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A honest yet refreshing Interview with Sanders Audio - Newbie should read


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Yes but that's showing it's constantly on........definitely not 4.5kw..... :D

 

comm'on they have to show it doing its thang.

 

its ok you can cover it with electrical then if you like .... and there will be no obvious signs of clipping anymore :D 

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Now here are some cool meters - same as the ones on my Vfet TAN 8550.

 

 

They're mechanical rather than electronic as the beams of light are reflected off mirrors on rotating drums.  They probably have the same limitations in displaying peaks as the mechanical needle ones though.

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Now here are some cool meters - same as the ones on my Vfet TAN 8550.

 

 

They're mechanical rather than electronic as the beams of light are reflected off mirrors on rotating drums.  They probably have the same limitations in displaying peaks as the mechanical needle ones though.

Similar limitations, but they are much faster than conventional needle pointers. Inertia is far lower.

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The Skytek 1000 does raise a good point, though, with its 1000 W peak power claim. The point being that the Sanders claim seemingly means we only need 500W peak rating, if it is to avoid clipping. Class G amps come to mind. But then the discussion gets even trickier, about how sustained do the peaks need to be, how well the amp design works at sliding or switching the rail voltages, etc.

 

In the end, the big hairy cover-all solution, with margin, is 500W continuous.

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So apart from looks, what's the point of these meters ?

 

C'mon, Trev ... sometimes you can be so dim!   :P

 

The purpose of these meters - whether they have rotating drums or moving needles - is to prove to the owners of these amps that they are never clipping!  Doh!!  :D

 

Andy

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Now you've spoiled Rob's world, Trev!   :D   He was quite happy in a state of blissful ignorance, believing that bcoz his (blue? ;) ) VU meters weren't moving, he wasn't clipping at all!  :D

Now he'll have to go looking for an amp with LED-based VU meters which will respond in a millisecond, so he can see what actually is happening!  :P

Andy

 

Naaah.     His speakers are almost twice as sensitive as the speakers used for the 500w generalisation .... and so his 200w amps is ~ fine.

 

 

 

Speaker sensitivity (voltage), load difficulty (current), listening distance and where you set the volume dial have an enormous impact.   I hope anyone reading this thread doesn't absorb the idea the "everyone needs more power" ....  but more so, takes Trevors advice that it is ""impossible generalise about this""

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The Skytek 1000 does raise a good point, though, with its 1000 W peak power claim. The point being that the Sanders claim seemingly means we only need 500W peak rating, if it is to avoid clipping. Class G amps come to mind. But then the discussion gets even trickier, about how sustained do the peaks need to be, how well the amp design works at sliding or switching the rail voltages, etc.

 

In the end, the big hairy cover-all solution, with margin, is 500W continuous.

 

And yet there are quite a few people on the Maggie forum who use 1Kw (continuous) W4S amps on just their bass panels (active setup).

 

Andy

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So apart from looks, what's the point of these meters ?

They're faster than regular moving coil meters with long needles on them, since they have far less inertia. Hold your arm close to your body such that your hand is near your face and move it as fast as you can across your body. Now do the same thing with your arm outstretched. You'll get the idea. It's also why gymnasts are so small. Short arms and legs = nimble. Big meters are slower than small ones.

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Now here are some cool meters - same as the ones on my Vfet TAN 8550.

 

https://www.youtube.com/watch?v=QcFPlPS2lVM

 

They're mechanical rather than electronic as the beams of light are reflected off mirrors on rotating drums.  They probably have the same limitations in displaying peaks as the mechanical needle ones though.

Tony,

I can sit there and watch those meters all day....:thumb:

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Tony,

I can sit there and watch those meters all day.... :thumb:

 

What is it Confucious said?

 

"Man who watch meters all day lose interest in women, food, wine - in fact everything good in life!".   :D

 

Andy

Edited by andyr
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What is it Confucious said?

 

"Man who watch meters all day lose interest in women, food, wine - in fact everything good in life!".   :D

 

Andy

 

And man who play with wine, women and song all day soon lose interest in those three very things, due to alcoholism, VD and deafness.

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The relevance is ... quasi-foil drivers are much, much more robust than true-ribbons.

 

So a clipping amp will not blow them up unless you have gone completely crazy with volume and are trying to reproduce a Motorhead concert (evidently, 140dB) in your living room.

 

Andy

 

EDIT: PS: Let's see if Bill lets you try your 40w amp on his 3.7is!! 

