hi All
Burning Man gave me a small grant to teach kids in a disadvantaged community how to build bicycle sound systems.
www.bvhpradio.org/boom
i'm looking for amplifier kits that can run off a motorcycle battery or lantern battery.
we are looking for two basic options:
--loud (mono or stereo) that can run off a lantern battery, about $10 Not counting batteries and speakers.
--and extremely loud (stereo), up to about $30.
Our plan is to mount the amps and power inside paint cans, and put the speaker drivers on each end of the can.
we're looking at these. Can anyone shed some light on which is a good choice?
TDA2030A Audio Amplifier Amp DIY Kit OCL18Wx2 BTL 1Set | eBay
TDA8920BTH 2x200W CLASS D Audio Power Amplifier AMP Kit | eBay
Audio Power Amplifier 20W - 2x TDA2003 - Assembling kit | eBay
Amazon.com: Velleman 30W Stereo Audio Amplifier Kit: Electronics
Complete 2 X 45 W (RMS) Hybrid Stereo Amplifier with Power Supply (Kit) (Special Deal)
2 X 30W AUDIO POWER AMPLIFIER K4003 - All Spectrum Electronics
50W Hi-Fi Audio Power Amplifier with Mute & Standby
2x25W Audio Amplifier (Closeout)
20 Watt Audio Amplifier Module Kit UAM2 - All Spectrum Electronics
Shop — Catalog Products — Amplifier - Stereo Power 15 Watt W Futurekit FA608 | Electric Sumo
GSS Tech Ed - CK194 - 2 X 20 WATT BRIDGED STEREO POWER AMP KIT
GSS Tech Ed - CK193 - 20 WATT BRIDGED POWER AMP KIT
10W Audio Amplifier - Cana Kit
50W Hi-Fi Audio Power Amplifier with Mute & Standby
ps, if you can provide us with a complete kit (including heatsinks) at better specs/price than any of the above, please let me know.
or, if you are in the bay area, and interested in assisting us with this project hands-on, that would be fantastic.
THANKS
johny radio
Burning Man gave me a small grant to teach kids in a disadvantaged community how to build bicycle sound systems.
www.bvhpradio.org/boom
i'm looking for amplifier kits that can run off a motorcycle battery or lantern battery.
we are looking for two basic options:
--loud (mono or stereo) that can run off a lantern battery, about $10 Not counting batteries and speakers.
--and extremely loud (stereo), up to about $30.
Our plan is to mount the amps and power inside paint cans, and put the speaker drivers on each end of the can.
we're looking at these. Can anyone shed some light on which is a good choice?
TDA2030A Audio Amplifier Amp DIY Kit OCL18Wx2 BTL 1Set | eBay
TDA8920BTH 2x200W CLASS D Audio Power Amplifier AMP Kit | eBay
Audio Power Amplifier 20W - 2x TDA2003 - Assembling kit | eBay
Amazon.com: Velleman 30W Stereo Audio Amplifier Kit: Electronics
Complete 2 X 45 W (RMS) Hybrid Stereo Amplifier with Power Supply (Kit) (Special Deal)
2 X 30W AUDIO POWER AMPLIFIER K4003 - All Spectrum Electronics
50W Hi-Fi Audio Power Amplifier with Mute & Standby
2x25W Audio Amplifier (Closeout)
20 Watt Audio Amplifier Module Kit UAM2 - All Spectrum Electronics
Shop — Catalog Products — Amplifier - Stereo Power 15 Watt W Futurekit FA608 | Electric Sumo
GSS Tech Ed - CK194 - 2 X 20 WATT BRIDGED STEREO POWER AMP KIT
GSS Tech Ed - CK193 - 20 WATT BRIDGED POWER AMP KIT
10W Audio Amplifier - Cana Kit
50W Hi-Fi Audio Power Amplifier with Mute & Standby
ps, if you can provide us with a complete kit (including heatsinks) at better specs/price than any of the above, please let me know.
or, if you are in the bay area, and interested in assisting us with this project hands-on, that would be fantastic.
