NAP-140 Clone Amp Kit on eBay

The former is based on the ncc220 from avondale audio, the latter is more based on the
nap140. Both are excellent amps by reputation, albeit I have never heard the ncc220
For the price, get both and then decide after some listening, thats my current plan.

:cool:


best regards



cds

p.s. there is a thread on pinkfishmedia.net that covers this also.
 
The beast lives!

After replacing the output transistors (using the Toshiba devices, does anyone know where to find the SanKens in the states?) Both boards are up and running.

Have them running off unregulated Dual-mono power supplies. 200va 25 volt torroids-- not ideal but I already had them-- rurp1560 rectifier diodes and Panasonic TSHA 10,000mf 63v filter caps.

Haven't made any direct comparison to either my tripath or LM3886 amps but I've been running it for about a week and a half and haven't been tempted to pull it out of the system. I take that as a good sign.

Quite enjoyable, really. Haven't tried any tweaking yet. It's good enough to live with as is for a while.
 
Capacitors

That is interesting. I didn't know TubesHunter still had the older NCC200 style boards for sale. I would have been more tempted to try a pair of those as I'm already quite familiar with the Naim sound but have never heard any of the Avondale products. People seem to speak well of the NCC200.

Anyhow, after giving the boards a few weeks to burn in I started to become intensely bored with listening to music. I just felt so far away from the performances. Not being sure if it was the new amp or my mood, I swapped in my LM3886 amp and POW! Music! I was so relieved to hear music again. Having owned a few Naim amps in the past I know that one thing they are not is boring. BUt this amp was merely making sounds-- not music. No pace, no timing, no real dynamics. So I decided to open the thing up again and mess around.

The biggest difference-- and I would highly recommend that anyone with the blue board version try this-- was to get rid of all the SILMICs. I was suspect of them as I have tried them in other projects and always thought they ruined the fun. Replace the 100uf caps with Panasonic FC and all the 10uf decoupling caps with solid Tantalum caps (ala Naim)-- the tantalums are not cheap (about a $1.60) but the bloby yellow beasts work very well in this position. Here is a link to the digikey listing:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=399-3579-ND

After the capacitor change the amp sounds very good, much better than the GC. And I have MUSIC again! Rhythm, detail, life and I feel much closer to the performances again. Definitely worth a few bucks and a few minutes worth of work.
 
Anyhow, after giving the boards a few weeks to burn in I started to become intensely bored with listening to music.
I am glad you've managed to change some parts and make it sound good. :)

I have a trades descriptions axe to grind about these so-called "clones" because they are nothing like the thing they purport to replicate. :mad:

The schematics are similar (not the same as Naim's) but the parts are significantly different in that the Naim requires carefully chosen values for things. This is because the Naim circuit is a high feedback design and is very sensitive to individual part tuning and layout and psu and wiring. I'm not convinced Avondale know what they are doing either.

So it is going to be a bit of a lottery how good each kit sounds when it is built. NONE of them will sound as good as a real Naim circuit.

The good news is you save money and enjoy the diy process. :)
 
traderbam said:

The schematics are similar (not the same as Naim's) but the parts are significantly different in that the Naim requires carefully chosen values for things. This is because the Naim circuit is a high feedback design and is very sensitive to individual part tuning and layout and psu and wiring. I'm not convinced Avondale know what they are doing either.

So it is going to be a bit of a lottery how good each kit sounds when it is built. NONE of them will sound as good as a real Naim circuit.

I wish I had a NAP140 to reference. There was a day (I don't miss those days) when I worked for a Naim retailer and had laods of gear for reference. Alas.

It does need some major fiddling. Right now it sounds decent--almost like music-- but it could definitely use more work. For the time being I think it's fine but, I'm rethinking PS and ground choices I made. Perhaps a more traditional Naim-like PS with half-wave bridges and center tap toroids would be better? And maybe moving the 0v point from the PS to a bar between the speaker grounds?

One way to find out I suppose...
 
Help please

Hi, i have just built a pair of these power amps, my first go at building amps.
I have built 3 power supplies 2 of which did not work but the 3rd seems to work,so of i went to check the amps.
My problem is when i wire one amp up, no speaker connected, i try and set the VR up but i get no volts at all.
There was no bang or smoke when i wired it up so thats not bad?
While i had power on i checked for voltage which i get from the speaker out put but its 40v.
I have also checked my other amp i have built and that is the same,i touched the out put trans and they were cold to touch and the board was not warm when i touched with my hand.
I have read all the posts and there is none with my fault so i cant go and check if i have a fault or i have built it wrong.
I have also checked the ground as was said in one of the posts and that is ok.
Any help or advice would be helpfull or do i bin them?
Thanks
George.
:confused:
 
force of 1/2 said:
It does need some major fiddling. Right now it sounds decent--almost like music-- but it could definitely use more work. For the time being I think it's fine but, I'm rethinking PS and ground choices I made. Perhaps a more traditional Naim-like PS with half-wave bridges and center tap toroids would be better? And maybe moving the 0v point from the PS to a bar between the speaker grounds?

