid%3D100338%26rk%3D4%26rkt%3D30%26sd%3D162128932458

author: Brumby
author_rank: Unknown
timestamp: February 18, 2017, 02:39:21 pm
content: I'm still curious as to the application.Having 4 microphones running into a single box is not at all unusual - but having each one going to its own power amplifier is, in my experience, rather curious.I would be interested to see how the output of these amplifiers is used.I would hope they are not being paralleled into a common load.

author: kentsangcanada
author_rank: Newbie
timestamp: February 18, 2017, 03:01:17 pm
content: They are to be used for 4 HIKvision camera in 4 separate location the cameras are PoEhttps://www.amazon.com/gp/product/B013JD3MK4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1I need to find a way to supply power to the Speakers and mic so I can have 2way communication to themThe speakers are 4Ohm 15W home theater MONO speakers i am putting the amp inside with a volume adjusting knob so i can crank it up or turn it down, because wiring is not easy, I perfer to use one single power supply for the mic and speakerso i use change direction with the PAM8610 but its stereo, I only have 1 speaker?I didnt realize the TDA2030 is 12v 15W, i just read 1amp.... so should the final calculation beI = 5.04 ampso would a 5amp power supply do it or should i go 6 amp now?should i attach 30mm 2amp fast-acting or normal fuse on each mic/speaker combo? is that enough to protect each set from burning out?should i use power supply Option A or C? does the Ctype last longer? type A laptop power supply always are poor quality and burns out

author: Hideki
author_rank: Frequent Contributor
timestamp: February 18, 2017, 03:46:57 pm
content: Quote from: kentsangcanada on February 18, 2017, 03:01:17 pm12V and 15W is an impossible combination. That chip can run on higher voltages, which is REQUIRED to get the rated wattage out of it. 12V is the absolute minimum voltage you can use, and according to earlier posts, the chip can get to within about 3 volts of the rails, so it's basically capable of about +/- 3V peak. With a 4 ohm speaker it may output about 1.12W, which is as you see, far away from 15W. You need a higher voltage if you want more power. But... maybe a single watt is all you need?

author: Audioguru
author_rank: Super Contributor
timestamp: February 18, 2017, 04:05:51 pm
content: Quote from: raspberrypi on February 18, 2017, 06:43:56 amSellers on ebay know nothing about electronics.They say it works at 12VDC (but it will barely work) and they say its can produce 15W (but only when its supply is 36VDC with an 8 ohm speaker or a 30VDC supply with a 4 ohm speaker). The TDA3020A datasheet shows a few Watts with 24VDC (the minimum voltage on the graph). The heatsink on thatvery cheapamplifier is so small that the IC will melt if the supply is higher than 12V and the output power is higher than a couple of Watts.The power amplifiers also need extra supply power for the heat they produce, maybe 1W each when the supply is only 12VDC.Ordinary cheap car amplifiers work on 12V but they have two amplifiers per speaker and the amplifiers are bridged so they double the voltage and double the current. Then their power output is almost 4 times as much as a single amplifier. They use a heatsink large enough to do proper cooling.

author: Audioguru
author_rank: Super Contributor
timestamp: February 18, 2017, 04:17:48 pm
content: Now you saytwo way communication?What about acoustical feedback howling when the sound goes around and around the mics, amplifiers and speakers? You need to press a button to activate your mic and disconnect your speaker when you speak.

author: Zero999
author_rank: Super Contributor
timestamp: February 18, 2017, 04:57:46 pm
content: Quote from: kentsangcanada on February 18, 2017, 03:01:17 pmIf you can find a cheaper mono amplifier which is just as good as the PAM8610 then go for that. Otherwise, you could use 4 PAM8610 models, each with only one channel used. They're not expensive and whilst it may seem wasteful to leave half of it unused, it might be the most economical option.QuoteIf you must stick with the old TDA2030, then you need to increase the power supply voltage considerably, to 24V or more. It will also need to be a larger PSU in general, than if you'd used a class D amplifier such as the PAM8610.Although a fuse is a good idea, it might not be necessary, if the power supply has short circuit protection built-in. Just ensure the cable to all of the amplifiers is thick enough to carry the full power supply current, plus about 50%. That way, if there is a short circuit, then the wire's insulation won't melt and cause a fire.