80w rms x 6

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SamV

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Joined 2008
bikeology.net
#1
Hi guys,

I'm looking for an amp that can do 80w rms @4ohm x6 channels that is as efficient as possible that runs off 12volts.

Any ideas?

It's to go on my new bike sound system system, this is the old one

1308425220_0e59643323_o.jpg


The new one will be similiar in size but at least 3db more efficient output wise, and a fair bit more efficient power wise due to upgraded components.

Any recommendations for amps? At the moment it's using a 4 channel JBL GTO75.4 car amp at 2ohm.
 
#3
Terrific looking bike sound system - good job 🙂

Are you interested in building your own amps or do you want to buy what ever is on the market from known manufacturers (like JBL, JVC, Kenwood, Magnat, Pioneer, ...)? 😕

In case you wanna go DIY my recommendations are the followings:

Either you decide to make your own class-D amps (look for such threads here) and the necessary SMPS (can be also found here) or you go for instance, if class-D would be to complicated for you, for class-H, in particular for TDA1562Q (from Philips => http://www.nxp.com/.

For the latter case you also find at least a PCB to buy at http://www.elektor.de/jahrgang/2000/februar/50-w-klasse-h-endstufe.59985.lynkx

If you've a colleague or friend who collects the magazine ELEKTOR (it's for sure published in NL and D but I'm not so sure about UK), it's in issue 350 from February 2000.

This chip-amp would be the closest to your power requirements with very few additional components and still some worth mentioning efficiency.
Talking about efficiency - considering the limited power resources you're going to "carry" with you (the batteries/accumulators), class-D amps cannot be outdo by other classes if we're talking about efficiency.

Good luck 😉
 
#8
TDA1562Q

Hi SamV,

Great system! Corax is on the ball and his suggestions are good. Class D are the most efficient.
I am currently evaluating a TDA1562Q amp kit (class H from jaycar in Australia) for use with a portable system. This chip uses extra capacitors to boost the rail voltage during peaks giving 36w rms into 4 ohms and 70wrms "music power" depending on battery voltage.

Most car amps draw a lot of current are rated at 2ohms and the RMS figures are BS!

Go for the high efficiency speakers. 94db/1w/1m is good but 100db/1w/1m would give you 4 times the acoustic output for the same amp power and battery life.

see here:
http://www.billfitzmaurice.com/

put some wheels on this!
http://www.billfitzmaurice.com/THT.html

maybe the last idea was a bit silly...

Regards Philip
 
#10
Trouble with 100db/1w/1m drivers is that they are not usually equipped with handle moisture and are usually expensive and heavy. Though yes 100db would be awesome.

I have had a look at the AMP9, but I'm not an electrical person, and my solder skills are a bit beginner, ideally I just I was hoping to find links to a 2x80w rms @4ohm amp boards which I could get three of and then ask a friend/someone to build them up to plans and then bung in a suitable power supply.
 
#11
SamV said:
Trouble with 100db/1w/1m drivers is that they are not usually equipped with handle moisture and are usually expensive and heavy. Though yes 100db would be awesome.

I have had a look at the AMP9, but I'm not an electrical person, and my solder skills are a bit beginner, ideally I just I was hoping to find links to a 2x80w rms @4ohm amp boards which I could get three of and then ask a friend/someone to build them up to plans and then bung in a suitable power supply.
Click to expand...

For PA and DJ use, there are a few efficient lightweight models with neo magnets. These are normally made weatherized for outdoor use. They're expensive, but so are extra-light recumbent bike components. 😉

On AMP9, there's a "basic" edition for easier soldering. If one were to start with the resistors, and use flux for ease, then it might be fairly easy to assemble.
 
#13
SamV said:
Any links for these 100db beasts?
Click to expand...

Here's some examples.
They have two specs in common:
#1 Neodymium magnet (lightweight and powerful)
#2 Prosound (dj) and/or bass guitar application

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=294-680
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=290-518
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-593
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=294-678

These are just an example of the category. I didn't check fitness of application because I think that you'll be shopping closer to home. Some Neodymium Prosound drivers are available in 4 ohms, good for Tripath, and the inductors for crossover are half size that way (slightly lighter weight crossover if using 4 ohm).
If compared to weight/vs price examples on bike components, the prices are a bargain. Anyway, its fun shopping.

Here is an example of a popular weatherproofing compound for prosound/dj use: http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=340-512

I have that odd, yet familar, feeling that I'm getting in over my head again. . . 😉
 
#15
Hoffmans Iron Law

Hi Sam,

Hoffman’s iron law relates to all speakers.
high efficiency, small enclosure, low cutoff, you can only pick two.

Maybe a large lightweight enclosure is what you need.

Decide on the largest "box" you could have, then you will need to choose low cutoff or efficiency. Once this choice is made it is time to look at drivers and enclosure types.

I am also a keen bike commuter. Can I ask when you would use this marvelous bike blaster?

Regards Philip
 
#16
Hmmm maybe I need to read up on Hoffmans law.

The sound systems get used on the monthly critical mass rides, the london freewheel, demostrations, music video shoots as playback, music festivals in the London parks and other big bike events. That particular system is currently in parts waiting to be rebuilt, I'm gonna be nicking her parts for the new system which is slightly wider but more efficient and a couple of kg less. Then I'll build up again.
 
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