Hi.
I have read info about Cmoy amp and about simple class A mosfet amps, but i think it's good idea to make OpAmp+Mosfet head-amp. What can You say about it? Maybe You can give me some advice?
P.s. Headphones are Beyerdynamic DT-990, it's 250 Om so amp must be rather powerfull. I have IRF 610 mosfets and AD8066 opamps and need just solution
I have read info about Cmoy amp and about simple class A mosfet amps, but i think it's good idea to make OpAmp+Mosfet head-amp. What can You say about it? Maybe You can give me some advice?
P.s. Headphones are Beyerdynamic DT-990, it's 250 Om so amp must be rather powerfull. I have IRF 610 mosfets and AD8066 opamps and need just solution
I have thought about building a simple Cmoy style amp with one of the discreet opamps like the OPA earth/sun/moon modules. Does anyone have any kind of idea what sort of current they will be able to deliver? My phones are 32Ohm and so I require more current than the 2132/34 style BB opamps can handle.
Hi,
for 1W into 32r0 I would suggest a peak transient output current of around 700mApk. That is mighty high for even a discrete opamp.
For 100mW into 32r0 the peak current reduces to around 200mA. That is more easily achieved.
That's the problem in designing a headphone amp.
High impedance phones need adequate voltage drive, but low impedance phone require lots of current ability.
for 1W into 32r0 I would suggest a peak transient output current of around 700mApk. That is mighty high for even a discrete opamp.
For 100mW into 32r0 the peak current reduces to around 200mA. That is more easily achieved.
That's the problem in designing a headphone amp.
High impedance phones need adequate voltage drive, but low impedance phone require lots of current ability.
opamp
I have testet the circiut, (right now just with a LM833N).
im currently testing it with cheap headphones just if something goes wrong, and testing with +/-6v and +/-9 to test the difference..
also tried with variable gain..
- are ther pros and cons about that ?..
the supply right now is not batteries because i just found out that my 9v batteries are dead :S.. anyways just have to ignore the minor humm a bit..
i'm not sure, but i think that there is a little to much high freq compared to bass..
----- ohm---
regarding the watts, it is in to at 50ohm headset i want around 1 watt..
I have testet the circiut, (right now just with a LM833N).
im currently testing it with cheap headphones just if something goes wrong, and testing with +/-6v and +/-9 to test the difference..
also tried with variable gain..
- are ther pros and cons about that ?..
the supply right now is not batteries because i just found out that my 9v batteries are dead :S.. anyways just have to ignore the minor humm a bit..
i'm not sure, but i think that there is a little to much high freq compared to bass..
----- ohm---
regarding the watts, it is in to at 50ohm headset i want around 1 watt..
Igla said:
No doubt they are loud enough. However, loudness does not equate to adequate drive. For example, My MP3 player can play quite loudly through my headphones but sounds much better with an adequate amp in between.
It is known for a while that the OPA 2132 is not capable of the current required for low Z phones.
hello.
once i have built a headphoneamp with the lm386.that is no high end opamp(if you turn down the volume to zero you can hear a small amount of noise),but it works properly with a 32ohm headphone and a 9volt battery.
a bassboost is built in: with cb=100nf.....more neutral;with cb=47nf or 33nf more boomy.
at the input there is a pot=10k for volumecontrol,or a resistor10k.
it is cheap and easy to build up.
have some fun..........
greetings.........
once i have built a headphoneamp with the lm386.that is no high end opamp(if you turn down the volume to zero you can hear a small amount of noise),but it works properly with a 32ohm headphone and a 9volt battery.
a bassboost is built in: with cb=100nf.....more neutral;with cb=47nf or 33nf more boomy.
at the input there is a pot=10k for volumecontrol,or a resistor10k.
it is cheap and easy to build up.
have some fun..........
greetings.........
Attachments
Check this link:
http://headwize.com/projects/index.htm
If you need more current... I bet you could drive small loudspeakers with some of that headphone amps.
Just don't let your head explode.
http://headwize.com/projects/index.htm
If you need more current... I bet you could drive small loudspeakers with some of that headphone amps.
Just don't let your head explode.
Forr,
Thanks for the compliment.
I agree entirely with your off-topic remark about complementary differential input pairs. It can only work well if the offsets are small and the gain of the paths from the input to the place where the two paths are tied together is low enough.
Igla,
Nice trick with the two op-amps. The lower op-amp still has its own feedback network, but this way you manage to reduce it to only one wire.
Best regards,
Marcel
Thanks for the compliment.
I agree entirely with your off-topic remark about complementary differential input pairs. It can only work well if the offsets are small and the gain of the paths from the input to the place where the two paths are tied together is low enough.
Igla,
Nice trick with the two op-amps. The lower op-amp still has its own feedback network, but this way you manage to reduce it to only one wire.
Best regards,
Marcel
Marcel;
it's just a parallel wiring from OPA227 datasheet for higher output current.
There was remark from Rembrant that OPA2132 has not enough current to drive lower impedance headphones. I've succesfuly drove lo-life low sensitivity cheap 32 ohm Chinese headphones with my OPA2132 Cmoy.
My goal was to build cheap, small and simple headphone amp running on batteries just because I was bored. I must say that I was surprised how well this thing plays music and now I've got ''headphone virus'' and I want to try some other designs - perhaps some simple discrete amp for a start.
it's just a parallel wiring from OPA227 datasheet for higher output current.
There was remark from Rembrant that OPA2132 has not enough current to drive lower impedance headphones. I've succesfuly drove lo-life low sensitivity cheap 32 ohm Chinese headphones with my OPA2132 Cmoy.
My goal was to build cheap, small and simple headphone amp running on batteries just because I was bored. I must say that I was surprised how well this thing plays music and now I've got ''headphone virus'' and I want to try some other designs - perhaps some simple discrete amp for a start.
Hello. Can Anyone cmment my post about PS for HeadAmp?
http://www.diyaudio.com/forums/showthread.php?postid=1716468#post1716468
If 40V Diodes will be ok ?
P.s. It is just beginnig, then I'll add Voltage Regs, LED and polyprop caps, if it's necessary.
http://www.diyaudio.com/forums/showthread.php?postid=1716468#post1716468
If 40V Diodes will be ok ?
P.s. It is just beginnig, then I'll add Voltage Regs, LED and polyprop caps, if it's necessary.
Stream said:
Diode switching results in voltage spikes that can become very high. Therefore as a general rule rectifier diodes should have more than 4,5 times the voltage rating of the rails. For 2 x 12 V rails the minimum would be diodes with 108 V or more then. Next standard value would be 150 V.
Interestingly though that safety margin is already included in bridge rectifiers. So if you bought one of them, you could use a nominal 24 V version, if that existed. In that case 40 V would indeed be enough.
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