THANKS
johny radio
On a bicycle, weight is a concern. Try to maximize efficiency by using a class D (or class T it is sometimes called) amp and the minimum battery capacity that will reach sufficient runtime.
Do you plan on the paint cans being waterproof? Ideally, it would be - you can't stop rain when you're out on a bike. Amp board sealed in a paint can is a cooling problem, heatsink should be external to the sealed enclosure, or amp board should heatsink to the enclosure itself, or be low enough powered that overheating isn't an issue.
A paint can will be horrible acoustically unless you treat the inside somehow to deaden it. Layers of epoxy coated fiberglass would work, but then you further insulate the heat inside and make attachment to an exterior facing heatsink more problematic. Also, putting a speaker on the end means you'll want a shielded speaker so the magnetic field isn't right against the amp board. I suggest it might be better to put the amp somewhere else besides in a small speaker enclosure, perhaps with the battery pack located remotely, ideally low on the bike to keep a lower center of gravity.
My point is I don't see a paint can as being very compatible with the output power you are seeking. Nema rated cast aluminum enclosure w/waterproof gaskets would work, put the battery and amp board in one, then the speaker elsewhere.
Otherwise, the 2nd one you linked is $42, others also exceed $30 then add shipping cost, but the budget was up to $30?
Maybe for a motorcycle some of these are reasonable but for a bicycle there isn't much benefit to something over 20W, it would take too much battery power to reach that output, higher than 12V battery voltage input, and heatsink size and weight keeps growing.
Is the project meant to get people soldering things together or would a ready to use amp board be better? I feel the following (basically it's the guts out of a Sonic T-Amp) might be the best all around option, but that extremely loud for $30 isn't a reasonable goal once you factor in the battery, heatsinking, inability for a paint can to handle a driver at that power level, etc.
Dayton Audio DTA-2 Class T Digital Audio Amplifier Module
Do you plan on the paint cans being waterproof? Ideally, it would be - you can't stop rain when you're out on a bike. Amp board sealed in a paint can is a cooling problem, heatsink should be external to the sealed enclosure, or amp board should heatsink to the enclosure itself, or be low enough powered that overheating isn't an issue.
A paint can will be horrible acoustically unless you treat the inside somehow to deaden it. Layers of epoxy coated fiberglass would work, but then you further insulate the heat inside and make attachment to an exterior facing heatsink more problematic. Also, putting a speaker on the end means you'll want a shielded speaker so the magnetic field isn't right against the amp board. I suggest it might be better to put the amp somewhere else besides in a small speaker enclosure, perhaps with the battery pack located remotely, ideally low on the bike to keep a lower center of gravity.
My point is I don't see a paint can as being very compatible with the output power you are seeking. Nema rated cast aluminum enclosure w/waterproof gaskets would work, put the battery and amp board in one, then the speaker elsewhere.
Otherwise, the 2nd one you linked is $42, others also exceed $30 then add shipping cost, but the budget was up to $30?
Maybe for a motorcycle some of these are reasonable but for a bicycle there isn't much benefit to something over 20W, it would take too much battery power to reach that output, higher than 12V battery voltage input, and heatsink size and weight keeps growing.
Is the project meant to get people soldering things together or would a ready to use amp board be better? I feel the following (basically it's the guts out of a Sonic T-Amp) might be the best all around option, but that extremely loud for $30 isn't a reasonable goal once you factor in the battery, heatsinking, inability for a paint can to handle a driver at that power level, etc.
Dayton Audio DTA-2 Class T Digital Audio Amplifier Module
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hi
thanks for the detailed reply.
yes, the goal is to get people soldering.
the paint can is not a requirement, just an idea we thought would be cheap and easy. the idea was to stuff it with acoustic bunting to deaden it.
feel free to suggest a different mount.
