Working Nait3 DIY amp
Output voltage without signal about 3-4mV
Input transistors the original BC239C
Attachments
That's great ! I remember that you found errors in 250.2 clone PCBs circulating on a Chinese forum. I've saved the supposed 250.2 schematics if you want a starting base for doing reverse engineering. (I imagine that there must be quite a few errors in these diagrams)
For the output transistors it's always a concern the 80 amps I don't know the BDY58 don't have this capacity only the BUV22 and BUR51 have that but I don't think they are still available. The BUV22 is available. The BUV 22 have 40 Amp so 80 with a matched paired.
Namely that if the circuit works like that of the original 250 depending on the routing carried out and the transistors used, you will have to adjust the RC circuits of the phase compensation.
for information:
NAIT and NAP90: BD743
NAP140 (prob. the new NAP150 too): 2SC2922 (Sanken)
historic: the old NAP250 used BDY58R and the old NAP110 used BUV20
https://www.diyaudio.com/community/threads/naim-clones.399/page-2
NAIT and NAP90: BD743
NAP140 (prob. the new NAP150 too): 2SC2922 (Sanken)
historic: the old NAP250 used BDY58R and the old NAP110 used BUV20
https://www.diyaudio.com/community/threads/naim-clones.399/page-2
I don't know that PCB. It looks not good 🙂
for information from NAIM manuel:
"
Naim equipment takes a considerable time to run in
before it performs at its best. The duration varies, but
under some conditions the sound may continue to
improve for over a month. Better and more consistent
performance will be achieved if the system is left switched
on for long periods. It is worth remembering however that
equipment left connected to the mains can be damaged
by lightning.
"
for information from NAIM manuel:
"
Naim equipment takes a considerable time to run in
before it performs at its best. The duration varies, but
under some conditions the sound may continue to
improve for over a month. Better and more consistent
performance will be achieved if the system is left switched
on for long periods. It is worth remembering however that
equipment left connected to the mains can be damaged
by lightning.
"
There you show me the PCB of the first 250 the old one
I was talking about the 250.2 released in the 2000s, this is the PCB shown by Oleg which has the power regulation integrated on the same PCB as the amplifier.
Here it's the old 250 !
I was talking about the 250.2 released in the 2000s, this is the PCB shown by Oleg which has the power regulation integrated on the same PCB as the amplifier.
Here it's the old 250 !
I think more interesting would be a NAP500 (non-DR) clone. Because the 250.2 is a relatively small improvement over the 250 compared to the 500 which is a totally different beast. The 500 trashes the lesser amps by a huge leap.
I promise: if you hear a 500 you will consider all smaller Naim amps as waste of time.
I promise: if you hear a 500 you will consider all smaller Naim amps as waste of time.
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I'm a little surprised by what you say because it seems to me that the NAP500 is actually made up of two bridged NAP250s.
On the other hand from the NAP300 the power supply is separated in another box which allows a better magnetic insulation and to put a larger power supply.
On the other hand from the NAP300 the power supply is separated in another box which allows a better magnetic insulation and to put a larger power supply.
Yes, the 500 contains four mono NAP amplifiers, but it seems it's not exactly as simple as a bridge amp...
Good day
In attachment
China clone board of 250.2 with mistakes
I search about 5 but I think this one sh..t have more…
P.s this boards are still with me because
not have chance for trade or DIY the boards with mistakes
Attachments
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My friend the NAP500 is not simple for DIY
This is a bridge amp with bridge methodology of buildings and ground stars..
For make diy the 500 amp needs all documents and experience from naim fabric 🙂) this is not simple amp
What amused me is that on their forum many contributors say they have mounted this clone of 250.2 and that it would work... not a single one found that it did not work correctly and that there were errors.
the mythomania is spread on the internet or once they bought the thing they didn't want to lose face and admit that it was a scam.
the mythomania is spread on the internet or once they bought the thing they didn't want to lose face and admit that it was a scam.
My friend maybe his buy the normal boards maybe not 🙂
I think you right
In my boards from Ali is not have many roads between parts
just check up photos
q4 is not connecting with 15k resistor… hhhhh and this just one error
Best way is a DRAW of new boards from original and make gerber to board in pcb factory
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But it will be worth the effort, and I think you guys are capable of making that dream come true!