NAP-140 Clone Amp Kit on eBay

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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 :)
 
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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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My Naim

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
 

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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 - :grumpy:

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.
 
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
 

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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.
 

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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.
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
are you saying that the left sch is better?
 
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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.
Last I looked, only modules @ over 200GBP ea. were available over the net from Avondale. Currently there are no prices other than 100GBP mains power leads visible so obviously, Les isn't keen on foreign business. A pair of Clone PCBS is around 13 GBP + post and the parts about 70GBP, depending of course, on what your choices were. That's a huge price difference. Anyways, its just not viable to DIY with modules at those prices and I see many guys modding their Ebay clones to avoid them. I don't know what extras and parts you guys in the UK can get from Avondale but someone correct me if I'm wrong in saying they aren't generally available to overseas purchasers.

The real deal I referred to is Naim, not Avondale sound - they are different tunings and have different results from different speed devices and tweaks. Some prefer one or the other but when correct devices are used in a clone and the actual schematic tweaks applied, you have acceptable sound for very little cash. Otherwise, you still have a simple and cheap, working, class AB amplifier. That is the real point of Ebay clones and the general direction of this thread.

Most builders will eventually realise that the generic schematic of a NAP250 that circulates with Ebay clones and is posted a few times in this thread, fits no particular model. Some have indeed built the clones and denounced them as awful sounding and the reasons are quite obvious, basic and discussed over and over. However, if you have the cash for quality, tested finished product and designs with pretensions to more genuine hi-end quality sound, you probably don't want the bother of tinkering with such problems at the board level with unknown parts anyway, so I can understand the decision to go with a proven DIY product and design and parts from a respected local source, if available. The NCC product certainly has enthusiastic support from all those dedicated Naim-modder forums. Amazing!
 
The clones don't come anywhere near a bog standard NCC200 and the Voyager spec is just miles in front.
Hello
All do I didn't purchased the Avondale kit I only use their schematic.
I do not want to pay for parts I know I will not use them.
To me the flat pack transistor sound better than the TO3. (These my opinion we can argue over these I did some test)
And that MJL power transistor (sounded the best to me) these type only avaleble in flat package.
Also I did tested the tantalum capacitors both wet (military type) and the type they use, I'd like to stay with the Silmic.
I can write yes I agree with you, the sound quality between the Naim 140 clone (Ebay or not) and the NCC200 is huge.
I have nothing to do with Avondale!!!!!
I started I did purchased a set from Tubeshunter from Ebay which used good parts (all orig transistors at least 4 years a go).
It used Tip driver transistors and Sanken (not the large case but orig Sanken) power transistors.
At the beginning I did like so much I ordered one more set. I started to change parts on it, like using ON semi MJ11034/35 drivers and MJL power transistors.
Dale & PRP resistors.
On the input I use BG non polar 10Uf (the best), and ZTX better than BD which came with the orig clone.
All the rest capacitor on the board are Elna Silmic 100Uf. Yes I did tried many different type like Philips, Nippon CC, etc.
To me Silmic is the best........
Another think the Ebay kit has a built in protection (that do degrade the sound very badly)
I took it out, and who-la the sound opened up, much cleaner, better bass and more increase dynamic.
Al do these caused a little problem when I turned of the amp and the voltage drop around 7-8V the power transistor open up and let the DC out to the speaker coil. I need to use speaker protection.
So on the end I realised almost I can't use nothing from the Ebay clone I sell them both after I made my own PC boards.
The last PC board was designed I can include the Greg modification to, that is not on the layout I'll post.
I didn't tested yet but at the Greg's forum someone tested step by step how Greg told him and improved the orig Avondale NCC200 kit.That is how they came up with these schematic.
Later I want to test that to, if is true probably I can improve further the sound. All do right now what I achieved I'm more than satisfied with!:)
I will post my lay out but because I did draw with the paint program I do not have parts list (silk screen) I use color code.
If you interested I post the list of the transistors I use now. I'm happy if I can help.There is no secret from my side.
Also I will make a picture from the old stuffed PC board and will posted so you can see it.
Greetings Gabor
 

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It's not that long ago since I bought some bare NCC boards from Les. Maybe he's giving up on the diy side. I did hear a whisper that he might be running down as he's well past the usual retirement age. There's always the HackerNap to try I suppose. Plenty of info over on the Pink Fish.

As for the clones I thought they sounded ok. I still have one pair built into an old Cambridge Audio P500 case using part of that psu ( I simply hacked it out of the old pcb) and the transformer. It's still in use and works fine but it's nothing to write home about. I did replace all the cheap caps though but nothing else. I found the bias hard to keep steady too and in the end I bought a pair of Avondale boards and that was that.
Personally I don't think the Avondale sound is that far removed from the Naim sound. Just enough that it doesn't irritate, maybe not so sharp but it's still very clean sounding just like the Naim. The clones don't sound much like Naim at all tbh. Thin and wiry might be the only two words of similarity :)
 
Hello
I would live to give a try to these amp
I have orig Hitachi 2SK1058 & 2SJ162 also I have 2SJ77 & 2SK214 but for the input I do not have the J Fet.
Just 2SK170/2SJ74 or 2SK246/2SJ103.
To design the layout a bit to complex to me with the pait program, I do not use bread board not even for testing.

Greetings Gabor
 

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Hi Ian and everyone , very nice to be back . I put in the Hitachi design as it seems to be easy to get right and almost is hi end ( almost read as is , Goldmund if I am right used it ) . Paul Kemble has found the all FET version and shows how it is slightly less good . I suspect a J FET input ( cascode ) would be interesting .

From the comments made here is seems it would be well liked . Exicon FET's seem slightly superior ( 10N16 10P16 ) . It can even have a Naim output stage in place of FET's .

I have built a JLH FET of my own design . I never finished it ( i.e. made it tidy ) . I would be happy to show it . To be honest the Hitachi is better . My JLH clone is 4 transistors , 8 watts class A , plenty of AB watts above 8 . It has DC offset compatible with DC coupling and unusual feedback from output to VAS . Distortion below - 60 dB @ 60 kHz .