".........headphones need to be loud as hell...."
You need to check out
http://www.headwize.com/articles/hearing_art.htm
Next ....you can use any of several opamps at the input stage ( OPA2134, LM4562 , NE5532 ,AD826, NJM4580 etc) and follow it with a buffer chip like BUF634 . That can easily drive headphones of all impedances. A few opamps can drive 600 ohms directly . However the BUF634 solves that problem.
Or you can go fully discrete !
I assume you are looking for a good sounding easy implementation. In that case the chips are the easiest and sound very good and can kill your hearing pretty fast ....if you are not careful.
You could stick to +/- 9 volt supplies to limit output but even that might be too much. Some opamps sound better at higher supply voltages ( like +/-12 to 15 volts). I'm not sure how good the BUF634 is at +/- 9 volts.
Check the headwize forum for circuit details or do a search on this forum.
Cheers.
You need to check out
http://www.headwize.com/articles/hearing_art.htm
Next ....you can use any of several opamps at the input stage ( OPA2134, LM4562 , NE5532 ,AD826, NJM4580 etc) and follow it with a buffer chip like BUF634 . That can easily drive headphones of all impedances. A few opamps can drive 600 ohms directly . However the BUF634 solves that problem.
Or you can go fully discrete !
I assume you are looking for a good sounding easy implementation. In that case the chips are the easiest and sound very good and can kill your hearing pretty fast ....if you are not careful.
You could stick to +/- 9 volt supplies to limit output but even that might be too much. Some opamps sound better at higher supply voltages ( like +/-12 to 15 volts). I'm not sure how good the BUF634 is at +/- 9 volts.
Check the headwize forum for circuit details or do a search on this forum.
Cheers.
kubeek,
You could use any chip you like, and then build a simple transistor output stage. Seems relatively easy enough.
Or, there is the AD815 High Ouput Differential Driver which seems to be well capable of driving low impedance loads. I seem to recall some projects here using this chip. A search of this site might reveal some useful information.
If you don't like the SMT version of this chip, BG-Micro still stocks an older 15-lead through hole SIP version for only $1.95 USD. This package is nearly identical to the LM3886, so it shouldn't be too difficult to work with. This chip was designed as an ADSL line driver, so it has good bandwidth and plenty of umph behind it.
Texas Instruments also offers their TPA6120 High Fidelity Stereo Headphone Driver, which is considered by some to be the best headphone amp on the planet right now.
Veteran has played with this, and may even have some PCBs available.
Rod Elliott at ESP has a write-up in his technical articles about this new TI headphone amp chip, and he details the prototype he built. He seems very well pleased with the final result. See THS6012 CFB Pre-Amplifier (about halfway down the page).
Notice two different TI numbers. IIRC, they seem to be nearly identical chips. Unfortunately, these chips use the new SMD PowerPAD heatsink config. which can make DIY a tad more difficult trying to solder the bug's belly to the PCB.
Headwize is a good resource for headphone stuff.
Hope this helps.
David
You could use any chip you like, and then build a simple transistor output stage. Seems relatively easy enough.
Or, there is the AD815 High Ouput Differential Driver which seems to be well capable of driving low impedance loads. I seem to recall some projects here using this chip. A search of this site might reveal some useful information.
If you don't like the SMT version of this chip, BG-Micro still stocks an older 15-lead through hole SIP version for only $1.95 USD. This package is nearly identical to the LM3886, so it shouldn't be too difficult to work with. This chip was designed as an ADSL line driver, so it has good bandwidth and plenty of umph behind it.
Texas Instruments also offers their TPA6120 High Fidelity Stereo Headphone Driver, which is considered by some to be the best headphone amp on the planet right now.
Veteran has played with this, and may even have some PCBs available.
Rod Elliott at ESP has a write-up in his technical articles about this new TI headphone amp chip, and he details the prototype he built. He seems very well pleased with the final result. See THS6012 CFB Pre-Amplifier (about halfway down the page).
Notice two different TI numbers. IIRC, they seem to be nearly identical chips. Unfortunately, these chips use the new SMD PowerPAD heatsink config. which can make DIY a tad more difficult trying to solder the bug's belly to the PCB.
Headwize is a good resource for headphone stuff.
