Are they better than Bose ...
I can see it now the "Insane Clown Posse" Bose special edition. Every jugaloo must have one.
I wish I could keep your determination and focus on a single diy subject for more than a week
Ela, George, which is very likely Yorgos, that's not fair. I am still very much and completely (in the sense that I am doing nothing alike of the kind) commited to the amp project, primarily because I want it for myself.
However, this is a fun (non-business) project, and therefore, it must take a back seat to regular business and family activities, which are very numerous and demanding at the moment. As far as I can see, the first time I will be able to dedicate say three straight whole days to it is when I get down to Kassandra, town of Afitos, hotel "Blue Bay", August 7 and onwards.
Besides, I never even remotely planned on chaging my speakers, I'm too happy with the ones I have. I am not the swiftly and frequently changing type.
Regardless.
The book is a collection of Thiele/Small papers laid down in a way from easy-basic to more detailed-advanced.
A good mind journey even for the summer time.
George
True, quality knowledge is never amiss, who knows whe one might need it.
But, for my wife and me, summertime is Greece time above all. 10 days of net stay (not counting the day to get there and the day to get back) in Greece is a sort of family tradition, we've been at it since 1994, and I personally since 1970. Pool and sea for me, shopping in (Thes)Saloniki for the wife, you get it, everybody's happy. Wife claims the Ikea there is the best she's ever seen, and trust me, she's seen a lot of them.
There you are, Scott, I was kinda wondering where had you gone.
Don't you guys think you're being a little too hard on Dr Amar G. Bose? I mean, he has bills to pay, so he needs to make and sell what people will pay for, and what we think of it is of no concequence even if we were buyers ourselves.
Also, please remember that he is of Indian descent, and Indians have been a trading nation way longer than even the Dutch. In a museum in Amsterdam, I was told that the Dutch had become a true trading nation in the 14th century, with chamvers of commerce and such like well under way by then. I mean, everybody traded, but they were the first in Europe to truly institutionalize trade.
I must admit I was never a fan of Bose gear, I never liked their 301 and other speakers, but they sold, like it or not. To my ears, AR was way better, but today, AR is gone and Bose is still going strong, so they must be doing something right, they adapted, whereas AR obviously didn't.
The optimal damping factor is the damping factor for which your loudspeakers are designed.
vac
Bose . Great ideas sabotaged by not going the extra mile with components ( I am being diplomatic now ) . The 901's can work . Problem is mostly due to customer misunderstanding they don't . 901's with a super tweeter might be very OK . A friend bought a Fostex full range unit . As good as it is the fundamental problem is still there ( about 5 kHz ) . I would recommend a 7 kHz crossover to the super tweeter and a pair of what people call sub woofers from 10 to 100 Hz to partner them . As for the equalizer , best say nothing . Best sound heard with them was in a church in Belgium and Kirkland's wine bar Liverpool . My PA friend says " no highs , no lows , that's ..............."
I used to spend a lot of time reading the archived Wireless World magazines at what is now Oxford Brooks University .
The test they did although primitive was interesting . A small wire touching a metal strip on a bass unit . They found a damping factor of 3 to work as a minimum . This was I think 1955 . The suspension of the speaker I suspect would have been much stiffer than now . The testing was done with a full understanding of the problem and not by some armature .
When the British Hi Fi press looked at this many years ago I seem to remember 16 was held to be where cables mattered more . The use of a series resistor on a normal amp ( damping factor > 100 ) will tell you much of what you want to know . Sid Smith of Marantz though some of the sound of tube amps was down to that alone . Some say it helps the negative feedback work better in the amp . Seems very likely it would . I think a resistor preferable to the usual choke if the amp allows . Big resistor small choke perhaps ideal ? 1 ohms seems OK to me . For choke 5 turns 1 mm x 10 mm air cored . Try earthing your speaker metal work also . It costs you nothing to try . Perhaps 2 x 1K non inductive to RF " hum-buck" it ( speaker +/- to ground , or caps ) ?
