Barry
Rank: Trio
Posts: 195
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Post by Barry on Feb 15, 2019 21:51:56 GMT
Excellent revision Chris and an improvement over the 'original'.
Radford were never part of the IAG stable. I don't know about Peter Comeau acquiring the rights to the Radford name; I had assumed that had been acquired by the company 'Radford Revival', who service and upgrade existing Radford designs.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Feb 15, 2019 21:06:03 GMT
The noise manifests itself as a current, and as such needs a circuit; a return path. Well, it's just MY thought experiment! When you ground an old fashioned crystal radio, you need that ground for good reception. However, there is no return circuit as such. That is because the electromagnetic wave that is the radio broadcast intecepts the receiver's antenna (usually a long piece of wire arranged like a washing line running down the garden), and the earth (ground). A voltage is set up between these two conductors and a current flows through the tuned circuit and the diode (the crystal). The diode removes one half of the alternating signal so the mean voltage is non-zero, and the signal is de-modulated by the mechanical inertia of the headphones. The remarkable thing is that all of the power required to activate the headphones comes from the power in the electromagnetic wave and nowhere else.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Feb 14, 2019 18:58:25 GMT
Can't say I agree with your thinking Martin.
There is no a priori reason why the Earth should absorb high frequency noise. The noise manifests itself as a current, and as such needs a circuit; a return path. The grounding boxes do not provide this.
If the noise is due to electromagnetic radiation, then there are materials that can absorb it, but they are not broadband and need to be impedance matched. I cannot see how the metal plates buried in the granular material contained within the box constitute efficient atennae.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Feb 13, 2019 22:51:38 GMT
I agree with John about Black Ravioli. No explanation for their seemingly impossible isolation/damping properties. On grounding boxes, I disagree. A thought experiment has me understanding what they are doing. They make more sense than many accessories I've tried.Care to elucidate Martin?
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Feb 13, 2019 22:48:34 GMT
>> The things for which there is no rational explanation as to how they might work.Ah, you mean grounding boxes. I used to paint the edges of my CDs green. But that worked. Peter Belt stuff - putting silver foil strips on equipment and a sheet of paper under one of the feet of a piece of gear and under one of the legs of all the furniture in the room. Etc. I did try some of that back in the day, and no, it didn't seem to do much of anything. No surprise there then! What about bottles of 'deionised' water placed near your electricity meter - did it make the TV picture any sharper?
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Nov 28, 2017 20:03:56 GMT
Favourite cartridges? Well there are several for me:
Fixed coil
AKG P8ES, ADC 25, ADC 10E Mk.IV, B&O MMC20EN, and (of course) Decca: Mk.IV(SC4E) and Mk.VI
Moving coil
EMT 15(sfl), Ortofon SPU GME, Ortofon MC200, and Van den Hul MC-1 Special.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Oct 27, 2017 21:48:15 GMT
Who can tell me what the airport announcer is saying on 'On the Run'?
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Aug 7, 2017 20:05:07 GMT
Based on the link, I'm somewhere between middle class and upper class (which is probably correct given my parent's background), but the link is not quite accurate: in Edwardian times, an informal 'dinner' (or 'supper') was often referred to as a "meat tea", to distinguish it from afternoon tea. Anyway I digress - tonight it was a heavily augmented Salad Nicoise with a nicely chilled 2012 Pouilly Fussé.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Aug 5, 2017 22:04:42 GMT
There are some members of AoS who are experimenting with these ultrasonic tweeters and reporting interesting results. Even though one cannot hear anything coming directly from the tweeters, they do seem to have subtle, but real, effects on the soundstage and imaging.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Aug 5, 2017 20:35:47 GMT
If we're talking about (afternoon) tea, rather than dinner, then a pot of Darjeeling or Lapsang Suchong, without milk but a slice of lemon.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Aug 5, 2017 20:31:26 GMT
How are you going to drive them Chris? Directly wired in parallel with your Mirages, or will you use a separate amplifier?
