Class D in a vintage car

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.

Zster

Member
2016-06-23 12:25 pm
Hi Guys

I know i shoud maybe go in the car section but didn't find anything suitable there. So here goes:

I am restoring an old car for daily driver purpose. I'm not a fan of modern car headunits and i have very few demands for music in the car.

I have been thinking about some kind of Class D amplifier, mainly because of price vs. performance and small footprint.

This can be easily hidden in a classic car opposed to the difficulties i meet with typical car amplifiers.

I have been reading about this kind of appliance and i understand that if i buy a plug and play unit rated for ~15V i can get it to work in a car at ~12V but not expect the advertised power output.

Is it possible to use a Step Up converter (this kind of stuff is brand new to me) to gain some more juice?
Or should i buy a bigger amplifier to get the desired effect at the voltage i have? I mean if i plan on 2x20W and gets 2x12W. if i buy 2x50W, do i then have something over 20W at the same voltage?

Sorry if this is complete off the charts. I think my problem is that this kind of stuff has a steep learning curve, but on the other hand i am a fast learner :D
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Without actually having searched, I somehow doubt you would get an off the shelf step up convertor of suitable current rating for changing 12 to 15 volts.

The difference in output between running an amp on 12 volts vs 15 volts would not be noticed. Even a doubling of power output would only increase the perceived maximum level by a small amount, its nothing like twice as loud as you might imagine thanks to the logarithmic way are hearing works.

A car engine (alternator) that's running will be providing anywhere from around 13.5 volts when hot to perhaps as much as 16 volts for a few seconds after a very cold start.
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
I've no experience of any of those tbh and so wouldn't like to say yay or nay.

You might be best asking about the step up convertor in a new thread (power supplies forum) and state what you want (vin and range of vout and what it is expected to power) and see if anyone has any recommendations.
 
Most Class-D boards you find that will run from 12V will give roughly the same output as any modern headunit. Don't get hung up on the advertised power output. 20W isn't equal to 20W if one rating is given at 10% THD and the other at 1% THD.

If you need more power than "headunit" level, you need more voltage. A non-isolated boost converter can cause noise problems though.
 
Hi,

There must be loads of class D amplifiers specifically designed
for car use, just like there are loads of car chip amplifiers.

In both cases anything specified to run from 12V to 15V is
nearly always designed towards ICE and is 4 ohm capable.

FWIW voltage in cars is 13.8 VDC typically, without heavy loads.

Just like chip amps expect about 20W 4 ohms from a BTL class D.

rgds, sreten.
 

phase

Member
2004-10-04 11:59 pm
I like the hidden plan, are you planning on using a Bluetooth dac to connect to a phone, for music playback?
My experience with most vintage cars is that you can't hear the stereo very much regardless without maybe 100 watts per door. While moving anyways...
 

dogshome

Member
2010-07-17 8:15 pm
My Saab 9-5 has a multiway Harmon Karden amp built in. It has a step up PSU and filters but is class B.

I like class D and am currently listening on bluetooth via a TPA3116 amp, Morel mids and tweeters and a JBL sub. The motor has JBL speakers to replace the (pretty reasonable) Saab kit, a Kenwood single channel 600W class D amp on the sub.

If you want class D power with internal step up, look here :)

Bass Face 4 Ch Four Channel Black Mini Class-D Digital Car Speaker Amplifier Amp 0617529407779 | eBay
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.