f-ing dropbox changed their public folder system so now 10,000' posts in this forum are dead, i cannot add attachments to post #1 and thereby not fix the missing images.
I get that. Unfortunate situation. Do you somehow have any data on this project stashed away somewhere? Please let me have it, I will provide my email. Let me know
I was asked to post my home AMP from a fellow user on talk.maemo.org so here it is 🙂
This is the classic TDA7294 AMP with LOTS more Power then normal, this is with using Power Transistors at the output stage, it is a simple Addon to make, it just requires a SYNC resistor and the feedback to be moved to the output after the Power Transistors.
So to make this AMP you can just start with the TDA7294 with one change, just need to "move" the feedback so you can connect it to the Output after the Power Transistors, in all the AMPS i have made with the TDA7294 the 6.8Ohm has been spot on when using the 2SC5200 & 2SA1943, if you use other transistors you may need to experiment with another value for the SYNC resistor.
Things to do when SYNC it is to listen to it, things to listen to are from very low volume (FROM a clean source) and go slowely up in volume, the POINT here is that it should just get louder like a normal amplifier would, if the SYNC is off then a normal thing will be that at audio peaks (like drums & bass) it will sound like someone is kicking your speakers because the Transistors kick in at a wrong volume then the amp is playing, believe me you will hear it, this needs to be corrected by changing the resistor else you will have an amp that only sounds good at very low volume and medium to high volume.
Component list: (1x AMP)
1x 680 (680R) Resistor
1x 10K Resistor
3x 22K Resistor
1x 6.8 (6R8) 5W Resistor
2x 0.15 (0R15) 5W Resistor
2x 10uF 50V Capacitor
2x 22uF 50V Capacitor
1x 1uF 63V MKT/BiPolar Capacitor
1x TDA7294 Chip AMP
1x 2SA1943 PNP Transistor
1x 2SC5200 NPN Transistor
Schematic:
NOTE: 6.8Ohm resistor is a 5W
Hole Print "Design": (Would like to make proper boards...)
Pictures:
STATS:
Output Power: well lets just say that speakers that where 250/500W 2Ohm (RMS/MAX) where played to the max with NO DISTORTION AT ALL
I will call the output at 400W+ (MAX) and this is based on that the TDA itself adds ONLY 20-40W (because of the much higher driving Ohm), but the 5200/1943 are some GOOD POWERFULL transistors and going through the datasheet it will deliver peeks over 600W (short pulse pr Transistor), they supply 100W but this is FULL DC and there are no audio tracks to my knowledge that has that kind of "sound"
Driving Impedance: i have been using it for 2-8Ohm speakers, the lowest i have driven was 1.3Ohm but as with all AMPS if you know your Transistors you know how many watts you can pull out, this AMP will drive what ever you hook it up to, JUST one thing, when i was using my 1.3Ohm set it did introduce some "noise" (sounded like 80' AMP hiss), and at this point the SYNC resistor properly needs to be changed, i did not do this, i took the lazy way out and put some 1.8Ohm POWER Resistors in line with the speakers instead.
I have been using this AMP for +3 years, it is good for driving 2-8Ohm speakers with current config (6.8Ohm RES & 5200/1943)
The only thing i can really say is BUILD it, you will not be disappointed i can guaranty that, as long as you follow the "guide" it will be fine, i will how ever RECOMMEND that you use the same components (5200/1943) then you should not go wrong and it will play beautiful the first time it is hooked up, and also with these components it is VERY cheap to make (depending on suppler), where i buy my components i can make 1 channel (All components) for about 15$, it is as always the POWER SUPPLY that is going to set the price back.
Link to the original Thread DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...) - maemo.org - Talk
Whats more to come, well more "stats", and the new AMP im building right now, it's the TDA7293 With Power Transistors x 4, for a nice POWERFULL BI-AMP system, but it can also be used as a 4.0 Surround AMP or a Bridged 2x 700W+, also more pictures etc.
This post will be updated again and again to meet questions and to add pictures, guides etc...
Test Results on this AMP done by zanden30 and cmorariu can be found here and some pages forward.
EDIT: 2014.03 - Now also on facebook https://www.facebook.com/groups/760434413975466/
EDIT: 2017.03 - Im still using this amplifier, i have used it now for about 10 years with no problems, it is on for minimum 12 hours a day and have been for years
This is the classic TDA7294 AMP with LOTS more Power then normal, this is with using Power Transistors at the output stage, it is a simple Addon to make, it just requires a SYNC resistor and the feedback to be moved to the output after the Power Transistors.
So to make this AMP you can just start with the TDA7294 with one change, just need to "move" the feedback so you can connect it to the Output after the Power Transistors, in all the AMPS i have made with the TDA7294 the 6.8Ohm has been spot on when using the 2SC5200 & 2SA1943, if you use other transistors you may need to experiment with another value for the SYNC resistor.
Things to do when SYNC it is to listen to it, things to listen to are from very low volume (FROM a clean source) and go slowely up in volume, the POINT here is that it should just get louder like a normal amplifier would, if the SYNC is off then a normal thing will be that at audio peaks (like drums & bass) it will sound like someone is kicking your speakers because the Transistors kick in at a wrong volume then the amp is playing, believe me you will hear it, this needs to be corrected by changing the resistor else you will have an amp that only sounds good at very low volume and medium to high volume.
