Over 5 years or more, we are bound to have compared them with every type of amplifier imaginable. The sound of NAP140 clones is dependent upon everything you use to build the amplifier with, so there is no point saying it will sound like one or another amplifier. They sound nothing like the original or other builds even, unless you construct them that way. Everyone hopes that their ideas of parts and construction will be best, so everyone gets different results - some great 
, some awful.
The basic kits come with different parts at different times and from different stores. Often there are poor parts that may be fake or just bad substitutes which work OK but may not sound very good compared to others. They are a playground for newbs and experienced DIYs alike, so enjoy.
On the other hand, Chipamps are usually very consistent as they are less dependent on components and tweaks and of course, the semiconductors, circuit and protection are precisely fixed by the chip processing.
Here, hundreds of opinions and different ideas, discussions, technical matters.
, some awful.The basic kits come with different parts at different times and from different stores. Often there are poor parts that may be fake or just bad substitutes which work OK but may not sound very good compared to others. They are a playground for newbs and experienced DIYs alike, so enjoy.
On the other hand, Chipamps are usually very consistent as they are less dependent on components and tweaks and of course, the semiconductors, circuit and protection are precisely fixed by the chip processing.
Here, hundreds of opinions and different ideas, discussions, technical matters.
The point I was making was, that they will all be different, so what you may hear depends on whose construction you compare as much as the kit you buy. There are several kits - all supply different semis and caps at different times and will perform differently. That means the sound character will vary as already stated.
No one can say that what you buy tomorrow will sound like any particular amplifier, when you fit your own power supply, capacitors, case and wiring.
Who knows what the semis really are going to be inside the plastic cases? No one building these just as they are supplied would compare them with original Naim amplifiers. The 20 or more I have heard over 4 years sound nothing like Naims until carefully reconstructed with original or similar selected components, layout, wiring and follow the real schematic, not a generic NAP250 schematic often shown simplified.
If you want to read subjective descriptions of what some DIYs hear when they test their particular amplifiers, you should really read the forums that focus on sound quality discussions like:d.i.y. - pink fish media
Just Googling NAP140 will find more forums discussing Naim designs and comparisons.
Think about what you are buying; you will only have the parts and PCBs of a pair of RCA design low-cost class Quasi-comp. AB audio amplifiers, ca. 1970. There may be a couple of tweaks fitted as per the Naim designs but they will likely sound awful compared to high-end builds that will cost a lot of time and expertise but by your own efforts, you can make simple improvements like these for the NCC200 version, that sadly, is no longer available. DIY Audio Power Amplifier modules : DIY Audio
Having said that, there are plenty of descriptions and pics of different builds in the linked thread, so read and enjoy what modifications people made, some of which were said to greatly improve the sound quality and still be reasonably inexpensive. That is where any sound quality will be - in the build and modifications. The kit of suspect parts is only worth and sounds like what you pay.
No one can say that what you buy tomorrow will sound like any particular amplifier, when you fit your own power supply, capacitors, case and wiring.
Who knows what the semis really are going to be inside the plastic cases? No one building these just as they are supplied would compare them with original Naim amplifiers. The 20 or more I have heard over 4 years sound nothing like Naims until carefully reconstructed with original or similar selected components, layout, wiring and follow the real schematic, not a generic NAP250 schematic often shown simplified.
If you want to read subjective descriptions of what some DIYs hear when they test their particular amplifiers, you should really read the forums that focus on sound quality discussions like:d.i.y. - pink fish media
Just Googling NAP140 will find more forums discussing Naim designs and comparisons.
Think about what you are buying; you will only have the parts and PCBs of a pair of RCA design low-cost class Quasi-comp. AB audio amplifiers, ca. 1970. There may be a couple of tweaks fitted as per the Naim designs but they will likely sound awful compared to high-end builds that will cost a lot of time and expertise but by your own efforts, you can make simple improvements like these for the NCC200 version, that sadly, is no longer available. DIY Audio Power Amplifier modules : DIY Audio
Having said that, there are plenty of descriptions and pics of different builds in the linked thread, so read and enjoy what modifications people made, some of which were said to greatly improve the sound quality and still be reasonably inexpensive. That is where any sound quality will be - in the build and modifications. The kit of suspect parts is only worth and sounds like what you pay.
