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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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11th Dec 2018, 2:12 am | #41 | |
Hexode
Join Date: Oct 2017
Location: Manchester, UK.
Posts: 363
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Re: R1155 Power supply question
Quote:
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11th Dec 2018, 2:23 am | #42 |
Hexode
Join Date: Oct 2017
Location: Manchester, UK.
Posts: 363
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Re: R1155 Power supply question
This is what i did about 1978,job done.
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11th Dec 2018, 6:40 am | #43 |
Tetrode
Join Date: Sep 2014
Location: Carlisle, Cumbria, UK.
Posts: 58
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Re: R1155 Power supply question
Ed Dinning is the chap to speak to on here re the R1155 psu's he has made several for me over the years as well as T1154 psu's, a friend also made me a dummy load for the 55 psu's which i can send a picture off with details if you like??
Cheers Mike 2E0MXP I did fit the DF meter and wiring myself but this is the last project done an R1155 psu with DF meter, variable HT and audio stage. Last edited by MJRC2000; 11th Dec 2018 at 6:42 am. Reason: additional info |
16th Dec 2018, 4:53 pm | #44 |
Tetrode
Join Date: Apr 2018
Location: Barcelona, Spain.
Posts: 62
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Re: R1155 Power supply question
The radio is alive using the attached circuit modification
The radio powers up nicely and the output with the radio on is 205v The audio is good The Amplifier is very noisy though, even when nothing is connected to the radio I thought it could be due to non shielded wires so i tested it without input wire and it is still doing some hiss I have tried a 10uf electrolytic cap from. 1 to 8, also a 100uf electrolytic from 6 to ground. Nothing makes it completely disappear I guess the lm386 is not as quiet...
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EA3IAV |
19th Dec 2018, 8:50 am | #45 |
Tetrode
Join Date: Apr 2018
Location: Barcelona, Spain.
Posts: 62
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Re: R1155 Power supply question
Another thing with the circuit above is that it neads audio line out attenuation. When driving the audio with the AVG setting on the radio, it delivers too much audio and there is a lot of distortion. In fact I have seen that the audio line coming from the radio actually drives a speaker on its own with no amplifier.
I used an "L" attenuation with 10k In series with the line out, and 1K to ground from the line out
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EA3IAV |
20th Dec 2018, 8:40 am | #46 |
Tetrode
Join Date: Apr 2018
Location: Barcelona, Spain.
Posts: 62
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Re: R1155 Power supply question
It is performing well I think. I have to fine tune the oscillation segment though
https://www.youtube.com/watch?v=_Iu0ZW4pEcI&t=5s Thank you all for your kind help
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EA3IAV |
20th Dec 2018, 1:47 pm | #47 |
Heptode
Join Date: Apr 2015
Location: Manchester, UK.
Posts: 710
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Re: R1155 Power supply question
Nice work Cesar.
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20th Dec 2018, 3:26 pm | #48 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 693
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Re: R1155 Power supply question
Well done Cesar,
I've been following this thread with interest and am pleased that you got a good result. Sadly, you seem to have a very high local noise level - I wonder what you are using for an antenna?
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Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
20th Dec 2018, 3:42 pm | #49 |
Tetrode
Join Date: Apr 2018
Location: Barcelona, Spain.
Posts: 62
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Re: R1155 Power supply question
Thank you Keith! Unfortunatelly I live in the heart of Barcelona City... It is a pain in the neck being a radioamateur here. I hooked a long wire antenna, about 16 feet long, the one I use for HF
regards!
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EA3IAV |
31st Dec 2018, 3:58 pm | #50 |
Pentode
Join Date: May 2010
Location: Wick, Scotland, UK.
Posts: 227
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Re: R1155 Power supply question
Be careful with your power supply
the HT minus is NOT to chassis!! |
31st Dec 2018, 4:01 pm | #51 |
Pentode
Join Date: May 2010
Location: Wick, Scotland, UK.
