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Naim-like amp that doesn't hum

Richard Dane at Naim once said that when Holden and Fisher went out of business the same factory kept making the same transformers to the same design but they just weren't branded H&F. He described it as an urban myth that there was any difference and doubted that anyone would have noticed if the company name hadn't changed. It was some time ago though so I'm paraphrasing.

Let's be honest though, he would have said that wouldn't he.
 
Why turn amps off when not in use?, they definitely sound better when left on in my experience.

I must have only explained this maybe 30 times on fora.... It wears things out, specifically electrolytic caps. Download any datasheet for electrolytic caps and the most prominent spec will usually be it's life time in hours. Anything will reach its optimum performance within an hour or so.
 
I must have only explained this maybe 30 times on fora.... It wears things out, specifically electrolytic caps. Download any datasheet for electrolytic caps and the most prominent spec will usually be it's life time in hours. Anything will reach its optimum performance within an hour or so.

My listening experience (no matter what the brand) leads me to agree wholeheartedly except that I think 30 minutes is nearer the mark :)
 
The nord amps are dead quiet, as is any quality design with a switch-mode power supply. Not Naim-like though, more neutral though Nord does offer the option of switchable op-amps to adjust the sound to suit. My Marantz PM-11S3 is dead quiet, as are all of their current amps to my ears.
 
Richard Dane at Naim once said that when Holden and Fisher went out of business the same factory kept making the same transformers to the same design but they just weren't branded H&F. He described it as an urban myth that there was any difference and doubted that anyone would have noticed if the company name hadn't changed. It was some time ago though so I'm paraphrasing.

I was there at the time. The transformers were subsequently made by a different manufacturer in a different country who had to be taught how to do it properly. There's a reason all those toroids have little stickers with numbers and letters all over them and it's because we had to test every single one of them. Of the passed ones, some of them even fitted the chassis they were bolted into so back to the drawing board again.

I can't keep saying this enough - the problem with Naim's amps is their stupidly wide aspect ratio and the necessity for the toroidal transformers to fit them. The slim range made this even worse. Our shoebox amps were taller for this reason and I took the opportunity to put a taller H+F derived transformer in it. As a result it's near silent and walks all over the NAP250. We have one left.
 
None of my Naim amps here in Suffolk hum. A Supercap does occasionally. I've my DIY dual- mono Voyager amp with Canerbury Windings transformer, and an old NAP150, both equally quiet when I used in Suffolk, but when used in our holiday home in Cumbria sometimes hum like bastards for no reason I can discern.
 
OK is it a Hum from the chassis?
What is your mains voltage?
How old is the amp?

It's purely mechanical - nothing from the speakers (apart from the usual slight volume related hiss)
Mains voltage is high - 250+
Ages vary on the amps - newly recapped CB 250, 180 which I think is unserviced, SuperUniti all hum to some degree.
 
I must have only explained this maybe 30 times on fora.... It wears things out, specifically electrolytic caps. Download any datasheet for electrolytic caps and the most prominent spec will usually be it's life time in hours. Anything will reach its optimum performance within an hour or so.

Since reading your posts I have started turning my kit off (trust the service engineer!), but aren’t those ratings at 85 or 105 deg C? So, a low quiescent current amplifier isn’t going to eat caps like an old Krell?
 
I was expecting something far less reasonable along the lines of "if you need to ask..."
Do they come n balanced versions? My favorite pre seems to work better balanced.

They come single-ended with RCAs because the circuit is not a balanced design.
 
Since reading your posts I have started turning my kit off (trust the service engineer!), but aren’t those ratings at 85 or 105 deg C? So, a low quiescent current amplifier isn’t going to eat caps like an old Krell?

Correct. The hotter the amp the shorter the life of the caps. PSU smoothing caps have to handle the ripple current and are under more stress than most others. I've had a Krell integrated in (not class A but runs warm) which had been left on and every cap was knackered other than the smoothing caps... and others where the more expected case of knackered smoothing caps was found but most others were still working... if not up to full spec.
Much varies depending on the quality of the caps, voltage on them etc.
Usually though if I get an amp in for repair and the owner says it's been on 24/7 I'm expecting the fault/s to be due to knackered caps and I'm usually right:)
 
To be entirely fair though, it just doesn't bother me one iota.
Best advice yet.

To the op, I wouldn't get bogged down with a bit of hum on the transformer, having had a few Nait 3 amps here with hum, they sounded exactly the same as my silent model.

It will have zero effect on sound quality, all that matters really.
 
fascinated tonight when i came to listen to the naim , it was humming ... never done that [ not the amp ] . mmmm ... moved a couple of cables away from each other and it went completely !!! my they are very sensitive machines !
 
My 135s hum a little. Can’t hear it at all when listening to music. Had a 300, 250, 200, 150, 90. Some had no discernible hum, some did. Just never got in the way of enjoying the music. Switch off when not in use.

Peter
 
Since reading your posts I have started turning my kit off (trust the service engineer!), but aren’t those ratings at 85 or 105 deg C? So, a low quiescent current amplifier isn’t going to eat caps like an old Krell?

Naim amps shut down automatically at 70 degrees, which is a shame, as I could save a lot of electricity if I could boil the kettle on mine.
 
