Hi folks,
The past weeks I've been cursing the paint off my ceiling trying to figure out what's wrong with my designs. I've even had a thread about a TDA2009 powered amp overheating and being noisy. Well I still can't figure the problem out, but I'm fairly convinced it has to do with me running the amps off of the same DC rail and probably/possibly the way I've been mixing the L and R channels to obtain a third for the subwoofer amp. Since I need this ASAP, I've ditched the TDA 2009 and used the innards of a cheapo PC speaker I had on hand to use as the stereo section, and it works fine aside from very light noise from the PC (if anyone has an idea on how to filter this, that's welcome too though it'll be okay as it is if it's too much a hassle).
Thusly I'd like your advice on the following. I'd need to run a stereo amp and a mono amp off of the same DC rail, and use a single stereo input to drive them in a 2.1 setup. I've attached a blank pic with connector symbols named appropriately. Could anyone suggest a way to wire this up?
Basically I have two amplifiers built based on the datasheet application schematics. I'd like to run these off of a PC's 12v powersupply rail, and mix a stereo signal to the stereo input of one amp, while tapping them both for a combined mono signal for the mono amp. I'm looking for suggestions on how to achieve this. I'd like to keep this as simple as possible, preferrably with all passive components. Any help is appreciated, THANKS!
GND is pin 2 on all connectors!
PS: I've also attached a pic of how I have them wired up now, which actually almost works, except the LA4460 keeps giving a rythmic mid-low frequency thumping and of course distorts as hell, the latter certainly because I've not wired a volume control in for the LA4460. Basically power comes to the stereo amp from the PC power rail, and is tapped right after the filter cap on the board, to go to the LA4460. Signals go straight to the stereo amp, where each channel is tapped through a 4k7 resistor, and grounds are joined and tapped through a 200k resistor, thus going to the LA4460.
The past weeks I've been cursing the paint off my ceiling trying to figure out what's wrong with my designs. I've even had a thread about a TDA2009 powered amp overheating and being noisy. Well I still can't figure the problem out, but I'm fairly convinced it has to do with me running the amps off of the same DC rail and probably/possibly the way I've been mixing the L and R channels to obtain a third for the subwoofer amp. Since I need this ASAP, I've ditched the TDA 2009 and used the innards of a cheapo PC speaker I had on hand to use as the stereo section, and it works fine aside from very light noise from the PC (if anyone has an idea on how to filter this, that's welcome too though it'll be okay as it is if it's too much a hassle).
Thusly I'd like your advice on the following. I'd need to run a stereo amp and a mono amp off of the same DC rail, and use a single stereo input to drive them in a 2.1 setup. I've attached a blank pic with connector symbols named appropriately. Could anyone suggest a way to wire this up?
Basically I have two amplifiers built based on the datasheet application schematics. I'd like to run these off of a PC's 12v powersupply rail, and mix a stereo signal to the stereo input of one amp, while tapping them both for a combined mono signal for the mono amp. I'm looking for suggestions on how to achieve this. I'd like to keep this as simple as possible, preferrably with all passive components. Any help is appreciated, THANKS!
GND is pin 2 on all connectors!
PS: I've also attached a pic of how I have them wired up now, which actually almost works, except the LA4460 keeps giving a rythmic mid-low frequency thumping and of course distorts as hell, the latter certainly because I've not wired a volume control in for the LA4460. Basically power comes to the stereo amp from the PC power rail, and is tapped right after the filter cap on the board, to go to the LA4460. Signals go straight to the stereo amp, where each channel is tapped through a 4k7 resistor, and grounds are joined and tapped through a 200k resistor, thus going to the LA4460.