Hey people, this is my version of this amp. It's two of these modules bridged in a way that second TDA module pin 3 (signal+) is connected ground and the input is taken from the output of the first module via 22k resistor and going to pin 2 of the second module (signal-). Its tested and its working fine. If you need PCB layout or any info please msg me, the PCB is made in program "Sprint Layout ver5"
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Hi and thanks. This is just a first pcb I made for testing and it worked great on first start. Still did not measured anything, but I'm wondering if this method would give some close measurements, if I put a 50Hz signal, then measure the voltage and the current that goes to the speaker and just multiply....
I have a car subwoofer 400W nominal and 1400W peak 2 x 4 ohm coils, on 4 ohms and with 300VA toroidal transformer 30-0-30V this amp shakes the roof on my garage
. I will try the 36-0-36V, that would give +-50V DC but its also 300VA, I have to get a larger transformator to test it completely. The sound is very clear, did not had any problems adjusting the 6.8 ohm resistor.Well, thats exactly what I built before this one. Two modules with TDA7293 in Master-Slave so they can push more current and then those two bridged. That should give 400 watts into 4 ohms, and the sound is amazingly clear, no hum at all. I built a mainboard with the power supply and modules can be inserted onto it, there is a place for preamp with Bass-Treble regulation. Here's a pic, If ya need any help just ask
An externally hosted image should be here but it was not working when we last tested it.
Nice work kebbz, and i can see that you can also confirm that this amp punches some REAL power, also you have the option of adding more Transistors like i posted.
I am however a bit disappointed in the "forum", i would have thought that someone would have replicated "my" amp (many others have made the design before me) much earlier than this, but i hope kebbz can do some measurements on it, i still haven't gotten around to it, i been making many other things over the years.
I will however make my 4x 7293 sometime in the next 6 months because i need it to finish my B&O project after i build my subwoofer to it, depending on if my normal 2x 7294 will work fine with some resistors on the speakers.
The current project:
http://www.facebook.com/media/set/?...073741825.100004867482301&type=1&l=0b484a5e9d
NOTE: Don't need facebook account since it is public.
EDIT: Still using my "ATX" amp in the TV, did not add a picture of it inside in the album.
EDIT: and kebbz the amp is 2 Ohm stable, and will also drive 1 Ohm and lower if you limit volume, add 1 more set of Transistors and you should have 1 Ohm Stable and ALOT of power
I am however a bit disappointed in the "forum", i would have thought that someone would have replicated "my" amp (many others have made the design before me) much earlier than this, but i hope kebbz can do some measurements on it, i still haven't gotten around to it, i been making many other things over the years.
I will however make my 4x 7293 sometime in the next 6 months because i need it to finish my B&O project after i build my subwoofer to it, depending on if my normal 2x 7294 will work fine with some resistors on the speakers.
The current project:
http://www.facebook.com/media/set/?...073741825.100004867482301&type=1&l=0b484a5e9d
NOTE: Don't need facebook account since it is public.
EDIT: Still using my "ATX" amp in the TV, did not add a picture of it inside in the album.
EDIT: and kebbz the amp is 2 Ohm stable, and will also drive 1 Ohm and lower if you limit volume
, add 1 more set of Transistors and you should have 1 Ohm Stable and ALOT of power
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I bought my TDA7294's in ~1999, bought some PCB's last year and some 2SC5200 and 2SA1946 last month. I'm picking up speed...
(The 7294's were for a failed high efficiency project with dual supply voltages).
I bought my TDA7294's in ~1999, bought some PCB's last year and some 2SC5200 and 2SA1946 last month. I'm picking up speed...
(The 7294's were for a failed high efficiency project with dual supply voltages).
Nice to see more, have you put it together then?
Hey, I did some measurements today. I put a signal generator program to my PC, generated 50Hz signal and connected the amp. Put the multimerer on peak hold and first I measured the voltage and got 37 volts on the output. Then I measured the current that flows into the speaker and I got 6.15 Amps. If P=U*I then I had 227.55 Watts. Please nothe that my toriod transformer is only 300VA and I did not pushed the input signal further cause I was afraid that something is gonna explode or the roof of my garage will collapse Oh yes, the amp supply voltage is DC +-50V, and Im sure with larger transformator this thing can deliver more power.
