Greetings!
I am a novice to audio amplification.
I am preparing a live busking performance system for electroacoustic music, with a Gel Cell 12V battery (perhaps at 75ah), power inverter, laptop, and a suitcase of USB-MIDI controllers. I will be starting with two home stereo speakers, and the ones I have on hand are 4ohm--but I look to move quickly up to four speakers, and perhaps someday to eight.
I am trying to decide on a particular amplifier to use with this setup. I am looking for something affordable, low power, and ideally multi-channel. Low-noise is nice, but then I will be playing in metros & city streets where this may not be a huge issue.
I was looking at the Sure 4x100W TK2050:
Sure Electronics 4x100W at 4 Ohm Class D Digital Audio Amplifier Board STA508 (TK2050)
Is this a good solution?
...and a suitable power supply would be this '24 VDC 6A 145W'?:
Sure Electronics 24 VDC 6A 145W Regulated Switching Power Supply
Although I wonder if I could run the Gel Cell battery into a voltage stepper, and skip the extra power supply. However, I would still need to run the battery into an inverter to power the laptop, midi controllers, and at some point basic lighting.
I would be very interested to hear of other ready made, assembled 4 channel solutions that would suit this purpose. I worry that 100W may be slightly under powered, but I feel like this combination should at least be more powerful than the average portable busking guitar amp used around town, especially when run into 4 speakers.
Regards,
Peter
I am a novice to audio amplification.
I am preparing a live busking performance system for electroacoustic music, with a Gel Cell 12V battery (perhaps at 75ah), power inverter, laptop, and a suitcase of USB-MIDI controllers. I will be starting with two home stereo speakers, and the ones I have on hand are 4ohm--but I look to move quickly up to four speakers, and perhaps someday to eight.
I am trying to decide on a particular amplifier to use with this setup. I am looking for something affordable, low power, and ideally multi-channel. Low-noise is nice, but then I will be playing in metros & city streets where this may not be a huge issue.
I was looking at the Sure 4x100W TK2050:
Sure Electronics 4x100W at 4 Ohm Class D Digital Audio Amplifier Board STA508 (TK2050)
Is this a good solution?
...and a suitable power supply would be this '24 VDC 6A 145W'?:
Sure Electronics 24 VDC 6A 145W Regulated Switching Power Supply
Although I wonder if I could run the Gel Cell battery into a voltage stepper, and skip the extra power supply. However, I would still need to run the battery into an inverter to power the laptop, midi controllers, and at some point basic lighting.
I would be very interested to hear of other ready made, assembled 4 channel solutions that would suit this purpose. I worry that 100W may be slightly under powered, but I feel like this combination should at least be more powerful than the average portable busking guitar amp used around town, especially when run into 4 speakers.
Regards,
Peter
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You should be able to eliminate the inverter from the loop by using dc-dc boost converters. The laptop and the midi power supplies are just taking the ac from the inverter and converting it back to dc. Efficiency will be at a premium with battery power.
Great, I have decided to go this route.
A good friend's family runs a commercial battery business, so I am in touch with him to find out details on how I should power all of this. Looks like I may need considerably more than 75AH, possibly 200AH or two 100AH 12V batteries.
It might be possible, that if I got hold of a 24v battery, I could altogether avoid the dc-dc boost converter? More research here. . .
If anyone else can suggest something besides the Sure 4x100W TK2050 board, I would be interested. I am looking for something low-power, affordable, and multichannel--though I would be happy using 2 stereo boards. In fact I may stick to just stereo for awhile, as four channels will have a huge impact on my power consumption !!
I may skip the inverter, and just pick up a bunch of spare batteries for the old junky Thinkpad I plan to use. Or alternatively switch it all over to a low power Odroid/Raspberry Pi, but that will take a little more effort.
Thanks!
Peter
So, I am trying to calculate how large a battery I would need to run a Sure 2x100W or 4x100W TK2050 4ohm board (Sure Electronics 4x100W at 4 Ohm Class D Digital Audio Amplifier Board STA508 (TK2050)), as well as my laptop.
