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Old 1st February 2013, 12:15 AM   #8331
fas42 is offline fas42  Australia
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Originally Posted by nigel pearson View Post
Our ears clip also in a very similar fashion . Very bad news if so as SPL is very high . I speculate that compression that does similar things as our ears goes unnoticed ?
Live music does overload our ears, and automatic gain control in our brain kicks in. So loud, natural sound doesn't sound loud, but rather, intense. And reproduced sound that doesn't fit the profile when the volume is turned up just sounds wrong, our minds reject it as "just being hifi".

We know instinctively, or have learnt over our lifetimes what the SPLs of the real thing is. My wife, a piano player, sometimes turns up the volume of some initially softly playing solo piano music until it sounds right to her, and virtually every time I find the setting to be a couple of clicks away from a particular one: only a few down from maximum volume ...

Frank

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Old 1st February 2013, 04:43 AM   #8332
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Originally Posted by nigel pearson View Post
I wonder how many very boring / competent amplifier out there might be improved by simple PSU upgrades ? Fit a larger toroid transformer and upgraded capacitors . Next a few tweaks to the power amp VAS supply . Graft 4700 uF next to output transistors . If knowing virtually nothing about electronics this should be possible and rewarding. If space allows use the old transformer to power the VAS etc (and preamp section if an all in one design ) . Rotel told me that their cheapest amplifier was simply a smaller transformer ( I think I recommended it and they did it about 1985 ) . It sounded very different ( anemic ) !
Yes! On the nose! I think that we proved all of that, over and over, in the thread at Power Supply Resevoir Size .

Along with increasing the transformer's VA rating, it would probably do even more good to also increase its output voltage. But that would be a lot more dangerous for the amplifier, if attempted by someone who wouldn't know how to tell if it would damage the unit. (And maybe it usually would, anyway.)

Putting uF (decoupling caps) right next to the output transistors seems like it would probably very-often provide an amazing improvement.

I was only 14 in 1971. But in late 1978 or early 1979 I bought an HK560. One channel finally went out, about 15 years ago. Wow I loved that receiver. When it died, I replaced it with a Luxman R1050, from eBay, that I think was at least as good. (More recently, I have ended up with what's practically a small museum of more of those plus some of their relatives. :-)

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I might tell a sad twist to that story . Comet was where I bought my Akai AA 8080 receiver when aged 15 ( 1971 139 ) . Comet probably launched the reborn Rotel of Stan Curtice and Tony Morpath . When I had a shop I used to send students to Comet to buy a Rotel amp ( RA 820 Silver ) ,then return to me to buy the rest ( 10 % student discount and all cables supplied ) . I was so impressed I phoned Rotel and became a dealer . I was I think the only independent then who sold it in the UK ( 1980 ) ? Comet were like Walmart , most shops wouldn't touch it if sold there . I didn't give a dam if it made money directly as it made money for me selling other things . Truth is it did make money and Rotel liked having an enthusiast to talk to who got involved with circuit design .

My shop closed in 1997 . Student grants were cut and parking became impossible . My little shop turned over 400 000 at the peak and 210 000 when we closed . Even by UK standards it was a small shop . It cost 38 000 from the profit just to open the door per year .

Comet ( all UK ) closed about a month ago . Rather than them being competition we shared business , the manager was astonished and I am sure he sent me twice what I freely sent him ! We both noticed if recommended by the other usually the sale was made . It was like the film Miracle on 34 th street ( 1947 ) . Opposite the shop was Pizza Hut , it was a prime secondary site . Also Jessop's the top photographic chain . Jessop's also have gone just after New Year .

I am told John who took the business I lost now has to do 1000 000 to survive ( Oxford Audio Consultants , I presume still there ) . No wonder we have no hi fi industry . Talk about the vampire drinking the blood of their cash cows .

When the shop was doing OK the UK was 60% non productive ( not making things ) . Now I guess 90 % ( UK = Greece with banking safety net ) ? In 1997 I went into manufacturing and never looked back . I was forced and also told a white lie at my kids school . When a teacher was having a go at my boy I said it's not surprising as I am an inventor and he is used to an eccentric life style . I never regretted that forced change of life . It has made me many friends and I have seen the world due to it . Never had any money and I guess I never will ? I am try to pass through the eye of needle without volunteering I guess ?
Yes, that is all rather poignant!

That is truly sad, and I truly hate what has happened, politically (not to even mention culturally), over here, and over there, and I am truly worried (or in a state of despair) about what it all means for today's kids and future generations, and I am so utterly sad for what they have lost in the future (or had taken) and for what they and the world will now never know or experience or produce, and maybe especially for the fact that most of them will never even know the difference, or even think about it.

Last edited by gootee; 1st February 2013 at 05:09 AM.
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Old 1st February 2013, 05:23 AM   #8333
gootee is offline gootee  United States
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I had a crazy thought, the other day, when I suddenly wondered if perhaps the counterculture of the 60s was helped-along by a Soviet and/or Hollywood communist plot that has now succeeded beyond anyone's wildest dreams. (Or maybe they knew exactly how it would turn out.) Alas, I think it's more due to clue-less politicians who found out that they could buy votes, with our money, and didn't understand the basic characteristics of positive feedback loops.
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Old 1st February 2013, 07:15 AM   #8334
dvv is offline dvv  Serbia
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Originally Posted by gootee View Post
I had a crazy thought, the other day, when I suddenly wondered if perhaps the counterculture of the 60s was helped-along by a Soviet and/or Hollywood communist plot that has now succeeded beyond anyone's wildest dreams. (Or maybe they knew exactly how it would turn out.) Alas, I think it's more due to clue-less politicians who found out that they could buy votes, with our money, and didn't understand the basic characteristics of positive feedback loops.
You've no idea just to what extent you're right, Tom. But, that's politics, let's not do it here.

