> Agisthos
My trafo (in black finish) is supplied by that supplier - www.toroidy.pl.
In my opinion and many guys from polish www.audiostereo.pl forum - this is one of the best trafos.
Ask Peter Daniel. He bought some trafos from Toroidy.pl.
Beardini
My trafo (in black finish) is supplied by that supplier - www.toroidy.pl.
In my opinion and many guys from polish www.audiostereo.pl forum - this is one of the best trafos.
Ask Peter Daniel. He bought some trafos from Toroidy.pl.
Beardini
The NAIT-II I had in the 80ies was not based on the 42.5. There was no linestage, as far as I remember, the power amp - same circuit like the other amps - just had higher gain. Also the phono-pre was not really the same as the phono-boards in the 42.
I liked the NAIT very much - and I have sold many of them btw. But the amp combis always were much better, specially with more difficult loudspeakers. But there were many setups (and rooms) where even a combination of a NAIT with LINN KANS sounded absolutely gorgeous.
As a DIY project I would forget about the NAIT, because it will be the same work to make a bigger amp - even in a combined case.
I liked the NAIT very much - and I have sold many of them btw. But the amp combis always were much better, specially with more difficult loudspeakers. But there were many setups (and rooms) where even a combination of a NAIT with LINN KANS sounded absolutely gorgeous.
As a DIY project I would forget about the NAIT, because it will be the same work to make a bigger amp - even in a combined case.
Hi Beardini, I have follow your circuit and made the power amp stage successfully. But, I have change the O/P stage to fully complementary.
I have employed ON Semiconductor matched pairs MJL1302 / MJL3281 and drivers MJE15032 / MJE15033. (Thanks for the sample support from ON-Semi http://www.onsemi.com/PowerSolutions/product.do?id=MJL1302A)
Thank you very much for your circuit diagram indeed.
I have employed ON Semiconductor matched pairs MJL1302 / MJL3281 and drivers MJE15032 / MJE15033. (Thanks for the sample support from ON-Semi http://www.onsemi.com/PowerSolutions/product.do?id=MJL1302A)
Thank you very much for your circuit diagram indeed.
Under below link there are some pictures finished Naim clone:
http://beardini.prv.pl/naim_assy_photos.htm
http://beardini.prv.pl/naim_assy_photos.htm
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Banned
Joined 2002
About the sound of Naim clones
A few words of warning for those who like the Naim sound and are interested in cloning a NAP250. Great challenge: go for it. BUT...I have intimate understanding of this design and it is extremely complicated. The schematic only tell half the story at best, and nowhere on any website have I ever seen an accurate schematic. Julian Vereker was a very cunning and sly fox, the devil is most definitely in the detail. This high feedback design will sound average to poor unless ALL the fine tuning is done right. And none of the Naim clone sites explain this...because they don't know.
Not saying you can't make one and get pleasure from it, just saying it is a really hard topology to get right and the odds of making one that sounds as good as Naim's is very low. So don't get your hopes up too high.
It is a good idea to use regulated supplies by the way because the PSRR of the basic circuit is not very good. When you do this you need to ensure that the regulator is wide-band and does not introduce any resonances. The NAP 250 supplies use the same high speed transistors as the amps. You cannot buy these transistors in the shop.
All of my amp designs are quasi-complementary. Even in the year 2006 no one has discovered the positron and therefore made electricity symmetrical. Nor can ON-Semi perform this miracle. This is a serious point. Just because a circuit looks symmetrical on paper doesn't mean diddly squat to an electron.
A few words of warning for those who like the Naim sound and are interested in cloning a NAP250. Great challenge: go for it. BUT...I have intimate understanding of this design and it is extremely complicated. The schematic only tell half the story at best, and nowhere on any website have I ever seen an accurate schematic. Julian Vereker was a very cunning and sly fox, the devil is most definitely in the detail. This high feedback design will sound average to poor unless ALL the fine tuning is done right. And none of the Naim clone sites explain this...because they don't know.
Not saying you can't make one and get pleasure from it, just saying it is a really hard topology to get right and the odds of making one that sounds as good as Naim's is very low. So don't get your hopes up too high.