$30 is not a hard ceiling for the loud system, just a rough range.
would a battery on a class D last longer than the same battery on a class A rated at the same output?
best,
j
thanks for the detailed reply.
yes, the goal is to get people soldering.
the paint can is not a requirement, just an idea we thought would be cheap and easy. the idea was to stuff it with acoustic bunting to deaden it.
feel free to suggest a different mount.
$30 is not a hard ceiling for the loud system, just a rough range.
would a battery on a class D last longer than the same battery on a class A rated at the same output?
best,
j
also, thanks for the dayton link. from the comments on that page, it sounds like 15 watts might not be loud enough for the parade.
Would a single channel 30 watter be as loud a 2-channel 15 watter?
here are some other class D's i found:
2 X 15Watt Class D Audio Amplifier DIY Kit - TPA3122_Audio Amplifier DIY Suite_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
2 X 25Watt Class-D Audio Amplifier Board - TPA3123 (AA-AB018)_Audio Amplifier Boards_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
1 X 25Watt Class AB Audio Amplifier DIY Kit - TDA2050_Audio Amplifier DIY Suite_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
2 X 25Watt Class D Audio Amplifier Board - TDA7492_Audio Amplifier Boards_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
but i am a little nervous about ordering from china, anyone have experience with this store?
oh, and here's a 200 watt x 2 class D amplifier for $20. Is that suspicious?
http://www.ebay.com/itm/TDA8920BTH-...&ps=63&clkid=2669763218370176526#ht_739wt_907
Would a single channel 30 watter be as loud a 2-channel 15 watter?
here are some other class D's i found:
2 X 15Watt Class D Audio Amplifier DIY Kit - TPA3122_Audio Amplifier DIY Suite_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
2 X 25Watt Class-D Audio Amplifier Board - TPA3123 (AA-AB018)_Audio Amplifier Boards_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
1 X 25Watt Class AB Audio Amplifier DIY Kit - TDA2050_Audio Amplifier DIY Suite_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
2 X 25Watt Class D Audio Amplifier Board - TDA7492_Audio Amplifier Boards_Audio Amplifier and other Audio Boards_Audio, Video Equipments_Sure Electronics' Webstore
but i am a little nervous about ordering from china, anyone have experience with this store?
oh, and here's a 200 watt x 2 class D amplifier for $20. Is that suspicious?
http://www.ebay.com/itm/TDA8920BTH-...&ps=63&clkid=2669763218370176526#ht_739wt_907
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First of all, recognize that when powering an amp from single rail 12V power source, that limits the output wattage. Even an efficient class-T amp like the one I linked, only reaches 11W/channel at 0.1% THD. Yes a class D or T amp rated for same output power as class A/B or especially class A, will run longer, they are significantly more efficient.
Decide what battery configurations you'd accept, size, weight, cost, voltage, charging requirements, etc. as the battery parameters are your greatest limitiation.
Next determine minimum run time that's acceptable. This will determine (ballpark) how high a wattage you can use and what would be overkill adding cost for no reason. In particular, to get more than about 15W you will need higher voltage, or a voltage boost circuit which adds cost and lowers efficiency.
For example the amps you linked in your last post, the first one needs 28V power to reach 15W/channel into 8 ohm speakers. The second amp linked needs 27V supply to reach 25W/channel. At 1% THD and 12V input it is only ~3.5W/channel. The linked TDA7492 won't even run with less than 14V input.
The last linked amp isn't $20, it's $42. They claim the cost difference as shipping but that is to get around ebay's fees, actual postage from China is subsidized and practically free compared to what it would cost to ship something the other direction. $42 is reasonable for what it is, but 200W, like above, depends on your input voltage and is quite high output power for something mobile running from battery power, and it's too much for a driver in a paint can.
