NJM4560L upgrade/replacement

[raul_ghiran]

Hi guys. I have an JBL M-Patch Active1 monitor controller, wich has the NJM4560L opamps as headphone amps. At first I did not notice the sound on headphones that the midrange is quite boosted, until I took the headphones out of the m-patch and pluged it in the soundcard's headphone output and it was a whole new world(an Antelope Orion Studio). Can you guys advise me if chaging the opamps on m-patch would give me a better sound on headphones and what replacement would you recommend?
Thank you

Raul

 

[NOON]

Unlikley a change of opamps will make a significant difference when the design of the whole headphone amp is 'entry level.'

 

[Khron]

... And you know for a fact the "boosted midrange" is due to the 4560's themselves, and not the circuitry before / around them? :

 

[Bo Deadly]

NJM4580L

But honestly RC4560 is not a horrible op amp for a headphone amp. It's got the same great output drive.

 

[gyraf]

..in short, don't expect any benefit from opamp rolling this..

 

[RuudNL]

In most 'simple' headphone amplifiers, there are series resistors at the output, to protect the output stage against short circuit or overload. These series resistors can influence the frequency response of headphones.
(Most headphones are dynamic, and a coil doesn't have a constant impedance for all audio frequencies.)

 

[raul_ghiran]

Thank you guys for your quick answers! So I'll just leave it as it is 

 

[living sounds]

NJM2068. But it's a DIL chip, so would require an adapter in your board.

http://nwavguy.blogspot.com/2011/08/op-amp-measurements.html

 

[Newmarket]

It's not the op amp that defines the frequency response.
You have to look at the circuitry as a whole.

 

[abbey road d enfer]

NJM2068. But it's a DIL chip, so would require an adapter in your board.

http://nwavguy.blogspot.com/2011/08/op-amp-measurements.html

AFAIK, NJM2068, although being an excellent challenger to the 5532, has not as much drive capability.

 

[abbey road d enfer]

Hi guys. I have an JBL M-Patch Active1 monitor controller, wich has the NJM4560L opamps as headphone amps. At first I did not notice the sound on headphones that the midrange is quite boosted, until I took the headphones out of the m-patch and pluged it in the soundcard's headphone output and it was a whole new world(an Antelope Orion Studio). Can you guys advise me if chaging the opamps on m-patch would give me a better sound on headphones and what replacement would you recommend?
Thank you

Raul

As RuudNL mentioned, the problem may be an excessive added resistance. You may want to try to locate it. You could do it by probing between the opamps' outputs and the H/P connector. If there is indeed a resistor, shunt it and replace the opamp with an NJM4556; it exists in SIP8 package ($0.75). It is designed for high current and is suitably protected.
Then you may face a potential problem with insufficient or poorly designed power supply decoupling. You may have to add ceramic decoupling caps right on the IC pins.

 

[raul_ghiran]

As RuudNL mentioned, the problem may be an excessive added resistance. You may want to try to locate it. You could do it by probing between the opamps' outputs and the H/P connector. If there is indeed a resistor, shunt it and replace the opamp with an NJM4556; it exists in SIP8 package ($0.75). It is designed for high current and is suitably protected.
Then you may face a potential problem with insufficient or poorly designed power supply decoupling. You may have to add ceramic decoupling caps right on the IC pins.

Thank you very much for the information! I will check this  and get back.

Thank's