Slightly under damped is usually nice . Especially if the speakers are correctly damped ( what your computer said was correct ) . The BBC used to say LS3/5A was critically under damped . Some who think the LS3/5A to be the world most accurate speaker might be surprised by that ?
BTW , please don't tell me WW were wrong . They weren't as at least they were trying to test the reality of the concept .
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Dvv
It was fair but it was written in a wrong way,
My best wishes for your vacations at this very nice place (Chalkidiki)
George
The key of completing a DIY project, in my view, is patience. One has to know exactly what comes first (family), what second (business), what third (friends) and what last (DIY games).
When I started out in April, I was clear on the fact that I will complete it effectively by the end of the year. This does not bother me, as I am doing this in an all out attempt to make myself and whoever else may want to make it, something as much out of the ordinary as I am able to do.
And things are moving along. I have purchased all necessary semiconductors, and am now down to making the PC boards. I have been interrupted by important family events, but never mind, I'm still firmly on the road, as soon as it's over, I'll just pick up where I stopped and continue.
As for Chalkidiki, I am almost a local there, every summer since 1994, this is my 16th time, two years in between were pauses. Afitos in particular - this is the 8th time in a row, 6 times in one hotel, and last year and this year in another, we think a better one overall.
I toured Greece in 1970, with my late parents - 21 places, from the eastern Turkish border to the Ioniona sea, down to Sparta. I had spent a whole year studying Greek democracy for my A levels in England, in particular the Athenian democracy, which was later the exact topic of my A level paper, which I graduated on in 1971.
Lastly, NEVER forget that to us Serbs, Greeks are really something like distant relatives, cousins. When the Slavs settled on the Balkans in VII century, it was the Greeks who gave us our language, customs and religion. Our Cyrrilic alphabet enables me to read each and every sign in Greece, even if I don't know what it actually means. In short, in Greece, I do not feel as if I am in a foreign country, more like visiting cousins.
Why else would I go there 16 times?
Dubrovnik is also called the Pearl of the Adriatic. Beautiful, unjustifiebly expensive, short of great beaches, but surround by extremely clear water. Also, good street music groups. Some very good hotels.
All in all, not a bad deal at all.
Only if something before pass transistors are bleeding such current that can damage them.
Thank you for the heads up, rest assured that I've been putting reverse diodes for like 20 years, ever since I fried to a crisp one such regulator because I was "saving" on the parts.
These days, my regulators are all discrete, and hence more complex and more expensive, so caution is necessary all the more so.
Anyway, Wave. In the total cost of it, a few diodes are meaningless. Anyway, a 1N4004 diode costs like a little more than nothing.
Besides, I am an out and out freak for safety. You've seen the not insignificant effort, money and PCB real estate I normally dedicate to all sorts of protection circuits. And you haven't seen all of it yet.
You would be too if you just saw all the EU electrical safety regulations I must satisfy to be able to sell in the EU. That is literally thousands of pages of text, mostly legalese, but some of it actually technical.
And then thers's the question of conscience. It it should ever happen, God forbid, that any one of my customers should get shocked, never mind the law, I would never forgive myself. That makes you think the darkest shade of black, because there is no end to human stupidity.
The design was supposed to be 'adequate'. BBC's words.
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In loudspeaker test specifications damping factor was only added in the latest revision. I think now, the driving equipment must have a source impedance of 5% of the loudspeaker's rated impedance.
The result is that many loudspeakers have been designed with test setups much above this. The prior idea was that you measure the voltage at the loudspeakers terminals and keep the voltage constant so the results should be good.
The change went through as fast as it could be typed out!
So if you are looking to the future more manufacturers will be voicing their systems with real damping factor of 20 or higher.
Of course for backward compatibility you can place a very small inductor/resistor combination in series with your loudspeaker line.
The result is that many loudspeakers have been designed with test setups much above this. The prior idea was that you measure the voltage at the loudspeakers terminals and keep the voltage constant so the results should be good.
The change went through as fast as it could be typed out!
So if you are looking to the future more manufacturers will be voicing their systems with real damping factor of 20 or higher.
Of course for backward compatibility you can place a very small inductor/resistor combination in series with your loudspeaker line.
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