I will of course @@andyr

If it does eventuate and Bill affords me the opportunity then I will post an invite to one and all.

I cant speak on Bills behalf but the fact that there would be extra punters in the shop is always good for business.

 

Cheers Ozzie

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It's complicated. First off: It is important to understand that some HF drivers can be damaged more quickly than others. Usually, a more robust HF driver will employ some kind of system to dissipate the energy being delivered to the driver. For coil type driver, that may mean a thermally conductive voice coil former (usually aluminium) and/or 'ferro-fluid'. Ferro-fluid systems, in particular, allow the HF driver to dissipate very large amounts of energy, over quite long periods. They do so, by allowing the magnet structure to act as a heat sink. I recall reading about the KEF KM1 (Professional monitor). The magnet structure was designed to allow temperatures of around 100 degrees C under normal (high level) operation!

Second off: Clipping (voltage limiting) occurs in most amplifiers, at least some of the time. When it occurs, the output spectral balance is skewed towards the HF end of the spectrum. This means that more energy that can usually be anticipated ends up in the HF drivers. This can cause damage.

Third off: It is IMPOSSIBLE to generalise about damage to HF drivers of low power amps vs. high power amps. For example: An NAD 3020 (one of the original ones) with the soft clipping set to 'ON', if driven hard would be LESS likely to damage an HF driver than a (say) 500 Watt amp which lacks a soft clipping system. This is because, when driven very hard, a 500 Watt amp will deliver far more HF energy to an HF driver than an NAD 3020 could ever hope to. In fact, I doubt that if the 3020 soft clipping system was switched off that it would lead to serious damage. There is just no where near enough power available. Lots of other amplifiers employ soft clipping systems, which make it far less necessary for owners to worry.

Fourthly: Small amounts of clipping rarely causes any issues. Most audiophiles are sensitive to clipping and will turn the volume down to avoid it.

 

Indeed. It is also very important not to differentiate between 'valves' and 'transistors' when discussing clipping severity. The afore-mentioned NAD 3020, for instance, will deliver far fewer harmful harmonics than almost any push pull, pentode amp available. The reason is that push pull pentode amps use large-ish amounts of global NFB, whereas the NAD 3020 cleverly employs a soft clipping system which is outside the global NFB system.

 

It's complicated. Maximum SPLs expected by some listeners in some rooms, can be wildly different to other listeners in other rooms. I once did a hi fi show and was put into a VERY large room (around 400 sq Metres). I was using my favourite amplifier of all time and a very large pair of German built speakers. The speakers used 30cm bass driver, midrange and a (true) ribbon HF driver. The amplifier, thoughtfully had clipping indicators. The owner (and importer) of the speakers was present for the 3 days of the show. I turned the volume up quite loud and found that the amp was operating below it's clipping point. The speaker owner then asked me to turn the volume up higher. I explained that the amplifier was brand new and I had no experience with it and I couldn't guarantee what damage may occur to the speakers. He said that he didn't care and had several set of spare parts in his vehicle. So, I cranked it up past the point of clipping, until he was happy with the SPLs. And so it went for three days. The HF drivers survived easily. The bass drivers, not so much. Rated at 4 Ohms, the speakers were absorbing the full 430 Watt output of the amplifier. Eventually, both bass drivers failed. We screwed another couple in and carried on. It was a prime example of how an amplifier which is fitted with a soft clipping system can clip gracefully for a very long time and not damage relatively fragile HF drivers.

 

Well, it's complicated.

Trevor,

Appreciate your insight.

Its obviously an oversimplification of what is a seemingly complex treatsie.

Cheers Ozzie

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ozzie I cringe at people using power claims quite frankly and your description above is clear indication of why. makers dont all measure wattage in same way many are just claims more based on marketing than anything (not that suggesting the sanders amps fall in that category). but my point is power spec on am amp is really only one aspect.

 

@@Zaphod Beeblebrox noticing your post above I have a question for you. I am not aware of any ME amplifiers spec'd at 500wpc and above (correct me if I am wrong)... would you suggest in that case that ME amplifiers would be unsuitable to drive MOST speakers?. would they be driving them to clipping ? asking you to generalise of course to go with the trend of the original article. not asking you to make comment on the sanders or suitability wiht his speakers or any aspect of his views .... just your thoughts with regards the ME amps that you know pretty well :)

@@betty boop I dont disagree with what you are saying however there has to be some sort of reference point.

ALL the manufacturers are compelled in some way to give figures to circumvent the issue of their customers using equipment which does not couple well.

