TDA7294 + Power Transistors AMP (TDA7293 to come also)

Jump to Latest
#663
Make it from the start again, often much easier then to trouble shoot if you connected it like the circuit you posted, it is a very simple amplifier to make and a good one.

Will be posting it in a newer version with SMD boards and in a 3D printed case with many options like IR, BT, Volume control and Fan control for a compact powerful amplifier (downloads for everything) on patreon and then 6 months later for free on Thingiverse
 
#664
Just a quick Q: It seems like you used this amp topology for quite some time. Did you have any problems or amp's near-death experience in this time? Like incidental shorts etc.

This particular topology in net effect disables the chipamp's protection, but I was thinking if it would be possible to add a diode bridge (2x PN drop in each pos/neg direction) across the 6.8R resistor to effectively bounce back the short circuit current to the chipamp to trigger the protection circuitry (the BJT pair emitter resistors would need to be scaled accordingly of course) ...

This plan works with small BJT-boosted opamp-based circuits, but ... there's much more smoke within a chipamp if something goes wrong.
 
#665
anti said:
Just a quick Q: It seems like you used this amp topology for quite some time. Did you have any problems or amp's near-death experience in this time? Like incidental shorts etc.

This particular topology in net effect disables the chipamp's protection, but I was thinking if it would be possible to add a diode bridge (2x PN drop in each pos/neg direction) across the 6.8R resistor to effectively bounce back the short circuit current to the chipamp to trigger the protection circuitry (the BJT pair emitter resistors would need to be scaled accordingly of course) ...

This plan works with small BJT-boosted opamp-based circuits, but ... there's much more smoke within a chipamp if something goes wrong.
Click to expand...

Well been about 8-9 years now, as long as you don't short the output when playing loud you will be fine, but yes it lacks that kind of protection, i have blown a few in my many experiments with DIY speaker units and such, else it's been so far over 5 years+ of on time, the last 3-4 years it has pretty much not been off

Would be nice to try the diode bounce back, but i don't have the time to do that right now

Now a days i use these boards by the way, going small 😉
IMG_20180809_181711_2.jpg
 
#666
dr frost dk said:
Well been about 8-9 years now, as long as you don't short the output when playing loud you will be fine, but yes it lacks that kind of protection, i have blown a few in my many experiments with DIY speaker units and such, else it's been so far over 5 years+ of on time, the last 3-4 years it has pretty much not been off

Would be nice to try the diode bounce back, but i don't have the time to do that right now

Now a days i use these boards by the way, going small 😉
View attachment 776247
Click to expand...

Nice, small PCB's 🙂
 
#669
dr frost dk said:
Thanks, doesn't take up much space as 3D printed amplifier is pretty small esp for the power it can produce, this time with temp controlled fan control
View attachment 776261
Click to expand...
First point. Thank you. One of the most interesting builds I have seen anywhere. Im doing it for sure. Want to do this setup both with a TDA and a LM just to see which sounds better. Id also like to build the PCB for 8 transistors. Start with one pair per channel. And then as my speakers get bigger add in more transistors. If I cant do that then maybe just build a 4 cah setup. The facebook page has a guy who has shared the PCB for such a setup.
I will need to figure out how to balance output between right and left as well as front and rear speakers. If you have any ideas to wire this up. It would save me some head scratching. Else Ill just open up one of my 4 channel amps and see how they wired it.

The reason I love this build is that it will allow me to hook up multiple speakers. As long as I dont get the final load under 2 Ohms.

Last point that heat sink looks really small. But you say you have been using this for years so it must work. If such a small heat sinks works I don't have to worry about adding CPU heat sinks with cooler fans. Right now I have it so that if the temps goes past 100c the fan comes on. Its a CPU fan so very little noise. I still have to tig weld the mounting holes for the CPU fan to the main heat sink. They sell the cheap heat sinks here by the MTR.

Good Heat sinks are not cheap. But you can get a CPU i7 or i3 heat sink and fan for like 2-3$ on amazon They looks cool. I have sourced all the parts for this build except for the 1.5 ohm resistor.

One again thanks. And Im naming my Amp Dr. Frost. Ill send you a pic for sure once its up and running.
 
You must log in or register to reply here.
Top Bottom