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Old 16th July 2012, 10:58 AM   #6721
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Personally, i'd favour a pre-ww2 Lagonda Rapid and drive around, pretending i'm uncle oswald.
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Old 16th July 2012, 10:59 AM   #6722
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Originally Posted by Charles Darwin View Post
Not really close at all.
Back then Bentley was entirely different from RR and is again since VW bought Bentley.
In between RR owned Bentley and they won nothing nor even competed in anything.

The main thing wrong with QUAD 405 amps is the severe current limiting applied to them so they stay stable when running ESLs with their brutal impedance curve.
Once that is done away with and the PSU replaced with something more substantial they are actually quite good amps, just look at their 520.
I agree with all of that . I suspect the Quad transformer is undersized . Parallel bridged 405/ 2 are good workhorses . I did see a tune up of the 405 that suggested the bridge balance was letting it down . If correctly balanced it could do what was pretended . The conclusion I read somewhere else said perhaps a cheaper way to build a 303 replacement more than being better . I also read that unless correctly balanced it is mostly a feedback amp . I don't know . I prefer 303 . 606 was better . 306 was polite .

Tempting trouble and please forgive this diversion . For me a Citroen Light 15 UK made 1957 with DS suspension ( some were ) . Citroen diesel fitted to help my meanness .

Last edited by nigel pearson; 16th July 2012 at 11:03 AM.
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Old 16th July 2012, 11:17 AM   #6723
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Re: Blower Bentleys

W.O. Bentley hated forced induction and Blower Bentleys were not a proper works effort which never won anything, at least not Le Mans due to their tendency to break.

From that era I'd prefer a Hispano-Suiza or Duesenberg (the last american made car which was in any way innovative) to cruise around.
Post war it would have to be a Facel-Vega II.

Re: QUAD
I once read an interview with Peter Walker, according to him the 05 and 06 in the amp designations refer to PSU size. He was quite proud of the 520, it is essentially a 606 with a pair of output transistors missing but instead it got a much, much larger power supply.
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Old 16th July 2012, 03:56 PM   #6724
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That's right , we called them Quad theater amps . As hi fi dealers we could sell those . Looking back we should have done . Some day I must get a 405 and do some serious evaluation . Change nothing that is good , especailly the reliability . I would perhaps put in a fan and beef stuff up . I do remember the first ever 405's ran hot on idle . That makes zero sense . The article about doing the bridge balance ( not output ) got distortion well below - 100 dB . Someone who did it claimed it sounded much better . Dr Ron Smith of Harwell , sort of person I trust when he says it . He got told off for spending money on cables at work . He had to explain that the measurements he was doing were at 10 - 9 amperes and cable did matter ( charges in cables ) . He said to me he would not doubt it in hi fi although with some reservations .

The light 15 although a bit sinister looking was fast and elegant . 1933 and still good today . Most modern cars have it as a parent . Least so BMW . The designer was from and aircraft company called Viosin I beleive ( 2CV certainly ) . 2CV was BMW motorcycle inspired . VW was 2CV inspired .

Last edited by nigel pearson; 16th July 2012 at 04:02 PM.
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Old 16th July 2012, 04:38 PM   #6725
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Except that the Beetle predates the 2CV by a few of years.

Voisin made cars after 1918 but couldn't pay all his draughtsmen so he recommended Andre Lefebvre to Louis Renault but Andre eventually ended up at Citroen where he was responsible for the T.A., 2CV and DS.
BMWs first ever car was an Austin Seven built under licence, after the war they were kept alive by the Isetta bubble car. A design bought in from Iso Rivolta of Italy who gave us the stonking Iso Grifo.
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Old 16th July 2012, 04:45 PM   #6726
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Old 16th July 2012, 04:47 PM   #6727
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... I would perhaps put in a fan and beef stuff up . I do remember the first ever 405's ran hot on idle . That makes zero sense . ...
Perhaps not. What happened to your theory of the first watt?

What if it got hot simply because it was run at a relatively high bias current?

On top of which, if memory serves, it was never exactly well endowed with heat sinks.

I never liked that "make it teeny weeny" philosophy. For the love of god Electron, give it space, give it heat sink area, let the poor thing breathe.
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Old 16th July 2012, 04:57 PM   #6728
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Quote:
Originally Posted by dvv View Post
Perhaps not. What happened to your theory of the first watt?

What if it got hot simply because it was run at a relatively high bias current?

On top of which, if memory serves, it was never exactly well endowed with heat sinks.

I never liked that "make it teeny weeny" philosophy. For the love of god Electron, give it space, give it heat sink area, let the poor thing breathe.
Quad-405 works with zero bias in output stage that works in class C. What draws the idle current, class A driver.

It is class A+C amp. On "first watt" current to the load is supplied by driver, when voltage drop on resistor from the driver output to the load (effectively between bases and emitters of output transistors) is enough to open an output transistor it starts assisting. I did similar trick in late 1970'th, but I used faster opamp and nested feedbacks, so did not need that "bridge" that Walker used for balance between fast and slow components of his amp.
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Old 16th July 2012, 05:06 PM   #6729
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Originally Posted by dvv View Post
Perhaps not. What happened to your theory of the first watt?

What if it got hot simply because it was run at a relatively high bias current?

On top of which, if memory serves, it was never exactly well endowed with heat sinks.

I never liked that "make it teeny weeny" philosophy. For the love of god Electron, give it space, give it heat sink area, let the poor thing breathe.

I have no idea . I know they recalled them . I feel the public expected a current dumper to run cool . I don't remember a sound difference worth noting .

The experimental 2CV was hidden during the war . I suspect it was seen pre war ? It was about 250 CC and inspired by the 1933 BMW motorcycle flat twin . The suspension was to be all torsion bar . The original had one headlight . Most 2CV's had none ? The design was said by a Williams engineer as more ideal than most . The suspension system if tightened up closer to ideal than many . The 2CV was for transporting eggs without braking them over rough roads . The 33 BHP versions if driven at 100 kph was very nice . 110 kph , forget it . The limit on French roads is 90 kph . They are superb when at the legal limit . No brakes required if so . If you steer hard the speed reduces , again no brakes required ( none fitted ) . I seem to remember that unworkable concept 2CV's were about in 1934 ? The suspension needed additional damping . One version had 2 engines ( 1936 ? ) . The 2CV 4 is said to be definitive . I drove one that had been owned by a French priest , immaculate in powder blue . It was not the best in my opinion ( mildly dangerous ) . Best was I think about fuel consumption in the 4 . I doubt it could exceed 90 kph .

Wow , that BMW . The 1948 Bristol I think was similar ? . Sorry about cars .
https://en.wikipedia.org/wiki/File:C..._prototype.JPG

Last edited by nigel pearson; 16th July 2012 at 05:30 PM.
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Old 16th July 2012, 06:05 PM   #6730
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The two-engined version was made for Total (the french oil company) who needed a 4wd car for the algerian desert. Citroen decided it would be easier to just fit a second motor in the rear rather than to run an extra drive train. Probably a wise decision considering the extra friction losses which would have occurred given the engines output was something like 23bhp.
Not sure when it was made but I suspect after the war.

Frazer-Nash reminds me of their famous chain gang cars.
They used to run rings around the competition in their class until well after the war.
This was mostly due to their derailleur type gearbox (very much like a ten-speed bicycle) which is vastly more efficient than a cog wheel based gearbox.
They kept winning until the advent of independent rear suspension negated their power advantage by having better road holding.

Bristol were given ownership of the BMW car and engine designs in '45 as part of the german reparations to the allies.
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