Aren't you really asking: What does a Naim amplifier sound like and will this clone sound the same?
I think you will already know what to expect with BJT Chipamps. All you need is to read a good review/
discussion of older Naim amplifiers but don't expect a straight build of the clones to sound like or as
good as them. This has some interesting comments about them, too.
I think you will already know what to expect with BJT Chipamps. All you need is to read a good review/
discussion of older Naim amplifiers but don't expect a straight build of the clones to sound like or as
good as them. This has some interesting comments about them, too.
In my recollection of listening a few years ago, there was only slight similarity between 3886 chipamps and discrete Quasi amplifiers
(basic RCA design). I would even say that the Naim 140 amplifier was more different again. I think that's reasonable, considering
there are more tweaks in the Naim than in those simple amplifiers and that tends to conceal the basic amplifier's distortion pattern.
Put simply, I don't think chipamps sound Naim-like because they aren't the same silicon topology and they aren't tweaked like the Naims.
(basic RCA design). I would even say that the Naim 140 amplifier was more different again. I think that's reasonable, considering
there are more tweaks in the Naim than in those simple amplifiers and that tends to conceal the basic amplifier's distortion pattern.
Put simply, I don't think chipamps sound Naim-like because they aren't the same silicon topology and they aren't tweaked like the Naims.
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Hi Gareth.
The NAP140 does have the same general schematic that applies to the generic NAP250 bridged mode design often seen published on the web. It's the only official NAIM amplifier schematic out there, as far as I know but be aware it didn't fit exactly with any simple amplifier.
In other words, the topology for all NAP models will be correct, but the specifics like resistor values for the LTP and current sources of the various models will most likely be wrong and so is the NAP140 title, when you get down to details. NAP 140 is often recalled as the best sounding of the bunch. I haven't heard them all, but it must be a fine line of difference between some models. I suspect that's the reason Chinese kit sellers named the kits accordingly. Otherwise, I can't think why anyone would make such a blunder.
You might be aware that Avondale Audio's ready-built Naim clone amplifiers were around for some years too, based on the same NAP 250 design but with Les Wolstenhome's own tweaks and variations to the design, which also turned up in his DIY kits, modules, bits and Naim mod. suggestions too. There are some specific parts that even he hasn't changed either - guess why. Some folk also prefer his NCC200 versions to the original Naim products which is reasonable, with hindsight on a design that dates back to the 1970s.
NAP140 supply rails are not 40V (34 actually) and the LTP collector resistors and current source emitter resistors are different to suit the supply voltages of all the NAP series, with some minor omissions such as the RC filters in the driver bases of the NAP90/early Nait series.
In the big NAP140 Ebay kit thread, the subject of sound quality turns up a lot because that's what most builders are hoping to find or at least get a taste to say yup, I know all about Naim sound and it's crap/amazing/so-so etc. - my DIY build proves it.....
My own experience is not huge but I've built several stereo NAP kits over several years and listened for many, many hours, comparing them with mods, as original and around 15 more different clone kits built by friends. I even own an original NAP140 myself (when its not on loan )
As far as defining sound quality goes, Naim still adhere to a few specific component types for reasons that become clear when you build a clone with whatever cheap parts or even modern, high Ft parts that ordinarily, would best suit the applications. The biggest mistake is to fit the D667/B647 VAS transistors now supplied or other low Cob transistors too - there goes that essential Naim sound you find with ZTX653/753. Why? Look at Cob -30pF! look at Cdom- only 39pF. Compensate by adding capacitance as you will but the added distortion of high Cob transistors is actually desirable and necessary for Naim sound but not easy to replicate any other way, if at all.
