Circuit topology of new gear
Posted by: Mr_Sukebe on 02 January 2004
I seem to remember reading a number of times that on all older Naim power amps, that the circuit design was basically the same, and that differences were not in the core design, but in the quality of components, size of transformers etc.
So what about the new gear, does that also conform to a very similar layout/design? Anyone know and care to comment?
So what about the new gear, does that also conform to a very similar layout/design? Anyone know and care to comment?
Posted on: 02 January 2004 by garyi
Well I see where you are coming from but I have had a peek inside a nap 90/140/180/250 and they are all very very different.
I can't pretend to know what is in there but I do know that its not simply better of the same.
The 90 for instance is little more than a transformer connected to the dins, where as the 250 has all these boards a f**k off caps, so your understanding can't fit.
Havn't seen much of the new kit inside.
I can't pretend to know what is in there but I do know that its not simply better of the same.
The 90 for instance is little more than a transformer connected to the dins, where as the 250 has all these boards a f**k off caps, so your understanding can't fit.
Havn't seen much of the new kit inside.
Posted on: 02 January 2004 by Paul Ranson
The 90/140/180/250/135 all have similar circuitry, probably interchangable boards (certainly between 180/250/135). The 250/135 have regulated power supplies, so extra boards and wiring. Each has differing transformers and smoothing caps, and layout of such.
The crude anatomy of a NAP250 is well known, but perhaps not well understood. It would be interesting to get some techinical detail on the new range both power and pre.
And personally I'm quite interested in what's going on inside the NAC552.
Paul
The crude anatomy of a NAP250 is well known, but perhaps not well understood. It would be interesting to get some techinical detail on the new range both power and pre.
And personally I'm quite interested in what's going on inside the NAC552.
Paul
Posted on: 02 January 2004 by Geoff P
Here's what's inside a 150
Geoff
Geoff
Posted on: 02 January 2004 by Geoff P
And here's what's inside the new 250
Geoff
Geoff
Posted on: 02 January 2004 by Geoff P
Actually bearing in mind the 250's regulated power supply as highlighted by Paul, the 150 board layout looks remarkably like a simplified version of the 250 whose output trannies are hidden under the black shields.
Geoff
Geoff
Posted on: 02 January 2004 by J.N.
Yow!
Thanks Geoff - Now I see why my new 250 is so much heavier than the 'olive' model. It also looks quite different, with an obviously bigger transformer.
Thanks Geoff - Now I see why my new 250 is so much heavier than the 'olive' model. It also looks quite different, with an obviously bigger transformer.
Posted on: 03 January 2004 by Paul Ranson
The amps have lost some of their internal appeal, I think. Which I suppose is fine given they're not designed to be looked at....
Paul
Paul
Posted on: 03 January 2004 by Basil
quote:
The amps have lost some of their internal appeal, I think. Which I suppose is fine given they're not designed to be looked at....
I don't think they look as well made as they used to, but as long as they sound better, it doesn't really matter.
Posted on: 03 January 2004 by London Lad
The 250 is a twin mono layout as well
Graham.
Not a lad any longer and not from London!
Graham.
Not a lad any longer and not from London!
Posted on: 04 January 2004 by Laurie Saunders
I concur with Paul here...I understand the basic configuration of the (olive) power amps to be the same. As you move up the range, the size/sophistication/regulation of the power supply improves. Which is quite reasonable if you accept JVs thesis that an amplifier is little more than a modulated power supply (I do up to a point)
I would also be intersted in the "secret" of the 552...is it just a refinement of the 52?....it does use a dual rail power supply, though would this alone account for the claimed supriority?
Laurie S
I would also be intersted in the "secret" of the 552...is it just a refinement of the 52?....it does use a dual rail power supply, though would this alone account for the claimed supriority?
Laurie S
Posted on: 04 January 2004 by London Lad
The 552 is also 'dual mono' is the 52 the same ?
Graham.
Not a lad any longer and not from London!
Graham.
Not a lad any longer and not from London!
Posted on: 04 January 2004 by quickie
What exactly do you mean by"dual mono"?
If they wern't you wouldn't have stereo
Paul.
If they wern't you wouldn't have stereo
Paul.
Posted on: 04 January 2004 by London Lad
In respect of the nap150 you can see one board, a stereo amp. In the pic of the new 250 you can clearly see two boards with one mono amp on each.
The 552 is described as dual mono on the NAIM US site but I have not seen the internal layout.
Graham.
Not a lad any longer and not from London!
The 552 is described as dual mono on the NAIM US site but I have not seen the internal layout.
Graham.
Not a lad any longer and not from London!
Posted on: 04 January 2004 by Mr.Tibbs
“I would also be intersted in the "secret" of the 552...is it just a refinement of the 52?.”
No, it’s a completely new design owing to the fact it uses a dual rail supply.
