Hello Everybody!
I am new in this forum. In fact I stopped my "do it yourself" projects for about 10 years. But well, passion never dies 🙄
Some days ago I bought a Receiver from NAD through e-bay. Don't ask why, but I needed it urgently, because...
It showed some issues with connectors inside, just the normal drawbacks (left chanel missing...).
The amplifiers all had nearly no quiescient current, but offered a good margin in thermal handling and a very good thermal compensation!
I decided to adjust the bias of the front amplifiers 4 times higher than original and found an impressive improvement in sound (no wonder..).
Up to now this modification did not show any disadvantages.
Besides this it had some ringing of the rear amplifiers when cold... right after turning it on for about 1 minute.
You could hear this ringing through all amplifiers, also in the stable ones...
This also showed some dependencies on internal connectors, but also from the connected load etc...
The rear amplifiers do not have adjustable resistors for the current bias of the output stage. But simply putting a 1k/5W resistor from each output to positive or negative rail (no matter) stabilized this ringing immediately.....
(May be I will find some time to set up a more reasonable correction of this issue.)
To be honest: This receiver seems to give a lot of opportunities to improve it!
But without detailed schematic I feel somehow "blind".
It would be really great if somebody has the service manual or knows where to get it or any other detailed information of the construction.
Bye
Markus
I am new in this forum. In fact I stopped my "do it yourself" projects for about 10 years. But well, passion never dies 🙄
Some days ago I bought a Receiver from NAD through e-bay. Don't ask why, but I needed it urgently, because...
It showed some issues with connectors inside, just the normal drawbacks (left chanel missing...).
The amplifiers all had nearly no quiescient current, but offered a good margin in thermal handling and a very good thermal compensation!
I decided to adjust the bias of the front amplifiers 4 times higher than original and found an impressive improvement in sound (no wonder..).
Up to now this modification did not show any disadvantages.
Besides this it had some ringing of the rear amplifiers when cold... right after turning it on for about 1 minute.
You could hear this ringing through all amplifiers, also in the stable ones...
This also showed some dependencies on internal connectors, but also from the connected load etc...
The rear amplifiers do not have adjustable resistors for the current bias of the output stage. But simply putting a 1k/5W resistor from each output to positive or negative rail (no matter) stabilized this ringing immediately.....
(May be I will find some time to set up a more reasonable correction of this issue.)
To be honest: This receiver seems to give a lot of opportunities to improve it!
But without detailed schematic I feel somehow "blind".
It would be really great if somebody has the service manual or knows where to get it or any other detailed information of the construction.
Bye
Markus
I got schematics for my NAD CD player by purchasing them from the NAD service manual dealer. This number worked last year: 1-800-263-4641. Tell them what you want, they should send you a CD for about $30.
Thanks for your hint. I will try this if no local service center in Munich will provide the manual.
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