 

My issue with the manufacturers is that they engage in the sex appeal of using "big" numbers especially when promoting electrical muscle when power by itself is

an expression of something else. There is NO power without voltage, current and resistance. Its a lot easier and more appealing to sell 500 watts per channel than

50 amps.

 

The point I think that needs to be made is that low powered amplifiers and positive performance with a magnepan speaker is NOT mutually exclusive. You can have both.

 

The figures can are revealing but often dont translate readily to the subjective experience of listening to the material during the coupling phase.

 

I KNOW what the Magtech is capable of. I have heard it drive a pair of 1.7i's maggies. I have also heard a NAK drive the same speaker and it was a joy to listen.

We can subject both amplifiers to the same level of testing but in the end the proof is in the listening experience. Critical listening performed without attention to 

what the volt meter is doing is to me more beneficial than anything else.

 

Just my candid opinion.

 

Ozzie

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  • 4 weeks later...

but addicted measurements showed something quite different, on his very inefficient speakers .... the max his amp ever consumes is 310w and that is a peak. for a class AB amp with say 60% efficiency thats 186w across both channels or 93wpc that the speakers are consuming. this is also just "old mathematics" :) and the law of conservation of energy :)

 

...

 

For a peak power that is drawn by the speakers over an instant, that won't be instantly and exactly followed by the power drawn from the mains. The peak power consumed by the speakers gets taken from the big capacitance of the capacitors, and from the big transformer (I think), and from the mains. The power supplied by the mains can take a bit more time (more than the instant of the audio peak) to charge up the capacitors after the peak has passed. So the power draw from the mains is smoothed out with reduced peaks, than the power drawn by the speakers.

 

So just because the amp may have consumed a peak of 310w at the mains, it does not necessarily mean the speakers were only drawing about 93wpc (from your calculations). They might have drawn 93wpc - or it could have been much higher. I am not sure you could really tell how much was drawn by the speakers just by measuring power use at the mains alone since you also have to take into consideration how long the duration was of the extra power that was drawn from the mains compared to the duration of the audio peak. Probably easier to figure out a way to measure it at the output of the amp than to try and work it out by measuring the mains.

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"My Magtech amplifier is the only high power amplifier available that has a regulated power supply"

Input stage, driver stage, output stage -- what's he talking about?? Don't know what he means by high power, but Yamaha were designing and implementing regulated power supplies for their superb vfet amplifiers -- errr back in >>>>>>>>>>>>> 1977....

 

I think Roger Sanders chooses his words quite carefully when he makes these statements so it is worth trying to interpret them all. He mentions "available" and I think it could be fairly interpreted that 1977 Yamaha vfet amplifiers are not available - even if you can buy them used. I think there was a high power Krell amp that used a regulated linear power supply, but I think this is also no longer available.

 

He mentions the whitepapers on his site that provide a lot more detail on the power supply in his magtech. I think they are required reading if people are going to pull apart and attack his statements from the interview.  From that it is clear he is talking about a regulated linear power supply for at the very least the output stage (though I think it is for the whole device) which is an amazing achievement for a 500w per channel into 8 Ohms amplifier. 

 

For the yamaha vfet amplifiers that you say have regulated power supplies, is this actually for the output stage? I can't find any other claims for this though I have not looked very far other then with a search engine. It is true, and if they are linear power supplies, it is very impressive even for amps of 100watts. If it is true I would expect the power supply would be consuming massive amounts or power due the the regulation. Do these vfets run very hot?

 

By high power, based on his other comments I would think he is talking 400watts plus into 8 Ohms, but that is just my assumption. If that is the case that rules out the vfet amps as well I think.

 

I wish he had put the word "linear" in his statement above as that would have clarified things a little. His magtech psu whitepaper goes into a lot more detail about switchmode and linear power supplies.

 

Anthony 

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Coming across as an Arrogant Yank is never going to endear a man to the majority of aussie readers. Maybe it comes across much better with an American audience, to whom the humble researcher type like Sean Olive or Floyd Toole might give the impression of being uncertain about his own conclusions. That's my speculation for the day.

 

As for the gear: Magtech looks like yet another uncoloured and highly capable (muscular) amp, with a bonus feature of fully regulated PSU, which he pushes hard as a technical and marketing edge -- although the claim of "only fully regulated PSU amp in the world" is bogus when you consider that any amp, class D or linear, with a switch mode PSU is fully regulated. (But of course that's poison in audiophile circles, despite Bruno Putzys correctly pointing out that, correctly designed and laid-out, they have no ill effect.) As for the ESL, probably another good ESL, but unless Sanders has found a way to prevent them beaming, they won't be the best-sounding speaker available, as claimed.