“..it does use a dual rail power supply, though would this alone account for the claimed supriority?”
The single rail, single ended design inherent in all of Naim’s preamps previous to the 552 have all had a performance ceiling dictated by the quality of the attached single rail power supply. The 252 with its complex multiple 24V power supply is sitting at the limit of single rail technology.
I think the design of the 552 owes a lot to the technology first used in the CDS2 - with some additional refinements. The CDS2 saw the introduction of discrete topology gain stages as opposed to the IC amps normally employed. These discrete gain blocks are no doubt closely related to the clever designs found in modern IC amps, but offer a performance advantage as they can be designed specifically for the intended application.
Dual rail design also allows for a direct coupled (no capacitor) link between stages and also does away with the complex 0V return system found in single rail designs.
Mr Tibbs
No, it’s a completely new design owing to the fact it uses a dual rail supply.
“..it does use a dual rail power supply, though would this alone account for the claimed supriority?”
The single rail, single ended design inherent in all of Naim’s preamps previous to the 552 have all had a performance ceiling dictated by the quality of the attached single rail power supply. The 252 with its complex multiple 24V power supply is sitting at the limit of single rail technology.
I think the design of the 552 owes a lot to the technology first used in the CDS2 - with some additional refinements. The CDS2 saw the introduction of discrete topology gain stages as opposed to the IC amps normally employed. These discrete gain blocks are no doubt closely related to the clever designs found in modern IC amps, but offer a performance advantage as they can be designed specifically for the intended application.
Dual rail design also allows for a direct coupled (no capacitor) link between stages and also does away with the complex 0V return system found in single rail designs.
Mr Tibbs
Posted on: 04 January 2004 by Paul Ranson
But what's actually in the NAC552? I think it is still ac coupled.
And why isn't the new active crossover split rail? And it uses the black blobs rather than individually packaged transistors. Inquiring minds are dead keen to know.
Paul
And why isn't the new active crossover split rail? And it uses the black blobs rather than individually packaged transistors. Inquiring minds are dead keen to know.
Paul
Posted on: 04 January 2004 by London Lad
And my slightly worn out mind needs to know as well
Graham.
Not a lad any longer and not from London!
Graham.
Not a lad any longer and not from London!
Posted on: 04 January 2004 by Mr.Tibbs
“But what's actually in the NAC552? I think it is still ac coupled.”
It may well still be AC coupled – it doesn’t have to be though. This aside, the main advantage of split rail design is its much superior noise rejection.
“And why isn't the new active crossover split rail? And it uses the black blobs rather than individually packaged transistors. Inquiring minds are dead keen to know.”
There’s bound to be a proper split rail crossover in the pipeline to match the 552, it’s only a matter of time – the existing single rail version would represent a serious performance bottleneck in a system already using the 552 preamp.
Mr Tibbs
It may well still be AC coupled – it doesn’t have to be though. This aside, the main advantage of split rail design is its much superior noise rejection.
“And why isn't the new active crossover split rail? And it uses the black blobs rather than individually packaged transistors. Inquiring minds are dead keen to know.”
There’s bound to be a proper split rail crossover in the pipeline to match the 552, it’s only a matter of time – the existing single rail version would represent a serious performance bottleneck in a system already using the 552 preamp.
Mr Tibbs
Posted on: 04 January 2004 by Paul Ranson
The point is that Naim have re-engineered the active crossovers using their newer technology and the new cases, it doesn't seem likely that they're about to redo the electronics again.
The Prefix is still single-ended, and I think there's no split rail output on the 552 to power a Super Prefix.
Back in the 70s there were some semi-mythological split rail NAC12s. So what goes around....
Anyway I'm sure all will become clear, but at present it all looks a bit inconsistent. Or more likely there's something we don't know...
Paul
The Prefix is still single-ended, and I think there's no split rail output on the 552 to power a Super Prefix.
Back in the 70s there were some semi-mythological split rail NAC12s. So what goes around....
Anyway I'm sure all will become clear, but at present it all looks a bit inconsistent. Or more likely there's something we don't know...
Paul
Posted on: 04 January 2004 by Martin D
Interesting stuff, but I do feel that the new stuff looks messy compared with the olive constuction - a bit thrown together maybe? Genuinely not sour grapes just an observation. I've heard the new stuff at the factory and its noticeably better, and different as well.
Full on olive owner.
Martin
Full on olive owner.
Martin
Posted on: 05 January 2004 by Mr.Tibbs
“The point is that Naim have re-engineered the active crossovers using their newer technology and the new cases, it doesn't seem likely that they're about to redo the electronics again.”
I’d argue there’s a market for both the existing single rail and a totally new split rail crossover. A new split rail crossover is going to take some time to put together, but will be the crossover of choice for the 552 owner who just has to go active with a bunch of 500’s – Imagine the price tag of that lot... well scary!
