Anyone know about power supplies?
Discussion
I'm setting up some distributed audio in my house. It's quite a simple setup, I've got speakers in the ceilings and wires back to a central point. Then I've got wires out to TVs etc to bring sound in to the central point. I've got a server that can output sound too. Each room will have it's speakers connected through a switch to both the server output and any inputs in the room. That gives the option of listening to something in that room, or listening to the same thing over the entire house. I'm using XBMC on Rasberry Pi as my primary means of outputting sound because I can use Yatse on my phone to log in to each device and control everything that way, with no need for a GUI.
Now, I'm just starting to put get some of the hardware together and I'm looking at amplifiers. I can't see any suitable 240v amps, so I've splashed £15 on a 12V car amplifier as that looks closer to what I need. I need to feed it with 12V obviously, but when everything is set up I'll be looking at 6 amplifiers.
Rather than getting transformers, can I run something like this:
http://www.ebay.co.uk/itm/UK-Stock-DC-12V-Universa...
I'm not sure I'm up to speed on the electrics, but for a 5 amp amplifier would I be looking at 30amps for powering 6 at once? And the quoted 5 Amps, would that be pulling lower amps on the other side of the transformer as the voltage is higher? Conscious that I only have 32 amps coming in at 240v, but my mains can more than cope with 6 of these amplifiers.
Have I got that right?
Looking at the device I've linked to, it looks like it would need boxing in as it appears to have 240V terminals that are unprotected.
Anyone know of any better options?
Now, I'm just starting to put get some of the hardware together and I'm looking at amplifiers. I can't see any suitable 240v amps, so I've splashed £15 on a 12V car amplifier as that looks closer to what I need. I need to feed it with 12V obviously, but when everything is set up I'll be looking at 6 amplifiers.
Rather than getting transformers, can I run something like this:
http://www.ebay.co.uk/itm/UK-Stock-DC-12V-Universa...
I'm not sure I'm up to speed on the electrics, but for a 5 amp amplifier would I be looking at 30amps for powering 6 at once? And the quoted 5 Amps, would that be pulling lower amps on the other side of the transformer as the voltage is higher? Conscious that I only have 32 amps coming in at 240v, but my mains can more than cope with 6 of these amplifiers.
Have I got that right?
Looking at the device I've linked to, it looks like it would need boxing in as it appears to have 240V terminals that are unprotected.
Anyone know of any better options?
A couple of questions.
Do you need 12 channels of amplification or 24 channels. You mention 6 car amplifiers car and these are often 4 channel devices. There are plenty of 240v zone amps which will take care of that but they may be over budget if you're currently looking at £15 per amp.
How many watts per channel do you have in mind ?
If you're going to stick with 12v then the 32A device you linked to is a 384w unit. I'm not sure what the output power spec of the amp you've bought is but so long as the combined wattage of 6 of them doesn't exceed 350 or so you'll be fine. Meanwell ( MW ) power supplies are probably the industry benchmark and the ones in the link look like MWs or copies.
http://www.meanwell.com/
http://www.meanwell.co.uk/
Do you need 12 channels of amplification or 24 channels. You mention 6 car amplifiers car and these are often 4 channel devices. There are plenty of 240v zone amps which will take care of that but they may be over budget if you're currently looking at £15 per amp.
How many watts per channel do you have in mind ?
If you're going to stick with 12v then the 32A device you linked to is a 384w unit. I'm not sure what the output power spec of the amp you've bought is but so long as the combined wattage of 6 of them doesn't exceed 350 or so you'll be fine. Meanwell ( MW ) power supplies are probably the industry benchmark and the ones in the link look like MWs or copies.
http://www.meanwell.com/
http://www.meanwell.co.uk/
Crackie said:
A couple of questions.
Do you need 12 channels of amplification or 24 channels. You mention 6 car amplifiers car and these are often 4 channel devices. There are plenty of 240v zone amps which will take care of that but they may be over budget if you're currently looking at £15 per amp.
