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Naim-like amp that doesn't hum

S-Man said:
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.
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Oh dear, and how many amps and power supplies have you designed in 50yrs of your working life ?
As to confidence on my designs try looking me up in Google or even bing.
And to be honest I care not about marketing just design, and the web page was not done by me, oh and it is still under construction.
The reason I do not write blurb is two fold 1) I am dyslexic 2) I have had to many designs stolen by non-designers and marketing thieves in the past. Oh and 3) If I explain the maths etc what would Joe Blog understand?

So what is your point S-man? friend of a friend maybe and politic maybe?

Oh and when did the "mut" come along you dog you he he
 
CJ14 said:
Oh dear, and how many amps and power supplies have you designed in 50yrs of your working life ?
As to confidence on my designs try looking me up in Google or even bing.
And to be honest I care not about marketing just design, and the web page was not done by me, oh and it is still under construction.
The reason I do not write blurb is two fold 1) I am dyslexic 2) I have had to many designs stolen by non-designers and marketing thieves in the past. Oh and 3) If I explain the maths etc what would Joe Blog understand?

So what is your point S-man? friend of a friend maybe and politic maybe?

Oh and when did the "mut" come along you dog you he he
Click to expand...

Colin I think you have the wrong end of the doggie stick! The questions are about GT's amp!
He might choose to take my comments as an affront, or maybe he will take them as useful market feedback from a punter and thereby improve his website?

Being pedantic, to answer your question: I have designed several SMPSs and an entire range of commercial linear PSs. However that was a long time ago.
I have also designed several power amps - but not commercial ones.

As for confidence in you, you seem to forget that we met several times when you were at Raytheon. I have the highest respect for your technical prowess (although I cannot claim to understand everything you told me).
 
david ellwood said:
Simply replace the transformers with switch mode power supplys.

It will remove the hum and you might prefer the sound.

Transformers are retro fittable and it probably represents the cheapest solution.
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Switch mode power supply is interesting. How would one go about doing this?
 
ryder said:
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.
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I’ve alway left my amps on 24/7. My Exposure 15 integrated amp is 25 years old. I replaced the main filter caps 13 years ago and that amp sounds great to me. My Exposure 19 preamp, 13 phono preamp and 18S power amp are all 19 years old and have also been running 24/7 with no service done to them. They also sound great. I hate the idea of having to power up my amps every time I want to listen to some music and knowing that they have always sounded better after being on for a couple days.

I worked in telecommunications back in the early 80’s and recall a bank of tubes that ran 24/7. I think back in the day tubes were used in that way for for various uses.
 
ryder said:
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.
Click to expand...

Complete bollox but please follow it as it gets me more work repairing the faulty gear:D
 
diybry said:
Switch mode power supply is interesting. How would one go about doing this?
Click to expand...
There are DIY options that can be made up with nothing more sophisticated than 2 lappy or printer power supplies, half an hour with a soldering iron and a box to put it in. You can even get away without a box. Or a soldering iron for that matter, if you can screw a chocolate block together.
 
diybry said:
Switch mode power supply is interesting. How would one go about doing this?
Click to expand...

Whooo a can or worms here.

There are many types.

1) Flyback need a constant load a very noise proun avoid in audio most common SMPS
2) Forward again need a constant load Ideal for loads up to 800W but can be bad for Audio.
3)Fullbridge big loads 10KW + again OKish for power amps.
4)Fullbridge Resonant , I love these sinwave out of the transformer high frequency 500K+ lowish noise and 100KW no problem

And many variants on a theme.

Best you read it in English

https://www.onsemi.com/pub/Collateral/SMPSRM-D.PDF

Have fun oh see if you can find stuff on CUK converter fantastic kit

https://en.wikipedia.org/wiki/Ćuk_converter

Here is a cheat guide th Flyback converters.

http://seca.freeforums.net/thread/97/flyback-transformer-guide
 
S-Man said:
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.
Click to expand...

