Indeed. I'm even soldering leads on a surface-mount naked staked film cap to get the right look of the Zobel capacitor.
Of course I'm doing my own two-layer boards, so contradictions abound.
BTW: that brings me to another question: has anyone found a trimpot that resembles the original ones Naim used?
I am wondering if you are aware that JV engaged a software expert to design the program he used for the pcb layout - he specifically wanted to be able to contour shapes using curves and graduations in trace widths.
At the time Naim had also come up with a computer model of the circuit which mapped everything.
There are a couple of points to make about JV's pcb - first heat in the Vas transistor will travel through the leads to large coppers area under the pcb.
Second there are no sharp edges that you might find in regular pcb layouts where bleeding of the signal can happen at angular points where straight lines cross.
There is also a problem with stray capacitance causing a decline in gain with increasing frequency - so there is more to JV's layout than as might appear at a glance.
Some of the NAP kits that have been sold on ebay claim to be 100% clones which includes the pcb. I see the pcb replica as one of the key elements to have.
I'm aware of the story, I'm just not sure I buy it. At the time something like an IMSAI 8080 didn't remotely have the horsepower to do something like that.
CAD was in its infancy in the 1970s. It ran mostly on mainframes and minicomputers (PDP11 primarily). The early players (Control Data, MCS, EDS, etc.) mainly focused on numerical control for the automotive and aerospace industries. Intergraph is probably the first to have done PCBs, but I believe that was entirely through 6-figure US government contracts.
Raster displays, Computervision, Silicon Graphics, etc. didn't come along until the very end of the decade. Even then, computers to run those systems were still in 6 figures.
So it's just about possible that JV managed to finagle extensive time on a university computer (remember that his software engineer would have needed to write the custom software on it as well). But I don't think it's likely.
CAD was in its infancy in the 1970s. It ran mostly on mainframes and minicomputers (PDP11 primarily). The early players (Control Data, MCS, EDS, etc.) mainly focused on numerical control for the automotive and aerospace industries. Intergraph is probably the first to have done PCBs, but I believe that was entirely through 6-figure US government contracts.
Raster displays, Computervision, Silicon Graphics, etc. didn't come along until the very end of the decade. Even then, computers to run those systems were still in 6 figures.
So it's just about possible that JV managed to finagle extensive time on a university computer (remember that his software engineer would have needed to write the custom software on it as well). But I don't think it's likely.
I regarded it as credible at the time which was later when Naim had become automated.
Anyway, the traces for the Vas transistor run in parallel on a tenuous route around a fairly tight loop and there was a degree of care in the way this was done.
Aspects like this should not be passed over without thinking about them - certainly not if everything matters.
Agreed, although he was also working under the constraints of a single-layer board without resorting to any jumpers on the top.
It's interesting to note that the NAP200 did resort to jumpers, but stayed with a single-layer board. I wonder why? It was well into the modern era, and the regulator boards are two-sided (with SMD components no less). Was the single-layer main board just nostalgia? It certainly looks old-school without the solder mask (although the silkscreen spoils it to some degree).
It all looks pretty chunky and DIY. It sounded good though. This was the first Naim model I ever heard, back in the late 70s. My schoolfriend's dad had one and I distinctly remember how well it played Boney M's Nightflight to Venus. Real driving rhythm. I had just started designing amps using Hitachi lateral MOSFETs.
I read somewhere the rumour that his girlfriend at the time designed the PCB. So I don't know. But I think it was single-sided without masking to keep it cheap as chips. Layout is important but I am more inclined to believe he used his common sense, which he had an abundance of, rather than software tools.
Naim probably use layout simulation tools now.
I wish I knew which one made such an impression on me.
In the mid-80s I had one of the first Linn amps (LK2), and blew it up. The dealer loaned me a full-width chrome-bumper Naim, but I don't know whether it was a 180 or a 250. Blew that up too. Dealer loaned me another LK2. Blew it up. Dealer loaned me a Perraux. It survived, but wasn't in the same sound-class. By this time Linn was involved and they sent me a pre-production LK280 to see if I could blow it up. I had that amp for 20 years or so.
But out of them all, the Naim sounded the best....
In the mid-80s I had one of the first Linn amps (LK2), and blew it up. The dealer loaned me a full-width chrome-bumper Naim, but I don't know whether it was a 180 or a 250. Blew that up too. Dealer loaned me another LK2. Blew it up. Dealer loaned me a Perraux. It survived, but wasn't in the same sound-class. By this time Linn was involved and they sent me a pre-production LK280 to see if I could blow it up. I had that amp for 20 years or so.