How many watts per channel do you have in mind ?
If you're going to stick with 12v then the 32A device you linked to is a 384w unit. I'm not sure what the output power spec of the amp you've bought is but so long as the combined wattage of 6 of them doesn't exceed 350 or so you'll be fine. Meanwell ( MW ) power supplies are probably the industry benchmark and the ones in the link look like MWs or copies.
http://www.meanwell.com/
http://www.meanwell.co.uk/
Thanks, that's really useful.Do you need 12 channels of amplification or 24 channels. You mention 6 car amplifiers car and these are often 4 channel devices. There are plenty of 240v zone amps which will take care of that but they may be over budget if you're currently looking at £15 per amp.
How many watts per channel do you have in mind ?
If you're going to stick with 12v then the 32A device you linked to is a 384w unit. I'm not sure what the output power spec of the amp you've bought is but so long as the combined wattage of 6 of them doesn't exceed 350 or so you'll be fine. Meanwell ( MW ) power supplies are probably the industry benchmark and the ones in the link look like MWs or copies.
http://www.meanwell.com/
http://www.meanwell.co.uk/
This is the amp I've bough to test:
http://www.ebay.co.uk/itm/261316539366?ssPageName=...
It is two channel, I need 6 x 2 channel as I've got 6 rooms with 2 speakers in and want to retain the option of running different sound in each. Actually a 4 channel amp to do the kitchen and conservatory together is probably what I want, so 5 x 2 and 1 x 4.
I've not heard of zone amplifiers before. If I'd googled that I might have found some! Want to keep the budget as low as possible without it sounding s
t. I'm no audiophile and don't need it very loud, so I'm taking a punt on a cheap amplifier first off. The cost will add up as I'm looking at £50 a pop for the RPis, £30-40 a pair for speakers, £15 amplifer and a tenner on connectors and switches. The account manager might complain if things aren't kept under control!The amplifiers say they're 100 watts, but I know there's different measures of watts for amplifiers, so I don't know how it translates to demand on the power supply? I thought Power = Current * Voltage, so 12v and 5 amps would be 60 watts drawn. The transformer has enough ampage to run the amps and at a fixed 12 volts it can't be over loaded. Is that right?
The amp spec doesn't tell us all we need to know but its possible to make some sensible assumptions.
Its rated at 100w total or 50w per channel. Car/boat amps are commonly designed to work into 4 ohm loads so it makes sense to assume that amp is 2 channels @ 25w per channel into 8 ohms.
Are the ceiling speakers 4ohm or 8ohm units ?
Its rated at 100w total or 50w per channel. Car/boat amps are commonly designed to work into 4 ohm loads so it makes sense to assume that amp is 2 channels @ 25w per channel into 8 ohms.
Are the ceiling speakers 4ohm or 8ohm units ?
paulrockliffe said:
I haven't bought the ceiling speakers yet, apart from a pair for the bathroom, they're 4 ohms. I had a feeling Ohms was going to make an appearance with his laws!
Looking at the amplifier's 5 amp spec ( 2.5 per channel ) its likely that the 50w into 4 ohms rating is a peak figure when fed with 13.8v. Its likely to be 30W continuous ( 2.5A x 12v ) when fed with a standard 12v supply however the Meanwell supplies usually have an adjustable voltage output so I think you could run the PSU at 13.8V if you wanted a fraction more output. Anyhow 6 stereo amps with 12 discreet channels capable of 30W continuous each equals 360W total so a 400w rated 12V power supply should be fine.
The amp advert says it has an adjustable input level which is good but it doesn't say what the range is. 1.0v in is a good place to start for a power amp.
Good luck.
Edited by Crackie on Friday 13th December 12:36
The manufacturer lists a completely different spec for that amp:
As does the BassJunkies website (yet Bassjunkies is the Ebay seller....)
