| StratoFan |
| Hi! I'm newbie here from Hungary. I would like to talk about TDA7293 or 7294S. I like to build paralel/bridge amp with these chips, but I'm not sure which the best one. If somebody tested, please tell me about. Which one have the best sound, best stability, how much the max output power, how much the max +-Vs. On the datasheet why no 22uF capacitor serial with 680 ohm resistor when bridged (on pin #2)? Can I connect stabilized 24V to the pin #5 (via resistor) for clipping led? :confused: |
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| StratoFan |
Now I have a plan for this idea:
http://rentahost.net/stratofan/pdf/..._TDA_Br_Par.PDF
I would like to use pin5 of 7293 (clip detector). Is my plan is good on schematic with 24V and 4.7K resistors? Not exactly clear how do I mean "RL=10Kohm to 5V" about clip detector on the datasheet of 7293 (page 3).
Another question, on the datasheet of 7294S the - + inputs of slave IC vired to the 0V (page 10), but on the datasheet of 7293 vired these inputs to the -Vs (page 10). I think the 7294S datasheet is better for parallel...
If somebody think how better, please tell me! :cannotbe: |
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| Dxvideo |
| On the schematic I saw 400W x 2... Does it really give that power? Two TDA7493 in parallel in ST's datasheet is available but output power doesnt given. |
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| StratoFan |
| I'm not sure about output power yet. I think with four 7293 I gan get about 350-400W/channel. Marshall Mode Four is same config for 350W. On bridge, the ST datasheet said 150W on 8 Ohm +-25Vs, and 170W on 16 Ohm +-35Vs. I think I can do double power with parallel mode on half speaker impedance. |
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| Dxvideo |
| I guess, parallel mode gives 200W to 4 ohm load with two devices. However, as I heard before, we cannot apply four devices in parallel for TDA74xx. But its possible to apply two parallel devices in bridge. |
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| StratoFan |
Yes, I heard same. If true what I heard, max three devices can be connected to parallel (one of them master, two slaves). But the speaker impedance must be lower if I want to get more power in parallel mode.
Somebody else have opinion about the schamatic? I looking for schamatic of PWM fan speed controller depending on the heat of heatshink. |
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| Dxvideo |
It's not PWM but it works fine (I tried). I hope it helps u... All diodes 1N4004.
Note: diodes have to attached to the same heatsink with output transistors/ics... |
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| StratoFan |
| Thank you! This is really simple. Is this switch on/off the fan, or controll the speed up/down if required? |
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| StratoFan |
Nisbeth sorry I can't understand these pages :bawling:
Dxvideo, as I see the circuit switch on/off the fan. I found a simple motor speed controller here:
I think will better :smash: I have to try this with thermoresistor :D |
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| StratoFan |
PARTS
U1: LM324N quad op-amp
U2: 78L12 12 volt regulator
Q1: IRF521 N channel MosFet
D1: 1N4004 silicon diode
LED1 Red LED
C1: 0.01uF ceramic disc capacitor, 25V
C2-C5: 0.1uF ceramic disk capacitor, 50V
R1-R4: 100K 1/4W resistor
R5: 47K 1/4W resistor
R6-R7: 3.9K 1/4W resistor
R8: 2.7K 1/4W resistor
VR1: 10K linear potentiometer
F1: 3 Amp, 28V DC fast blow fuse
S1: toggle switch, 5 Amps
for the pwm circuit... |
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| iCebReakEr409 |
| Marshall is using TDA729Xs ? Now that is interesting...:) |
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| StratoFan |
Yes. I didn't wanna belive too... :xeye:
But somebody checked by multiemter, and look at this PDF: :eek:
http://www.marshallamps.com/images/...ur%20review.pdf
This is the new marshall amp. Don't know which TDA used, because the partnumber missing, but we can sure there are four 729?... :hot: |
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| iCebReakEr409 |
Yeah..it could really be TDA7293s. Marshall only allow 8 or 16 Ohm speakers for this amp. This could be another hint.
Hehe, now they got a really cheap power amp. I wonder why the amp is so expensive :) Well, I guess it took them some time to tweak the circuit...TDA7293 don't seem to be the most stable devices.