The existing re-engineered and cased single rail crossover will be the choice of the 252 owning poor relation... I almost feel sorry for them.
“Back in the 70s there were some semi-mythological split rail NAC12s. So what goes around....”
That’s interesting.
Did you ever come across the cute little Meridian 101 preamp? It featured a PC motherboard with some plug in daughter-board modules, namely a buffer stage, a line stage and a phono stage. Each module contained a stereo pair and all of the modules featured fully discrete split rail topology.
It sounded good too – I used one to drive a big valve power amp back in the early 80’s.
“Anyway I'm sure all will become clear, but at present it all looks a bit inconsistent. Or more likely there's something we don't know...”
Yeah, all will be revealed in the fullness of time...
Mr Tibbs
I’d argue there’s a market for both the existing single rail and a totally new split rail crossover. A new split rail crossover is going to take some time to put together, but will be the crossover of choice for the 552 owner who just has to go active with a bunch of 500’s – Imagine the price tag of that lot... well scary!
The existing re-engineered and cased single rail crossover will be the choice of the 252 owning poor relation... I almost feel sorry for them.
“Back in the 70s there were some semi-mythological split rail NAC12s. So what goes around....”
That’s interesting.
Did you ever come across the cute little Meridian 101 preamp? It featured a PC motherboard with some plug in daughter-board modules, namely a buffer stage, a line stage and a phono stage. Each module contained a stereo pair and all of the modules featured fully discrete split rail topology.
It sounded good too – I used one to drive a big valve power amp back in the early 80’s.
“Anyway I'm sure all will become clear, but at present it all looks a bit inconsistent. Or more likely there's something we don't know...”
Yeah, all will be revealed in the fullness of time...
Mr Tibbs
Posted on: 05 January 2004 by London Lad
Mr Tibbs,
Can you explain more what you mean by dual rail?
I thought a super cap was 'multi rail' ??
Graham.
Not a lad any longer and not from London!
Can you explain more what you mean by dual rail?
I thought a super cap was 'multi rail' ??
Graham.
Not a lad any longer and not from London!
Posted on: 05 January 2004 by Mr.Tibbs
“Can you explain more what you mean by dual rail?”
Hmm, somewhere I just might have said ‘dual rail’ but meant to say ‘split rail’??
Sorry for any confusion.
Any talk with ‘rail’ in it simply refers to the type of power supply rail in use.
Here’s a short guide as to what the terms actually mean.
Single rail: Some of Naim’s early preamps like the 32 and 42 used a single 24V supply rail. The circuits ‘hang’ between the 24V positive supply rail and the 0V return or ‘ground’. The early SNAPS is a single rail supply.
Dual rail: The later preamps like the 62, 72, 102 etc (and the . 5 versions of the 32 and 42) were all capable of being powered by two 24V rails. Later versions of the SNAPS and then the HICAP had two 24V rails.
Multiple rail: The 52 and 252 are designed to make use of the Supercap which has something like fourteen separately regulated 24V rails. The circuitry is still basically the same as in the lesser preamps and hung between the 24V rail(s) and the 0V return system.
Split Rail: This is the kind of supply normally found in power amps and for IC opamps. The supply consists of two rails of opposite polarity and a 0V line connected to the transformer centre tap. In a power amp the rail voltage might be in the region of +/- 35V or more. A preamp would usually run at +/- 18V or thereabouts. The 552 uses gain stages that have much in common with power amp and IC opamp design.
Mr Tibbs
Hmm, somewhere I just might have said ‘dual rail’ but meant to say ‘split rail’??
Sorry for any confusion.
Any talk with ‘rail’ in it simply refers to the type of power supply rail in use.
Here’s a short guide as to what the terms actually mean.
Single rail: Some of Naim’s early preamps like the 32 and 42 used a single 24V supply rail. The circuits ‘hang’ between the 24V positive supply rail and the 0V return or ‘ground’. The early SNAPS is a single rail supply.
Dual rail: The later preamps like the 62, 72, 102 etc (and the . 5 versions of the 32 and 42) were all capable of being powered by two 24V rails. Later versions of the SNAPS and then the HICAP had two 24V rails.
Multiple rail: The 52 and 252 are designed to make use of the Supercap which has something like fourteen separately regulated 24V rails. The circuitry is still basically the same as in the lesser preamps and hung between the 24V rail(s) and the 0V return system.
Split Rail: This is the kind of supply normally found in power amps and for IC opamps. The supply consists of two rails of opposite polarity and a 0V line connected to the transformer centre tap. In a power amp the rail voltage might be in the region of +/- 35V or more. A preamp would usually run at +/- 18V or thereabouts. The 552 uses gain stages that have much in common with power amp and IC opamp design.
Mr Tibbs
Posted on: 05 January 2004 by London Lad
Got it. Thanks
Graham.
Not a lad any longer and not from London!
Graham.
Not a lad any longer and not from London!