Manufacturer Specification:
2 CHANNEL MOSFET POWER AMPLIFIER
Max Power: 600W
Max Power Per Channel: 2x 300W
S/N Ratio: 100dB
Frequency Response: 10Hz - 40KHz
THD: 0.05%
Channel Separation: 76dB
High and Low Pass: 40Hz-240Hz
Damping Factor: 180
Bass Boost: 0/6/12dB
Dimensions: 270 x 237 x 55mm
Gold Plated Terminals
Built-in LOW/HIGH Pass Crossover
It looks as though they had added an extra trailing zero to all the specs.
Ebay Specification
2 CHANNEL MOSFET POWER AMPLIFIER
Max Power: 100W
Max Power Per Channel: 2x 50W
S/N Ratio: 70dB
Frequency Response: 20Hz - 20KHz
THD: 0.5%
Channel Separation: 60dB
Dimensions: 78 x 38 x 100mm
Built-in LOW/HIGH Pass Crossover 150Hz
Power Consumption 5 Amp
Power supply 13.8 Volts DC
Imput Level Adjustable
ETA:
You might well be better off with one of the below.
There is a 20w x 2 here
Looking at the datasheet for the chip (TA2020-20) suggests a fairly 'honest' 11w into 4 ohms.
Specification
T-Amp IC Tripath TA2020-20
Output Power 2 x 20W @ 4ohm, 2 x 12W @ 8ohm
Signal-to-Noise Ratio (SNR) 98dB
Dynamic Range 98dB
IHF-IM Distortion 0.1% @ 1W, 4ohm
THD Distortion
0.03% @ 9W, 4ohm
0.1% @ 10W 4ohm
0.1% @ 6W 8ohm
10% @ 23W 4ohm
10% @ 13W 8ohm
Power Efficiency 81% @ 20W, 4ohm, 88% @ 12W, 8ohm
Input Sensitivity 200mV
Audio IN: RCA X1 & 3.5mm earphone jack x 1
Power socket (5.5mm/2.1mm) x 1
Output
Speaker OUT (Left) x 1 pair (+ / -)
Speaker OUT (Right) x 1 pair (+ / -)
Power Indicator (Blue LED) x 1
Power Supply input DC 12V~14.6V5A
Dimensions
(W)140mm x (H)40mm x (D)120mm
Weight 300g
Output Power
(Continuous Average/Channel)
THD+N = 0.1%
RL = 4Ω 11w
RL = 8Ω 7w
THD+N = 10%
RL = 4Ω 18w
RL = 8Ω 10w
Or this 25w x 2
Specification
Power:
25W, 4Ω
13.5W, 8Ω
Efficiency:
81% @ 25W, 4Ω
88% @ 13.5W, 8Ω
Dynamic Range: 100dB
External dimensions: 148*97*32
I suspect this is an honest 15w into 4 ohms too.
According to the datasheet for the TA2021B (the chip it uses)
Output Power
(Continuous Average/Channel)
THD+N = 0.1%
RL = 4Ω 15.5W
RL = 8Ω 9W
THD+N = 10%
RL = 4Ω 23.5W
RL = 8Ω 14W
So realistically you're looking at 15w of useable power into a 4 ohm speaker, and 9w into an 8 ohm speaker.
Which, by the way, is probably quite adequate to fill a room with background music, depending on size of room and how many people in it at the time...
As does the BassJunkies website (yet Bassjunkies is the Ebay seller....)
Manufacturer Specification:
2 CHANNEL MOSFET POWER AMPLIFIER
Max Power: 600W
Max Power Per Channel: 2x 300W
S/N Ratio: 100dB
Frequency Response: 10Hz - 40KHz
THD: 0.05%
Channel Separation: 76dB
High and Low Pass: 40Hz-240Hz
Damping Factor: 180
Bass Boost: 0/6/12dB
Dimensions: 270 x 237 x 55mm
Gold Plated Terminals
Built-in LOW/HIGH Pass Crossover
It looks as though they had added an extra trailing zero to all the specs.
