pejinm said:
I would expect that measurements with sensitive instruments would show some slight differences, but I doubt whether you would hear any difference. For example; the distortion v power plot might be slighly different, but if you can hear the difference between 0.02% and 0.03% then you have better ears than I have.
AndrewT said:
The circuit of course would work fine and any differences in transistor gain or other attribute would be fixed to a degree by negative feedback, but it would not be optimal. Whether you would hear anything different is again speculative. In true complementary amplifiers the PNP transistors are not exact opposite copies of the NPN transistors either, but the amps still sound great.
Cheers
Q
Vivek said:
The 2N3055 has a Vce of only 60 volts, so this indicates a maximum rail voltage of +/- 30 volts. It is often used with rails of +/- 40 volts and this is probably the maximum. So the transistor can be used but you need to make sure that your power supply idle voltage never exceeds +/- 40 volts. Use a 28 v AC (unloaded) 200va transformer.
idealist2002 said:
The MJ15024 is a good choice for this amplifier. Good luck with your build.
Cheers
Q
Quasi, as you are aware about my queries in the other thread, I suppose about 200W will be sufficient for each of my subs. How much power would 40 V rails be able to put out?
One more thing, which amp (mosfet or bipolar) will be better for HT sub applications? I think it would require good transient current capabilities, right? I also remember you telling me that the mosfets can be pushed harder.
One more thing, which amp (mosfet or bipolar) will be better for HT sub applications? I think it would require good transient current capabilities, right? I also remember you telling me that the mosfets can be pushed harder.
60 to 80W into 8ohms from+-40Vdc. If you build it really well for high power the 4ohm capability could be 120W to 150W.
Not so well optimised and you'll get as little as 100W into 4ohms.
For most audio uses BJT amd FET perform just as well. It's the circuit and build that makes the far bigger difference.
AndrewT said:
Best case power (big power supply) will be;
40 - 5% (regulation) - 4 volts (amp drop) = 34 volts * 0.7 = 23.8 volts RMS. Into 8 ohms this is 70 watts and maybe 140 watts into 4 ohms. Don't worry if you get 10 watts less, you wont hear the difference. More important to have a strong power supply.
Cheers
Q
Waiting for heatsinks...
Hi all,
Here is my almost finished amp modules,
I must say, i'm having problems with case, heatsink and transformer layout inside the case.I want all to fit in 2 unit rackmount aluminium case.The boards are so large so I must go for smaller hetsinks if I want all to fit in. I must then configure the better air flow to compensate smaller heatsinks...
Regards...
Hi all,
Here is my almost finished amp modules,
I must say, i'm having problems with case, heatsink and transformer layout inside the case.I want all to fit in 2 unit rackmount aluminium case.The boards are so large so I must go for smaller hetsinks if I want all to fit in. I must then configure the better air flow to compensate smaller heatsinks...
Regards...
Attachments
Hi guyes,
I am entring firt time in fourm,
i am sixty years old yong man and retired from services,
the audio was not my job but now istarted it and need help from all of members to win in these audio projects,
i make pcb and built amplifier (bipoler and mosfet) but still I did not power on because I failed to get instruction for first time powering these amplifiers and what should check before powering the amp.
please inform me what are instruments are required for these projects,
I have purchased FLUKE199 FLUKE 97 scopemeter and digital multi meters, also I purchase PEAK atlas component analyser(the component analyser is not working for thristors where mentioned in cat of instrumet it can test the traiks ans scrs but this is not working for traiks and scr's) so please inform me what are other then then these instruments are requied for projects,
I am trieng to make a varyable supply,
also I have a vary able tronsformer wih me,
I am thanking for the members how help me and guide me in future
Thanks and regards,
Abdul Majeed
I am entring firt time in fourm,
i am sixty years old yong man and retired from services,
the audio was not my job but now istarted it and need help from all of members to win in these audio projects,
i make pcb and built amplifier (bipoler and mosfet) but still I did not power on because I failed to get instruction for first time powering these amplifiers and what should check before powering the amp.
