Distorted output on NTP 182-120

[jakobz]

Hi there.
Im having a distorted output on a NTP 182-120 eq.  Since there do not seem to be any schematics for this, i have tried tracing the signal around with  the scope, and did find what seems to be a pretty messed up signal on the outputs of one of the opamps,(image attached) Im going to look further tomorrow, but wanted to ask, if anyone had any advice on how to pursue this, when there dont seem to be any schematics around.

 

[gyraf]

I'd very strongly suspect a dead opamp

https://groupdiy.com/index.php?topic=46971.20

/Jakob E.

 

[jakobz]

lots of great info there, I missed that thread completely  thank you.

 

[gyraf]

I have the full manual somewhere, but it's too large for this server (~9mb IIRC) Perhaps email me your email address, and I can send it there. But I'm on my way to Porto right now, I won't be in office until next week some time.

/Jakob E.

 

[jakobz]

sounds great Jakob. I dropped you a message on facebook  If it turns out to be the opamp do you know if there are any replicas out there?
Beside the obvious footprint differences and sonical characteristics,  wouldnt opamps behave pretty much the same? in a circuit Would a random DIL packaged opamp i may have lying around, work as a replacement for  a M100 or  API 2520 for instance?

 

[Conviction]

sounds great Jakob. I dropped you a message on facebook  If it turns out to be the opamp do you know if there are any replicas out there?
Beside the obvious footprint differences and sonical characteristics,  wouldnt opamps behave pretty much the same? in a circuit Would a random DIL packaged opamp i may have lying around, work as a replacement for  a M100 or  API 2520 for instance?

51xAudio/[silent:arts] makes a M100 clone. Not the same footprint, but shouldn't be too much work. Perhaps he can even provide one with the same footprint? Thinking of getting some for my Tore Seem TSM6-2A (although the originals work, I'm just curious).

 

[jakobz]

51xAudio/[silent:arts] makes a M100 clone. Not the same footprint, but shouldn't be too much work. Perhaps he can even provide one with the same footprint? Thinking of getting some for my Tore Seem TSM6-2A (although the originals work, I'm just curious).

Thanks for the advice, i was wondering if it was a suitable replacement beside the different footprint, i just wrote him and asked about it.

 

[Conviction]

I have the full manual somewhere, but it's too large for this server (~9mb IIRC) Perhaps email me your email address, and I can send it there. But I'm on my way to Porto right now, I won't be in office until next week some time.

/Jakob E.

Jakob, I'd be very interested in that. I'll send you an email?

 

[jakobz]

It was indeed  one of the opamps gone bad. I replaced it with a generic DIL opamp, wired on a small piece of proto PCB. I have not done any intense listening tests, but it seems to sound just the same as the other unit with all original opamps