Oh yes, the amp supply voltage is DC +-50V, and Im sure with larger transformator this thing can deliver more power.is that 37V a peak value, i.e. 37Vpk?Hey, I did some measurements today. I put a signal generator program to my PC, generated 50Hz signal and connected the amp. Put the multimerer on peak hold and first I measured the voltage and got 37 volts on the output. Then I measured the current that flows into the speaker and I got 6.15 Amps. If P=U*I then I had 227.55 Watts. Please nothe that my toriod transformer is only 300VA and I did not pushed the input signal further cause I was afraid that something is gonna explode or the roof of my garage will collapse
Is that current of 6.15 Amps a peak value, i.e. 6.15Apk?
Then Maximum power when feeding a resistive load is 1/2 * Vpk * Ipk = 113W
BTW, something is in error:
6.15Apk into 4r0 is 24.6Vpk (not 37Vpk).
6.15Vac sinewave into 4r0 is 34.78Vpk (not 37Vpk).
Hi, well that was just a rough measurement. I have first measured the voltage across the speaker, then disconnected everything and after that measured the amps that are going to the speaker. The error must be brcause the input signal was slightly different in these two separate measurements. Yes I turned on the peak hold on the multimeter but I did not even had to because it was a sinus signal and multimeter was showing constant values. Can you please explain the 1/2 in the formula? Because my opinion is that if we have a constant sinus signal it should be just pure P=U*I. It was not a soundtrack that will cause values to jump around, but real steady values with slear sound coming out from the speaker. Sorry, im not a real expert in this field
power comes from the original DC conditions when only batteries existed to generate non varying electrical current.
P=Idc*Vdc=Idc^2*Rload=Vdc^2/Rload.
Then they invented AC generators and needed to find a way to define the heating effect of the AC current that was exactly equivalent to the correct and accurate method adopted for DC current.
They came up with:
P=Irms*Vrms=Irms^2*Rload=Vrms^2/Rload.
If you can measure the rms value of the current and/or voltage acurrately then the formula is just as good as the original DC version.
For a sinewave:
Irms = Ipk/sqrt(2)
Vrms=Vpk/sqrt(2)
Now go and stick those equivalences into your power formula and see where the 1/2 comes from.
P=Idc*Vdc=Idc^2*Rload=Vdc^2/Rload.
Then they invented AC generators and needed to find a way to define the heating effect of the AC current that was exactly equivalent to the correct and accurate method adopted for DC current.
They came up with:
P=Irms*Vrms=Irms^2*Rload=Vrms^2/Rload.
If you can measure the rms value of the current and/or voltage acurrately then the formula is just as good as the original DC version.
For a sinewave:
Irms = Ipk/sqrt(2)
Vrms=Vpk/sqrt(2)
Now go and stick those equivalences into your power formula and see where the 1/2 comes from.
Most multi-meters, particularly the hand held, measure average.
This is OK for DC
For AC the average is scaled up to give a reading that is equivalent to a sinewave rms.
BUT, it is NOT an rms reading measurement.
Further, the average only holds true for a very narrow range of frequency.
You need to look at the specification for the multi-meter.
You may find that the multi-meter has acceptable tolerance for frequencies from 50Hz to 400Hz. Note also that AC accuracy is not as good as DC accuracy.
The few multi-meters that do measure rms usually do so for a much wider frequency range, some go as wide as 1Hz to 1MHz and more.
This is OK for DC
For AC the average is scaled up to give a reading that is equivalent to a sinewave rms.
BUT, it is NOT an rms reading measurement.
Further, the average only holds true for a very narrow range of frequency.
You need to look at the specification for the multi-meter.
You may find that the multi-meter has acceptable tolerance for frequencies from 50Hz to 400Hz. Note also that AC accuracy is not as good as DC accuracy.
The few multi-meters that do measure rms usually do so for a much wider frequency range, some go as wide as 1Hz to 1MHz and more.