| neutron7 |
I need 6 small 1-3w amplifiers they are going in to a guitar for a sustainer device.
there is one channel for each string so i need 6 of them! multiple amps per package would be good. and the less external components the better.
can be powered from +- 9v
can power electromagnet coils (im thinking relay coils of some type)
pretty much what a speaker load would look like
digital would be great to save battery life. using 9v rechargeables.
distortion doesn't matter as long as its below around 1%
the pick guard of the guitar is solid aluminium, (big strat type) so it can serve as a heatsink.
maybe theres something they use for those crappy little surround systems with tall speakers or cheap tvs/radios
any suggestions would be greatly appreciated.
thanks! |
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| theAnonymous1 |
The first device that comes to my mind is the TI TPA1517.
It has the output power you're looking for and requires minimal external components. You could power it with your two rechargeable 9v batteries in series. The only limitation of the IC is the gain is internally fixed at 20dB. If 20dB is enough for your application, then I think it's a good candidate. |
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| neutron7 |
fixed gain might not do it, the output of the preamp has almost the voltage i need just not the current.
i wouldnt want to atenuate and then amplify again, I think i need a gain of around 2-5 |
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| neutron7 |
| actually i can live with that. it comes in DIP, and needs almost no other components, ill try it :) |
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| Brett |
| quote: | Originally posted by neutron7
using 9v rechargeables. |
Can't think of a suggestion of the PA OTTOMH, but consider powering it offboard. A 3 wire lead and jack would do it, with greatly reduced chance of it failing on stage, or limiting yourself because of batteries.
My Alembic bass eats the two batteries in about 40 hours, so I never even install them and just use the external supply. |
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| DigitalJunkie |
| quote: | Originally posted by theAnonymous1
The first device that comes to my mind is the TI TPA1517.
It has the output power you're looking for and requires minimal external components. You could power it with your two rechargeable 9v batteries in series. The only limitation of the IC is the gain is internally fixed at 20dB. If 20dB is enough for your application, then I think it's a good candidate. |
I built a small amp 'dead-bug' style with one of those,on a piece of copper-clad PCB material.. The whole circuit is about the size of a small book of matches.
Another thought is the LM4950 you can get it in TO220,or the smaller SMD version. each chip is two channels,and only needs a few parts.
one of the LM4950's 'cousins' might work too.
Hmm..
KA2209
TDA2822
TEA2025
LA4480,though it might be a bit large.
Some possibilities,Just off the top of my head. |
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| theAnonymous1 |
:bigeyes: :bigeyes: :bigeyes: :bigeyes: :bigeyes:
I just built up one of these small TPA1517 amps and I am shocked to say the least. I was expecting it to sound like an anemic clock radio. This little IC has PUNCH!!
First, let me say this officially counts as my first ever "chipamp" build. I mean I have built dozens of Tripath class-d amps and a handful of various headphone amps, but never a linear chipamp powerful enough for speakers.
I've had a tube of these sitting around for ~2 years but never had the ambition to do anything with them; I figured it would be a waste of time. Boy was I wrong. I didn't think it would play this loud single ended into an 8R load off a 14v supply. I'm playing some bass heavy "Dubstep" music through it right now on a pair of passive 3-ways and it has no problem keeping up.
I think I will build up some differential input BTL boards and run a dual mono setup. I already have an OPA1632 single ended input to differential output board built that I will use for the front end.
Here is a pic of my P2P job.......
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| SpittinLLama |
If you really want small, easy gain setting then look into the LM4954. Single supply but check it out. You could probably fit 6 of these chip in the DIP space. A little harder to solder tho.
-SL |
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| theAnonymous1 |
| quote: | Originally posted by SpittinLLama
If you really want small, easy gain setting then look into the LM4954. Single supply but check it out. You could probably fit 6 of these chip in the DIP space. A little harder to solder tho.
-SL |
That looks much better suited for his application. The biggest advantage being no need for bulky output capacitors. Too bad it only comes in the micro SMD package. |
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| SpittinLLama |
Ah, yeah, that could be a real problem for a DIY type of job. Maybe the LM4951? It comes in a bigger package but still might be too hard to solder.
-SL |
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| neutron7 |
| quote: | Originally posted by Brett
Can't think of a suggestion of the PA OTTOMH, but consider powering it offboard. A 3 wire lead and jack would do it, with greatly reduced chance of it failing on stage, or limiting yourself because of batteries.
My Alembic bass eats the two batteries in about 40 hours, so I never even install them and just use the external supply. |
Yeah i guess all those amps would eat batteries pretty fast! good suggestion, thanks. |
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| neutron7 |
| quote: | Originally posted by SpittinLLama
If you really want small, easy gain setting then look into the LM4954. Single supply but check it out. You could probably fit 6 of these chip in the DIP space. A little harder to solder tho.
-SL |
I dont think i can solder anything that small.
they would be great though. |
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| EWorkshop1708 |
With SMD chips, you can solder tinned-wire leads on the PCB first, then solder the SMD chip to one wire first, then bend each other lead to the other pins of the smd one at a time, and melt them together with the iron tip.
After you are done, it's kind of like a small DIP. |
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| neutron7 |
| Well i am sure i will have to rebuild it a few times as i figure out exactly how to make it more usable and playable. i dont fancy doing that too many times. maybe on the final, when wattage has been decided ill use SMD amps. |
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| mikesnowdon |
I have a pair of cheap PC speakers using the TEA2025 chip.
As a little biginners project ive rigged it to power a pair of Mission 700 speakers and its not too bad. I'll be removing the amp board and re housing it in good chassis etc....
Details here:
Ive been searching for hours on the net to see if theres a better quality compatible chip I can use, without changing or tweaking the circuit too much.
Any ideas? |
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