But I wonder how they get 350W out of 4 chips. |
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| StratoFan |
Now I have a very simple diy poweramp with stereo bridged 7294 and working very well, I like it. Very simple circuit. Now I have about 150W with +-25Vs on 8 Ohm. The price is really interesting :hot:
this is the reason why I want to try birdged/parallel version with 7293 on +-50Vs 4 ohm :devilr: .
Why do you think it's not stable enought? |
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| StratoFan |
I wonder, what's the best, if I use bridge application without line driver like DRV134 or DRV135 like in the datasheet of 7294V on page 13:
http://eu.st.com/stonline/books/pdf/docs/1057.pdf
or better to use with opamp like DRV134 with bridge? |
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| quekky |
hi,
me and my friend have came out with a pcb that can have up to 3 TDA7293 in parrallel. This board is inverting configuration. I use slow startup for the mute/stby according to the datasheet (the 2 caps and small resistors at the lower left side)
The 6 big caps are the psu caps for the 3 ICs. the big white resistors are optional, we put there just in case the IC didnt feed equal current. so far we tested the ICs do feed equal current, so it means that the datasheet is correct. I design the input cap to be optional as well. Signal resistors are very close to the master IC
my friend have tested 1 board and he says it works very well, with 0mv offset. he sortof lost the 2nd board i pass him at a shopping center :smash: i'm on budget now so wun be doing mine till a long time later... :p |
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| StratoFan |
Nice board :)
How much +-Vs uses?
Do you use pin 5 for clipping detector? Have to use one more PNP transistor to drive the clipping led, or can I connect the led via resistor directly to pin 5? No sample on the web... |
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| quekky |
up to the max that TDA7293 specify, as long as the caps is rated above the voltage
we have not tried pin 5 yet. however i have left a jumper on the pcb for furture use when we figure it out |
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| StratoFan |
| Would you share if you can drive a led successfully via pin 5? |
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| StratoFan |
I compared the datasheet of 7294 and 7293. The parallel example is not same. With 7293 the slave +- inputs connected directly to the -VS:
and:
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The datasheet of 7294 is different:
and:
Really MUST be connected +- IN pins same as in datasheet depending on type of chip, or one of them good for both ICs? :bawling: :confused: :mad: :dead: |
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| StratoFan |
I don't wanna belive nobody saw the difference between 7294 and 7293 datasheet. :smash: I think the example of 7294 is better for 7293, but I don't think the slave-mute pins MUST be connected to the ground....
Is this right? :whazzat: |
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| StratoFan |
| Thanks Artur! Unfortunately 7294 have no pin 11, what I want to use with 7293. 1000uF bootsrap cap isn't too much? |
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| quekky |
| quote: | Originally posted by StratoFan
Thanks Artur! Unfortunately 7294 have no pin 11, what I want to use with 7293. 1000uF bootsrap cap isn't too much? |
that seems to be a lot. I only use 220uF, but i guess anything above 66uF will be enough (according to datasheet, 3x22uF) |
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| StratoFan |
| quekky, what do you think about post #21? |
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| quekky |
Are you looking at TDA7294S? orginal TDA7294 does not support parallel
i have no experienced with the TDA7294S. I think you should follow the datasheet |
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| StratoFan |
| Yes, I linked pages of datasheet 7294S and 7293. But now I think, the datasheet of 7293 is wrong. When you built parallel with 7293, how you wired the input pins (2,3) of slaves? I think, -Vs not the best solution like in the datasheet. |
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| StratoFan |
| Yes, I know this PDF, this is the reason why I think the example in 7293 datasheet is wrong. |
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| quekky |
| quote: | Originally posted by StratoFan
Yes, I know this PDF, this is the reason why I think the example in 7293 datasheet is wrong. |
it is correct. the pcb i built have mute and stby in parrallel, and IN+/IN- of the slaves connected to V-
the mute and stby of 7294 and 7293 is the same |
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| StratoFan |
Thanks quekky.
It's interesting. You say, the +- inputs of 7294 must be connected to the -Vs if slave, but if the chip is 7293, the inputs must be connected to the ground. :confused: :hot: :bigeyes: :dead: |
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| StratoFan |
| quote: | Originally posted by StratoFan
Thanks quekky.