Component list: (1x AMP)
1x 680 (680R) Resistor
1x 10K Resistor
3x 22K Resistor
1x 6.8 (6R8) 5W Resistor
2x 0.15 (0R15) 5W Resistor
2x 10uF 50V Capacitor
2x 22uF 50V Capacitor
1x 1uF 63V MKT/BiPolar Capacitor
1x TDA7294 Chip AMP
1x 2SA1943 PNP Transistor
1x 2SC5200 NPN Transistor
Schematic:
NOTE: 6.8Ohm resistor is a 5W
Hole Print "Design": (Would like to make proper boards...)
Pictures:
STATS:
Output Power: well lets just say that speakers that where 250/500W 2Ohm (RMS/MAX) where played to the max with NO DISTORTION AT ALL
I will call the output at 400W+ (MAX) and this is based on that the TDA itself adds ONLY 20-40W (because of the much higher driving Ohm), but the 5200/1943 are some GOOD POWERFULL transistors and going through the datasheet it will deliver peeks over 600W (short pulse pr Transistor), they supply 100W but this is FULL DC and there are no audio tracks to my knowledge that has that kind of "sound"
Driving Impedance: i have been using it for 2-8Ohm speakers, the lowest i have driven was 1.3Ohm but as with all AMPS if you know your Transistors you know how many watts you can pull out, this AMP will drive what ever you hook it up to, JUST one thing, when i was using my 1.3Ohm set it did introduce some "noise" (sounded like 80' AMP hiss), and at this point the SYNC resistor properly needs to be changed, i did not do this, i took the lazy way out and put some 1.8Ohm POWER Resistors in line with the speakers instead.
I have been using this AMP for +3 years, it is good for driving 2-8Ohm speakers with current config (6.8Ohm RES & 5200/1943)
The only thing i can really say is BUILD it, you will not be disappointed i can guaranty that, as long as you follow the "guide" it will be fine, i will how ever RECOMMEND that you use the same components (5200/1943) then you should not go wrong and it will play beautiful the first time it is hooked up, and also with these components it is VERY cheap to make (depending on suppler), where i buy my components i can make 1 channel (All components) for about 15$, it is as always the POWER SUPPLY that is going to set the price back.
Link to the original Thread DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...) - maemo.org - Talk
Whats more to come, well more "stats", and the new AMP im building right now, it's the TDA7293 With Power Transistors x 4, for a nice POWERFULL BI-AMP system, but it can also be used as a 4.0 Surround AMP or a Bridged 2x 700W+, also more pictures etc.
This post will be updated again and again to meet questions and to add pictures, guides etc...
Test Results on this AMP done by zanden30 and cmorariu can be found here and some pages forward.
EDIT: 2014.03 - Now also on facebook https://www.facebook.com/groups/760434413975466/
EDIT: 2017.03 - Im still using this amplifier, i have used it now for about 10 years with no problems, it is on for minimum 12 hours a day and have been for years
Attachments
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What, if anything, would need to be changed to make this work with TDA7293?
I have the OPT devices, Fairchild not Toshiba, and the rest apart from maybe a resistor or two.
Transformer I'm planning on using is 500VA 2x24VAC toroidal.
I have the OPT devices, Fairchild not Toshiba, and the rest apart from maybe a resistor or two.
Transformer I'm planning on using is 500VA 2x24VAC toroidal.
Also I have pins 9&10 connected directly to +vs from previous configuration, can it still work or is it required to connect the caps and resistors? Thank you
Will a 500VA 2*24Vac toroidal transformer be sufficient to power the TDA7293+2SC5200/2SA1943?
For main supply caps I was thinking 4*10000uF/63V.
The amp is to drive a pair of Dayton 15" IB woofers in H-baffles (with dipole compensation).
For main supply caps I was thinking 4*10000uF/63V.
The amp is to drive a pair of Dayton 15" IB woofers in H-baffles (with dipole compensation).
Wonderful News indeed. I am totally Tired of all the External links on DiyAudio that disappear. Work within the site restrictions and attach stuff on site. If I wanted a F-Box, I could find one.
Hi , just made the TDA7294 + 2 transistors version on a spider-build setup just for testing , unfortunately , i just get the distorted signal that i input (music or test signal).
I put the scope on the ouptut of the TDA7294 (pin 14) and all i get is a distorted waveform , triple-checked the connections and added 2 capacitors for decupling as close as i could to the TDA7294 thinking that maybe it shuts down or it
oscillates(like the TDA2003) , but this was not the case since the sound is not powerfull enough.
Nothing gets worm , separating the output transistors and touching the bases gets me hum in the speaker.
Any ideas?
I put the scope on the ouptut of the TDA7294 (pin 14) and all i get is a distorted waveform , triple-checked the connections and added 2 capacitors for decupling as close as i could to the TDA7294 thinking that maybe it shuts down or it
oscillates(like the TDA2003) , but this was not the case since the sound is not powerfull enough.
Nothing gets worm , separating the output transistors and touching the bases gets me hum in the speaker.
Any ideas?
EDIT: 7 years now (in this config, ATX power supply case) and still going strong, have tested a lot of amps on the side and this still works and sounds best.
And when i say 7 years i mean 10+ hours a day for 7 years, well in the last 2+ years it has been 14+ hours a day on average, as it sometimes runs 24/7 for weeks since im lazy and it only shuts off when the computer shuts off 🙂
And when i say 7 years i mean 10+ hours a day for 7 years, well in the last 2+ years it has been 14+ hours a day on average, as it sometimes runs 24/7 for weeks since im lazy and it only shuts off when the computer shuts off 🙂
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