Nige might remember that in the 70ies, it was a crying shame when your electronics did only as specified - it was a point of honour to do better than specified.

Today, all the honour has been spent and the leftovers discarded because they cannot be turned into dollars, or euros, or yen, or whatever, so who needs it?
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Old 1st February 2013, 09:17 AM   #8335
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Originally Posted by gootee View Post
I had a crazy thought, the other day, when I suddenly wondered if perhaps the counterculture of the 60s was helped-along by a Soviet and/or Hollywood communist plot that has now succeeded beyond anyone's wildest dreams. (Or maybe they knew exactly how it would turn out.) Alas, I think it's more due to clue-less politicians who found out that they could buy votes, with our money, and didn't understand the basic characteristics of positive feedback loops.

The most important thing about positive feedback loops is chaos . It says something will happen sometime and we will know afterwards ( turbulence ). Great .

I was at a meeting as a guest of our Roundtable ( bit like Free Masons for charity ) . I met Dr Evan the Historian at Oxford ( his counterparts at Cambridge is Dr Evans also ) . The fat cats at the meeting thought Dr Evan a bit light weight , I thought him absolutely brilliant . I asked one of the cats about the crash and why none of them saw it . They said " it is a well known fact that money grows exponentially ( thinking I have no idea what that meant , to say it is to show no understand , the mathematical equivalent of blood letting ) . Always has and always will " . I said bacteria grows exponentially , they die in their own waste products . I never got invited again ( phew ) .

Positive feedback hey .

Seriously . Positive feedback seems to cause common mode problems .
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Old 1st February 2013, 09:45 AM   #8336
gootee is offline gootee  United States
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MAYBE I don't.

Back then, that type of honor was still discussed out loud more often, too.

Maybe honor is a luxury that not as many can afford, these days.

If so, then it seems ironic to mourn its loss while also disdaining the means to revive it.
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Old 1st February 2013, 09:57 AM   #8337
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Positive feedback I suppose is optimism . The fat cat told me without optimism we all would at best be living the 18 th century life . It was his near religious belief in what he was saying that worried me .

When in Vagus I was asked by a lady serving drinks if I gambled . No . she smiled and said " I knew you didn't " . how come I asked ? " you don't look like a looser " ! My answer was did the casino's build themselves ? I like Vagus , I am an exploiter when there (cheap food , beer , hotel , winter sun and nothing else , CES show ) . I met some old ladies from NY , I doubt any below 85 . They had a loosing budget for each day . Sometimes they would win by loosing slower . They calculated the heating cost more in NY so why not ?
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Old 1st February 2013, 10:05 AM   #8338
gootee is offline gootee  United States
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Originally Posted by nigel pearson View Post
The most important thing about positive feedback loops is chaos . It says something will happen sometime and we will know afterwards ( turbulence ). Great .

I was at a meeting as a guest of our Roundtable ( bit like Free Masons for charity ) . I met Dr Evan the Historian at Oxford ( his counterparts at Cambridge is Dr Evans also ) . The fat cats at the meeting thought Dr Evan a bit light weight , I thought him absolutely brilliant . I asked one of the cats about the crash and why none of them saw it . They said " it is a well known fact that money grows exponentially ( thinking I have no idea what that meant , to say it is to show no understand , the mathematical equivalent of blood letting ) . Always has and always will " . I said bacteria grows exponentially , they die in their own waste products . I never got invited again ( phew ) .

Positive feedback hey .

Seriously . Positive feedback seems to cause common mode problems .
Those types of people rarely rate others based on intellect.

You, however, are delightfully intellectual, and do, and I tend to be that way too.

But we have to realize that being intellectual is a luxury. And for a society or culture to have people like you in it is a luxury, for that society or culture. But to be able to have the conditions that enable us to afford such luxuries, we need the fat cats, and as many others as possible, to remain very fat.
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Old 1st February 2013, 10:16 AM   #8339
fas42 is offline fas42  Australia
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But to be able to have the conditions that enable us to afford such luxuries, we need the fat cats, and as many others as possible, to remain very fat.
I would beg to differ ... it's about time for mankind to grow up a little bit, to use a touch more intelligence and rely a little less on pure greed to get things moving. The earth itself is giving us a few warnings that this "path" is fast running out of manouvering room ...

OK, off the soapbox now, naughty boy ...

Frank
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Old 1st February 2013, 11:18 AM   #8340
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When talking to Dr Evens he reminded me of my maths teacher Chris Bartrum . They seem to have an intellectual gearbox that can happily stay in first gear to please others and especially themselves for everyday life . The Roundtable mistook his gentle ways for incompetence I feel . He hadn't amused them . I was asking Dr Evans about Herodotus . He was delighted and said between 400 AD and 1900 I would have been one of a handful of Englishmen to read it . It would have been required reading before 400 AD . If wondering Herodotus is a great alternative to the other great book of antiquity . One that many here would love , Egyptian engineering especailly . Some say the deserts were water filled at the time of building the pyramids , not exactly so if you read Mr H .

These fat cats do good locally and I am sure England is only fed by what they do ? Problem is it makes me feel a bit like a pimp . 90 % of my money comes from outside of the UK . If I had to live on my UK money I would no problem passing through the eye of a needle .
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