Hey,
I concur. NJM4580 and NJM4556 are both pretty darn good. You know 4556 is used for Grado RA-1?
Originally, I wanted 4556, but I could not buy these in Tokyo. They are supplied through some odd supplier chain. So I could only get 4580. Eventually, I had to pull some favors to get 4556. (you know shady
booths with smoking old lady?)
Recently I upgraded my old headphone amp and plz look at the pic:
This is utterly funny. Using EVM for a headphone amp. (and you know it's a type of CMOY amp.
Tomo
I concur. NJM4580 and NJM4556 are both pretty darn good. You know 4556 is used for Grado RA-1?
Originally, I wanted 4556, but I could not buy these in Tokyo. They are supplied through some odd supplier chain. So I could only get 4580. Eventually, I had to pull some favors to get 4556. (you know shady
booths with smoking old lady?)
Recently I upgraded my old headphone amp and plz look at the pic:
An externally hosted image should be here but it was not working when we last tested it.
This is utterly funny. Using EVM for a headphone amp. (and you know it's a type of CMOY amp.
Tomo
Tomo : Did you compare the NJM 4580 and 4556 ?
Any audible differences ? Is it used as a line stage or headphone amp ? If a headphone amp , what headphone did you use.
The Juli@ sound card also uses the NJM4580 V ( the smallest package ). I was trying to get some of those to replace some faulty ones.
Cheers.
Any audible differences ? Is it used as a line stage or headphone amp ? If a headphone amp , what headphone did you use.
The Juli@ sound card also uses the NJM4580 V ( the smallest package ). I was trying to get some of those to replace some faulty ones.
Cheers.
Hey,
I was using those to drive my 32 ohms headphones as the output stage of an experimental YAHA amp. Initially I was using 4580 but later tried out 4556. But these guys are good in "coloured" way. So I think you should not use it for line-stage.
I would go with something like AD797 or something. After all, upgrading to "cheap" opamps doesn't sound like "Upgrading" at all.
With this I meant, they are good "for the price". This doesn't mean they can out-do OPA627 or AD8610. Sorry for the confusion.
But I do own handful of these for "experimentation".
Tomo
I was using those to drive my 32 ohms headphones as the output stage of an experimental YAHA amp. Initially I was using 4580 but later tried out 4556. But these guys are good in "coloured" way. So I think you should not use it for line-stage.
I would go with something like AD797 or something. After all, upgrading to "cheap" opamps doesn't sound like "Upgrading" at all.
With this I meant, they are good "for the price". This doesn't mean they can out-do OPA627 or AD8610. Sorry for the confusion.
But I do own handful of these for "experimentation".
Tomo
Hey,
I think he means this:
http://www.tnt-audio.com/clinica/dynamicopamp_e.html
Usually opamps are designed to drive fairly high impedance. So it isn't good to directly drive headphone via opamp. Which is why I thought it was good to use a cable driver (which wasn't the best idea ... as all the trouble it caused me. ... Fun as an electronics student.)
Hey, one more thing. There was some rumor about cheap driver called TDA1308. Sijosae (spell?) wrote something in Korean, but I failed to understand the document. How about it?
Tomo
I think he means this:
http://www.tnt-audio.com/clinica/dynamicopamp_e.html
Usually opamps are designed to drive fairly high impedance. So it isn't good to directly drive headphone via opamp. Which is why I thought it was good to use a cable driver (which wasn't the best idea ... as all the trouble it caused me. ... Fun as an electronics student.)
Hey, one more thing. There was some rumor about cheap driver called TDA1308. Sijosae (spell?) wrote something in Korean, but I failed to understand the document. How about it?
Tomo
^^ Not bad, actually. It is used as the output for the front speakers on my SB Live! The sound is pretty much mauled by the resampling and the cheap little CS4297 DAC before it, but i seems quite capable and the spec sheets aren't too bad either, better than lots of opamps. I seem to prefer the LM4562 and Philips DAC combo on the rear speakers though.
Hey,
Going back to,
I am curious as well. There are many designs, but some reliable people go with simple opamp and transistor pushpull. Are those good? I mean does it worth it to go really far by using more sophisticated topology?
There is also a design like Sheldon Stoke's amp where the usual AB-output stage is pulled to class A and lower transistor becomes a current source.
Personally, I was thinking about use CHEAPO transistors like 2N3906/4. 200mA right? Isn't it enough?
Tomo
Going back to,
I am curious as well. There are many designs, but some reliable people go with simple opamp and transistor pushpull. Are those good? I mean does it worth it to go really far by using more sophisticated topology?
There is also a design like Sheldon Stoke's amp where the usual AB-output stage is pulled to class A and lower transistor becomes a current source.
Personally, I was thinking about use CHEAPO transistors like 2N3906/4. 200mA right? Isn't it enough?
Tomo
".............Going back to,
quote:
So what do you think about this? Transistors will probably be 2n5551/5401 and MJE340/350, with NE5534 as opamp.
I am curious as well. There are many designs, but some reliable people go with simple opamp and transistor pushpull. Are those good? I mean does it worth it to go really far by using more sophisticated topology?............."
Yes , try the simple topology and you will not be disappointed.
Stop searching around for more. By now you should have had a functional unit up and working.
