Hey all!
My name is Rob, I'm an engineering student in Massachusetts. I've been lurking on this forum for a while now and I thought that I would finally put together an account.
I'm putting together a head unit for my car and I'm trying to find the right chip to use. I built a passive preamp based off of a PT2322 chip and I'm currently using a crappy 12v amp I had lying round, but I'd like to upgrade to something nice. The only thing keeping me from doing so is the voltage I'm working from, 14.4v. I haven't been able to find a decent chip to run ~15w rms without a fairly high THD, so I haven't made much progress lately.
I recently stumbled upon some fairly cheap DC-DC boosters on eBay while I was looking for LED drivers, which got me thinking about the possibility of running higher voltages using a booster. I found a reasonable chip based on the higher voltage range, and it seems like my issue is solved.
To cut to the chase, my question is this: would I run into any issues using a DC to DC step up module like this with a chip amp like the TDA7575B?
My name is Rob, I'm an engineering student in Massachusetts. I've been lurking on this forum for a while now and I thought that I would finally put together an account.
I'm putting together a head unit for my car and I'm trying to find the right chip to use. I built a passive preamp based off of a PT2322 chip and I'm currently using a crappy 12v amp I had lying round, but I'd like to upgrade to something nice. The only thing keeping me from doing so is the voltage I'm working from, 14.4v. I haven't been able to find a decent chip to run ~15w rms without a fairly high THD, so I haven't made much progress lately.
I recently stumbled upon some fairly cheap DC-DC boosters on eBay while I was looking for LED drivers, which got me thinking about the possibility of running higher voltages using a booster. I found a reasonable chip based on the higher voltage range, and it seems like my issue is solved.
To cut to the chase, my question is this: would I run into any issues using a DC to DC step up module like this with a chip amp like the TDA7575B?
Have you looked at TDA8566? It can do your wattage at 14.4V provided you've a low enough impedance pair of speakers. Also sounds excellent - I have a schematic here : Possibly the most frugal high-end sounding amp? - Page 2
I use eBay DC step up converters all the time for audio. They can work well but you may need some additional filtering with CRCRC or maybe CRCRLC and bypass C with low ESR ceramics. Some may balk at the larger capacitances. But basically you need to test it and measure noise spectrum to make sure it's not adding noise.
14V dynamo, bridge-tied, can directly give 10V Sine rms or 25W in 4 Ohms, minus losses.
There are whole families of chips which do about as good as possible under these limits. 18W @ 4r @1% is routine.
*ALL* higher-power Car Audio amps use DC up-converters. Get a dead PyleBuster 900W, open it up, rough-trace the guts. There is a +/25V audio power amp, and a switching power supply which buzzes the 12V battery up to +/-25V or whatever the goal is for that model.
This is *really* something better bought than DIY-ed. Aside from all the fun of designing (and burning-up) large audio amps, there is the learning-hill for up-converters, and then integrating the two without weird squeals, and custom heatsinking which stays just cool enough in a hot trunk.
> I'm an engineering student
Well, go for it *as a lesson*. I'd still go to the boom-car store (or your friends' garages: many "dead" amps aren't) and buy a hunk of fins to fill your car pending your super-amp's final check-out.
There are whole families of chips which do about as good as possible under these limits. 18W @ 4r @1% is routine.
*ALL* higher-power Car Audio amps use DC up-converters. Get a dead PyleBuster 900W, open it up, rough-trace the guts. There is a +/25V audio power amp, and a switching power supply which buzzes the 12V battery up to +/-25V or whatever the goal is for that model.
This is *really* something better bought than DIY-ed. Aside from all the fun of designing (and burning-up) large audio amps, there is the learning-hill for up-converters, and then integrating the two without weird squeals, and custom heatsinking which stays just cool enough in a hot trunk.
> I'm an engineering student
Well, go for it *as a lesson*. I'd still go to the boom-car store (or your friends' garages: many "dead" amps aren't) and buy a hunk of fins to fill your car pending your super-amp's final check-out.
abraxalito, I had previously been turned away from that chip by the class b architecture and the high listed THD, but after looking through your writing on the chip I think I'll give the chip a try. Thank you for putting together such a rigorous study into that particular chip and documenting it all!
For now I think I'll just try to run off of 14v, looks like the chip can take 18v if I decide to try to up the wattage later. I can also always just get some more sensitive or lower impedance speakers down the line.
PRR, I think I'll save the lesson for a bit later. If I do decide to try a DC up-converter I'll just pull it from a dead amp
For now I think I'll just try to run off of 14v, looks like the chip can take 18v if I decide to try to up the wattage later. I can also always just get some more sensitive or lower impedance speakers down the line.
PRR, I think I'll save the lesson for a bit later. If I do decide to try a DC up-converter I'll just pull it from a dead amp
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.