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Aug 5, 2017 20:25:23 GMT
Laurie Anderson – ‘Big Science’I was critical of this album as being a bit ‘weird’, but had to admit I hadn’t played it in years. So I though to be fair I had better listen to it again. Yep – still weird: “uh uh uh uh uh uh uh ………..” Abdullah Ibrahim – ‘Water From an Ancient Well’Kate Rusby – ‘Hourglass’Traditional English folk – but not quite of the ‘hand clasped to the ear’ ethnic purity. Van Morrison – ‘Astral Weeks’Otis Redding – ‘Otis Blue/Otis Redding Sings Soul’Eric Clapton – ‘Me and Mr Johnson’An excellent appreciation of the works of Robert Johnson. Bob Marley – ‘Legend’Tìr Na Nóg - ‘Tìr Na Nóg’“Tìr Na Nóg” translates as “Land of the Fairies”, but this is no hippy ‘tree hugging’ lovefest. More akin to the style and subject matter of Fairport Convention. Nihonjin – ‘Too Many People’Recommended by someone who’s taste I trust, this Jap prog group is heavily influenced by the likes of Pink Floyd. Two long tracks, neither of which IMO use the time to fully develop. A bit of a disappointment – luckily I didn’t have to pay the full price. A couple of vinyl records I picked up in a charity shop for peanuts: Hoyt Axton – ‘Road Songs’Country music. Not my usual cup of tea, but this import isn’t too bad. Think I’ll keep it. David Sanborn – ‘As We Speak’A sort of cross between John McLaughlin and Steely Dan. Jazz funk - I’m not sure I like it.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Jul 22, 2017 15:01:30 GMT
Great work Chris.
It's come a long way since I had it perched on a stool in front of my system.. Glad to hear you are now getting great results from the G99. Well done!
Barry
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Apr 28, 2017 10:53:49 GMT
Can't really answer that question pinkie. According to Wiki wiki.diyfaq.org.uk/index.php?title=Earthing_Types, a TT earthing system could have a Ze of anywhere between a few and several hundred Ohms. I think in the UK the maximum Ze for a TT earthing arrangement is <8 Ohms, but I could well be wrong. If you live on bare rock, the conductivity of the ground is going to be very low, which is why TT earthing systems must only be used with RCBs (residual current circuit breakers), which will trip within three half cycles if the difference between the current in the live and neutral conductors is >30mA.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Apr 28, 2017 2:02:53 GMT
The earth-neutral impedance will vary depending on which system is in use: TN-C, TN-S, or TN-CS. en.wikipedia.org/wiki/Earthing_systemMy mains supply uses the TN-S arrangement, for which the IEE limit is < 0.8 Ohm. In mine it is < 0.3 Ohm. If the system is the same as Martin's (TN-CS), the relevent figure is < 0.32 Ohm. Nowhere should the resistance be as much as 40 Ohms, let alone 200. I have also measured the DC offset on my mains supply: -18mV. Toroidal transformers are more prone to buzzing due to DC on the mains than bi-limboid designs, or those using E-I laminated cores. If the DC offset is ~ 100mV buzing can occur. However it depends on the rating of the transformer. DC offset is not a problem with toroidal taransformers of < 300VA rating owing to their high primary resistance. Toroidal transformers of rating > 500VA have a lower primary resistance so even a small offset of 100mV will set them buzzing. The mechanical noise is caused by the core momentarily saturating at the peak of each half cycle. When the core saturates, the inductance falls and the current rises and the primary impedance falls. In normal operation transformers are always on the verge of saturation. This is deliberate, if the transformer used more primary turns to more easily avoid saturation, it would have poor regulation because the primary resistance would be too high. So if you are going to use a toroidal transformer (even if it is in a BMU), fitting a DC block is a good idea.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Apr 14, 2017 12:08:52 GMT
All three boxes now spoken for.
Thank you for your interest.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Apr 13, 2017 21:17:09 GMT
One box spoken for.
The rest will be going to landfill at the end of the month, if there is no further interest.
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Barry
Rank: Trio
Posts: 195
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Post by Barry on Mar 31, 2017 21:16:01 GMT
I find Photobucket these days to be a slow as the movement of tectonic plates. Uploading images takes forever.
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