It's interesting. You say, the +- inputs of 7294 must be connected to the -Vs if slave, but if the chip is 7293, the inputs must be connected to the ground. :confused: :hot: :bigeyes: :dead: |
Sorry, I want to say: 7294 inputs must be connected to the ground, but 7293 most be connected to the -Vs... Why different????? :confused: :confused: :confused: |
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| StratoFan |
| quote: | Originally posted by quekky
it is correct. the pcb i built have mute and stby in parrallel, and IN+/IN- of the slaves connected to V-
the mute and stby of 7294 and 7293 is the same |
quekky, here is another datasheet of 7293:
http://ml.blastnet.ee/supikas/tda7293.pdf
The inputs of slave connected to to the ground, and the table on page 3 is not same. |
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| quekky |
i think it doesnt make a difference. When i started to look around with 7293 around july, ST gave this datasheet (with IN to gnd). several months later i checked ST website and they gave a different datasheet, this time it is IN to V-
look at this image, taken from the old datasheet (blasnet). seems like what determines the slave is pin 4. and if it's slave what goes into IN is not important |
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| StratoFan |
| quote: | Originally posted by quekky
i think it doesnt make a difference. When i started to look around with 7293 around july, ST gave this datasheet (with IN to gnd). several months later i checked ST website and they gave a different datasheet, this time it is IN to V-
look at this image, taken from the old datasheet (blasnet). seems like what determines the slave is pin 4. and if it's slave what goes into IN is not important |
Yes I think same. The date of the datasheet where the slave inputs (pin 2,3) connected to the ground is year 2000. The another where the inputs conected to the -Vs dated 2003. But I visited the PCB of parallel example on the datasheet, and I see, the pin 2 and 3 not used on slave chip. So I think, the pin 2 and 3 of slave is really not important, because it's off via pin 4. Thanks :))) |
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| StratoFan |
Finaly I did PCB for bridge/parallel 7293 chipamp. Not tested yet, I will back soon with photos when I changed my older amp to this new :)
the PCB is 30cm long for stereo amps, included protection with UPC1237, and with PWM fan controller.
Capacitors and 7293 chips will be included soon :)
I'am not sure, it was a good idea to put resistors and capacitors very closed tho the chipamps. Maybe the chips will too hot... |
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| abid_rehan |
Mr Strato:
Having looked at your last post I was looking forward if you be kind enough to email or post schematics of the circuit along PCB design..
It would be of great help. |
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| StratoFan |
Hi again!
I finished the test of this "gainclone".
First I changed the toroid from 600VA to 1200VA with soft start.
The toroid is 8 kg :)
the softstart circuit is very simple and working well:
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After I changed the poweramp on rack:
While testing, the 2nd chip demaged. Because 2 pins shorted :bawling:. Not at all, later the "-" part of power supply disconnected from the plug. All included chips demaged. :bawling: :bawling: :bawling: Finaly the bridge with 4 chips working well, the parallel chips will be tested later. |
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| Cro maniac |
In the datasheet is written that max voltage on input pins referred to -Vs is 90V. That means that you could connect the inputs of the slave chip to +Vs (if supply voltage is less than +-45V), and you won't damage them (if the datasheet is correct).
So, connecting inputs to GND or -Vs really makes no difference.
How did you make soft start circuit ? |
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| abid_rehan |
Strato:
I downloaded the PDF files that u mentioned earlier, there is a PCB design in them, however, that is only the component side what about other side of PCB.. |
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| StratoFan |
| quote: | Originally posted by Cro maniac
In the datasheet is written that max voltage on input pins referred to -Vs is 90V. That means that you could connect the inputs of the slave chip to +Vs (if supply voltage is less than +-45V), and you won't damage them (if the datasheet is correct).
So, connecting inputs to GND or -Vs really makes no difference.
How did you make soft start circuit ? |
I made this simple softstart:
http://mitglied.lycos.de/Promitheus...for_toroids.htm
Yes, now I know the input voltage of the slave chips not important. I think the input stage off in this mode. |
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