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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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29th Nov 2019, 11:13 am | #61 |
Dekatron
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Re: Nostalgia? Probably.
I have a video I made at Gerry wells place and an interview with him, its on VHS so the quality is not that good. Someone did offer to copy it on to DVD sometime ago but I have forgotten who it was. If anyone can do that I am quite happy for it to be circulated - if I can find it.
Peter |
1st Dec 2019, 1:18 am | #62 |
Nonode
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Re: Nostalgia? Probably.
Hi!
Keith Skues's Sunday Night programme can still be picked up.on 411m m.w. in certain areas, and don't forget he has a "Wireless Of The Week" feature – there's no better programs for testing and enjoying old sets on! Apart from that, my aim with vintage electronics is to try and get it working with h.t. line voltages as close as possible to those given on the maker's original service–sheet, it has been my experience, that valve (and transistor in some cases!) voltages, tend to be noticeably higher, sometimes as much as 50V over, on a typical valve radio h.t. line, which doesn't do elderly valves & components a lot of good! Generally high mains voltages, along with silicon diode rectifiers and low e.s.r. h.t. smoothing electrolytic capacitors are the main case of this, and I found countless times that if you don't watch this point you'll.be chasing about after replacement valves or transistors more often than you ideally should be! I'm also in total agreement about using modern components where appropriate – the yellow 1613 axials and good–quality carbon–film (power oxide for 1–3W types) and RIFA electrolytics, will provide stabilty and reliability of valve circuit operation to a far greater degree than was possible with the components of the time! One really annoying troublesome vintage item, tho', is the "baretter" – this lightbulb like device has an almost constant–current characteristic over its rated operating voltage for the specific current it was rated to run at, but was also very fragile and replacements are almost impossible to come by new – the modern aluminium–housed metal–clad wirewound resistor bolted discreetly under the chassis with a suitable NTC in series is the best way of substituting this! "Magic Eye" phosphors that degrade to the point of almost invisibility are another vintage restorer's annoyance, altho' my experience with the EM34 type has been that altho' they go dimmer very rapidly from new, their brightness is fairly steady over a much longer period – my Dad had at least six sets fitted with them and all were bright enough to be usable! Sometimes too low a target–anode voltage can speed up deterioration as well as too high a voltage can, and a trawling of innumerable sets and bridge circuits, etc., suggests 210–220V is about the best voltage to use on most end–viewed types. Old coils, I.F. transformers, etc., we're generally designed to have a very high 'Q' on account of the lower mutual–conductance of the valves then available, and short of obvious physical damage or obvious corrosion from a moisture–laden environment it should be virtually never necessary to replace such a coil or transformer! Unfortunately the one thing that ultimately decides the future extent of our hobby, apart from our own lifetimes, is how long a.m. and f.m. radio transmissions remain operational for, and me thinks gentle pressure ought to be put on the powers–that–be to make them aware there is far more interest in analogue radio then they may realise! Mains and output transformers aren't normally a problem these days, Ed can deal with "odd–ball" requirements and plenty are still being manufactured new altho' the prices have always been silly in my opinion! Meter movements – the AVO CT160 is the most notorious one of all, the last one I saw was almost £400! – but I think you can still obtain movements of lower sensitivity that will fit the unit and have the same or similar appearance, but in the end the time may come when it may be necessary to rebuild a more modern movement about 50 or 100uA f.s.d. into the original case and rescale it together with a current amplifier. Chris Williams (I think Tonne's Meter software will reproduce a CT160 scale plate)
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1st Dec 2019, 5:07 pm | #63 | |
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Re: Nostalgia? Probably.
Quote:
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1st Dec 2019, 6:20 pm | #64 |
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Re: Nostalgia? Probably.
In the context of voltages, it's always worth checking what your DNO is providing as 'line voltage' - here I'm only 1Km from the substation [a nice big dual-500KVA-transformer 33KV-incomer job] and regularly see an as-delivered 252V - which could be a bit much for gear originally intended for 115-230V or 120/240V duty.
At least with such a 'chunky' upstream I'm less subject to the horrors of "someone plugs a kettle in next-door, line-voltage goes down 5V and I'm chasing 2KHz of local-oscillator-drift on 14MHz" nastiness. |
1st Dec 2019, 6:24 pm | #65 |
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Re: Nostalgia? Probably.
For the benefit of newcomers to both the hobby and this forum, it might be worth (re)stating that an AVO model 7, which was the standard multimeter many years ago had an impedance of 1000 ohms per volt on it's DC ranges. Some inexpensive analog meters today, I believe, are only 1 or 2kohms per volt. The AVO 8 is 20kohms per volt on DC, which places 20 times less loading to a circuit than the 7, meaning that the voltage read will, in most cases, be higher, than with a 7. Valve Voltmeters and DMMs of course have a much higher impedance, typically 10 Megohms, so DC voltage readings taken with this type of instrument will be considerably higher than with any analogue voltmeter. Those of us who have worked with electronics for years are of course aware of these differences, but newbies probably aren't, so I thought it worthwhile to point this out.
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1st Dec 2019, 6:32 pm | #66 |
Hexode
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Re: Nostalgia? Probably.
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1st Dec 2019, 6:38 pm | #67 | |
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Re: Nostalgia? Probably.
Quote:
Lawrence. |
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1st Dec 2019, 6:44 pm | #68 |
Heptode
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Re: Nostalgia? Probably.
It would be resistance on DC ranges. Impedance is AC.
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1st Dec 2019, 7:19 pm | #69 |
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Re: Nostalgia? Probably.
Sorry, Geoff and everyone. I've only been working with electronics for 50 years. Should know better!! ( My statement is otherwise essentially correct, though!)
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1st Dec 2019, 9:41 pm | #70 |
Heptode
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Re: Nostalgia? Probably.
