Hello guys,
I hope you can help me.
Is it possible in a denon PMA1560 to use the opa2134pa as replacement of njm2082d op-amp
Service manual:
DENON_PMA-1560_SM.pdf - Windows Live
Regards Rick...
I hope you can help me.
Is it possible in a denon PMA1560 to use the opa2134pa as replacement of njm2082d op-amp
Service manual:
DENON_PMA-1560_SM.pdf - Windows Live
Regards Rick...
OK thank you guys, this amp have 2 defect op-amps on both channels.
Last week they send instead of njm2082d 4x lmt2904. People say to me here on this forum that the lmt2904N (lm2904) i think is a low budget op-amp.
A lot of people say that the opa2134 is a really good op-amp.
So it`s no any problem to use them?
And another little question. On this channels there where 3x 2sa1142 (P) or (Q) burn out.
I will to replaced them with mje350, do you think this is a good choice.
Regards Rick...
Last week they send instead of njm2082d 4x lmt2904. People say to me here on this forum that the lmt2904N (lm2904) i think is a low budget op-amp.
A lot of people say that the opa2134 is a really good op-amp.
So it`s no any problem to use them?
And another little question. On this channels there where 3x 2sa1142 (P) or (Q) burn out.
I will to replaced them with mje350, do you think this is a good choice.
Regards Rick...
The op-amps is in the optical bias adjust circuit and i would guess that you could change them to almost anything.
The "green" NEC 2sa1142 are located in the audio path and you could mess up the original sound if switched to something else.
2sa1142 are available but not the NEC NOS green ones.
Swap to any 2sa1142 is my recommendation.
I own 2 of these pma-1560´s.
The circuitboards aren´t complete identical between the amplifier boards.
my board numbers are 2229210006 and 2229210103.
Biggest pain with repairing these amplifiers is that you have to redo all soldering.
2 out of every 10 soldering joint are bad.
On both of amplifiers the front leds had to be resoldered.
It´s very important to check the bias both at idle and with 10mv 1khz because with the later you adjust the class-a bias and that is important because the amp switches back to class a/b when input signal goes over a cirtain level.
With proper adjustment you remain in class a as long as possible.
When these amps are fully working you have some nice sound capabilities.
Newer amplifiers uses more output devices to draw low impedance speakers.
I checked the schematics on the PMA-2000R but can´t say that i am impressed.
When it comes to sound i´m biased to sanken bjt´s.(cant explain why!)
Pelle
The "green" NEC 2sa1142 are located in the audio path and you could mess up the original sound if switched to something else.
2sa1142 are available but not the NEC NOS green ones.
Swap to any 2sa1142 is my recommendation.
I own 2 of these pma-1560´s.
The circuitboards aren´t complete identical between the amplifier boards.
my board numbers are 2229210006 and 2229210103.
Biggest pain with repairing these amplifiers is that you have to redo all soldering.
2 out of every 10 soldering joint are bad.
On both of amplifiers the front leds had to be resoldered.
It´s very important to check the bias both at idle and with 10mv 1khz because with the later you adjust the class-a bias and that is important because the amp switches back to class a/b when input signal goes over a cirtain level.
With proper adjustment you remain in class a as long as possible.
When these amps are fully working you have some nice sound capabilities.
Newer amplifiers uses more output devices to draw low impedance speakers.
I checked the schematics on the PMA-2000R but can´t say that i am impressed.
When it comes to sound i´m biased to sanken bjt´s.(cant explain why!)
Pelle
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