Stabist said:
hi,Stabist:
the values is referenced to nap135 & 140 & 250...
I have do simulation at this schematics ,it can work,but output point voltage isn't 0V to the groung,so I have to adjusting R6 to let output point is 0V...and adjusting R13 to let output stage Iq is 150mA.output power 40W(RMS),THD=0.022%...
please trust the circuit topology only,because I don't know the devices and their values!
cheers!
WINCO
all the same...
the interesting thing is that, there really are no other naim amps, ie 90, 140, 250, they are all the same circuit, its only the psu that differs.
ditto with the preamps, they are all the same, just the switching and perhaps features, and bit more regulators.
the basic amplifying circuit is identical.
so naim have gone on for 20 years or so, making the single same amplifier under a lot of different names with only psu differences.
isn't that fascinating, and frustrating? it means perhaps they can't design much different, or perhaps, is the only circuit that gives that definable naim sound, and changing it even slightly will completely alter the sound, so anything else isn't naim.
what other company could survive by making exactly the same product, no development, improvement for 20 plus years?
they had to resort to bridging for the bigger amps, the newer 500 as they again, couldn't change that circuit for more power.
I would say on the whole, its a bit of a con trick, but yes a landmark circuit, something to do with goodmans, emi or rca transistor manual, rather like the hitachi mosfet circuit, all used and adapted, ditto here.
most non engineering educated people really are totally in disbelief when I told them the 90 was the same as a 250.
they were so religioiusly blind, and it is a total utter cult, that they almost refuse point blank to believe it.
but the amp DOES have a unique and individual sound, punchy bass, and nice tonality, perhaps due to the imperfect design, and I have a theory, that the older and simpler the circuit the more unique and perhaps emotive the sound, natural materials and simpler circuits you see, anyting complex kills the nuances, but that's my theory, ymmv
ineresting I tried a power amp on its own and it wasn't terribly remarkable, its the naim pre's that give the raw edgyness and punch, and they are simply 3 stage single transistor designs pretty much, check out mcbride
I was totally shocked when I realised how simple and unremarkable the circuity, I thought there would be magic untold therein, but no, its just down to basic topology, components and devices, was a real learning point for me.
check out this...
and lift the photos for own use...
http://cgi.ebay.co.uk/Pair-of-Genui...286.c0.m14&_trkparms=66:2|65:10|39:1|240:1318
but don't be surprised, they are 'typical' minimal british amps, and there are quite a few, with hand drawn glass fibre? pcb's, and even upto £2000 Uk sterling, amps and co are still built to a price and won't be massively complex, remember that, that commercial ones are in fact quite simple in essence. don't be surprised or expect so see total revolutions or massively optimised.
the interesting thing is that, there really are no other naim amps, ie 90, 140, 250, they are all the same circuit, its only the psu that differs.
ditto with the preamps, they are all the same, just the switching and perhaps features, and bit more regulators.
the basic amplifying circuit is identical.
so naim have gone on for 20 years or so, making the single same amplifier under a lot of different names with only psu differences.
isn't that fascinating, and frustrating? it means perhaps they can't design much different, or perhaps, is the only circuit that gives that definable naim sound, and changing it even slightly will completely alter the sound, so anything else isn't naim.
what other company could survive by making exactly the same product, no development, improvement for 20 plus years?
they had to resort to bridging for the bigger amps, the newer 500 as they again, couldn't change that circuit for more power.
I would say on the whole, its a bit of a con trick, but yes a landmark circuit, something to do with goodmans, emi or rca transistor manual, rather like the hitachi mosfet circuit, all used and adapted, ditto here.
most non engineering educated people really are totally in disbelief when I told them the 90 was the same as a 250.
they were so religioiusly blind, and it is a total utter cult, that they almost refuse point blank to believe it.
but the amp DOES have a unique and individual sound, punchy bass, and nice tonality, perhaps due to the imperfect design, and I have a theory, that the older and simpler the circuit the more unique and perhaps emotive the sound, natural materials and simpler circuits you see, anyting complex kills the nuances, but that's my theory, ymmv
ineresting I tried a power amp on its own and it wasn't terribly remarkable, its the naim pre's that give the raw edgyness and punch, and they are simply 3 stage single transistor designs pretty much, check out mcbride
I was totally shocked when I realised how simple and unremarkable the circuity, I thought there would be magic untold therein, but no, its just down to basic topology, components and devices, was a real learning point for me.
check out this...
and lift the photos for own use...
http://cgi.ebay.co.uk/Pair-of-Genui...286.c0.m14&_trkparms=66:2|65:10|39:1|240:1318
but don't be surprised, they are 'typical' minimal british amps, and there are quite a few, with hand drawn glass fibre? pcb's, and even upto £2000 Uk sterling, amps and co are still built to a price and won't be massively complex, remember that, that commercial ones are in fact quite simple in essence. don't be surprised or expect so see total revolutions or massively optimised.
