modify an NAD 7020?

[peace brainerd]

Can anyone suggest where to find info on worthwhile
mods/tweaks for this receiver?

[Leolabs]

Starting with the filtering and signal coupling caps.

[planarboy]

I want to resurrect this thread.
Now I have a NAD 502 CD player AND a NAD 7020 receiver.
I want to mod them to learn about it.
I already have a clock upgrade for the 502. It was cheap. I don't want to spend heaps per part first up.
First a friend of mine will just get them working, neither do.
Then I want to learn how to make them sound better bit by bit.
I guess my first step could be caps and that clock upgrade, followed by...who reckons what?
It might seem a little sad to some people but I'm behind my little project.
Do I need to get something called "torroidals" in there, or do they just look better. I don't want to get into batteries yet....
I know NAD is some pretty moddable gear.
Dave

[baldrick]

On the NAD 502:

Remove the four NE5521 dual op amps and replace them with TI / Burr Brown OPA2134s. Solder in some chip sockets first if you want to audition other dual op amps.

It will sound like a much more expensive player with OPA2134 opamps.

You could also upgrade the electrolytics on each of op amp's + and - supplies.

[planet10]

The 7020 can be dramatically improved, and is easier to work on that a 3020 because it has more room and the I/O is not captive to the circuit board.

Here is the service manual: http://homepage.mac.com/planet10/man...ly_servMan.pdf

I corresponded with a fellow that changed every cap in his 7020 with something better, replacing elsos in the signal path has the greatest effect.

Upgrade, increase the size (not too much), and bypas the main power amplifier elcos.

Be very carefiul with the regulared power supply for the front-end, it is easy to upset.

Put the power switch on the back -- replace it with a more robust toggle (the failure of the power switch is common, moving it to theback keeps the AC mains in a small corner of the amp. Disconnect the AC convienience plugs while you are at it.

replace the speaker terminals with proper 5-way binding posts... bypass the speaker switch with short wires directly from the board (eliminating a whole bunch of wire and circuit board traces.

Replace the RCAs you use with better.

Replace the steel junpers with a set of real patch cords (or just hardwire on the inside if you can live without pre-out/power-om

Jumper over the tone controls.

That should keep you bisy for a bit.

PS: be careful with the solderng iron, the NAD used really good topology to overcome low cost build to get good sonics -- it is easy to kill traces.

dave