Switching off the 180 is fair enough, but it's a bit of a faff with the SuperUniti, and the family expect to just hit a button on the remote to get instant sound :-/
And I don't see why I should 'just get over it'. It's not cheap kit, why should I compromise?
 
I must have only explained this maybe 30 times on fora.... It wears things out, specifically electrolytic caps. Download any datasheet for electrolytic caps and the most prominent spec will usually be it's life time in hours. Anything will reach its optimum performance within an hour or so.

On the matter of leaving amplifiers on or off, I've actually checked with an experienced E&E engineer who specialises in the repair of audiophile components since I am aware that Naim recommends their amplifiers to be permanently left on. His advice was to leave the amps on to prolong the lifespan of the amp. I am well aware on the lifespan of electrolytic capacitors, transistors or other components. However, after a little research on the internet it appears that it's not so much about the caps wearing out but the constant activity of switching the amp on and off that wears things out.

An excerpt from an article below (link : http://audiophilereview.com/tubes/leave-it-on.html )

When I asked this question of the Engineer, his answer was that, yes, all of it was turned-on, all the time, twenty-four hours of every day, and that they kept it that way for reasons of both security and economy: Security, because if any piece of equipment were ever to fail, the station would always have another of the same thing, already warmed-up to replace it, and would never have to risk going off the air. Economy, because, even despite the electricity cost (remember that this was in the early '60s and electricity was very cheap), all of those tubes would last MANY times longer, saving on both the cost of the tubes and the labor to replace them. He went on to explain that the thing that causes tubes to "wear out" is not their operation, but the repeated heating and cooling cycles that come from turning equipment on and off again whenever it is used. This, he said, eventually results in a form of "fatigue" to the metal elements of the tubes and finally results in their failure. Just as a light bulb will last much longer if you just turn it on and LEAVE it on, he said, so will an electron tube.

I used to leave my Naim amps permanently switched on 24/7 for 7 years, perhaps switching them off once or twice in a year. Nowadays, I switch the amps off once or twice in a month. Just a change of habit.
 
It's purely mechanical - nothing from the speakers (apart from the usual slight volume related hiss)
Mains voltage is high - 250+
Ages vary on the amps - newly recapped CB 250, 180 which I think is unserviced, SuperUniti all hum to some degree.

It sounds like due the high voltage that the transformer is saturating , I also suspect DC on the mains and this will sound like 100Hz not 50Hz.
Try and get a mains conditioner ,with a Sine Wave output.
We in the UK were supposed to be 230VAC but I am seeing more and more much higher voltages some as high as 285VAC with a 11-15V DC not good, I wonder if the mains voltage was cranked up when we all had incandescent bulb and more power required so voltage drops on line was higher and now we are all moving to LED lighting the load is reduced but the Elec Trickery folk have not corrected the change.

DC blockers will work fine but make sure the caps can take the max input peak inrush current this will remove the DC, but not correct the over voltage. Oh a tip at 50Hz the ESR of the cap makes very little difference as the Impedance of the cap is much higher.
 

I mut say that the blurb on you website doesn't inspire confidence:
Here are some design features:

  • 50watt Class AB design
  • Input sensitivity switchable for 1.2 volts to 3 volts
  • Very short signal path So what?
  • Exceptional power supply How so?
  • Solid state design Like most amplifiers
  • High quality film capacitors Where, why? Noting unusual here.
  • Precision matched parts Which ones? What's the benefit?
  • High quality custom transformer Specification? What is special about it?
  • High quality gold RCA input connectors Solid gold? Gold coloured? So what?
  • WBT speaker binding posts So what?
  • CNC machined chassis So what?
  • Hand assembled in England So what?
  • All parts supplied by English companies Could be very limiting. Are these companies English owned?

Basic sales/marketing: Feature and benefits

For an amp geek like me I would also like to see a pic of the inside so that I can judge if the unit looks well designed and well put together. The outside looks very smart, by the way.
 
When I asked this question of the Engineer, his answer was that, yes, all of it was turned-on, all the time, twenty-four hours of every day, and that they kept it that way for reasons of both security and economy: Security, because if any piece of equipment were ever to fail, the station would always have another of the same thing, already warmed-up to replace it, and would never have to risk going off the air. Economy, because, even despite the electricity cost (remember that this was in the early '60s and electricity was very cheap), all of those tubes would last MANY times longer, saving on both the cost of the tubes and the labor to replace them. He went on to explain that the thing that causes tubes to "wear out" is not their operation, but the repeated heating and cooling cycles that come from turning equipment on and off again whenever it is used. This, he said, eventually results in a form of "fatigue" to the metal elements of the tubes and finally results in their failure. Just as a light bulb will last much longer if you just turn it on and LEAVE it on, he said, so will an electron tube.
I'm no expert but would have thought valves and solid state might be different. Regardless of that, there is no way on earth I would leave a valve amplifier permanently on, especially in my absence. And it's time all the Naimees did their bit for the environment.

S-Man - so like pretty much every other amp description then. I guessed the 'SS design' was to differentiate from the valve amps Tron make.

GT how much is the Atlantic power amp in UK?
 


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