please inform me what are instruments are required for these projects,
I have purchased FLUKE199 FLUKE 97 scopemeter and digital multi meters, also I purchase PEAK atlas component analyser(the component analyser is not working for thristors where mentioned in cat of instrumet it can test the traiks ans scrs but this is not working for traiks and scr's) so please inform me what are other then then these instruments are requied for projects,
I am trieng to make a varyable supply,
also I have a vary able tronsformer wih me,
I am thanking for the members how help me and guide me in future
Thanks and regards,
Abdul Majeed
SMPS
Hello all,
I assambeled mosfet amplifier with 10 nmosfet IRFP450 and also I assambeld bipoler with eigh transisstors3773, Now I need to make a switch mode power supply,
and for smps i need schematic and other stuff like component lay out and pcb lay out if available by any member,
in contoury the line volts are 220/50hz
thankyou for co-operation
regards
Abdul majeed Tahir
Hello all,
I assambeled mosfet amplifier with 10 nmosfet IRFP450 and also I assambeld bipoler with eigh transisstors3773, Now I need to make a switch mode power supply,
and for smps i need schematic and other stuff like component lay out and pcb lay out if available by any member,
in contoury the line volts are 220/50hz
thankyou for co-operation
regards
Abdul majeed Tahir
Questions catch-up time
Hi Miodrag, I do not have a finished short cct protection schematic at this stage. I did post a draft schematic of a universal one some time ago that used an optocoupler, but this is not yet tested.
Nice work Miodrag, good to see the use of second hand parts from PC power supplies too. In trying to make it all fit, have you thought about mounting both modules on one heatsink (one on top of the other). The heatsink would then run down the middle of the case with the power supply on the other side. In my amp I used a mains voltage fan slowed down by a suitably rated capacitor and achieved noiseless airflow. I have not been able to achieve noisless airflow with a 12v DC fan.
Hi Abdul Majeed,
Welcome to the thread. I see you have been busy already and I wish you good luck with your build.
I have not used these modules with a switchmode power supply, but provided the supply is well filtered there should be no problems.
The mosfet amp is very powerful and should provide good reliable service. The bi-polar transistor version will give slightly more power for the same voltage rails but will not be anywhere near as robust.
I would be grateful for any images of your work you are able to post here.
Cheers everyone
Quasi
pejinm said:
Hi Miodrag, I do not have a finished short cct protection schematic at this stage. I did post a draft schematic of a universal one some time ago that used an optocoupler, but this is not yet tested.
pejinm said:
Nice work Miodrag, good to see the use of second hand parts from PC power supplies too. In trying to make it all fit, have you thought about mounting both modules on one heatsink (one on top of the other). The heatsink would then run down the middle of the case with the power supply on the other side. In my amp I used a mains voltage fan slowed down by a suitably rated capacitor and achieved noiseless airflow. I have not been able to achieve noisless airflow with a 12v DC fan.
Abdul Majeed Aw said:
Hi Abdul Majeed,
Welcome to the thread. I see you have been busy already and I wish you good luck with your build.
I have not used these modules with a switchmode power supply, but provided the supply is well filtered there should be no problems.
The mosfet amp is very powerful and should provide good reliable service. The bi-polar transistor version will give slightly more power for the same voltage rails but will not be anywhere near as robust.
I would be grateful for any images of your work you are able to post here.
Cheers everyone
Quasi
Hi Quasi,
I finally succeeded with my PCB layout for the Bryston 4B retrofit of the NBIP circuit.
http://www.diyaudio.com/forums/showthread.php?postid=1344398#post1344398
Can you give it a quick look to see if my track routing is acceptable? I tried to maintain your 'style' as much as possible, though I modified a few of the cap footprints to suit my appetite for polypropylene.
..Todd
I finally succeeded with my PCB layout for the Bryston 4B retrofit of the NBIP circuit.
http://www.diyaudio.com/forums/showthread.php?postid=1344398#post1344398
Can you give it a quick look to see if my track routing is acceptable? I tried to maintain your 'style' as much as possible, though I modified a few of the cap footprints to suit my appetite for polypropylene.
..Todd
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