Power amp rebuild

Decided to attack one of my monoblocs today. In a previous life it was a NAP140, but then i bought another, removed a NAPA board in each one, then put a minicap module in and finally a NCC200. I left everything in it's original position and had the ncc in the position furthest from the transformer. I have lived with it for a number of years but recently got tired of the messy wiri g and thought tidying it up and rejigging things would be worth the hassle. Well i was not disappointed.

I prefer to work with solid core power wiring and so stripped some 2.5mm twin and earth. Only red and black colours available but i am sure they sound better than other colours . Made sure i put the spade connector insulators on this time. For the speaker 0V returns and signal output wiring i butchered some rather nice chord company speaker cable i had lying around unused.

With the layout i put the 200VA transformer at the front of the case instead of to the rear as Naim positioned it. The NCC200 i have put at the back with the signal in spades near the incoming signal din socket. Replaced din socket with a cable gland and signal snaic runs right to the amp ncc board, screened all the way. Minicap i have positioned with the retifier diodes near the on/off switch and it's outputs in line with the spade connectors on the ncc board.

As i will be moving my speaker xovers from the speakers to the hifi rack and biwiring them i decided to biwire right back as far as i could. So two wires from the ncc signal output and two wires from the 0V conection on the ac side of the minicap going to two pairs of speaker outlet sockets on the back panel. Then two sets of avondale black link to the speakers.

There are other mods in the pipeline. Independent psu for the front end, simple 3 component gyrators piggybacked on the ncc200 right above the tp1 & 2 points, new transformer for the output stage. As an intermediate stage i was thinking of plumbing the gyrators in where the diode and 220 ohm resistors are as Teddy Pardo did all those years ago. It should drop no more voltage than the diode and resistor, maybe even less.

I have not bolted the transformer down as things are going to change again so as an experiment i moved it onto the table next to the amp as far as the secondary leads would allow. It was an enlightening experience.

I am very pleased with my new tidy wiring looms, the last version was cobbled together as quickly as possible. Tidy and organised wiring really does make a hell of a difference! Overall i am very pleased with the improvements especially as i have only done one of the monoblocs. The difference between the two channels was easy to hear and i can't wait to get the other one done. Maybe these mods have all been done years ago but i am having so much fun ,learning lots and discovering new things all the time. Maybe in another ten years time i wil have my perfect system ?

Pics to come when i have found the camera.

Stu

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Last edited by mega lord; Today at 01:18 PM. Reason: added stuff

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Power amp rebuild