One way to find out I suppose...

It won't hurt to shamelessly copy Naim. I'll be happy to comment on your grounding and psu and so on if you email me. The Naim's I've seen, like the 250, use dual secondary xformers and two full-wave bridge rectifiers. Like making two separate dc supplies and then connecting them in series to form a - 0 + supply. The star ground is best located near the psu caps to minimize the noisy wiring runs.
 
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Joined 2002
Paid Member
Re: Help please

geowhitt said:
Hi, i have just built a pair of these power amps, my first go at building amps.
I have built 3 power supplies 2 of which did not work but the 3rd seems to work,so of i went to check the amps.
My problem is when i wire one amp up, no speaker connected, i try and set the VR up but i get no volts at all.
There was no bang or smoke when i wired it up so thats not bad?
While i had power on i checked for voltage which i get from the speaker out put but its 40v.
I have also checked my other amp i have built and that is the same,i touched the out put trans and they were cold to touch and the board was not warm when i touched with my hand.
I have read all the posts and there is none with my fault so i cant go and check if i have a fault or i have built it wrong.
I have also checked the ground as was said in one of the posts and that is ok.
Any help or advice would be helpfull or do i bin them?
Thanks
George.
:confused:

Have you connected signal ground to star ground?
 
Hi and thanks for the replys, i have checked the sig ground and were its solderd to the board both grounds are solderd in the same place? and i have checked it with my meter and they are connected.
I tried to make a power supply? that looked so easy to make!!!!!
I bought 10 10,000 uf 63wv caps as i was going to use 5 per bank
My first try well that went up in sparks and one of the caps was like expanding foam and i had the plug in my hand ready to switch it off,i was to slow.
The supply i have now works? i have 3 rails 40v+ .0. 40v- the 0 or ground i fitted to the 0 rail and the 40v+ to the red wire and the 40v- to the black wire and the ground wire nr the input i put to the 0v rail.
I did not put a feed to the input as i want to set the amps up.
I also fitted two wires so i could the VR with my meter but when i checked them no volts were found and thats the same with the other board.
I will try and att some pics.
File to big?
 

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Power Supplies

Here are a few quick drawings of some PS schemes for the 140c:

The first here is what I am currently using:
http://i240.photobucket.com/albums/ff23/forceof1-2/140cgndschmweb.jpg

140cgndschmweb.jpg



Here is a drawing of where I was considering moving the Ground star too:
http://i240.photobucket.com/albums/ff23/forceof1-2/140cgndschm2web.jpg

140cgndschm2web.jpg


Here is what I believe to be the the NAP PSU scheme (ala NAP250):
http://i240.photobucket.com/albums/ff23/forceof1-2/NAP250PSU.jpg

NAP250PSU.jpg


It has been a number of years since I've had a 250 so if the drawing is incorrect please correct me.
 
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Joined 2005
Paid Member
On your last pic, you need to send each + and - from each rectifier to the + and - of each cap. then join the + for the first cap to the - of the second cap. This will serve as your 0V power ground. The remaining + from the second cap and the - from the first cap are your positive and negative rails.

So each rectifier has its own cap. then just join the +/- from both caps and form your 0V

Whoa- wait. What are the green lines from the tranny? Are they centertaps? I thought you had dual secondaries.

I have never seen dual centertapped secondaries, so wait for someone else to chime in.
 
NAP250 PSU

john65b said:

Whoa- wait. What are the green lines from the tranny? Are they centertaps? I thought you had dual secondaries.

I have never seen dual centertapped secondaries, so wait for someone else to chime in.


Yes, sorry, I forgot to mention in the drawing. The toroid has dual center tapped secondaries.-- Oh, no, I did mark the drawing correctly.
 
Member
Joined 2005
Paid Member
I think you should be able to do as I stated previously, and do not use the secondary centertaps at all. You would just cap the centertap ends individually (do not connect the two centertaps together or to ground).

You may want to wait to have someone confirm me tho...
 
Hi to all, is there anyone in the uk who can look at my boards i have built?
I am having no luck at getting them to work,one amp when trying to set the VR volts as in the manual will not go below 100mv.
The other amp there is no volts at all.
I have checked all my soldering and it seems ok,nothing has burnt or gone pop.
I am using a 35.0.35 transformer which is giving me 41v+ and 41v- and a 0 rail.
As this is my first full kit build this is all new to me.
Can i thank all who have helped me.
If you can help please pm or email me my email is geowhitt@netscape.net
Many thanks.