amp for bike stereo - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st February 2008, 09:30 PM   #1
notrobb is offline notrobb  Canada
diyAudio Member
 
Join Date: Feb 2008
Default amp for bike stereo

Hi, I'm brand new here, but searched around and didn't see this question anywhere else, so here goes..

I'm wondering if anyone can recommend an amp for me to build that would be good for a bicycle stereo, i guess like a diy sonic impact t-amp, but i'd rather build it myself (not because i'm cheap, it's really more of a pride thing)

- stereo output (from what i understand i might build 2 identical amps?)
- portable (ideally fit into a cigarette tin, which is slightly larger than an altoids tin)
- battery powered (might convert to solar eventually)
- output to 2 small computer speakers that will be mounted on my bike
- input from my ipod

I'm fairly new to electronics, so the theory is still hazy, but i'm learning. And i can follow schematics and instructions well (i just built an APC from scratch).

Thanks in advance for any input!
  Reply With Quote
Old 21st February 2008, 10:50 PM   #2
Bearman is offline Bearman  United States
diyAudio Member
 
Join Date: Apr 2005
Location: Utah
You might try a small Amp3 from the 41hz website. They are basically a better sounding T amp that runs on 12 volts. Using a 12v 3amp SLA battery should last for a couple of days.

At Jans site also, he has a AMP9 that is 4 channels that can run on 12v too. A bit higher wattage amp, so the battery life is not as long. Thay are all class D amps so the efficiency is much higher than the chipamps are.

They both require soldering small SMD resistors and caps so they do need a steady hand and a pair of tweesers and a soldering iron that has a small tip.

Good forum for ideas and help over there too.
  Reply With Quote
Old 25th February 2008, 05:31 PM   #3
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
What kind of bicycle is it, and is "lightweight" a primary factor?

Edit: I meant to ask if its the sort of bike that zooms over rocks, or if its the sort of bike that's expected to climb tall pavement hills at near-racing speeds?
  Reply With Quote
Old 25th February 2008, 05:36 PM   #4
diyAudio Member
 
xiphmont's Avatar
 
Join Date: Apr 2007
Send a message via AIM to xiphmont
Quote:
Originally posted by danielwritesbac
What kind of bicycle is it, and is "lightweight" a primary factor?

Edit: I meant to ask if its the sort of bike that zooms over rocks, or if its the sort of bike that's expected to climb tall pavement hills at near-racing speeds?

... or are we talking 'Gold Wing'? :-) OK, I know we're not, those come with surround stereos, but some other big bike...

[edit: oop, never mind, he did eventually say 'bicycle'.]
__________________
"My name's Monty, and I break things."
"Hello, Monty!"
  Reply With Quote
Old 25th February 2008, 06:05 PM   #5
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Unlike the motorcycle, the bicycle has limited flywheel capacity, which is the rear wheel. With the cyclist (even if skinny), there's already an insufficient flywheel. This causes the propulsion to be in "micro-pulses" so that the weight of the bicycle is a limiting factor on its speed.

That's why I was thinking that a smallest size canvas handlebar bag could contain the amplifier as well as serve for speaker enclosure. There's a little "can shape" model from SunLite, and it has round, speaker-size, nylon canvas ends, as well as a sturdy hard plastic sheet that covers the insides, except for the ends. Ah! A speaker enclosure.

One could fetch a pair of "grandma kitchen" type portable plastic radios from the local thrift store, and remove the hyper-efficient speaker drivers. Those are about 3 inches, 8 ohms, with over 100db efficiency (typical). They're better than usual computer speakers. These could be somewhat waterproofed with polyurethane for furniture, or the prosound speaker waterproofing compound.

A disc of super-light waterproof material could be made to assist in gluing the now water-resistant speaker drivers inside the ends of the above handlebar bag. Its cutout for the drivers would be slightly smaller than the drivers so that it could press them into place. Siliconized construction adhesive (nail pro) is strong enough to hold the described disc in place (which holds the speakers in place). That will keep the backwave from eating up the bass response.

Then a miniature class-D amplifier could run this pair of speakers; however, one would want to increase its efficiency by selecting input filter caps (very small polyester) that are able to remove bass that couldn't come out of that size speakers.