I have some spare h/p amp pcb's . If you want one I can send it to you . It uses BD139/140 for the output and works off +/- 12 volts . +/- 9 volts also possible.
Cheers,
Ashok.
quote:
So what do you think about this? Transistors will probably be 2n5551/5401 and MJE340/350, with NE5534 as opamp.
I am curious as well. There are many designs, but some reliable people go with simple opamp and transistor pushpull. Are those good? I mean does it worth it to go really far by using more sophisticated topology?............."
Yes , try the simple topology and you will not be disappointed.
Stop searching around for more. By now you should have had a functional unit up and working.
I have some spare h/p amp pcb's . If you want one I can send it to you . It uses BD139/140 for the output and works off +/- 12 volts . +/- 9 volts also possible.
Cheers,
Ashok.
Hey,
Is this what your amp like?
http://sound.westhost.com/project113.htm
I suppose so. I am finding it hard to believe, but I know Rod is reliable. Hum ...
T
Is this what your amp like?
http://sound.westhost.com/project113.htm
I suppose so. I am finding it hard to believe, but I know Rod is reliable. Hum ...
T
Almost similar. I don't use any diodes .
But I have another one also which I discovered has also been used by others . The opamp I used was a FET input opamp. You can use other opamps and make sure the proper value resistors are used.
I used an inverting input and reduced the capacitor count . The end result on both boards is very good . I find it hard to make out if anyone is better than the other.
I did use a 1uF polyester cap at the input. I prefer polyprop caps generally but as I discovered all polyprop's are not the same and not all polyester's are worse than polyprop's.
You will need to experiment.
Want the board ?
But I have another one also which I discovered has also been used by others . The opamp I used was a FET input opamp. You can use other opamps and make sure the proper value resistors are used.
I used an inverting input and reduced the capacitor count . The end result on both boards is very good . I find it hard to make out if anyone is better than the other.
I did use a 1uF polyester cap at the input. I prefer polyprop caps generally but as I discovered all polyprop's are not the same and not all polyester's are worse than polyprop's.
You will need to experiment.
Want the board ?
Hey,
How do you compare with OPAMP-BUFFER (chip eg BUF634)? I got bunch of those. I ask this because many people swear by discrete stuffs like:
http://www.audiodesignguide.com/Headphone_amp/headphoneamp.html
And, look at the parts! They are quite affordable. I just need to build a transistor tester. (I could buy one, but I just like to "build" one. Kinda give me this illusion that I am a "productive" gradstudent.)
Regarding the boards, I would love one. But I live in Japan you know? I think shipping cost can get exorbitant.
How should I contact you?
T
How do you compare with OPAMP-BUFFER (chip eg BUF634)? I got bunch of those. I ask this because many people swear by discrete stuffs like:
http://www.audiodesignguide.com/Headphone_amp/headphoneamp.html
And, look at the parts! They are quite affordable. I just need to build a transistor tester. (I could buy one, but I just like to "build" one. Kinda give me this illusion that I am a "productive" gradstudent.)
Regarding the boards, I would love one. But I live in Japan you know? I think shipping cost can get exorbitant.
How should I contact you?
T
Konichiwa !
I spent 8 months in Japan several years ago !
Great place !
BUF634 should probably be good too. I couldn't find it's distortion figures but with unity gain it must be low.
However if you use it as is , the quiescent current is only 1.5mA . Class AB for sure.
It does go up to 15 mA if the bandwidth control pin is connected to -V supply. I have no idea if the quiescent current does make an audible difference in the sound . Maybe if you load it heavily with a 16 ohm load.
Wonder if anyone has checked this. I haven't seen it mentioned in the posts I have seen so far.
You can send me a private mail at
ashokm(at)sify(dot) com.
Cheers.
I spent 8 months in Japan several years ago !
Great place !
BUF634 should probably be good too. I couldn't find it's distortion figures but with unity gain it must be low.
However if you use it as is , the quiescent current is only 1.5mA . Class AB for sure.
It does go up to 15 mA if the bandwidth control pin is connected to -V supply. I have no idea if the quiescent current does make an audible difference in the sound . Maybe if you load it heavily with a 16 ohm load.
Wonder if anyone has checked this. I haven't seen it mentioned in the posts I have seen so far.
You can send me a private mail at
ashokm(at)sify(dot) com.
Cheers.
I am so sorry. I can't get the picture right!
It's on:
http://www.national.com/ds.cgi/LM/LME49740.pdf
Later page under line driver. Can any one of you guys get the picture right?
Tomo
It's on:
http://www.national.com/ds.cgi/LM/LME49740.pdf
Later page under line driver. Can any one of you guys get the picture right?
Tomo
I have very successfully used a Sanyo LA 6550 power op amp as a headphone amplifier. It is a single channel (mono) 5 pin package that is very easy to heatsink.
Can be powered from +/- 18 volts and can output 1 amp into a load. So it will go as loud as you like!
There is a two channel version LA 6515 in a 10 pin SIP package - but this can only supply 0.5 amp......
Can be powered from +/- 18 volts and can output 1 amp into a load. So it will go as loud as you like!
There is a two channel version LA 6515 in a 10 pin SIP package - but this can only supply 0.5 amp......
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