This is an old thread to rekindle.
I should warn any innocent bystanders that I wouldn't touch any Naim pcbs that Avondale Audio have modified. They really don't have a clue how the Naim circuits work, as evidenced by their own version of the circuit shown on their website. Naim experts will vouch for this. Naim UK does not endorse Avondale Audio.
I should warn any innocent bystanders that I wouldn't touch any Naim pcbs that Avondale Audio have modified. They really don't have a clue how the Naim circuits work, as evidenced by their own version of the circuit shown on their website. Naim experts will vouch for this. Naim UK does not endorse Avondale Audio.
here...
the differences, obviously 1 or 2 component quality "substitutions"
but additions/subtractions
1/ decoupling caps in psu. extra
2/ diode network on power rails
3/ removal of current limiting network
4/ addition of series inductor
5/ removal of capacitor/resistor in parallel with feedback resistor.
6/ addition of local feedback degeneration in differential pair
I think that's it.
I don't FULLY understand functions of
1/ reduces impedance of psu at hi freqs.? but I have heard this enhances stability which I have no idea .....????
2/
5/
and the series capacitor/resistor network in the signal path...obviously phase alteration tho', apart from dominant pole miller caps, I don't have a clue about the rest of phase shifting cap networks anywhere
the differences, obviously 1 or 2 component quality "substitutions"
but additions/subtractions
1/ decoupling caps in psu. extra
2/ diode network on power rails
3/ removal of current limiting network
4/ addition of series inductor
5/ removal of capacitor/resistor in parallel with feedback resistor.
6/ addition of local feedback degeneration in differential pair
I think that's it.
I don't FULLY understand functions of
1/ reduces impedance of psu at hi freqs.? but I have heard this enhances stability which I have no idea .....????
2/
5/
and the series capacitor/resistor network in the signal path...obviously phase alteration tho', apart from dominant pole miller caps, I don't have a clue about the rest of phase shifting cap networks anywhere
Attachments
Thanks but I already knew that the NCC200 was different from the NAP topology. The thing is - whats wrong with it in terms of how it sounds? The NCC200 is based on the NAP circuit but as far as I can tell its a major improvement - or refinement of the design. Ive not heard a NCC200 but from what I have read - many accounts - the NCC200 is an improvement over the NAP.
I'm a regular on 'pinkfishmedia.net' and I reiterate: All accounts I have read on Avondale modified NAP's (with the addition of their PSU's. amp boards, or both) have been highly positive.
Im wondering what traderbam's problem is?
I'm a regular on 'pinkfishmedia.net' and I reiterate: All accounts I have read on Avondale modified NAP's (with the addition of their PSU's. amp boards, or both) have been highly positive.
Im wondering what traderbam's problem is?
"They really don't have a clue how the Naim circuits work, as evidenced by their own version of the circuit shown on their website. Naim experts will vouch for this. "
Please point out the evidence to us.
Who are these Naim experts?
The only issue I can see is the removal of the SOA protection in a circuit that has no other means of protecting itself or the speakers.
Please point out the evidence to us.
Who are these Naim experts?
The only issue I can see is the removal of the SOA protection in a circuit that has no other means of protecting itself or the speakers.
DIY on.Please Traderabam, tell us all about the myriad problems and issues you have heard of with people using Avondale circuits.
I'm a regular on all the diy and UK forums and I've never heard one bad word said against from anyone who has owned or built one. There are always idiots talking **** about them, who have a NAim owners members club card in their back pocket, but surprisingly never any bad words from owners....
put up or shut up.
I'm a regular on all the diy and UK forums and I've never heard one bad word said against from anyone who has owned or built one. There are always idiots talking **** about them, who have a NAim owners members club card in their back pocket, but surprisingly never any bad words from owners....
put up or shut up.
what's your agenda?? are you allied with naim?
and any decent knowledgable member here will tear you to shreds on that one, youy don't have a clue yourself, they are nigh identical!!
ur making yourself look ridiculous.
why so opinionated, you obviously either have an axe to grind, or bias, naim's commercial, avondale vies for their custom, of course they don't support them, les W, has studied RCA amps of which the naim is a copy for decades, and knows them better than most, people are delighted with his work, I don't need to use his services, I can do it myself mostly, but he's at least not a conman, naim are, pricewise.
mikeS, its not different, topology is identical, just tweaks, like what julian vereker did with RCA/goodmans/Emi amps, he worked there, sadly not here to defend himself, but he wouldn't have liked the way the companies gone now, charlatans.
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