Are these bicycle amps for a one-time only event, or something meant to be reasonable to use regularly riding a bike? If the former, perhaps a bit larger battery isn't as much of an issue and you could use 2 x 12V SLA batteries in series for 24V, with them costing roughly $15 each that's $30 for the batteries, about $20 for the amp, add wiring and connectors, multiplied times number of bicycles and it starts getting really expensive and I'd wonder if sound should come from one higher output amp rather than several smaller ones on each bicycle.
Decide what battery configurations you'd accept, size, weight, cost, voltage, charging requirements, etc. as the battery parameters are your greatest limitiation.
Next determine minimum run time that's acceptable. This will determine (ballpark) how high a wattage you can use and what would be overkill adding cost for no reason. In particular, to get more than about 15W you will need higher voltage, or a voltage boost circuit which adds cost and lowers efficiency.
For example the amps you linked in your last post, the first one needs 28V power to reach 15W/channel into 8 ohm speakers. The second amp linked needs 27V supply to reach 25W/channel. At 1% THD and 12V input it is only ~3.5W/channel. The linked TDA7492 won't even run with less than 14V input.
The last linked amp isn't $20, it's $42. They claim the cost difference as shipping but that is to get around ebay's fees, actual postage from China is subsidized and practically free compared to what it would cost to ship something the other direction. $42 is reasonable for what it is, but 200W, like above, depends on your input voltage and is quite high output power for something mobile running from battery power, and it's too much for a driver in a paint can.
Are these bicycle amps for a one-time only event, or something meant to be reasonable to use regularly riding a bike? If the former, perhaps a bit larger battery isn't as much of an issue and you could use 2 x 12V SLA batteries in series for 24V, with them costing roughly $15 each that's $30 for the batteries, about $20 for the amp, add wiring and connectors, multiplied times number of bicycles and it starts getting really expensive and I'd wonder if sound should come from one higher output amp rather than several smaller ones on each bicycle.
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thanks for the detailed reply. How do you calculate battery volts needed for the amplifier to deliver watts power? I'm familiar with-
Watts = Volts x Amps
Therefor, 12 volts x 3 amps = 36 watts
Does that mean a 12 volt 3 amp battery will drive any capable amp to 36 watts for an hour? That doesn't sound quite right. It must also have to do with the efficiency of the amplifier, as well as how loud you drive it (but let's assume we're turning up to "10").
Battery cost: $5 to $20
Weight: lighter than a lead motorcycle battery.
Time: 3 solid hours
What does "too much" mean? If you mean it would overdrive the speakers, then we would only use speakers rated for the wattage our amplifier is outputting. How does the type of enclosure affect that?
But we also need solo loud systems.
I'm open to cheaper SLA's for the one-time event. But in that case, i'd want to enable participants to upgrade at their own expense to lighter batteries. For that, please see my next message about battery clips and mounting...
thanks!
Watts = Volts x Amps
Therefor, 12 volts x 3 amps = 36 watts
Does that mean a 12 volt 3 amp battery will drive any capable amp to 36 watts for an hour? That doesn't sound quite right. It must also have to do with the efficiency of the amplifier, as well as how loud you drive it (but let's assume we're turning up to "10").
Battery cost: $5 to $20
Weight: lighter than a lead motorcycle battery.
Time: 3 solid hours
What does "too much" mean? If you mean it would overdrive the speakers, then we would only use speakers rated for the wattage our amplifier is outputting. How does the type of enclosure affect that?
We are interested in doing a bike-fleet approach, with an FM receiver and a lower power amp on each bike, and one bike with the FM transmitter.
But we also need solo loud systems.
I'm open to cheaper SLA's for the one-time event. But in that case, i'd want to enable participants to upgrade at their own expense to lighter batteries. For that, please see my next message about battery clips and mounting...
thanks!
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i realize battery is a big obstacle. The best prices i can find are roughly 2 amps at 12 volts in lithium or NiMH, for about $15.