I think the secret sauce is not so much in some special design technique, but an adherence to what we'd now call errors in part selections in the early days of Naim and perhaps with the first series NAP200. Smart as he was, Vereker was not an engineer and did things his way, putting his spin on the pleasing and surprisingly successful results. Even today, professionals still pooh-pooh the general design despite its phenomenal success and survival over decades.
The clone kits though, will be disappointing as they come, even the more expensive kits and built modules with quality components, if you are familiar with the Naim sound quality you seek or perhaps you're a casual audiophile looking for something interesting in retro audio. You're going to need an original model or very close, to be confident that subjectively, you do have what you were you're aiming at - not an easy ask at all.
for reference, the NAP250 and generic NAP schematic:
The NAP140 does have the same general schematic that applies to the generic NAP250 bridged mode design often seen published on the web. It's the only official NAIM amplifier schematic out there, as far as I know but be aware it didn't fit exactly with any simple amplifier.
In other words, the topology for all NAP models will be correct, but the specifics like resistor values for the LTP and current sources of the various models will most likely be wrong and so is the NAP140 title, when you get down to details. NAP 140 is often recalled as the best sounding of the bunch. I haven't heard them all, but it must be a fine line of difference between some models. I suspect that's the reason Chinese kit sellers named the kits accordingly. Otherwise, I can't think why anyone would make such a blunder.
You might be aware that Avondale Audio's ready-built Naim clone amplifiers were around for some years too, based on the same NAP 250 design but with Les Wolstenhome's own tweaks and variations to the design, which also turned up in his DIY kits, modules, bits and Naim mod. suggestions too. There are some specific parts that even he hasn't changed either - guess why. Some folk also prefer his NCC200 versions to the original Naim products which is reasonable, with hindsight on a design that dates back to the 1970s.
NAP140 supply rails are not 40V (34 actually) and the LTP collector resistors and current source emitter resistors are different to suit the supply voltages of all the NAP series, with some minor omissions such as the RC filters in the driver bases of the NAP90/early Nait series.
In the big NAP140 Ebay kit thread, the subject of sound quality turns up a lot because that's what most builders are hoping to find or at least get a taste to say yup, I know all about Naim sound and it's crap/amazing/so-so etc. - my DIY build proves it.....
My own experience is not huge but I've built several stereo NAP kits over several years and listened for many, many hours, comparing them with mods, as original and around 15 more different clone kits built by friends. I even own an original NAP140 myself (when its not on loan ) As far as defining sound quality goes, Naim still adhere to a few specific component types for reasons that become clear when you build a clone with whatever cheap parts or even modern, high Ft parts that ordinarily, would best suit the applications. The biggest mistake is to fit the D667/B647 VAS transistors now supplied or other low Cob transistors too - there goes that essential Naim sound you find with ZTX653/753. Why? Look at Cob -30pF! look at Cdom- only 39pF. Compensate by adding capacitance as you will but the added distortion of high Cob transistors is actually desirable and necessary for Naim sound but not easy to replicate any other way, if at all.
I think the secret sauce is not so much in some special design technique, but an adherence to what we'd now call errors in part selections in the early days of Naim and perhaps with the first series NAP200. Smart as he was, Vereker was not an engineer and did things his way, putting his spin on the pleasing and surprisingly successful results. Even today, professionals still pooh-pooh the general design despite its phenomenal success and survival over decades.
The clone kits though, will be disappointing as they come, even the more expensive kits and built modules with quality components, if you are familiar with the Naim sound quality you seek or perhaps you're a casual audiophile looking for something interesting in retro audio. You're going to need an original model or very close, to be confident that subjectively, you do have what you were you're aiming at - not an easy ask at all.
for reference, the NAP250 and generic NAP schematic:
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Hi Ian,
Fantastic reply - thank you - you have piqued my interest in this amplifier.
I'm not one for clone kits, although I enjoy taking my que from giants that went before me I like to roll my own when it comes to implementation. I bought 4 metal boxes from eBay a few years ago with the idea of building a different amplifier into each box. I am hoping that after all the boxes are finished I can stop my addiction to Class AB amplifiers and move on to other interesting aspects of this hobby ! Anyhow, it means that I would prefer to layout my own pcb to suit the details of the box.