Some of the 1 to 3 watt class-D are able for sufficient power on 3x AA batteries, and could run all day long with more than enough volume, considering 103db speaker as a resource. Those amplifiers will be over at the Class D forum.
  Reply With Quote
Old 25th February 2008, 06:15 PM   #6
notrobb is offline notrobb  Canada
diyAudio Member
 
Join Date: Feb 2008
well, i ride a fairly light roadbike. mostly around the city and not in a racing sort of way. a pocket sized amp is definitly what i'm hoping for.

i'm considering doing a CMOY in a tin and getting some cheap battery powered computer speakers. it's more for me to hear music than to be blasting it to the whole block anyway.....
  Reply With Quote
Old 25th February 2008, 06:15 PM   #7
notrobb is offline notrobb  Canada
diyAudio Member
 
Join Date: Feb 2008
thanks for the advice daniel,
that sounds like the sort of setup i'm going to shoot for.
R
  Reply With Quote
Old 25th February 2008, 07:19 PM   #8
diyAudio Member
 
xiphmont's Avatar
 
Join Date: Apr 2007
Send a message via AIM to xiphmont
Batteryspace.com semi-regularly has sales on LiIon + charger combos. I don't think they have a sale going on now, but that's how I got the batteries for the lights on my bike. 5g per watt-hour... mmm.... I can run low beams for a whole day for only 250g. :-)
__________________
"My name's Monty, and I break things."
"Hello, Monty!"
  Reply With Quote
Old 25th February 2008, 09:17 PM   #9
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
On the Oklahoma Freewheel (amost 500 miles with no outlets available), I take a Kodak digital camera (2gb card), an RCA Pearl, a Serfas 8 led light, and then some. All of these can work with rechargable (usually), lithium, or standard--And, if the music quits, you can get back to the music fast with a quick stop at the Quick Shop for ordinary size batteries.

Or, if using lIon, you could plug it into the nearest electrical outlet and wait. . . and wait. . . This is usually fine for the mountain bike, because they usually return to home base, and that's a more seemly location for it to nurse upon electrical outlets.

However, on the road bike, travel bike, and new turbo-hybrid (traditional Dutch comfort on an otherwise racing bike), they follow a $1 (us) per gram performance to weight ratio, in general. They also cover long distances, usually 80 miles with very little effort. Although the effort involved is mostly reliant on a good fit (like good clothes fit), still any increase in the effort could decrease its range.
Remember, these bicycles repeatedly accelerate rather than use a flywheel, so the machine weight is a vital consideration when designing an audio system for it.

So, that's why I suggested the miniature (postage stamp size) Class-d amplifier (small batteries) and hyper-efficient speakers.

Some athletes maintain 2 bicycles, both with an identical fit, but one is much less efficient for extra exercise (the workout bike). So, if the audio system is for a "workout bike" then by all means tape a hi-fi to it.

P.S. For a small Class-D amp, its possible to cause it a slight power boost by running the speakers as a capacitive load. Perhaps a 10v, 1000uf cap or smaller (its small anyway) in series with the speakers, could help. Polarity is usually the same as connecting speakers in series. Capacitive loads can perform a soft-clip instead of the usual Class-D hard clip. So, while that isn't really more power, it will sound like it.
That's good for an exuberant moment with the Ipod. Specifically, I mention this because some MP3 players have a terrible sound at the EQ Flat setting, but the other settings may cause a miniature amplifier to clip. If your source has the variable 5 band EQ instead of the fixed selections, then you probably don't need the output cap. Otherwise, its worth a try.
  Reply With Quote
Old 4th March 2008, 03:13 PM   #10
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Silicon Valley, California
Quote:
Originally posted by notrobb
well, i ride a fairly light roadbike. mostly around the city and not in a racing sort of way.
Safety Nazi Say:
DON'T RIDE YOUR BIKE IN TRAFFIC WHILE PLAYING MUSIC. If you look it up, you'll find that it's also illegal (for a good reason). Come on, you're extra vulnerable as it is on a bike, so why add to the distractions?
Carry on...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My Russian Bike Zen Mod The Lounge 52 12th September 2008 01:21 PM
Motor bike parked gmphadte The Lounge 3 31st July 2008 06:02 AM
15 mile commuting bike ash_dac The Lounge 92 21st October 2007 05:00 PM
New bike? (Must have Campag Record) EC8010 The Lounge 35 17th July 2006 05:43 AM
My stereo bike project HELP!! amp problems.. the bass master Car Audio 0 7th February 2004 05:33 PM


New To Site? Need Help?

All times are GMT. The time now is 03:13 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2