Frankly, if i get 3 solid hours out of any of the amps, with $5 to $10 of batteries (for the low-power systems), and $15 to $20 of batteries for the louder system, i'm happy. So i guess the question is, how many watts can i drive for 3 hours with 12 volts @ 2 amps of batteries? And what should the amplifier be rated at for max efficiency?
i want to give my participants the option to use 2 or more batteries at their expense, so i plan to design a battery mounting method that can handle any number of batteries. For example, velcro, with battery clips that can enable easy end-to-end expansion of the battery pack (in parallel or series, depending on which is better for the given amplifier).
(my bad for posting amps that require a minimum of more than 12 volts, i intended only those rated to run at 12).
Frankly, if i get 3 solid hours out of any of the amps, with $5 to $10 of batteries (for the low-power systems), and $15 to $20 of batteries for the louder system, i'm happy. So i guess the question is, how many watts can i drive for 3 hours with 12 volts @ 2 amps of batteries? And what should the amplifier be rated at for max efficiency?
i want to give my participants the option to use 2 or more batteries at their expense, so i plan to design a battery mounting method that can handle any number of batteries. For example, velcro, with battery clips that can enable easy end-to-end expansion of the battery pack (in parallel or series, depending on which is better for the given amplifier).
(my bad for posting amps that require a minimum of more than 12 volts, i intended only those rated to run at 12).
You look at the amp chip datasheet to see watts output at power supply voltage. Runtime is a different matter, you have to guesstimate the volume level and current at that volume.
A 12V 3A battery can't power a 36W amp for an hour, the voltage itself limits the amp output power and will be around 3W for class A/B, around 10W for class D or T.
It seems you want things that are incompatible. The low cost, light weight, high voltage to achieve high volume and runtime, aren't all possible. I still suggest the amp I linked first and powering it from a 12V, ~7Ah SLA battery which is about $15-$20. For the higher powered amp you could put another 12V, 7Ah battery in series for 24V to power a different class D or T amp but I don't know what is the most cost effective amp for 24V input.
To realize high output (wattage) your drivers will have quite a bit of excursion (movement) and so a small sealed paint can just won't work, sound will be distorted and more than just some material stuffed in would be required. The enclosure would need be stiffer, larger, and the speaker itself fairly expensive to handle that power level.
I suppose a summary of what I'm stating is high power isn't cheap or small or light weight. Velcro won't cut it on a moving bicycle prone to road bumps/etc unless you're only using some minimal power source like a few AA or Li-Ion batteries with low capacity and weight.
I'm pretty much out of ideas, perhaps someone knows of the best way to come as close as possible to what you want but it would seem to hinge on finding a great price on the amp and batteries.
A 12V 3A battery can't power a 36W amp for an hour, the voltage itself limits the amp output power and will be around 3W for class A/B, around 10W for class D or T.
It seems you want things that are incompatible. The low cost, light weight, high voltage to achieve high volume and runtime, aren't all possible. I still suggest the amp I linked first and powering it from a 12V, ~7Ah SLA battery which is about $15-$20. For the higher powered amp you could put another 12V, 7Ah battery in series for 24V to power a different class D or T amp but I don't know what is the most cost effective amp for 24V input.
To realize high output (wattage) your drivers will have quite a bit of excursion (movement) and so a small sealed paint can just won't work, sound will be distorted and more than just some material stuffed in would be required. The enclosure would need be stiffer, larger, and the speaker itself fairly expensive to handle that power level.
I suppose a summary of what I'm stating is high power isn't cheap or small or light weight. Velcro won't cut it on a moving bicycle prone to road bumps/etc unless you're only using some minimal power source like a few AA or Li-Ion batteries with low capacity and weight.
I'm pretty much out of ideas, perhaps someone knows of the best way to come as close as possible to what you want but it would seem to hinge on finding a great price on the amp and batteries.
see "Cooler Tunes" for biking or anywhere!!