Hope this helps.
David
How about a discrete output stage ? That must be easy to get.
Say BD139/140 !
Can you tell me what your requirements are ?
1. Does it need an on board power supply ? ( say 12-0-12 v ac input to the board )
2. Does it need an onboard headphone socket.
3. Does it need an on board volume control ?
4. Any restrictions on the board size ? ( 4x4 inches ? )
There might be ready made boards available .
Cheers,
Ashok.
Say BD139/140 !
Can you tell me what your requirements are ?
1. Does it need an on board power supply ? ( say 12-0-12 v ac input to the board )
2. Does it need an onboard headphone socket.
3. Does it need an on board volume control ?
4. Any restrictions on the board size ? ( 4x4 inches ? )
There might be ready made boards available .
Cheers,
Ashok.
It will be probably 4 stereo amps on one board.
Power supply is not yer decided, I would prefer single railed because you can use cheap wall wart as power source instead of a costly new transformer. So tha t means caps on output, can the on-thump destroy headphones?
I can do the board design and manufacture by myself, I only need help with choosing cheap and simple output stage.
I never designed discrete amp by myself, so I would appreciate your help with that.
So my requirements could be 12v supply, 1-2W per channel.
Thanks
btw what about LM386? is it usable? I used it a looong ago for some experimenting and it wasnt too great..
Power supply is not yer decided, I would prefer single railed because you can use cheap wall wart as power source instead of a costly new transformer. So tha t means caps on output, can the on-thump destroy headphones?
I can do the board design and manufacture by myself, I only need help with choosing cheap and simple output stage.
I never designed discrete amp by myself, so I would appreciate your help with that.
So my requirements could be 12v supply, 1-2W per channel.
Thanks
btw what about LM386? is it usable? I used it a looong ago for some experimenting and it wasnt too great..
Try this web-site for ideas. If you drill down far enough , somewhere in this web-site he compares many op amps. This might give you some ideas. Good luck!
http://tangentsoft.net/audio/
Regards//Keith
http://tangentsoft.net/audio/
Regards//Keith
Hi kubeek,
Your circuit seems OK. I'll sim it for you later today and see how it fares. I think it's OK. In fact you might be able to get away without those diodes . Just run the output stage in a low quiescent current class A design and dump the diodes and put a couple of resistors instead. I've tried that and it sounds fine. The slight current variation with temperature will not matter at all. Very unlikely to have a runaway bias condition. I'll put in the required resistor values also.
Cheers,
Ashok.
Your circuit seems OK. I'll sim it for you later today and see how it fares. I think it's OK. In fact you might be able to get away without those diodes . Just run the output stage in a low quiescent current class A design and dump the diodes and put a couple of resistors instead. I've tried that and it sounds fine. The slight current variation with temperature will not matter at all. Very unlikely to have a runaway bias condition. I'll put in the required resistor values also.
Cheers,
Ashok.
I just did the distortion analysis (without the proper transistors..) and the diode version shows about 2x lower distortion than with resistors.
I compared it at 4.5mA quiescent, and into 16ohm resistive load. The diode version shows 0.01%THD with 10kHz signal measures up to 100kHz. It is mostly even-order distortion.
I compared it at 4.5mA quiescent, and into 16ohm resistive load. The diode version shows 0.01%THD with 10kHz signal measures up to 100kHz. It is mostly even-order distortion.
This is not for monitoring in the way of hearing the mix when mixing/mastering, this amp will be for the people who are recording and need to hear themselves and the pre-recorded rest of the band in the headphones. And because for this you can use almost any cans, I want it to work with low impedance as well.
I don´t think that class A is a must here, so I guess AB will do it well.
I don´t think that class A is a must here, so I guess AB will do it well.
I think its no need making a especial headamp for studio.
FYI:
in my studio,I get all return monitor headphone powered from my pc multimedia speaker.I split 6 stereo channel via some 47ohm resistors from the speaker.
there are one k141m for recording room and some k100 for musicians,they work great.
Zang
FYI:
in my studio,I get all return monitor headphone powered from my pc multimedia speaker.I split 6 stereo channel via some 47ohm resistors from the speaker.
there are one k141m for recording room and some k100 for musicians,they work great.
Zang
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.