NAP-140 Clone Amp Kit on Ebay

[Ian Finch]

I think you are referring to what's commonly called the output Zobel network. That's exactly what it's for and particularly necessary with the Naim design which has few other means of damping oscillation, preventing RF from causing havoc or damping ringing with capacitive loads. You may be aware of the many comments on forums about the need for reasonably inductive speaker leads and the extra series 0R22 resistor which is claimed to work similarly to an output coil/resistor combination found in virtually all other designs. (i.e. use our brand speaker cables!)
Well, that part may look wrong and a trap for the unwary but it seems Naim have been largely successful with the arrangement regardless. Good for you that it was soon spotted

[Spuds]

Well done.

I am thinking of giving the Sanken's a try just to see how they sound.

[grimy]

OK 4th time I've tried to post this my mistake I'm sure but when I preview I only seem to have the choice to close or go back. So this post might be un pre-viewed.
I built the Naim clones from ebay. Had some issues but didn't blow them up before getting them working great.
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I can't afford a new enclosure so I used my old JVC AX-1. It was an award amp at the time so I thought it must be good. So wrong it sounded "Dead" and to be honest it killed my hifi hobby till now. I'm still using my KEF celeste speakersas they are faultless for what they are.
So the PICs..
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The JVC pre mod.
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[gaborbela]

Hello

These will be my NAIM (NCC200) clone.
I build it as a dual mono system in one enclosure. These actually the NCC200 clone.
I started with a pair of Tubeshunter's kit. It sounded nice but after I did more research I ended up cloning the NCC200.
It sound way better than the NAIM kit from Ebay. I did listen that NAIM kit from ebay about 4-5 months. After I started to listening the NCC200 I could not listen the NAIM clone anymore.I did tried several time but after one track I turned off. With the same PS of course.
My NAIM kit came with great parts Elna Silmic capacitors etc.
I did a lot of research (about 6 moths) on my NCC200 clone tested all the parts specially the capacitors and the driver and power transistors which sound better or which set up give the best sound. Also the input cap is very important..
I can say these amp rocks, sound excellent!
I still want to test the large Sanken power transistors and one more set Toshiba driver.
I'm very-very pleased and happy already with the result. I can listen these amp with all type of music Jazz, Folk, Gospel etc, and I can listen with out make me tired etc. It has huge deep bass well controlled, nice Naim like mids but more open and cleaner all do has the same charm, clean nice high.
Now I do not say the Naim Clone from Ebay is bad, I started with that (I did upgraded of course) and I listen for 4-5 months.
Until now I used these amp on a piece of wood, I think now I must build it.. I made new PC boards because the old was burned from soldering parts in and out.
If someone has experience about the 2SC2922 Sanken transistor compare to the ON semi transistors please share with me.

Greetings Gabor

[Ian Finch]

What a great result, Gaborbela. It would be wonderful if we all had the same experience with Ebay clones. The circuit diagram is so close and the NCC parts are actually lower grade than genuine Naim parts so I believe the problem, as always, is fake semiconductors. At the price for the entire kit and even completely assembled, it cannot contain genuine power transistors.

I retro-fitted genuine, used Sanken 2SC2922 output transistors and Zetex VAS transistors for a guy near me who built the kits and was not happy at all with the sound. I agreed, so we fitted known good parts and Voila! Absolutely much better sound and they did not burn, like some clones do when powered at high levels, even with just a dummy 8R load. If these are not available, at least fit genuine 2SC5200 parts as these are quite cheap and just as good sound-wise. Even those $3 parts are faked now -

If you can still buy plain PCBs and can afford to buy genuine parts, you can build either design if you wish. Bear in mind that it's the Naim design that still demands top money, even if the parts and small details still get upgraded with the times.

[gaborbela]

Hello Ian
Thank you!
To be clear what I wrote my amplifier based on the NCC200 clone (circuit). I use my own (selected transistors after many hours exhausting listening tests) set.
Every transistor was tested, replaced until I get the best sound out..
I did not bought the NCC200 PC board, I used the McBride layout modded several time until I did like the result. I made 4 different version until I got these now.
Right now I use all ON semi (orig from ON semi) transistors, ZTX and one from ST the BD139.
I invested a lot of time to improve the sound. It was well worth it.
The NAIM Chrome Bumper (the best) used the 2SC2922 Sanken but be careful because that is a fast transistor.
You have to pick the right driver transistor for that how they did MJE243 & 253
I learned one think not always the best parts give the best over all result (sound), I think more important how we match all those parts together (up to the last wire) to get good result.
Of course with fake transistor we can't go far.
I did purchased Sanken at the local store for $17 and exploded at power up into pieces..
Another think DIY-ers many time use the 100nF next to the electrolytes on the PC board with out testing if it improve the sound or degrade. Not always the best idea.
I did tried to next to the Silmic 100uF to use ERO and Wima 100nF and it degrade the sound a lot..
One think is sure these amplifier is very sensitive almost most of the parts and wires we use, but with patient and tests you can get a very high quality sound out from her..
I attached 2 circuit the orig NCC200 and one was modified by Greg Ball (SKA designer) I didn't tested that yet.

Greetings Gabor

[AndrewT]

The modifications shown in the sch on the right (Greg Ball) make a lot of sense.

A few of the values in the left sch look bonkers !

[harwoodspark]

Originally Posted by Ian Finch

If you can still buy plain PCBs and can afford to buy genuine parts, you can build either design if you wish. Bear in mind that it's the Naim design that still demands top money, even if the parts and small details still get upgraded with the times.

If you can afford genuine parts why would you want to build a clone? Go straight to Les at Avondale and buy his NCC200 boards and build the real deal. I've built three pairs of these 140 clones and a pair of NCC200s which are now up to Voyager spec. The clones don't come anywhere near a bog standard NCC200 and the Voyager spec is just miles in front.
This is one of my NCC200 Voyagers with my own VBE board.

[AndrewT]

Does that mean you believe the left sch is better?

[harwoodspark]

Originally Posted by AndrewT

Does that mean you believe the left sch is better?

I'm not too good at reading circuit diagrams so I wouldn't know the difference and tbh I wouldn't want to look at a circuit diagram to decide how something sounds.