Now I get it. A headphone amp not power amp. Big power FETs for a head phone amp.
It runs pure class A at 100mA to 150mA bias current so puts out around 3 W heat so needs a power MOSFET with heatsink capability.
Don't feel bad. I have a headphone amp kit on a Asian site named after me which can be purchased.
I guess I should have said the amp uses the circuit schematic by EUVL and the layout by Prasi. You did state your objections to how the layout was executed and that was noted. But it seems the built amp works just fine and is quite small and convenient size.
Prasi did not design the circuit so I wouldn't say you had nothing to do with it. I will be sure to qualify my words more carefully in the future when crediting folks with stuff they designed.
I think Prasi added 3 components which are considered good practice in layouts: the 10R ground lift and back-to-back diodes for protection. I don't consider them in the audio path, but rather a practical and a nice feature to have.
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The link does not take it to exact post no. so here it is again for convenience. http://www.diyaudio.com/forums/pass-labs/271926-f5-headamp-80.html#post4840666 post #791
This link takes me to post791
Xrk's link takes me to post784 where another PCB is shown.
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yes, post #791 has the final gerbers with which xrk ordered his PCBs. So post no. 791 is the correct post containing the final gerbers.
yes xrk's link was wrong.
New TDA7294 on the block
After experimenting with the LM3886, LM4780 and LM1875, it was time for a new amplifier with a different IC; this new amplifier is based onto a TDA7294. It produces about 2x 48W @ 8 ohms with 2x 21VAC rails. Although it can produce more power at a higher rail voltage, the voltage has been kept deliberately a bit lower, so the amplifier could still be compact with adequate thermal management. The VU-meters originate from a JVD KD A5 cassette deck. The driver circuit is my own design.
Hereby some pictures:
And a little movie:
https://youtu.be/wTQaHvHGNf4
Hopefully you all like it
After experimenting with the LM3886, LM4780 and LM1875, it was time for a new amplifier with a different IC; this new amplifier is based onto a TDA7294. It produces about 2x 48W @ 8 ohms with 2x 21VAC rails. Although it can produce more power at a higher rail voltage, the voltage has been kept deliberately a bit lower, so the amplifier could still be compact with adequate thermal management. The VU-meters originate from a JVD KD A5 cassette deck. The driver circuit is my own design.
Hereby some pictures:
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.
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.
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.
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.
And a little movie:
https://youtu.be/wTQaHvHGNf4
Hopefully you all like it
Actually, all of Kaplaars projects are amazing. He is the consummate diy'er extraordinaire
Best,
Anand.
Very nice Kaplaars !
The chassis you have reminds me of ones I have used for preamplifier and headphone amplifiers:
Fab
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Beautiful, as usual!!
Can you point me to where you bought this case? Is it all metal?
Thanks people!!!
The cabinet is fully made of aluminum. Although it was a lot of filing, it was quite doable to cut the holes for the VU's. More difficult was the rear plate which is 1 cm thick. The front plate is actually the rear plate but, since I still don't have a CNC, I used the rear plate as front plate and vice versa. I added thermal compound between all the rounded T-connections and the side plates. This makes the whole cabinet more or less one big heatsink It works quite nicely; even without ventilation holes the temperature never exceeds 40 degrees Celsius when on full load for 0.5 h.
The chassis is categorized as 'Rounded aluminum chassis 2106T'. There are several vendors on Ebay and Aliexpress that offer the same cabinet. There are also bigger ones available, just as the ones fab posted.
The cabinet is fully made of aluminum. Although it was a lot of filing, it was quite doable to cut the holes for the VU's. More difficult was the rear plate which is 1 cm thick. The front plate is actually the rear plate but, since I still don't have a CNC, I used the rear plate as front plate and vice versa
. I added thermal compound between all the rounded T-connections and the side plates. This makes the whole cabinet more or less one big heatsink It works quite nicely; even without ventilation holes the temperature never exceeds 40 degrees Celsius when on full load for 0.5 h. The chassis is categorized as 'Rounded aluminum chassis 2106T'. There are several vendors on Ebay and Aliexpress that offer the same cabinet. There are also bigger ones available, just as the ones fab posted
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