If you are only using 8Ohm then 2x won't do anything more then 1x Power Transistors, however if you make a 4x AMP with a inverting opamp on 2x Channels and thereby bridging that AMP to 2x then 2x Power Transistors (PR. AMP) will give you a 4 Ohm stable AMP capable of driving ALOT of power, can't say how much but in peak/max i will saw way over 1000W, RMS sound yield 400W+
Would be nice for someone that has testing equipment to build this and give the exact numbers.
Again as posted before, the 7294 + Power Transistors as i posted in Post #1 will drive speakers with 250/500 (RMS/MAX) to the limit WITHOUT distortion, even at near breaking point for the speakers the sound is just clear because of the power handling of the Transistor set and the fact that the TDA7294 is only pulling 8Ohm (2Ohm speaker + 6.8Ohm "balance" resistor) so the TDA7294 is never really near it's limit at any time no matter if you are pulling 8Ohm or 0.25Ohm
Would be nice for someone that has testing equipment to build this and give the exact numbers.
Again as posted before, the 7294 + Power Transistors as i posted in Post #1 will drive speakers with 250/500 (RMS/MAX) to the limit WITHOUT distortion, even at near breaking point for the speakers the sound is just clear because of the power handling of the Transistor set and the fact that the TDA7294 is only pulling 8Ohm (2Ohm speaker + 6.8Ohm "balance" resistor) so the TDA7294 is never really near it's limit at any time no matter if you are pulling 8Ohm or 0.25Ohm
correct me if im wrong but for driving 8ohm speakers i need to make two TDA7294 boards each with two pairs of power transistors. then i need to bridge them using inverting op amp on one chanel thus giving me an bridge capable of driving 8ohm speakers?
Anyway i also have 4Ohm 300w rms speakers and to drive them its enough only to have single tda7294 with 2x power transistors (comes to 2xNPN and 2xPNP) ?
P.S. would it be enough to use tda7294 + 4x/6x/8x power transistor couples to drive 8Ohm's?
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For 2 to 8Ohm speakers just use TDA7294 with 1x set of Power Transistors, it is 2 Ohm stable, for driving speakers with less then 2 Ohm you will need:
1 Ohm = 2x Power Transistors - Max Power about 800W
0.5 Ohm = 4x ~~ - ~~ 1600W
0.25 Ohm = 8x ~~ - ~~ 3200W
Last but most obvious you need a power supply big enough for the application.
Again for 2-8Ohm 1x set is enough, even for 4-8Ohm bridged 1x set is enough just remember it is now only 4Ohm stable, just power output in 4Ohm is very high (this i have tested with easily putting a 700W woofer to it's max), more then 1x set will provide more A to speakers but should make no difference when driving 2-8Ohm
Hope im making myself clear, not the best of explaining things....
I think i better get on the whole youtube thing and post a video some day with this amp maxing out a pretty powerfull woofer, also need to put my electro ciao on there......
But again you only need more Transistors the LOWER Ohm you need to drive, or if you need 2Ohm stable in bridge
1 Ohm = 2x Power Transistors - Max Power about 800W
0.5 Ohm = 4x ~~ - ~~ 1600W
0.25 Ohm = 8x ~~ - ~~ 3200W
Last but most obvious you need a power supply big enough for the application.
Again for 2-8Ohm 1x set is enough, even for 4-8Ohm bridged 1x set is enough just remember it is now only 4Ohm stable, just power output in 4Ohm is very high (this i have tested with easily putting a 700W woofer to it's max), more then 1x set will provide more A to speakers but should make no difference when driving 2-8Ohm
Hope im making myself clear, not the best of explaining things....
I think i better get on the whole youtube thing and post a video some day with this amp maxing out a pretty powerfull woofer, also need to put my electro ciao on there......
But again you only need more Transistors the LOWER Ohm you need to drive, or if you need 2Ohm stable in bridge
Thanks for explaining. I still have some stuff that needs explaining but first i need to build the amp and test it out 🙂
Sorry for double post but i cant edit my last post.
Anyway made proper schematics and board layout in EAGLE 6.2.0 🙂
Could any one check for mistakes and etc. for me it looks ok. 🙂
Added up to 4x transistors for just in case situation 🙂
connectors:
Audio in: 1.In 2.Gnd
Power: 1.+Vss 2.Gnd 3.-Vee
Speaker: 1. Out 2.Gnd
P.S. adding used libraries too.
View attachment lbr.zip
View attachment TDA7294+power transistors.zip
Anyway made proper schematics and board layout in EAGLE 6.2.0 🙂
Could any one check for mistakes and etc. for me it looks ok. 🙂
Added up to 4x transistors for just in case situation 🙂
connectors:
Audio in: 1.In 2.Gnd
Power: 1.+Vss 2.Gnd 3.-Vee
Speaker: 1. Out 2.Gnd
P.S. adding used libraries too.