Take a look at this other thread found with a small search. Seems to have similar objectives.
http://www.diyaudio.com/forums/multi-way/192220-cooler-tunes-biking-anywhere.html
Take a look at this other thread found with a small search. Seems to have similar objectives.
http://www.diyaudio.com/forums/multi-way/192220-cooler-tunes-biking-anywhere.html
May I suggest you have a look at this thread?
http://www.diyaudio.com/forums/class-d/104402-boominator-another-stab-ultimate-party-machine.html
It may help you.
If it's not loud enough, you can still have 24V with 2 batteries and run low impedance (4 ohm or evne less) speakers. For sure it will not last for a while but that's where balance has to be found ;-)
http://www.diyaudio.com/forums/class-d/104402-boominator-another-stab-ultimate-party-machine.html
It may help you.
If it's not loud enough, you can still have 24V with 2 batteries and run low impedance (4 ohm or evne less) speakers. For sure it will not last for a while but that's where balance has to be found ;-)
Here are some cheap slightly used 7AH, 12V SLA batteries, but shipping could be costly.
Used 12V/7AH Sealed Lead Acid
Used 12V/7AH Sealed Lead Acid
Fantastic ideas.
Yep, I realize there has to be a trade-off someplace, and battery weight is first. If I have to go with SLAs, that's doable.
Re shipping, I'm going to research local battery supply.
The prebuilt system is an option I'm going to offer for those who don't want to solder, but they will have to pay a bit. Even tho the prebuilt might actually be a bit cheaper, we want to create the incentive to solder.
Yep, I realize there has to be a trade-off someplace, and battery weight is first. If I have to go with SLAs, that's doable.
Re shipping, I'm going to research local battery supply.
The prebuilt system is an option I'm going to offer for those who don't want to solder, but they will have to pay a bit. Even tho the prebuilt might actually be a bit cheaper, we want to create the incentive to solder.
First off, thanks for linking to my "Cooler Tunes" thread.
Secondly, I just wanted to point out that there is a nice little light weight battery that I found if weight savings is a must for a project.
Ballistic 4 Cell EVO2 Battery (2113-0258) by Ballistic Batteries - Direct Harley Parts -
http://www.ballisticparts.com/downloads/pdf/BallisticBatteryInstructions.pdf
Product information:
Ballistic #100-010
4 Cell EVO2
Dimensions: 60MM (L) x 60MM (W) x 103MM (H)
Positive Terminal Location: Left
Weight: 400 grams (.885 lb)
Voltage (Charged): 13.6V
Amperage: 8 Pbeq A/H
Cold Cranking Amps: 135 CCA
Operating Environment: -18°C (0°F) to 60°C (140°F)
Typical Applications: 550cc and under multi-cylinder motorcycles, scooters, and ATV’s.
4 Cell EVO 2 (100-010)
Also, I am expanding on my builds to make some semi-softside coolers. I have a new pic of one on my facebook page. http://facebook.com/cyclepartytunes
Secondly, I just wanted to point out that there is a nice little light weight battery that I found if weight savings is a must for a project.
Ballistic 4 Cell EVO2 Battery (2113-0258) by Ballistic Batteries - Direct Harley Parts -
http://www.ballisticparts.com/downloads/pdf/BallisticBatteryInstructions.pdf
Product information:
Ballistic #100-010
4 Cell EVO2
Dimensions: 60MM (L) x 60MM (W) x 103MM (H)
Positive Terminal Location: Left
Weight: 400 grams (.885 lb)
Voltage (Charged): 13.6V
Amperage: 8 Pbeq A/H
Cold Cranking Amps: 135 CCA
Operating Environment: -18°C (0°F) to 60°C (140°F)
Typical Applications: 550cc and under multi-cylinder motorcycles, scooters, and ATV’s.
4 Cell EVO 2 (100-010)
Also, I am expanding on my builds to make some semi-softside coolers. I have a new pic of one on my facebook page. http://facebook.com/cyclepartytunes
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