 

"only fully regulated PSU amp in the world" is a misquote, in the interview it says "My Magtech amplifier is the only high power amplifier available that has a regulated power supply". They have slightly different meanings. I think part of the problem is, Roger left out the word linear in that statement in regards to the amplifier and in regards to the power supply. On the web page for his magtech on his site it says "the only amplifier with a linear, voltage regulator". On that statement he left out the parts "available" and "high power" but they were in the statement from the interview.

 

I think at the time of the interview in 2013, a statement like this would have been true for him and may still be true (note this is not a quote from Roger): "My Magtech amplifier is the only high power linear (rather than class d) amplifier currently commercially available that has a linear regulated power supply, and by high power I mean 400+ watts into 8Ohms". It is less poetic though.

 

Regarding switch mode power supplies, he does discuss these quite a bit in his magtech whitepaper. He indicates issues with them when used in amplifiers. His whitepaper I think was written over 5 years ago though and I would not be surprised if there have been good advances with switch mode power supplies since then. I expect he may be overstating the issues with them perhaps.

 

I am not directing this question to anyone specifically. Taking everything he says here into account, without just picking out bits of it such as ignoring that he is talking about high power amplifiers for example, are these issues true nowadays (or ever)?:

 

"But there are big problems when using switching power supplies in high power applications.  The main one is noise -- both electrical and mechanical.  When switching high power and voltages at high frequencies, radio frequencies are produced.  These emissions can adversely affect associated audio electronics and cause instability, oscillation, noise, and general misbehavior.

Powerful switchers also make mechanical noise because there is physical vibration of the switching transistors due to the high currents involved.  Switching power supplies are vastly more complex than a simple, 3-part, linear supply and therefore the reliability of switching supplies can be a problem.

There are also many technical problems when designing switching power supplies that make them quite difficult to make work satisfactorily.  I won't get into any more detail about this, but rather simply point out that because of all the problems, it is extremely rare to find a linear amplifier with a switching power supply.  They do exist, but are not 100% efficient and are not a practical solution for the voltage regulator problem in power amplifiers." - from the magtech white paper.

 

I don't know Bruno Putzys mentioned above, but from the quote "correctly designed and laid-out, they have no ill effect" and the fact that switch mode power supplies are becoming more common, I would think that at least in some cases they are a practical solution.

 

I know I have arrived late to this thread, and everyone is probably tired of it, but what am I to do - I only just found it - sorry.

 

I do encourage people who are at least mildly technical to have a read of the magtech whitepaper. To my moderate technical understanding his solution to a regulated linear power supply for a high power amplifier that does not create massive amounts of heat is fascinating and brilliant. There should be a movie about it :P  It can definitely be considered a unique solution. It does really seem to be a better solution than no regulation or switchmode regulation. For a medium or high power amp I would also consider no regulation better than traditional linear regulation methods that wastes massive amounts of power and produces massive amounts of heat, just for the regulation.

 

Anthony

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I should really get my CRO out and measure the output across the speaker terminals while at the same time have the watt metre in place at the mains so I know what's watt... :thumb: I can but I really don't care...:D. I know for a fact that I don't have the ability to drive the 1.7 to the max as I'm using a NAD M51 as a pre with a 2-2.3v Max output. However I can drive the 1.7 to deafening levels that I'm not comfortable remaining in the room, so I'm not even gonna go there...:P.

@@aab,

I was at one stage considering the nc400 and was willing to pull the plug on them, brand new around the $3k, $3.6k landed. Brilliant amp for the money. I was never a fan on SMPS and as a printer tech I have replaced one too many. I had a nc400 with its dedicated SMPSU, we listened to my DIY MOSFET that's over 22 yrs old, we then moved onto a 200W MF integrated that had glowing reviews, then it was time for the nc400. On switch on, it blew up, took out the main 40A circuit breaker of the switchboard. When we open it up the SMPS was the cause, some components under the PCB had vaposise and can't be repaired. Bruno from Hypex was nice enough to honour the warranty and send it free of charge, luckily the nc400 module has output protection. So from that experience I prefer to spend the extra $3k and get a Magtech with old fashion linear supply with through the hole components that I can repair if things don't go as planned.

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