Ebay Specification
2 CHANNEL MOSFET POWER AMPLIFIER
Max Power: 100W
Max Power Per Channel: 2x 50W
S/N Ratio: 70dB
Frequency Response: 20Hz - 20KHz
THD: 0.5%
Channel Separation: 60dB
Dimensions: 78 x 38 x 100mm
Built-in LOW/HIGH Pass Crossover 150Hz
Power Consumption 5 Amp
Power supply 13.8 Volts DC
Imput Level Adjustable
ETA:
You might well be better off with one of the below.
There is a 20w x 2 here
Looking at the datasheet for the chip (TA2020-20) suggests a fairly 'honest' 11w into 4 ohms.
Specification
T-Amp IC Tripath TA2020-20
Output Power 2 x 20W @ 4ohm, 2 x 12W @ 8ohm
Signal-to-Noise Ratio (SNR) 98dB
Dynamic Range 98dB
IHF-IM Distortion 0.1% @ 1W, 4ohm
THD Distortion
0.03% @ 9W, 4ohm
0.1% @ 10W 4ohm
0.1% @ 6W 8ohm
10% @ 23W 4ohm
10% @ 13W 8ohm
Power Efficiency 81% @ 20W, 4ohm, 88% @ 12W, 8ohm
Input Sensitivity 200mV
Audio IN: RCA X1 & 3.5mm earphone jack x 1
Power socket (5.5mm/2.1mm) x 1
Output
Speaker OUT (Left) x 1 pair (+ / -)
Speaker OUT (Right) x 1 pair (+ / -)
Power Indicator (Blue LED) x 1
Power Supply input DC 12V~14.6V5A
Dimensions
(W)140mm x (H)40mm x (D)120mm
Weight 300g
Output Power
(Continuous Average/Channel)
THD+N = 0.1%
RL = 4Ω 11w
RL = 8Ω 7w
THD+N = 10%
RL = 4Ω 18w
RL = 8Ω 10w
Or this 25w x 2
Specification
Power:
25W, 4Ω
13.5W, 8Ω
Efficiency:
81% @ 25W, 4Ω
88% @ 13.5W, 8Ω
Dynamic Range: 100dB
External dimensions: 148*97*32
I suspect this is an honest 15w into 4 ohms too.
According to the datasheet for the TA2021B (the chip it uses)
Output Power
(Continuous Average/Channel)
THD+N = 0.1%
RL = 4Ω 15.5W
RL = 8Ω 9W
THD+N = 10%
RL = 4Ω 23.5W
RL = 8Ω 14W
So realistically you're looking at 15w of useable power into a 4 ohm speaker, and 9w into an 8 ohm speaker.
Which, by the way, is probably quite adequate to fill a room with background music, depending on size of room and how many people in it at the time...
Edited by TonyRPH on Friday 13th December 14:02
Hi Tony,
Looks like T1 need to have a word with whoever manages their website.
The T1-100 has the same spec published, on their site, as the next model up in the range the T1-600. Looks like Bassjunkies have just copied what the manufacturer has published...........
The spec on Bassjunkies e-bay advert appears to be reasonably plausible.
By the way Tripath chips are superb imho
Looks like T1 need to have a word with whoever manages their website.
The T1-100 has the same spec published, on their site, as the next model up in the range the T1-600. Looks like Bassjunkies have just copied what the manufacturer has published...........
The spec on Bassjunkies e-bay advert appears to be reasonably plausible.
By the way Tripath chips are superb imho
Wired the amp up to some cheapo speakers, using that power supply, at the weekend. Pleasantly surprised by the volume and quality! To someone not that into audio stuff, it sounds great and is loud enough to give background music around the house from the one room.
Have been streaming Christmas music from my phone via Spotify while I set up XBMC.
Going to order a load more speakers and amplifiers and get the rest rocking too.
Talk me through the best way to take one output and run it through several amplifiers?
Have been streaming Christmas music from my phone via Spotify while I set up XBMC.
Going to order a load more speakers and amplifiers and get the rest rocking too.
Talk me through the best way to take one output and run it through several amplifiers?
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