I found some instructions for calculating amp-hours. My calculations are below for a 2x100W TK2050 amp, and a 65W laptop, and I wonder if these are accurate. I look to have ~6hr capacity:
However, reading an 'Instructable' on the topic of 'Off-Grid Party Systems' suggests that a two channel TK2050 should run for 6-8 hours on an 18AH battery. (Off-Grid Party Sound Systems : Power, Batteries and Chargers)
So, what am I missing?
I found some instructions for calculating amp-hours. My calculations are below for a 2x100W TK2050 amp, and a 65W laptop, and I wonder if these are accurate. I look to have ~6hr capacity:
Code:
Watt hours...
Amplifier: 2(100W) x 6h = 1200W
Computer: 65W x 6h = 390W
Efficiency...
Amplifier efficiency is 90% so...
Amplifier: 1200W/0.9 = 1333.3
Need to find energy efficiency of adapter...estimate is 85%?
Computer: 65/0.85 = 76.5
1333.3 + 76.5 = 1409.8
Total watt hours divided by voltage (for a 12 volt battery):
1409.8/12 = 117.5ah to run for 6 hoursHowever, reading an 'Instructable' on the topic of 'Off-Grid Party Systems' suggests that a two channel TK2050 should run for 6-8 hours on an 18AH battery. (Off-Grid Party Sound Systems : Power, Batteries and Chargers)
So, what am I missing?
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The crux is the speaker efficiency.
Look for high speaker sensitivity if you run a battery system.
Fullrange speakers like the Visaton BG20 have that plus nice soundquality and decent bass (for the low cost), plus no need for a crossover.
With a two way system you should look into active filters; minidsp is a pretty nice device for that!!
Each speaker should get its own amp channel (like in the link). (*)
On a 18Ah battery you should be able to power two channels at high spl for a whole weekend.
Look at the TDA7492 amp.
Very cheap boards are available and the soundquality is really nice for the cost.
If you wnat to spend a little more look at the TAS5611 (or its bigger brothers like 5613 or 5630).
They are able to drive 4 Ohm loads.
(*) If you sum your signal to mono (right at the inputs or in a preamp) you can use one two channel board with two 8 Ohm woofers in parallel on one channel and two 8Ohm tweeter horns (one might be enough if efficiency is much higher than on the woofers) on the other channel.
That doesn't make any sense to me.
Look at the units you are using.
What do you try to calculate?
i do not see the need for a voltage converter here.
Get two 12V batteries from your friend and you are fine.
Get two 12V batteries from your friend and you are fine.
Can you describe all of your required musical set up?
As far as amplification goes, you can easily do it with a 12V amp, using 8"speakers , and a 7Ah battery, sucking 2-4W (not 100W) with incredible fidelity and loud, for 5 hours.
Are you running a mixer as well?
As far as amplification goes, you can easily do it with a 12V amp, using 8"speakers , and a 7Ah battery, sucking 2-4W (not 100W) with incredible fidelity and loud, for 5 hours.
Are you running a mixer as well?
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You may also check for the Beyma 8AG/N in comparsion to the BG20.
Btw:
This all belongs on how much bass you want, efficieny of your speakers and what music is your programm. 🙂
i.e.
100W into 85dB/W is the same as 10W into 95dB/W is the same as 1W into 105dB/W - so SPL is the key.
Btw:
Code:
Watt hours...
Amplifier: 2*100W (lets assume 100Wrms_total) -> 100W x 6h = 600Wh
Computer : 65W (lets assume 35Wrms at normal load) 35W x 6h = 210Wh - lets further assume, that your laptop-battery is initially fully charged (runtime ~2h) -> 210Wh - 2h*35W = 140Wh
Efficiency...
Amplifier efficiency is 90% so...
Amplifier: 600Wh/0.9 = 667Wh
Computer adapter...estimate is 85%?
Computer: 140Wh/0.85 = 165Wh
667Wh + 165Wh = 832Wh
Total watt hours divided by voltage (for a 12 volt battery):
832Wh/12V = 70ah to run for 6 hours
Or battery power per hour:
Amp:
100W / 0.9 = 111W
Computer: 35W / 0.85 = 41W
-> 111W + 41W = 152W -> 152W/12V = 12.7A -> 12.7Ah/hThis all belongs on how much bass you want, efficieny of your speakers and what music is your programm. 🙂
i.e.
100W into 85dB/W is the same as 10W into 95dB/W is the same as 1W into 105dB/W - so SPL is the key.
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