It is a good idea to use regulated supplies by the way because the PSRR of the basic circuit is not very good. When you do this you need to ensure that the regulator is wide-band and does not introduce any resonances. The NAP 250 supplies use the same high speed transistors as the amps. You cannot buy these transistors in the shop.
I can only confirm that point in all parts. You may succeed - like I did - to some stage and level, but only with a lot of experience and knowledge. And - I have said that in this forum since years - I have not heard a NAIM clone which was better than the orginals, never. Alas not even mine.
Naim amp is designed (handled) carefully, thoughtfully. I received a NAIT-2 from a friend to replace those old caps (10 yrs already). I am using my DIY 100W Class A DC amp. I listened to it before I set out the surgery. A very British sound, soft and musical. (when the music stopped, I can hear humming sound !) . I measured the f-low is 5Hz and f-high is only 32kHz. That means the freq. roll off will start somewhat 50Hz and 15kHz. It reproduces square wave into a sine wave shape. 6800uF /25V x2 filter caps look more like a preamp PSU. (so it hum !). It's o/p clip softly and a flat top happens at 36Vpp (20W/8£[). It can't rock as hard as my Class A and sound stage and image is not solid with dynamic orchestral piece. I would like to express its sound is WELL CONTROLLED (instead of well design).
Its soft-clipping circuit (current limiter) prevent the amp to reproduce a fast rising punch (a harder clipping will be) for us to hear. The insufficient filter cap prevent the amp to have the energy to driver the speaker a greater dynamic so the sound is overall softer (musical feeling). I have tried changing the cap to 33,000UF x 2 and the sound immediately stronger, you can feel the "attack" of the signal but also the sound become more harsh. Not the sweetly sound (if you want to call it) as before. Finally, I tried togther with the Current Limiter removed and the sound is more harsh and the "attack" of the signal became real attack to my ear when I turn the vol. higher. Yes. It can rock hard finally but it rock and jazz like a PA amp. My memory reminded me about the sound pattern at that time. A true Class B amplifier sound. Only when I turned the BIAS up for only a while (very hot before secondary breakdown I think). All the sweetly came back and it was better than NAIT-2. I have resumed it back to original circuit and values because my friend love the original "Sweetly" sound.
So, I think, in order to maintain (clone) the signature "MUSICAL" sound of NAIT-2. The rules of "Insufficient Filter caps" and the "Current Limiter" must be kept.
Its soft-clipping circuit (current limiter) prevent the amp to reproduce a fast rising punch (a harder clipping will be) for us to hear. The insufficient filter cap prevent the amp to have the energy to driver the speaker a greater dynamic so the sound is overall softer (musical feeling). I have tried changing the cap to 33,000UF x 2 and the sound immediately stronger, you can feel the "attack" of the signal but also the sound become more harsh. Not the sweetly sound (if you want to call it) as before. Finally, I tried togther with the Current Limiter removed and the sound is more harsh and the "attack" of the signal became real attack to my ear when I turn the vol. higher. Yes. It can rock hard finally but it rock and jazz like a PA amp. My memory reminded me about the sound pattern at that time. A true Class B amplifier sound. Only when I turned the BIAS up for only a while (very hot before secondary breakdown I think). All the sweetly came back and it was better than NAIT-2. I have resumed it back to original circuit and values because my friend love the original "Sweetly" sound.
So, I think, in order to maintain (clone) the signature "MUSICAL" sound of NAIT-2. The rules of "Insufficient Filter caps" and the "Current Limiter" must be kept.
Yes,
Naim have engineered differences in sound quality in each of their models so that there is a consistent graduation of sound quality between the cheapest and most expensive. The Nait is the cheapest model.
Naim have engineered differences in sound quality in each of their models so that there is a consistent graduation of sound quality between the cheapest and most expensive. The Nait is the cheapest model.
Yes, that is right. The closed loop frequency response is deliberately tailored. The open loop speed is very high.
I think you may have scared it!