That's fairly tame compared to some.. I guess that in that example it is, as Sman says "so what?" to most of the bullet points but I regularly see bumph for hi fi gear which tries to be technical and is in fact a pack of lies combined with utter BS. A common one is along the lines "Acme engineers have after intense research developed new and unique circuitry which... blah blah.." and when you get to see what it actually is it's something that's been in any electronic text book for 40 years! Another one is when they go to great lengths to explain how they have, at great expense, optimised some part of the amp which is completely irrelevant to SQ and it wouldn't matter if it had been done cheap as chips!
 
It's tame but lacking any info, which I found frustrating when I went to his site to see why a valve man would produce a ss amp and what he thought he could bring to the table. Seemingly nothing new.

If he wants to make a lacking-in-info but more effective sales pitch then he needs to follow the basic sales and marketing method of stating the "benefits" of the "features" e.g:
"exceptional power supply" is meaningless. He could say something like "exceptional power supply with low impedance across the audio band provides clarity and dynamics". It's still sales bollocks but at least we can see what he thinks is important (low impedance) and why (clarity and dynamics).
 
Sorry to hear the Tron website doesn't meet with your expectations. You're right, the website doesn't tell you everything about Tron, or it products, but it does give a flavour of what we do and what we make, as well as high lighting our reputation designing and building high end audio electronics within the industry during the past 20 years. The "design features" listed are just bullet points, nothing more and if anyone goes through the list and compares against other manufacturers products around the same price, they will see you get a lot for your money with the Tron Convergence Stereo or Mono amplifiers. Normally, if someone is interested in one of our products, or has a question(s) about the design, we get a phone call, or an email, or both. I am more than happy to discuss any details regarding my designs with any serious inquiry.
 
CJ14 said:
Whooo a can or worms here.

There are many types.

1) Flyback need a constant load a very noise proun avoid in audio most common SMPS
2) Forward again need a constant load Ideal for loads up to 800W but can be bad for Audio.
3)Fullbridge big loads 10KW + again OKish for power amps.
4)Fullbridge Resonant , I love these sinwave out of the transformer high frequency 500K+ lowish noise and 100KW no problem

And many variants on a theme.

Best you read it in English

https://www.onsemi.com/pub/Collateral/SMPSRM-D.PDF

Have fun oh see if you can find stuff on CUK converter fantastic kit

https://en.wikipedia.org/wiki/Ćuk_converter

Here is a cheat guide th Flyback converters.

http://seca.freeforums.net/thread/97/flyback-transformer-guide
Click to expand...
jeez-guess i'll leave the hiCap in place, but thanks for the info.
 
And why not it works very well, Gary Crocker did a great job on that,he was the chief designer at Naim a lovely man I enjoyed working with him.
 
CJ14 said:
And why not it works very well, Gary Crocker did a great job on that,he was the chief designer at Naim a lovely man I enjoyed working with him.
Click to expand...

I knew Gary but he didn't design the Hicap - that was Guy Lamotte.

Of course Gary may have designed the DR which was long after I left.
 
I use a variety of LPSUs from Custom Hi-Fi cables. None of them make a sound. They also make Naim PSUs but I've not tried one.
 
MJS said:
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.
Click to expand...
I've heard it in my system as a loaner for my 250 and it does indeed walk all over it...shame I can't afford it at the moment!
 
Last edited:
never had naim amps , but heard a few , most have a hum problem. . Never had a transformer hum issue with any audio since 60s.. don't buy into dc offset of mains all the time. design.manufacturing ,position issues come into the equation. its worth testing your earthing with qualified spark
 
Quick update - the postie has just brought me a shiny new Amptastic Mini-1.
For just over £100, this little box is astonishingly good. I've got it in power amp mode, with a NAC82/Dual TeddyCap which I'll admit is probably not a typical set up. It's utterly mechanically silent at idle, and speaker hiss is noticeably lower than my NAP180. Time will tell if it's as musically satisfying, but so far I'm very impressed...
 
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