View attachment lbr.zip
View attachment TDA7294+power transistors.zip
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hi gud day
im interested on this add on.i just want to ask if i can use the power supply seen in the attached schematic.i've done that project(the one in schematic) and i want to try the add on.
any advice?
tia
im interested on this add on.i just want to ask if i can use the power supply seen in the attached schematic.i've done that project(the one in schematic) and i want to try the add on.
any advice?
tia
yes if you change it alittle, if you want to use the 7293 use this schematic
There are just a little change to pin 6 & 12 & 14, so DO ONLY use this for the 7293 and it will work, i know this since i build and tested it.
And sorry for the GIANT absence from the forums, i been very busy in the last LONG time, i will have to complete my 4x 7293 for my TV project
http://www.facebook.com/media/set/?...073741825.100004867482301&type=1&l=0b484a5e9d
An externally hosted image should be here but it was not working when we last tested it.
There are just a little change to pin 6 & 12 & 14, so DO ONLY use this for the 7293 and it will work, i know this since i build and tested it.
And sorry for the GIANT absence from the forums, i been very busy in the last LONG time, i will have to complete my 4x 7293 for my TV project
http://www.facebook.com/media/set/?...073741825.100004867482301&type=1&l=0b484a5e9d
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dont want to abuse, may ask your opinion?
what result from undervolt?
my xfrmer is 25-0-25 125 va
want to squeeze the max out of the PS,
and about to use parallel 2 chip, which
i think is more like your design?
i already have the bipolars from scratch.
I wish your TV project goes allright and everything OK!
martinnez
uruapan michoacan
what result from undervolt?
my xfrmer is 25-0-25 125 va
want to squeeze the max out of the PS,
and about to use parallel 2 chip, which
i think is more like your design?
i already have the bipolars from scratch.
I wish your TV project goes allright and everything OK!
martinnez
uruapan michoacan
you may have to "experiment" with the 6.8Ohm resistor if it sounds "off", if you use dual set transistors with that voltage it will be 0.5-1.0 Ohm stable so you can get alot of power if your speakers are at 1 ohm, but you will still be limited to 125va from you "input" power.
If you mean bridge to get higher power at higher Ohm then you need to try it out your self, i have never attempted to bridge my amp in the usual way as described in the TDA729x schematic, BUT it works just fine with an inverted input on one channel by using an opamp.
EDIT: and the TV is almost done, just need to build a Subwoofer that will occupy almost all space in the top of the TV.
and make a parallel port transistor power drive to the motor in the "foot" so it can be turned via the computer
If you mean bridge to get higher power at higher Ohm then you need to try it out your self, i have never attempted to bridge my amp in the usual way as described in the TDA729x schematic, BUT it works just fine with an inverted input on one channel by using an opamp.
EDIT: and the TV is almost done, just need to build a Subwoofer that will occupy almost all space in the top of the TV.
and make a parallel port transistor power drive to the motor in the "foot" so it can be turned via the computer
yes my limits are the 125 va xfrmr and 8 ohm speaker.
is it ok? or need something else?
what can i expect?
will have near 90 w output?
or less..?
is it ok? or need something else?
what can i expect?
will have near 90 w output?
or less..?
at that voltage you need to bridge amps to get some power at 8ohm else you will only get 25-50W 8 Ohm
Bridged you will get 100W+
Bridged you will get 100W+
don't know, try it.
it is not so much my design, many have made this amp with the transistors before, just all the ones i tried sounded terrible because the balance between TDA729x and Transistors where off, only thing to do here is to change value off 6.8Ohm resistor, but for most speakers 2-8Ohm the 6.8Ohm works fine.
it is not so much my design, many have made this amp with the transistors before, just all the ones i tried sounded terrible because the balance between TDA729x and Transistors where off, only thing to do here is to change value off 6.8Ohm resistor, but for most speakers 2-8Ohm the 6.8Ohm works fine.
then if i use 1x bipolars and +-50V, and 8 ohm
speaker,what output can i get,and with what
transformer-ps?
speaker,what output can i get,and with what
transformer-ps?
Thanks for your answers!
And to get the most what transformer is needed?
and how much capacitance?
Please?
I get the idea but if you recomend something,
it will be used full power all the time for hours
sometimes in hot weather so i´ll use fans and big
heatsinks.
And to get the most what transformer is needed?
and how much capacitance?
Please?
I get the idea but if you recomend something,
it will be used full power all the time for hours
sometimes in hot weather so i´ll use fans and big
heatsinks.
if you have a transformer that gives watts = RMS watt needed then your fine, capacitors?, well there are formulas everywhere, i usually go by what i have laying around, and this is normally much more then stock amplifiers (NAD, phillips etc...).
thanks again!
I get the notion, i´ll be trying
with 2200x8 and 4700x4,(on different
amps), i have a 40-0-40 xformer dont
know the capacity; it´s a toroid about
4in tall and a bit less wide
what VA rating do you think it might
have? I want to try it with some regulation
for the chip and ful V for the transistors.
I get the notion, i´ll be trying
with 2200x8 and 4700x4,(on different
amps), i have a 40-0-40 xformer dont
know the capacity; it´s a toroid about
4in tall and a bit less wide
what VA rating do you think it might
have? I want to try it with some regulation
for the chip and ful V for the transistors.