Class D Amp for 28v (for a 24v lorry)? |
Post Reply |
Author | |
dunkh
Registered User Joined: 03 May 2016 Status: Offline Points: 17 |
Post Options
Thanks(0)
Posted: 09 May 2016 at 1:28am |
Im converting a horsebox into a live in vehicle and would like to have a small sound system I can place outside the lorry. Probably 2 small speakers. I would like to use a Class D amp as the efficiency is good. Something over 20w per channel. However most are rated up to 24v. The supply would be 2x 12v lead acid batteries which are more like 28v. Are there any class D chips out there that can cope? Or perhaps a more traditional class A/B chip amp? Or should I get a 24v to 12v dc converter and use that?
|
|
jannes
Registered User Joined: 30 August 2013 Status: Offline Points: 17 |
Post Options
Thanks(0)
|
Both the STA508 and TK2050 will work with your supply voltage.
|
|
dunkh
Registered User Joined: 03 May 2016 Status: Offline Points: 17 |
Post Options
Thanks(0)
|
Nice one, the TK2050 max is 28v so might die is left connected whilst charging the battery but the STA508 looks ideal. 50w a channel and 34v max. £9 too!
|
|
studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3863 |
Post Options
Thanks(0)
|
Since the power output of those amps is directly related to the rail voltage, you stand to lose a few watts as the batteries discharge. This might not be too much of an issue, but you could avoid it - and any potential over-voltage issues as well - by using a "buck/boost regulator" board, commonly available on eBay. These take in a wide range of supply voltages, usually 5 to 30v, and keep their output voltage set steady at some point within that range. This would ensure your amps were always seeing a solid 24v regardless of what the battery or charging system was doing.
|
|
Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
|
|
Sweex
New Member Joined: 10 May 2016 Status: Offline Points: 5 |
Post Options
Thanks(0)
|
The downside is that the often only has an effiency of 80% och less :/. i have one that i mesured to an effiency of 62%
|
|
studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3863 |
Post Options
Thanks(0)
|
True that, it's a tradeoff between power, sound quality and battery life. The efficiency goes up with output current though, so if you're powering multiple amps from one board that figure can be improved.
I'm of the opinion that direct battery power can be quite "spongy" and poorly regulated, depending on your battery's condition, state of charge and your wiring, and that's generally not a good thing for power amplifiers - they tend to work best when given a very solid power supply that doesn't change voltage much under load. So from that viewpoint, some form of regulation is a must. But, if your goal was maximum battery life and you were prepared sacrifice a little volume to achieve it, I suppose a regulator would be unnecessary.
|
|
Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
|
|
Post Reply | |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |