TDA2005 schematic problem - Page 1
Forum section: electronics / general

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 18, 2011, 12:21:47 am
content: Hi all. I have built this circuit many times, and I have had no success.I've been powering it from a 12v 8Ah Lead-Acid battery & It will produce sound, but only when its all the way up.. but it's SUPER distorted and extremely quiet. I also have the TDA2005M attached to a semi-large heatsink. Any help??? am I getting the schematic wrong in any way?

author: IanB
author_rank: Super Contributor
timestamp: December 18, 2011, 12:30:09 am
content: What kind of input are you feeding it? Maybe your input signal is too weak?

author: Unknown
author_rank: Unknown
timestamp: December 18, 2011, 12:48:57 am
content: What exactly do you mean by you have built this many times?Could it be a damaged TDA?

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 18, 2011, 06:03:23 am
content: Im feeding in direct input from my ipod.. its application in mainly for car stereos.. so i think my input should be fine. -- and by many times i mean as in 2 different configurations. it never gets crazy hot.. just barely warm, which lets me know that nothing with the chip itself is bad. ill post a pic of ?the built up circuit tomorrow. do you see the what appears to be not-connect trace it the schematic that runs through another wire? Im not sure if it is or not. that may be my problem..

author: Zero999
author_rank: Super Contributor
timestamp: December 18, 2011, 10:50:29 am
content: Quote from: ElectronicFanatic1 on December 18, 2011, 06:03:23 amNo it doesn't, you could still have a faulty chip.QuoteIs the PCB layout similar to the example given on the data sheet?

author: Psi
author_rank: Super Contributor
timestamp: December 18, 2011, 10:59:35 am
content: i've corrected a few bits that may have been confusing.

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 18, 2011, 10:26:24 pm
content: Quote from: Hero999 on December 18, 2011, 10:50:29 amcurrently it is only breadboarded. And I have tried building it the way you have corrected it, but I seem to get worse result with that, receiving no sound at all. Should I do something different with the TDA?

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 18, 2011, 10:38:20 pm
content: Here's the video:

author: Neganur
author_rank: Unknown
timestamp: December 19, 2011, 01:10:27 am
content: The circuit should get reasonably warm with that gain (50 dB) setting.Don't crank up the volume on the iPod, the TDA2005 in bridge configuration will blow the speaker away.Have someone else check the breadboard connections.Is the speaker OK?Do you really have your supply voltages where they should be?Is the battery flat? (the TDA requires quite some current)I don't recommend to use the battery while prototyping, it will kill stuff happily when you short circuit anything by accident.Breadboard connections can be annoying. Tin those stranded wires. Also, the Vs+ solder joint at the TDA looks cold.Missing GND somewhere?

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 19, 2011, 02:22:15 am
content: I have tried multiple speakers, all with the same results.. and I suppose the only thing it come be is the chip itself. so I guess its time to switch that one.. and the battery is just fine.. I an draw well over 12+ amps in spurts, and easily anything lower than that for hours.

author: RCMR
author_rank: Frequent Contributor
timestamp: December 19, 2011, 02:36:54 am
content: I'm not familiar with the TDA2005 but that doesn't look like a practical bridge amplifier to me.It seems to rely on feeding the output of the top amp into the inverting input of the second amp -- which would potentially introduce all sorts of instability issues due to *unwanted* phase shifting (ie: not just 180 degrees) between the two signal paths.I'm picking that there's a parasitic oscillation going on there -- throw a scope on it or (if you don't have a scope) use your DVM on AC with an 0.1uF coupling cap to see if there is any parasitic oscillation across the speaker when no/low signal levels are applied.

author: amspire
author_rank: Super Contributor
timestamp: December 19, 2011, 02:58:38 am
content: Quote from: RCMR on December 19, 2011, 02:36:54 amThe circuit is correct - it is the one suggested by the manufacturer. Stability shouldn't be a huge problem as the first amp should not be affected by the second amp much.I would start checking the DC volts on the outputs to battery negative with no signal and no speaker attached - both should be half the battery voltage and there shouldn't be much DC voltage between the the first output and the second.Measure the gain of the first stage. The AV output to ground volts should be almost 100x the voltage in. If it is not, there are only a few parts that could be involved - the IC, C1, C5, R2, C6 and R5.That will be a start.Richard.

author: Psi
author_rank: Super Contributor
timestamp: December 19, 2011, 08:53:11 am
content: Breadboard can be quite annoying, its easy to make mistakes and cover them up with other components.It's also prone to bad connections.

author: Zero999
author_rank: Super Contributor
timestamp: December 19, 2011, 09:25:01 pm
content: You should check all the connections for continuity.Anther problem with breadboards is parasitic capacitance and inductance, although not usually a problem at audio frequencies, it's possible some unintended capacitance is causing instability.