Expect we get use to saying 'input or output impedance' for signal circuits being measured even though the measurement is the DC resistance of the circuit under test. The main requirement should be the measuring equipment should be as invisible as possible to the set under test.
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2nd Dec 2019, 7:15 am | #71 |
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Re: Nostalgia? Probably.
Impedance is the general case, resistance is specific to DC voltages and currents.
As you approach zero Hertz, inductors tend towards shorts and leave only their wire resistance, capacitors tend towards opens and leave only their insulation resistance. So the reactive parts of an impedance vanish, leaving only the resistive part. As reactances are frequency-dependent, then any impedance with a non-zero imaginary part doesn't have a single value, it has a graph of complex impedance versus frequency. It seems quite reasonable for this graph to show where it passes through the zero Hertz plane. It's needed for completeness. I have no problems with DC impedance. We have silly terminology in various places. DC voltage is funny when you consider what that 'C' stands for. 470+j0 is still a resistor David
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2nd Dec 2019, 10:32 am | #72 |
Nonode
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Re: Nostalgia? Probably.
Seeing operator j being mentioned certainly brings back complex Nostalgic memories to me.
John |
2nd Dec 2019, 11:01 am | #73 |
Nonode
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Re: Nostalgia? Probably.
I have no nostalgia beyond the received or imagined, as I was born just before the Wall came down so my childhood was more Gameboys and Nintendo 64s. However, from the environmental perspective, repair is always better than buying new. Old equipment, as others have mentioned on this thread, assumed repair would be in order at some point.
Valves are fascinating to me because of their existence on the cusp of understanding - the cathode, anode and grid can all be seen, and the electrons imagined, which can't be said for an NPN! I think this makes circuits including them more impressive and mind-blowing than the simply hand-waving black box magic of a touchscreen. There is also the humanity of a case with some kind of human touch (in the older wooden objects designed to be a stalwart part of the home furnishings) and in professional gear, the solidity of construction and the absence of plastic. New metal or wood pieces can be produced, and like the Japanese practice of Kintsugi (in which broken pottery is repaired with glue containing gold so the repair is visible and beautiful) all actions add to the history and archaeology of the object. Perhaps someone in 50 years will come across my old radio and think of what I might have listened to, as I do to those before me. There is a custodianship that is missing in much of modernity. Buildings are razed and demolished instead of re-used and adapted; clothes are discarded causing huge problems for traditional high-quality textile makers; skills are devalued as robots are viewed as saviours, and humans are made stupid by our reliance on them. Richard Sennett's 'Homo Faber' trilogy explores these themes. He argues that we are human through our making capability, not our intelligence. 'The Craftsman' should be required reading. Case in point: I have had some windows made for a project that involve two panes of glass mounted on wool felt, secured with battens. The wool absorbs any condensation and any repairs can be carried out with simple tools on site, the only expense being a pane of glass. By contrast a double-glazed unit is usually imported from Austria, is energy-intensive in its production as noble gases have to be concentrated to fill the cavity and will leak and become compromised. Its only fate can be landfill because of the chemical bonding agents used. The former were inspired by my experiences behind this kind of glazing in -30C winters in Sweden. They work excellently, but it is hard for a company predicated on the new to make money from them like double-glazed units, despite being basically simple and sustainable. Well that became a thesis. This morning I'm working on repairing some C18th joinery, and I think I'm the first to see it since the joiner put it in all those years ago. One feels close to the past at these moments. |
2nd Dec 2019, 11:50 pm | #74 | |
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Re: Nostalgia? Probably.
Quote:
"Was it really only yesterday ... The future's missing here ..." . Cheers, GJ
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3rd Dec 2019, 12:35 pm | #75 |
Octode
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Re: Nostalgia? Probably.
For me it was coming across piles of old TV chassis and radio parts dumped in woodland and by the roadside back in the '70's. Even now I walk in the woods and find interesting things, last Friday I hauled back an old Belling boiling ring that had been in the woods 40 years or more! I often take things to the woods for others to find (faulty AVO's, radio chassis and bakelite telephones, all gone a few weeks later), it all makes for an interesting walk when you can come back with something and give something back at the same time, a sort of "technical foraging".
Neil
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3rd Dec 2019, 1:02 pm | #76 |
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Re: Nostalgia? Probably.
Well,I have been out with my camera taking shots in a wood this morning but found no old kit at all. Must be the wrong wood!
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3rd Dec 2019, 1:03 pm | #77 | |
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Re: Nostalgia? Probably.
Quote:
Last time I checked, fly tipping was a punishable offence. Lawrence....woodland manager. |
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3rd Dec 2019, 5:57 pm | #78 |
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Re: Nostalgia? Probably.
I pulled an old karaoke machine out of a blackberry patch.
It is due for reperposing as a garden radio. |
3rd Dec 2019, 8:45 pm | #79 | |
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Re: Nostalgia? Probably.
Quote:
However, consider this version of it. Round here, a suburban area, it has become the custom in the last 10 years or so to place unwanted items, typically children's toys, in the street against the garden wall for anyone in need of the item to just take it. Sad to say so far I haven't scored any round Ekco's etc. but I have had a couple of bikes, a music keyboard, and even a running machine, each of which only required an hour or two TLC. I imagine some Councils would take a dim view, but here they seem to see it as the altruism that it is, and turn a blind eye. Not sure if they see the ecological benefits of re-use vs the LA definition of "recycling".
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3rd Dec 2019, 9:14 pm | #80 | |
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Re: Nostalgia? Probably.
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Please don't dump your castoffs on other-peoples' property. I have a large and enthusiastic 50+ Kilogram dog who will happily 'interview' anyone caught trying to dump stuff on my land! |
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