I don't have access to an original NAIM amplifier but in my youth they were an item of envy, out of my reach. My late wife has a friend in Oxford who is an Opera critic with large CD collection and is a passionate fan of NAIM. The reputation of the amplifier intrigues me.
I believe you when you say the VAS is one of the keys to the sound. With my AKSA clones I have found that the VAS compensation makes all the difference once you have the rest of the amplifier set up properly.
The ZTX753 is still available - are the current production devices the same thing that was used in the NAP140 and available 40 yrs ago though because I don't see them being made on the same wafer process that would have been running back then ?
Fantastic reply - thank you - you have piqued my interest in this amplifier.
I'm not one for clone kits, although I enjoy taking my que from giants that went before me I like to roll my own when it comes to implementation. I bought 4 metal boxes from eBay a few years ago with the idea of building a different amplifier into each box. I am hoping that after all the boxes are finished I can stop my addiction to Class AB amplifiers and move on to other interesting aspects of this hobby ! Anyhow, it means that I would prefer to layout my own pcb to suit the details of the box.
I don't have access to an original NAIM amplifier but in my youth they were an item of envy, out of my reach. My late wife has a friend in Oxford who is an Opera critic with large CD collection and is a passionate fan of NAIM. The reputation of the amplifier intrigues me.
I believe you when you say the VAS is one of the keys to the sound. With my AKSA clones I have found that the VAS compensation makes all the difference once you have the rest of the amplifier set up properly.
The ZTX753 is still available - are the current production devices the same thing that was used in the NAP140 and available 40 yrs ago though because I don't see them being made on the same wafer process that would have been running back then ?
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Thanks for the feedback too. Its not easy to tell what one is communicating by trying to sum up designs in a historical context, unless you're a journalist, I guess. I often look at old texts and design cookbooks showing the technical thinking of the times and look for comments from others here, who have a better grip on UK audio electronics of the past.
Interesting point you make about process changes in the transistors over the years. I hadn't considered it but unless the specs lie about ZTX 653/753, a high Cob of 30pF would tell you there is a still a big chunk of transistor in there. Perhaps that's all that's necessary to match the original sound quality.
Interesting point you make about process changes in the transistors over the years. I hadn't considered it but unless the specs lie about ZTX 653/753, a high Cob of 30pF would tell you there is a still a big chunk of transistor in there. Perhaps that's all that's necessary to match the original sound quality.
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I agree, the designers intent is as important as the circuit. I enjoyed working through an understanding of the AKSA amp with Hugh Dean for this reason (I still have one to tweak) and I have some designs from Shindo that may become a project - somebody else with a strong sense of what they were trying to achieve. The designers worked with the components like an artist works with clay, until they found the form and function created in their minds eye. Much more is to be learned from understanding what they envisioned.
Do you think this amp benefits from being fed with a regulated supply ? I've read some claims that it does. But would it also lose the 'magic' it is known for if regulated ?
Do you think this amp benefits from being fed with a regulated supply ? I've read some claims that it does. But would it also lose the 'magic' it is known for if regulated ?
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It's evident from the sales of various models that regulating the whole supply to a Naim doesn't adversely affect the sound quality. It has to sound somewhat different if the supply rails don't droop at high power and noise is lower but regulating just the front end or input stage, thus breaking the amplifier's secondary signal path, certainly does have an adverse effect. Rensli showed his work (and disappointment) with this in the big thread.
I'm sure there's more to this when you review Hugh's comments on back-emf and the tweaks he exploited in the AKSA but For the NAP series, there's supporters of both regulated and unregulated supplies and that could just as well be a price issue. I only play with unregulated types but I don't miss much when listening to NAP250 on occasion.
On the general identity and qualities such as regulation of the various models, this link might be interesting if you haven't already seen it. It's a bit dated in regard to suggested mods and some substitutions seem to be more window dressing than wisdom but it should be a reasonable primer for your own ideas: Modifying Naim Audio power amplifiers
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