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Re: AC and DC -- was RE: [HallicraftersRadios] S-38B Tuning Shaft Query
开云体育Yes, back in the 70’s big steel mill motors were all DC, but by then most were SCR driven and could be very smooth, with few contactors to wear out.? That left the problem to be the commutators and brushes, at 4000 amps anything but a perfect motor leaves sparks, and worse, and will flash over if you try much over 1000 volts on it. ?So now it is back to making a better AC mouse trap system, but that’s all beyond me. ? From: [email protected] [mailto:[email protected]] On Behalf Of Don VE3IDS
Sent: Thursday, August 1, 2024 11:57 AM To: [email protected] Subject: Re: AC and DC -- was RE: [HallicraftersRadios] S-38B Tuning Shaft Query ? I used to install wheelchair lifts. They always used to have 1 HP AC motors and were always noisy. The whole lift would vibrate. They started offering DC versions and they were so quiet and smooth and would run on small lead acid batteries. No worries with power outages and no heavy AC line required. Win win.? ? 73 Don ve3ids? ? On Thu., Aug. 1, 2024, 10:40 a.m. Mike Langner via , <mlangner=[email protected]> wrote:
_._,_._,_ -- don??? va3drl |
Re: S-38B Tuning Shaft Query
开云体育Seems to me I suggested a polarized plug, and somebody asked if that could be used to connect to DC mains, and were there any DC “mains” left?? And, yes I took it further, afield, and tried to apologize, but here we are. Self moderation does not work well, especially with us ADD prone members. It is rather late but I’ll try to compensate a bit I tried to find previous threads about the S-38 series? “hot chassis” and found this ?????/g/HallicraftersRadios/message/28090 Remember ..the S-38B was the last hot chassis, the S-38C and all after changed the symbols to the image just below ?And previous to that, halli was unclear speaking about the S-38 series, you had to closely look at the schematic notes for the above ? Now, here is a new copy ?showing the sleazy change from hot chassis to? something a little better.. this did not jump out to me, I went hunting some time back ? ? From: [email protected] [mailto:[email protected]] On Behalf Of n7qmm25
Sent: Thursday, August 1, 2024 10:58 AM To: [email protected] Subject: Re: [HallicraftersRadios] S-38B Tuning Shaft Query ? What does this subject have to do with tuning shaft query? -- don??? va3drl |
Re: Hallicrafters SX17 modifier noise limiter
If I recall properly, the SX-17 had variations with time of build, and eventually became an sx-18. I wonder if it is more like an SX-18? ??? ? august 3? sorry all this^ is total hogwash, I never learn not to shoot from the hip. I should have at least looked at Dachis before shooting. -- don??? va3drl |
Re: AC and DC -- was RE: [HallicraftersRadios] S-38B Tuning Shaft Query
I used to install wheelchair lifts. They always used to have 1 HP AC motors and were always noisy. The whole lift would vibrate. They started offering DC versions and they were so quiet and smooth and would run on small lead acid batteries. No worries with power outages and no heavy AC line required. Win win.? 73 Don ve3ids? On Thu., Aug. 1, 2024, 10:40 a.m. Mike Langner via , <mlangner=[email protected]> wrote:
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Re: S-38B Tuning Shaft Query
Known as subject drift. Maybe I made that up. So, one can change the
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subject to something more appropriate but loose the continuity in the archive or continue to use a subject that has nothing to do with the discussion. We are now onto steam. Heigh-ho. On 8/1/2024 7:58 AM, n7qmm25 wrote: What does this subject have to do with tuning shaft query? --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |
Re: S-38B Tuning Shaft Query
开云体育What does this subject have to do with tuning shaft query? On 8/1/2024 7:50 AM, Richard Knoppow
wrote:
Yes, there were many AC/DC sets previous to the AA5. The AA5 uses a |
Re: S-38B Tuning Shaft Query
Manhattan for years had steam plants that generated steam for
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industrial use. The New York Steam Company was one. The steam was distributed via pipes underground and one can see pictures of steam coming out of manholes. Well, I had to look and found: <> Turns out it became a division of Consolidated Edison. If I read this article right it is still operating. On 8/1/2024 6:27 AM, Maynard Wright, P. E., W6PAP via groups.io wrote: Manufacturing facilities and workshops used to distribute water or steam --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |
Re: S-38B Tuning Shaft Query
Yes, there were many AC/DC sets previous to the AA5. The AA5 uses a
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set of tubes designed for series heater use one 115V circuits without the need for an additional dropping resistor. Some earlier sets used balast tubes or series resistors mounted in metal cans or "curtain burner" resistive line cords. More complex radios used different combinations of tubes but the idea was to have the filaments run directly off the line. BTW, the Germans had a set of tubes after WW-2 also made for AC/DC specials but for 240 volt lines. The notorious tube used in the Telefunken (Neumann) U-47 microphone was a high voltage heater tube, designed for that use. Its purpose in the U-47 was to run the heater off the same supply as the bias for the microphone element. The more expensive, variable pattern mic, the M-49, had a conventional power supply since it had to have variable bias to change the directional pattern. On 8/1/2024 2:21 AM, Jim Whartenby via groups.io wrote: First town to be electrified using overhead wires, Roselle, NJ, 19 --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |
AC and DC -- was RE: [HallicraftersRadios] S-38B Tuning Shaft Query
开云体育Another reason that early – and still, many, many – elevators run on DC is that a shunt would motor produces huge torque while starting.? Add to that, a number of relays (contactors) with differing amounts of resistance (at high wattage) as the controller interface, and you get strong, smooth acceleration and deceleration, low vibration, and easily adjustable t positioning for no-trip-and fall-down entry and exit to and from floors. ? Mike Langner |
Re: Hallicrafters SX17 modifier noise limiter
The mod to the SX-28 is a major one. The SX-28 was built with a Lamb
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noise blanker, AFAIK the first application of Lamb's patent. Unfortunately, it didn't work very well so, eventually, an extensive mod was published in a service note to remove it and replace it with a conventional series diode clipper. The SX-28 is a classic antique and I would never mod one like that. The later, cheaper, version, the SX-32 was essentially the same arrangement as the the modified version of the 28, i.e. it had a conventional noise clipper and much simpler IF. I have not looked at the SX-17 circuit. It is too early to have the Lamb silencer (silence of the Lambs?) but triode clippers were used in some receivers, for instance, the Super-Pro. Also, a triode could be connected as a diode and used as a clipper. As far as circuits for a series diode clipper they were used very widely after about 1945. See for instance, the S-40A. Earlier receivers often used shunt diode clippers, they have some advantage for CW but the series diode is biased by the carrier which sets the clipping level automatically for AM. Some earlier receivers have a NL clipping control to set the bias manually. I think the S-20R has a shunt diode but not an adjustable one. The 6J5 is a medium mu triode, very commonly used for oscillators and audio amplifiers. BTW, if you use a 6H6 or the miniature equivalent the 6AL5 as a series limiter its usual practice to reduce the heater voltage by means of a resistor across it. The purpose is to eliminate hum. This became almost universal for these tubes. On 8/1/2024 12:50 AM, John via groups.io wrote: PS, I am aware that the 6H6 was used as a modification in the SX28 and I --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |
Re: S-38B Tuning Shaft Query
Manufacturing facilities and workshops used to distribute water or steam
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power from a limited number of sources (sometimes just one) via shafts, pulleys, belts, etc. to machine tools of various types. "Elements of Mechanics and Machine Design," authored by Erik Oberg and published by The Industrial Press in 1923 provides design information for such shafting even through electric motors had been available for quite a few years. The motors must have still been expensive enough during the 1920s to justify all that shafting and associated components so that only a limited number of motors (maybe only one) would be required. Maybe transformers were also very expensive early on and remained that way for awhile. 73, Maynard W6PAP On 8/1/24 00:38, Richard Knoppow wrote: I don't know. The articles I found don't make it clear. I can't even |
Re: S-38B Tuning Shaft Query
In the late 1940s while I was living in Oakland, CA at about age 7, I
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dimly recall the adults discussing whether an electric train they were setting up for me should be set up to operate from AC or DC. My impression was that they had no idea what the differences might be. I am pretty sure now that the only reason they were concerned was because the instructions for the train must have said something about that. I suspect now that Oakland never had DC distribution. 73, Maynard W6PAP On 8/1/24 00:38, Richard Knoppow wrote:
I don't know. The articles I found don't make it clear. I can't even |
Re: Hallicrafters SX17 modifier noise limiter
Hi gang, The 6H6 dual diode was used in many Hallicrafter rx's, as noise tube. Check Bama for: S85, S40, and other series rx's schematics. I have an S85, that is wired as an late S40B, for the noise limiter ckt., and not as shown for S85 schematic. The factory did many wonderful running changes,( my sarcasm) and using?up of?parts. They are a good receiver. Good Luck, Dale, N2DM.?? On Thu, Aug 1, 2024 at 8:00?AM John via <siloam=[email protected]> wrote:
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Re: S-38B Tuning Shaft Query
First town to be electrified using overhead wires, Roselle, NJ, 19 January 1883, See: To answer the question on what prompted the development of? AC/DC radios was the elimination of the most expensive single component in an AC powered radio, the power transformer.? It seems that the AC/DC radio design predates the AA5, see:?? This shows the Stewart Warner Model R-108 circa 1933. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Thursday, August 1, 2024 at 03:11:25 AM CDT, don Root <drootofallevil@...> wrote:
