OP-AMPS in Marantz PM7000 Amplifier

Alex2 · 17th February 2004, 08:06 AM

Hello,

My name is Olek, I'm from Poland, and sorry for my english.

I have very important for me question/request about Integrated Amplifier Marantz PM7000 (or PM8000). I have PM7000 (and Marantz CD6000-after upgrade) and I want to change op-amps (Operational Amplifiers) inside to better ones. But I don't know which is responsible for what audio module/unit/signal_patch (I don't have any electronics and elements scheme or chart). I can see on the little plate inside (near the volume potentiometer/regulator) four op-amps (I think all are dual, for L and R channel):

1. 7501 - NJM2068DD (7501, 7502, 7503 are on the parallel board/plate to basis-ground)
2. 7502 - NJM2068DD
3. 7503 - .................. ?
4. .... ? - NJM2114D (it is only one op-amp on board/plate with the volume potentiometer/regulator, board parpendicular to basis-ground)

Which is to tone control in bas ?
Which is to tone control in treble ?
Which is to volume control ?
What for is the fourth op-amp ?
Maybe I'm wrong and their destiny and using is even different ?

Maybe photos with these op-amps will be helpfull: http://garmin.webpark.pl/pm8000.htm
(pictures nr: 7 - there are 3 op-amps, and 8 - there are 1 op-amp)

I listen only in Direct mode/patch (tone control and balance are disabled). Which is the most important to change for me ?
I want to change e.g to: OPA2604 or AD825.

I will be very grateful, much obliged and appreciate.
Thank you very much.

Best Regards
Alex2

jean-paul · 17th February 2004, 07:36 PM

Hello Olek, your post should be in another section I think. This is the digital section. Never mind. I think OPA2604 can be used for all opamps but a service manual/schematic would be very helpful. The NJM opamps ( all bipolar dual opamps BTW ) that are in the amp are lousy except for the reasonable 2114. OPA2604 outperforms them all. 2068 has a slewrate of 6V/us, 2114 has 15V/us and a max. output current of 60 mA ( headphone amp ? ).
Max. power supply voltage of 2068 is +/- 18 V, 2114's max. supply voltage is +/- 22 V. You're safe with OPA2604.

You can leave the opamps in the tone control section where they are since you don't use the tone control. Replacing them for OPA2604 won't hurt.

Alex2 · 18th February 2004, 10:14 AM

Hi,

Thanks a lot, but do you know what is destiny to each op-amp in these pictures. Op-amps are with numbers 1-4.

Alex

17th February 2004, 08:06 AM	#1
Alex2 diyAudio Member Join Date: Feb 2004 Location: Bydgoszcz	OP-AMPS in Marantz PM7000 Amplifier Hello, My name is Olek, I'm from Poland, and sorry for my english. I have very important for me question/request about Integrated Amplifier Marantz PM7000 (or PM8000). I have PM7000 (and Marantz CD6000-after upgrade) and I want to change op-amps (Operational Amplifiers) inside to better ones. But I don't know which is responsible for what audio module/unit/signal_patch (I don't have any electronics and elements scheme or chart). I can see on the little plate inside (near the volume potentiometer/regulator) four op-amps (I think all are dual, for L and R channel): 1. 7501 - NJM2068DD (7501, 7502, 7503 are on the parallel board/plate to basis-ground) 2. 7502 - NJM2068DD 3. 7503 - .................. ? 4. .... ? - NJM2114D (it is only one op-amp on board/plate with the volume potentiometer/regulator, board parpendicular to basis-ground) Which is to tone control in bas ? Which is to tone control in treble ? Which is to volume control ? What for is the fourth op-amp ? Maybe I'm wrong and their destiny and using is even different ? Maybe photos with these op-amps will be helpfull: http://garmin.webpark.pl/pm8000.htm (pictures nr: 7 - there are 3 op-amps, and 8 - there are 1 op-amp) I listen only in Direct mode/patch (tone control and balance are disabled). Which is the most important to change for me ? I want to change e.g to: OPA2604 or AD825. I will be very grateful, much obliged and appreciate. Thank you very much. Best Regards Alex2

17th February 2004, 07:36 PM	#2
jean-paul diyAudio Moderator Emeritus Join Date: Sep 2002 Location: The Netherlands	Hello Olek, your post should be in another section I think. This is the digital section. Never mind. I think OPA2604 can be used for all opamps but a service manual/schematic would be very helpful. The NJM opamps ( all bipolar dual opamps BTW ) that are in the amp are lousy except for the reasonable 2114. OPA2604 outperforms them all. 2068 has a slewrate of 6V/us, 2114 has 15V/us and a max. output current of 60 mA ( headphone amp ? ). Max. power supply voltage of 2068 is +/- 18 V, 2114's max. supply voltage is +/- 22 V. You're safe with OPA2604. You can leave the opamps in the tone control section where they are since you don't use the tone control. Replacing them for OPA2604 won't hurt. __________________ It's only audio

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