I'm sure you are right in the case of this Nait-2 but I know this isn't a general rule. The big amps have big reservoirs and non-invasive limiters. The Naim sound isn't musical because of any slowing of the circuit, quite the opposite.
question
Diyers help
I build an channel of naim clone this work well..but have an question…
When turn on/off the amp have an small boom in my diy probe speaker…I tester the speaker terminals an have tension in the moment of turn on/off…an second or less..after is ok 0V (normal ) at 40ma…
Is normal this problem….the sound is good this have best detail an more bass,,,, (p3a) is good but less fine
Help help Diego
Diyers help
I build an channel of naim clone this work well..but have an question…
When turn on/off the amp have an small boom in my diy probe speaker…I tester the speaker terminals an have tension in the moment of turn on/off…an second or less..after is ok 0V (normal ) at 40ma…
Is normal this problem….the sound is good this have best detail an more bass,,,, (p3a) is good but less fine
Help help Diego
re re
Thanks for the response…. LOHK
Ok all my amps have relays in the outputs an dc detect….but have an intrigue about the original naims …have this bumppp when turn on this?
I build some amps…arcam a60 clone and some fets but no have this bump …
*Several years ago I was working in a shop (in Vienna, Austria) repairing these amps, so I know them quite good - although NAIM never provided any schematics or spares (a very arrogant company - at least in those days). But for me this amps always were the reference, I rarely heard anything better, at least for this price. *
Icopy this…Question have an schematic of an correct naim amp…I have information of webs but all circuits are similar but no have coincidence.
Ones have two series diodes other an red led …protection transistor circuits …diodes an resistors in series in +/-V ??? how schema is ok….
I like this sound is detail and clear but are schematic confused …..
Do your have and schema please send an posd to my e-mail or at this forum..
Thanks Diego
Ps transistors type …bc…bd ….
Thanks for the response…. LOHK
Ok all my amps have relays in the outputs an dc detect….but have an intrigue about the original naims …have this bumppp when turn on this?
I build some amps…arcam a60 clone and some fets but no have this bump …
*Several years ago I was working in a shop (in Vienna, Austria) repairing these amps, so I know them quite good - although NAIM never provided any schematics or spares (a very arrogant company - at least in those days). But for me this amps always were the reference, I rarely heard anything better, at least for this price. *
Icopy this…Question have an schematic of an correct naim amp…I have information of webs but all circuits are similar but no have coincidence.
Ones have two series diodes other an red led …protection transistor circuits …diodes an resistors in series in +/-V ??? how schema is ok….
I like this sound is detail and clear but are schematic confused …..
Do your have and schema please send an posd to my e-mail or at this forum..
Thanks Diego
Ps transistors type …bc…bd ….
NAIMs is not just "amps", but systems. A definite grounding schema, corresponding pre-amps, special power-supplies etc. The schematics are simple but highly refined, partly by modifying tiny details or special parts. The power-transistors of their better amps were always custom-made.
I have hundreds of pages of infos about NAIMs - but quite a lot can be found in the internet too. Also here in this forum... Pick out your choice.
Can you post what you have already build?
I have hundreds of pages of infos about NAIMs - but quite a lot can be found in the internet too. Also here in this forum... Pick out your choice.
Can you post what you have already build?
re
Ok friends thanks again
TO LOHK:
I want build only an naim amplifier the power not is important for me ….i need drive an pair of LS70 Polk speakers.
I build an prototype and detect what the sound change when change some components in the board…caps….in particular….more high frequency response and 3d sound……
I am astonished …the bass are incredible ..controled ,compact …..powerful….al low level the music have body…(better than my HK1400 line amp)
It’s a pity what when turn on/off the amp have the boomp over the speakers…an relay..ok.
Lohk. Be a bit more specific - and then you will probably get a more specific answer.
Only need an genuine schema of naim amp…the just..ok
The original naim have this boomp to start on?
Thanks
Ok friends thanks again
TO LOHK:
I want build only an naim amplifier the power not is important for me ….i need drive an pair of LS70 Polk speakers.
I build an prototype and detect what the sound change when change some components in the board…caps….in particular….more high frequency response and 3d sound……
I am astonished …the bass are incredible ..controled ,compact …..powerful….al low level the music have body…(better than my HK1400 line amp)
It’s a pity what when turn on/off the amp have the boomp over the speakers…an relay..ok.
Lohk. Be a bit more specific - and then you will probably get a more specific answer.
Only need an genuine schema of naim amp…the just..ok
The original naim have this boomp to start on?
Thanks
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