Posts: 227
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Re: R1155 Power supply question
The July 1946 modification of the r1155 was definitely the best way to go and you had a reply containing this in pdf format, stick with it, perfect, I used this several times on these sets with no problems, still have one.
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31st Dec 2018, 4:03 pm | #52 |
Tetrode
Join Date: Apr 2018
Location: Barcelona, Spain.
Posts: 62
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Re: R1155 Power supply question
Hello! What do you mean? I did not connect the chassis to anything i guess. The only ground i see coonectes to the chassis of the psu is the speaker i guess, as it touches the case.
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EA3IAV |
31st Dec 2018, 4:59 pm | #53 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,652
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Re: R1155 Power supply question
Where people typically get tripped up by this requirement to keep the HT negative separate from chassis is in the use of electrolytic smoothing capacitors in aluminium cans.
Most of these have the negative side of the capacitor connected to the aluminium case. So if you then mount that capacitor directly to the chassis of your power supply, the HT negative will automatically be connected to chassis too. Then you have a problem. Of course its very easy to overcome. Just use electrolytic smoothing capacitors in insulated cases - as indeed most are these days. The problem usually arises when someone digs out one of the old style electrolytics from their junk box...... Richard |
31st Dec 2018, 8:13 pm | #54 |
Nonode
Join Date: Oct 2008
Location: Warsaw, Poland and Cambridge, UK
Posts: 2,677
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Re: R1155 Power supply question
My R1155 came with a power supply and the remains of some wiring. Having sorted it out somewhat, I found a significant problem was that the audio ground is shared with the heater ground. The several amps of 6.3V AC heater current creates a noticeable voltage drop in even a fairly heavy-gauge wire, and thus appears in series with the audio output. This gives terrible hum on the audio. Running a separate audio ground to the receiver only helps if there's no mains earth anywhere else in the system - the heater return is also chassis and thus the safety earth on the R1155, so the conditions for an earth loop are perfect.
Has anyone else come across this problem and solved it? The best fix I could think of was to add an audio isolating transformer in the cable to the Jones plug which fits the receiver. I'm trying to leave the receiver unmodified. I suppose taking a pair of wires from the receiver's audio output and its chassis and then feeding that to a transformer or differential amplifier at the audio amplifier would also work. Chris
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1st Jan 2019, 12:29 pm | #55 |
Pentode
Join Date: Apr 2011
Location: Swansea, Wales, UK.
Posts: 144
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Re: R1155 Power supply question
Chris, it's ok if you have 6.3v DC on the heaters, as for the T1154, but unfortunately I did same as you for a latest psu. I did use a screened cable for the audio line although I know the screens get joined to the same place. There is a moderate hum, certainly not terrible. A transformer at the amp end would have been a good idea.
I included a switchable parallel LC circuit to peak audio at about 700 Hz for CW and that takes out all hum. I could experiment with a switchable 50Hz notch filter if I could find a suitable small size L. 73, HNY Andrew |
8th Jan 2019, 5:06 pm | #56 | |
Pentode
Join Date: May 2010
Location: Wick, Scotland, UK.
Posts: 227
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Re: R1155 Power supply question
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your amp will not be as good as the standard 6V6, stick to the well proven mods on these sets. |
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8th Jan 2019, 5:12 pm | #57 | |
Pentode
Join Date: May 2010
Location: Wick, Scotland, UK.
Posts: 227
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Re: R1155 Power supply question
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If you connect your power supply HT Neg to chassis and the pos to HT line you will not have bias see attached circuit. http://www.tuberadio.com/robinson/mu.../R1155bias.gif |
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8th Jan 2019, 7:46 pm | #58 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: R1155 Power supply question
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Although it was many decades ago when I owned an R1155 and made various modifications to it, I very vaguely recall that I rewired the heaters so that they were above ground. Why did I do that? Too long ago: can't remember! Al. |
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