I saw another article or two indicating DC to an area of mostly textiles , and elevators in ?apartments. My guess would be that houses, apt units, would want the new gadgets that mostly ran on AC, but the elevators would be a costly upgrade. Here in southern Ontario in the 1950’s 25 cycles was replaced with 60 cycle, and the hydro co/govt did conversions or bought you a new washing machine etc. Sorry to everyone for my part in hijacking 110 AC/DC and twisting it up to HVDC etc ? From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow
Sent: Thursday, August 1, 2024 3:39 AM To: [email protected] Subject: Re: [HallicraftersRadios] S-38B Tuning Shaft Query ? I don't know. The articles I found don't make it clear. I can't even Richard, just for the record, did they distribute DC to homes? Exactly where --
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Re: S-38B Tuning Shaft Query
开云体育I saw another article or two indicating DC to an area of mostly textiles , and elevators in ?apartments. My guess would be that houses, apt units, would want the new gadgets that mostly ran on AC, but the elevators would be a costly upgrade. Here in southern Ontario in the 1950’s 25 cycles was replaced with 60 cycle, and the hydro co/govt did conversions or bought you a new washing machine etc. Sorry to everyone for my part in hijacking 110 AC/DC and twisting it up to HVDC etc ? From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow
Sent: Thursday, August 1, 2024 3:39 AM To: [email protected] Subject: Re: [HallicraftersRadios] S-38B Tuning Shaft Query ? I don't know. The articles I found don't make it clear. I can't even Richard, just for the record, did they distribute DC to homes? Exactly where -- _._,_._,_ -- don??? va3drl |
Re: Hallicrafters SX17 modifier noise limiter
PS, I am aware that the 6H6 was used as a modification in the SX28 and I have found and downloaded a circuit diagram for that modification as a reference. Possibly the SX17 circuit might be be similar but it would be interesting to hear whether anyone else has encountered this valve in the SX17? |
Hallicrafters SX17 modifier noise limiter
I have been working on a hallicrafters SX17 receiver and so far work is progressing (audio and detector circuit restored and interstage transformer replaced) although a bit slowly and cautiously. Yesterday, when I removed it for the first time, I discovered that in the position of the 6J5 'silencer' triode, was actually a 6H6 double diode. This puzzled me initially until I Google and looked at the datasheets and discovered that the 6H6 can be used for the noise limiter function. Both the early and late versions of the circuit diagrams I have so far found both show the 6J5 in that position. It is no wonder that the voltages don't match the table in the manual! However, was this modded by someone, or was it a factory design? I couldn't see any obvious indication of changes to the wiring, only that some components were different. However, someone gave me a hint to have a look at the valve base, which I did this morning and it is stamped 6H6! This does suggest that the modification was added at the factory.
?
I wonder, does anyone have or come across a circuit diagram showing this modification, i.e. a 6H6 rather than a 6J5 in the noise limiter circuit?
Has anyone already reverse engineered it perhaps? I am minded to reverse engineer it anyway, but it might help if there is already an updated circuit in existence somewhere.
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Re: S-38B Tuning Shaft Query
I don't know. The articles I found don't make it clear. I can't even
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find a list of cities that had DC power. Evidently New York, or at least Manhattan did and parts of Boston. Power was distributed to buildings and factories but I can't find specific references to homes. There is a pretty extensive article on the "war of the currents" at <> Which has some information on early power distribution, but you link this so have already read it. Now, comes the question of why Hallicrafters and virtually all other radio manufacturers made AC/DC radios and phonographs. Was there a big market or was it due to the economy of not having to use transformers? Since transformerless sets could operate inherently on both AC and DC the DC might just have come with the territory. DC was also used on many ships and boats so radios made to work on them would have to run on DC. But, Hallicrafters made an AC/DC version of the S-40 receiver as the S-52 and later the S-77. These were advertised as marine receives but don't have the MF marine band, they are essentially the same as the S-40 series with some changes in tubes to allow series heaters. So, perhaps the marine market was large enough to justify manufacturing them. You have piqued my curiosity so I will do some more searching. On 7/31/2024 4:40 PM, don Root wrote: Richard, just for the record, did they distribute DC to homes? Exactly where --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |