Its not about that, some component value like capacitors and resistors are there for a reason of +/-40vdc. build a working AX11 firts before of thingking modifiying the circuit.
Good. Is it necessary to heat sink the drivers (BD139/40)? What about thermal touch sensation?
Regards.
ok,i will test it on a +/-25v supply ,and then make modifications,and then wind a higher voltage transformer
The amplifier operates from the very first moment. No offset, silent with open input. The sound (only basic car speakers for the test) is very clear and transparent and strong and fully in the basses. The amplifier is absolutly competitive with any commercial amplifiers of this class.
I like it! Thanks to apex!
regards Olaf
I was so curious to try it. Now I have trouble with my wife - friday night and not others then audio-amplifiers
Nice work and this is the first AX11 made by forum member, I'm sure there will be many others in the future.
Regards
Hi,
BD139/140 are warm but not to mutch. You can touch them without any problem. But BC639/640 are very hot. The amplifier runs with +-38V DC. And I have not tested yet with power.
regards Olaf
Maybe testing with another pair BD139/140 replacing BC639/640. Same characteristics, better dissipation (to-126 x to-92).
Any recommendation from Apex?
Regards.
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BF471/472, BF871/872... many pairs can be use in this design, also CCS current and heat on VAS transistors can be reduce: just use 220R instead 180R in CCS. Gain can be increase: use 680R instead 2k2 in feedback... this amp is for fan.
I've played a bit. A small heatsink connected with thermal adhesive (more for peace of mind;-). Some photos for 20kHz, 10kHz and 1 kHz with signal generator until 30V peak to peak at output. Load resistance and heatsink are good warm (too small).
In each perspective the amplifier operates stable and has a warm and transparent sound.
It is a very nice, cool amplifier - typical apex.
It's fun to build it and you get an impressive sound.
Thanks again to Apex.
regards
In each perspective the amplifier operates stable and has a warm and transparent sound.
It is a very nice, cool amplifier - typical apex.
It's fun to build it and you get an impressive sound.
Thanks again to Apex.
regards
Attachments
...... what kind of topology rectifier it's used .......not bridge ?
Regards Alex
Hi Alex,
Good to see u around... actually its not finish that's why It's non labeled and can be change for something preferable one...
Regards,
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