But out of them all, the Naim sounded the best....
It seems Perreaux is still in business. Still making Maplin style power amps no doubt. Class AB mosfets. Not a great topology but relatively easy to manufacture. These little start-ups often get bought out and a marketing guru owner put in; then nice looking, expensive boxes and brochures.
I’m trying to decide what “The sound of New Zealand” is. I’ve been there. It’s a quiet sort of place. The triumphant haka dance at the Maori tourist centre came close to causing a few kiwis to take flight.
I’m trying to decide what “The sound of New Zealand” is. I’ve been there. It’s a quiet sort of place. The triumphant haka dance at the Maori tourist centre came close to causing a few kiwis to take flight.
I like the life style here - the quieter the better. Every now and then I escape to our property near the beach away from suburbia - I am spending what is left of the good weather before the arrival of autumn at the beach.
I have heard Perreaux and Plinius amplifiers.
The Perreaux was in a shop that also dealt with Naim and Linn so I was able to hear these at the same time. The Naim was an early NAP 250.
McLaren is another brand that started up in New Zealand.
I have not bought any item of Hi-Fi equipment that has been manufactured here.
Your disdain for mosfets is showing, Traderbam.
Perreaux products, in their day, made large inroads into Hifi in short order from "a little start-up" at a time when the market seemed to be wallowing in mediocrity. Their sound quality swept away a lot big names here in Oz, where we may have a lot more consumers but we ceased manufacturing audio electronics in the 1970s when even tariffs couldn't slow the shiploads of cheaper and better quality electronics from Japan.
New Zealand maintained their heavy tariffs much longer and this created a haven for local electronics enterprise there. Perreaux would have received its initial success in that environment but that help would have tailed off as pressure on currency values took its toll in later years.
Perreaux was also better recognized in the US than we may think and that market remains critical to global sales because of its promotional reach. There are still plenty of examples in the Australian used audio market but if you were looking to buy the up-market and current products, I think the US would be where to look.
Last edited:
Perreaux uses the Hitachi topology. The latfet itself has serious issue in that it has very low gm with a tendency for unmusical, flat and boring sound, like the Perreaux. Few people if any know how to drive such output stage transistor. The original Hitachi uses D756/B716 while Perreaux uses smaller transistor alike MPSA92/42. This topology is useless unless using unobtanium parts.
Goldmund has similar topology with extra driver for each output pair. JLH has different approach and one of his best is modified by Mooly becoming the 'My Mosfet Amplifier Designed For Music' (M1).
I myself prefer to use CFA topology. Even basic cfa like the VSSA or PeeCeeBee has better acceptance.
Goldmund has similar topology with extra driver for each output pair. JLH has different approach and one of his best is modified by Mooly becoming the 'My Mosfet Amplifier Designed For Music' (M1).
I myself prefer to use CFA topology. Even basic cfa like the VSSA or PeeCeeBee has better acceptance.
Hitachi application note
Discussion of the Hitachi topology (same as Maplin's) needs a new thread. JV did assess MOSFETs, obviously, but decided against them. Johnego's description is also my experience of the Maplin amps.
Discussion of the Hitachi topology (same as Maplin's) needs a new thread. JV did assess MOSFETs, obviously, but decided against them. Johnego's description is also my experience of the Maplin amps.
The reason I ask is that some of the early Exposure amps are basically a Naim front end driving lateral FETs. There seem to be quite a few people who think they are better than the equivalent Naim.
Also, the Incatech Claymore is basically the Hitachi apps note. However the designer (Colin Wonfor) chose european small signal semi over the "bright" sounding Japanese equivalents. Again, lots of people preferred the Claymore over the equivalent Nait.
Also, the Incatech Claymore is basically the Hitachi apps note. However the designer (Colin Wonfor) chose european small signal semi over the "bright" sounding Japanese equivalents. Again, lots of people preferred the Claymore over the equivalent Nait.
I
mosfets.The way they get used as simple source followers in output stages, as if they were bipolars, does not make the best use of their characteristics.
I don't think there is such thing as Naim front end. Basically it is a Lin topology with quasi output. What makes it special is how it is designed and the use of some inconventional compensation techniques. I have never seen such compensation used somewhere else and i will be using shortly it to my P3A amplifier.
Claymore is probably better due to the chosen output mosfet. The old BUZ and Exicons etc are dual matched one that will allow reduction of source resistors. Even the Exicons are usually measured better than the old Hitachi.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.